Table of Contents - Geological Society of America

Transcription

Table of Contents
Abstracts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Maps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9, 10
Schedule of Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Program of Technical Sessions
Thursday, 27 May . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Friday, 28 May . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Saturday, 29 May . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Index of Authors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
Program
JOINT MEETING
Cordilleran Section, GSA
& Pacific Section, AAPG
with Western North America Regional, SPE
106th Annual Meeting of the Cordilleran Section, GSA
85th Annual Meeting of the Pacific Section, AAPG
Marriott Anaheim
Anaheim, California, USA
27–29 May 2010
www.geosociety.org/sectdiv/cord/2010mtg/
Joint Meeting
106th Annual Meeting of the Cordilleran Section, Geological Society of America
and
85th Annual Meeting of the Pacific Section, American Association Petroleum Geologists
(jointly with Western North America Region Conference of the Society of Petroleum Engineers)
with
Pacific Section, Society for Sedimentary Geology (SEPM)
Council on Undergraduate Research (CUR)
Los Angeles Basin Geological Society
Pacific Coast Section, Society of Exploration Geophysicists
Cordilleran Section GSA Officers
Chair. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Karen Grove
Vice-Chair. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Luca Ferrari
Past Chair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Andrew Meigs
Secretary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rodney Metcalf
Pacific Section AAPG Officers
President . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Scott Hector
President-Elect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cynthia Huggins
Vice President. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tony Reid
Past President . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Don Clarke
Secretary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Jeff Gartland
Treasurer-Elect. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cheryl Blume
Treasurer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Donna Thompson
Editor-in-Chief . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Karen Blake
2 2010 GSA Abstracts with Programs 50% Total Recovered Fiber
10% Post-Consumer
SPE Executive Committee Members
Jerry Anderson
Brandy Fellers
Rick Finken
Larry Gilpi
AB Gorashi Abdulrahman
Candra Janova
Ed Santiago
Jack Smith
Vanessa Perez
Mike Utt
Robert Visser
Katherine Wallgren
Eric Withjack
Local Committee
General Co-chairs. . . . . . . . . . . . . . . . . . . . . . . . . Phil Armstrong (GSA), Curtis Henderson (AAPG)
SPE Chair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Jalal Torabzadeh
SPE Co-chair. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Scott Hara
Technical Program Co-chairs. . . . . . . . . . . . . . . . . . . . . Jeff Knott (GSA), Hilario Camacho (AAPG)
SPE Program Chair. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Iraj Ershaghi
Exhibits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Michelle Thompson (AAPG), John Foster (GSA)
Field Trips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Brady Rhodes (GSA), Nelson Doris (AAPG)
Short Courses and Workshops . . . . . . . . . . . . . . . . . . . . . . . . . . Diane Clemens-Knott, Galen Carlson
Field Trip Guide Publication. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ray Ingersoll (SEPM)
Student Help Coordinator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nicole Bonuso
Finance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Richard Finken
Catering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tara Kneeshaw, Patricia Butcher
Convention logo. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Brandon Browne
2010 Cordilleran Section, GSA/Pacific Section, AAPG/Western North America Regional, SPE Meeting 3
Sponsors
Thank you to the following companies for their generous contributions and support!
Diamond Level $10,000
Occidental Petroleum Corporation (NYSE: OXY) is an international oil and gas exploration and production company,
as well as a major North American chemical manufacturer. We are the fourth-largest U.S. oil and gas company, based on
market capitalization of $48.6 billion at year-end 2008, with more than 10,000 employees and 20,000 contractors on four
continents.
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throughout the company’s worldwide operations. Oxy’s success is built on technical expertise, business acumen, strong partnerships and proven ability to deliver superior results.
Aera Energy LLC (Aera), a California limited liability company, is one of California’s largest oil and gas producers,
accounting for approximately 30% of the state’s production. With headquarters in Bakersfield, most of Aera’s production is
centered in the San Joaquin Valley. The company also has oilfield operations in the L.A. Basin and in Ventura and Monterey
Counties. Aera produces approximately 160,000 barrels of oil and 50 million cubic feet of natural gas each day and has proved
oil and gas reserves equivalent to approximately 800 million
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Chevron is one of the world’s largest integrated energy companies. Headquartered in San Ramon, California, we conduct
business in countries all around the globe. We are engaged in every aspect of the crude oil and natural gas industry, including
exploration and production, manufacturing, marketing and transportation, chemicals manufacturing and sales, geothermal,
and power generation. We’re also investing in renewables and advanced technologies.
Emerald Level - $2,500
DHI Services Inc. (DHI) is a client oriented company that provides quality well-site Formation Evaluation Services (FE)
for Oil, Gas and Geothermal exploration companies. DHI relies on critical in-house R&D hardware and software departments to ensure clients receive increased value in their endeavors.
DHI’s unique combination of experienced international management and effective R&D departments positions the company for global expansion. The Management is experienced in all aspects of domestic and international energy exploration
and production markets. For many years, members of DHI management and staff have been directly involved in the development as well as implementation of the current technology and practices used in the well logging industry. Their experience,
combined with our commitment to deliver high quality service, forms a dynamic well logging company that utilizes the newest
generation of well logging tools manned by qualified and experienced field personnel.
4 2010 GSA Abstracts with Programs Message from the Meeting Co-chairs
When we started putting the pieces together for our meeting, we were asked about a meeting “theme.” Coming up with
a theme is not an easy task, but we wanted to incorporate the urban setting surrounded by incredible geology that, as much
as about any place on Earth, dictates the lives of the people that live there. We also were facing great economic problems
and political struggles in America about bringing politics to Main Street. So the theme “From Mountains to Main Street”
was hatched as a joint venture of the 106th Annual Meeting of the Cordilleran Section of GSA and 85th Annual Meeting
of the Pacific Section of AAPG at the Anaheim Marriott in Anaheim California. Later in the planning stages, the Society
of Petroleum Engineers joined with AAPG to run the Western North America Region Conference of SPE jointly with our
meeting. Several sponsoring societies are involved, including the Pacific Section of the Society for Sedimentary Geology
(SEPM), who have taken the reins on sponsoring several sessions and field trips as well as editing and publishing the field trip
guidebook. The Paleontological Society and the Council for Undergraduate Research are also sponsoring theme sessions. The
end result of the joint efforts of our organizations and sponsoring societies is an outstanding technical program with 43 oral
sessions, 14 poster sessions, 10 field trips, 6 short courses, student workshops, society luncheons, and special keynote speaker.
These sessions, field trips, short courses, and other events span a wide array of scientific, technical, and educational disciplines,
just as one would hope for in a joint effort of our meeting. We thank all the individuals who put in the hard work to make
this meeting a success.
We hope you can take advantage of this exciting program as well as the variety of activities and attractions that our meeting venue offers.
Cordilleran Section GSA
Phil Armstrong
Department of Geological Sciences
California State University, Fullerton
Pacific Section AAPG
Curtis Henderson
Long Beach Gas & Oil
City of Long Beach, California
Message from the Pacific Section AAPG President
Welcome to Anaheim! This is wonderful location for petroleum geologists to get together, to study the dynamic structural
and stratigraphic complexities of one of the richest oil basins (in terms of barrels per acre) on Earth. We were fortunate this
year that Curtis Henderson and his Convention Committee put together a great program. There will be many technical sessions, and several short courses and field trips. We also have many convention exhibitors, ready to show you the latest in
technological innovations for the oil and gas industry. Add to this that we are only minutes away from Disneyland and Knott’s
Berry Farm, and you have a great location for family as well as geoscientists. The Geological Society of America’s joint meeting
announcement calls Orange County “a Geological Disneyland.”
The technical sessions look exciting, both those provided by the AAPG and also those presented by the other societies
that are joining us in the convention: the Pacific Section SEPM, the Cordilleran Section of the GSA, and the Society of
Petroleum Engineers (SPE). My thanks on behalf of the PSAAPG go to Hilario Camacho, our technical program Co-chair.
We will have a symposium on the Reconstruction of the San Andreas Fault System, in honor of John Crowell, Tor Nilsen,
Tom Dibblee and Perry Ehling. One of the SEPM sessions is on climate-biosphere interactions through time, which sounds
very interesting! If enough politicians attended, this might end the Global Warming and/or Cooling Debate! The SPE and
AAPG are jointly hosting sessions on carbon sequestration and petroleum resources offshore California. For those of you who
prefer to be called “hard rockers,” the GSA, under the leadership of Convention Co-Chair Phil Armstrong and Technical
Co-Chair Jeff Knott, have put together a lineup of talks that vary from Understanding Magma Petrogenesis to the Evolution
of the Southern Big-Bend Region of the San Andreas Fault to Micro-Plate Basements and even Detrital Zircon Studies. You
can choose from these many symposia and stay in, or bounce among many “geologist’s time zones”: Late Quaternary, Late
Neogene, Late Pleistocene, Holocene, Jurassic-Cretaceous, Triassic, Oligocene, and Early Miocene. The convention floor plan
is user friendly; you don’t have to walk far at all to attend all the talks, breakfasts, lunches and dinners that you want, all an
easy stone’s throw from each other!
But, if you want to get outside, there is a lot to do. There are ten (10!) field trips to choose from. Some will only last a day.
Others will take up to three days. Another field trip, led by my friend Jeff Unruh and others, will take participants on a threeday loop trip through the Northern Eastern California Shear Zone. The NECSZ is an area of the Mojave Desert made up of
predominantly right-lateral faults that is thought to accommodate up to 25% of the Pacific-North American plate boundary
deformation. The ten different field trips should offer something for everyone!
However, if you want to stay inside and learn, you can do that, too! There are six short courses/workshops offered at this
Anaheim location (#1: on U-Th-Pb geochronology using a mass spectrometer; #2: An Introduction to GIS; #3: Teaching K–12
Students about earthquakes; #4: Strategies to Engage Students in geoscience-related classes: #5: Petrel Session 1-Basics to
Data Visualization; and #6: Petrel Session 2: Petrel Geostatistical Overview). My thanks also go out to Diane Clemens-Knott
and Galen Carlson, both of California State University Fullerton, for putting the workshops and short courses together.
Let’s add to this list something your “significant other” might enjoy: a Temecula Valley Wine Tour (Friday, 28 May) and/or
a major league baseball game (the Angels against the Seattle Mariners on Saturday, 29 May). Fortunately, these events are not
on the same day, so that you can drink the wine one day and clearly enjoy the baseball game the next.
Our keynote speaker for the Pacific Section AAPG Luncheon and Awards Banquet on Friday the 28th is Dr. John C.
Lorenz, President of the National AAPG. Dr. Lorenz is a world-wide expert in fractures, and this promises to be a very exciting talk. Dr. Lucile Jones of the USGS will give the keynote address for the GSA on the same date, but in the evening from
5:30 to 6:30 p.m.
This is a convention that is obviously packed with exciting things to do! I look forward to your attendance and hope that
it is a thoroughly enjoyable experience for all of you.
Scott T. Hector
President
Pacific Section AAPG
6 2010 GSA Abstracts with Programs Message from the Cordilleran Section GSA Chair
Welcome to the 2010 Cordilleran Section meeting in southern California, a fabulous location to share our developing
geologic ideas about the western edge of North America. We anticipate lively discussions and productive interactions.
The Section Management Board, which consists of the Chair, Vice Chair, Past Chair, and Secretary/Treasurer, has been
working on scheduling future meetings and on continuing our collaborations with other professional societies. In 2011, our
meeting will be held jointly with the Rocky Mountain Section in Logan, Utah. In an effort to encourage our Mexican colleagues to participate more actively in the section, our 2012 meeting will be in Juriquilla, Mexico. In 2013, we will meet in
Fresno, California, and hope that PS-AAPG will agree to join us again that year. Please contact a board member if you have
ideas about future meetings or other activities. In Anaheim, we encourage you to attend our Business Meeting on Thursday,
27 May, 5–6 p.m. to hear about section activities and to share your ideas. Drinks and light refreshments will be served.
Karen Grove
Chair
Cordilleran Section GSA
Message from the SPE WNRM General Chair
The 2010 SPE Western North America Region Conference will be held jointly with Cordilleran Section of the Geological
Society of America and Pacific Section of the American Association of Petroleum Geologist during 27–29 May, in Anaheim,
California.
On behalf of the SPE Organizing Committee, I invite you to register and participate in this important professional convention. This joint meeting is a showcase by the North America Western Region geoscientists and engineering professionals
to disseminate information, exchange ideas, and share knowledge on engineering and geological sciences related to optimized
oil and gas production technology. The convention offers hundreds of diverse and interdisciplinary technical papers and presentations organized into topical and panel sessions and posters. Enhancing the technical program are workshops, continuing
education courses and field trips with many great opportunities to enhance your professional skills.
The SPE part of the meeting includes 84 outstanding peer-selected technical papers offered in 16 sessions, plus 21 excellent poster presentations. Additionally, a very informative plenary panel session on “Opportunities and Challenges in the
Western North America Region,” moderated by the SPE President Dr. Fattahi, will highlight the first day of the convention.
With the proximity of the meeting location to Disneyland, we encourage you to bring the whole family and spend Memorial
Day Weekend in Southern California.
I look forward to your participation and attendance at this unique interdisciplinary conference GSA-AAPG-SPE (Western
North America Region). I hope to see you in Anaheim.
Jalal Torabzadeh, California State University, Long Beach
General Chair
SPE WNRM
General Information
Welcome to the 106th annual meeting of the Cordilleran
Section of the Geological Society of America (GSA) and the
85th annual meeting of the Pacific Section of the American
Association of Petroleum Geologists (AAPG). This meeting
is being held jointly with the Western North America Region
Conference of the Society of Petroleum Engineers (SPE). Our
venue is the Anaheim Marriott in the Disneyland Resort district of Anaheim, California. The local host for Cordilleran
GSA is the Department of Geological Sciences at California
State University, Fullerton. The local host for Pacific Section
AAPG is the Los Angeles Basin Geological Society. We’d
like to highlight the support of our sponsoring societies,
especially the Pacific Section of the Society for Sedimentary
Geology (SEPM) for sponsoring several sessions and field trips
and for editing and publishing the field trip guidebook. We
also thank the Paleontological Society and the Council for
Undergraduate Research for sponsorship of theme sessions.
The Venue
The meeting is being held in the Anaheim Marriott Hotel
located conveniently in the heart of the Anaheim Resort
District and just steps away from Disneyland, California
Adventure, Downtown Disney, and the Anaheim Garden
Walk. The theme for our meeting is “From Mountains to
Main Street” to highlight the geologic diversity that surrounds our suburban venue. Temperatures are mild in late
May (60–75°F), making the weather perfect for recreational
activities.
Getting to the Meeting
At least four major airports are located within 40 miles
of the Anaheim resort area including the Los Angeles
International Airport (32 miles), John Wayne Airport
(aka, Santa Ana or Orange County) (9 miles), Ontario
International Airport (36 miles), and the Long Beach
Airport (18 miles). If coming from any of these airports
(John Wayne recommended), you will want to get on the
Santa Ana Freeway (I-5).
If heading north on I-5: Exit on Katella Avenue/Disney
Way. Merge onto Anaheim Way. Turn left on Katella Avenue
and head west about 0.8 miles. Turn left (south) on Harbor
Blvd for 0.3 miles. Turn right on Convention Way.
If heading south on I-5: Exit on Harbor Blvd. Keep right
and follow Harbor ~1 mile. Turn right on Convention Way.
The Anaheim Marriott is located at 700 W. Convention
Way adjacent to the Anaheim Convention Center. You can
generally navigate to the Marriott by following signs to the
Convention Center.
8 2010 GSA Abstracts with Programs Accommodations
A block of rooms has been reserved at a discounted rate
at the meeting venue hotel, the Anaheim Marriott, 700
West Convention Way, Anaheim, CA 92802. The deadline
for hotel reservation at the discounted rate was 26 April
2010, but you may still be able to get the discounted rate.
Call the hotel at +1-800-228-9290 and make sure to specify
the Anaheim Marriott located on Convention Way. Request
a reservation under “Geological Society of America and
American Association of Petroleum Geologists.”
Parking
Meeting attendees can park on-site in the self-parking
areas of the Marriott for a discounted rate of US$10 per day,
with in and out privileges. To get the rate, simply tell the selfparking attendant that you are with the Geological Society
of America/American Association of Petroleum Geologists
conference.
Dining
There are many dining opportunities at the Marriott
and within a 10–15 minute walk from the hotel. The hotel
concierge has restaurant maps and local advice. The Marriott
houses a JW’s Steakhouse, Café Del Sol (California cuisine),
Pizza Hut, Degrees Wine and Patio Bar, and Starbucks
Coffee. A popular eating area is the Anaheim Garden
Walk, which has a variety of eateries (see web at http://
www.anaheimgardenwalk.com/dining/). The Garden Walk is
located on Harbor Blvd, a short 10 minute walk north. Many
additional restaurants are available en route along Harbor
Blvd and in Downtown Disney.
Getting Around the Area
Most local attractions and restaurants are within walking distance of the conference hotel. For those who prefer not to walk, the City of Anaheim provides a farebased ride service called Anaheim Resort Transit, or ART
(http://www.rideart.org/). ART kiosks are throughout the
resort area. Daily passes cost US$4; 3-day pass costs US$10.
Internet Access at the Meeting
Wireless internet access in the hotel is available for
US$12.95 per day.
Accessibility
GSA and AAPG/SPE are committed to making its
meetings accessible to all. The Anaheim Marriott is ADA
compliant.
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Anaheim CA 92802-3483
714.750.8000
www.marriott.com/laxah
Registration
All meeting badges will be distributed on-site.
On-Site Registration and Badge Pickup Schedule
Anaheim Marriott. Registration will be in the main
lobby of the hotel on Wednesday afternoon and evening and
in the Platinum Ballroom Foyer area on Thursday through
Saturday.
Wednesday, 26 May....... 4–8 p.m.
Thursday, 27 May........... 7 a.m.–4 p.m.
Friday, 28 May................ 7:30 a.m.–4 p.m.
Saturday, 29 May............ 7:30 a.m.–noon
10 2010 GSA Abstracts with Programs On-Site Registration Fees (all fees are in
U.S. dollars)
Standard
One Day
Professional member......................$235.................. $125
Professional non-member..............$295.................. $185
Student member............................$90.................... $45
Student non-member....................$105.................. $65
Professional member 70+..............$115.................. $60
K–12 professional..........................$75.................... $40
Guest or spouse..............................$75.................... N/A
Field trip or Short Course only.....$45.................... N/A
Cancellations, Changes, and Refunds
Requests for additions, changes, and cancellations must
be received at GSA Headquarters by 3 May 2010. No refunds
will be made on cancellation notices received after this date.
Refunds will be mailed after the meeting; refunds for fees paid
by credit card will be credited to the card identified on the
registration form. Refunds will not be provided for on-site
registration, abstracts with programs, or event ticket sales.
Special Events
Exhibits Opening. Noon–1 p.m., Thursday, 27 May,
Platinum Ballroom, Anaheim Marriott. Come enjoy hors
d’oeuvres and refreshments with the exhibitors.
Evening Reception. 6–8 p.m., Thursday, 27 May, Anaheim
Marriott. Please come celebrate the conclusion of day one.
Includes light snacks and a free drink.
Keynote Address. 5:30–6:30 p.m., Friday, 28 May,
Dr. Lucile M. Jones, U.S. Geological Survey. When the
Mountains Come to Main Street: Helping California Live
with Natural Disasters. The U.S. Geological Survey’s Multi
Hazards Demonstration Project was formed to demonstrate
how hazards science can be used to improve a community’s
resiliency to natural disasters. The project has created public products integrating hazards science with engineering
and social science that support decision making for disaster
management, including the ShakeOut Scenario and the
soon to be released ARkStorm Scenario. Many of the ideas,
science and partnerships thus formed have been tapped as
Los Angeles County deals with the aftermath of the Station
fire and the potential for some of the largest debris flows in
southern California’s history.
Special Session. Easter Earthquake in Northern Baja.
Saturday, 29 May, 8:30 a.m.–noon, Platinum 8. Come hear
talks on preliminary evaluations of the magnitude 7.2 earthquake that struck northernmost Baja Mexico on Easter Sunday
(4 April 2010).
A Special Lunchtime Talk. Saturday, 29 May, Noon.
Platinum 7. Dr. Stephen Testa. Conflicts Between Josiah D.
Whitney and William P. Blake, and the Fate of the First California
Geological Survey.
Friends of the California Geological Survey Reception.
Saturday, 29 May, 5 p.m. Elite 2. Please come enjoy discussions and old stories with CGS friends. Cash bar.
Business Meetings And Luncheons
Cordilleran Section GSA Annual Board Meeting.
Thursday, 27 May, 7–8 a.m., Gold Key I.
AAPG House of Delegates Breakfast. Thursday, 27 May,
7–8 a.m., Elite 1.
Cordilleran Section GSA Annual Business Meeting.
Thursday, 27 May, 5–6 p.m., Gold Key I.
Pacific section AAPG Executive Committee Meeting.
Thursday, 27 May, 5–6 p.m., Elite 1.
Pacific Section AAPG Luncheon and Awards Banquet.
Friday, 28 May, 11:30 a.m.–1:30 p.m. Marquis NW. John
Lorenz, AAPG President (2009–2010). Got Fractures?
Now What? The Application of Fracture Studies to Reservoirs.
Cost: US$65.
Society of Petroleum Engineers Luncheon. Friday,
28 May, 11:30 a.m.–1:30 p.m., Marquis NE. Mr. Stephen
Chazen, President and Chief Financial Officer, Occidental
Petroleum Corporation. Cost: US$65.
Guest Activities
The meeting venue is in the heart of the Anaheim
Resort District providing easy walking access to Disneyland,
California Adventure, Downtown Disney, and the Garden
Walk. Additional Southern California activities and attractions abound. Links to many additional guest and attendee
activities can be found at http://geology.fullerton.edu/GSA/
Guest_activities.
Temecula Valley Wine Tour. Friday, 28 May 2010.
Explore Southern California Wine Country on a private tour
excursion. The Temecula Valley offers robust wines in an intimate setting within arms’ reach of Orange County, CA. Enjoy
the day sampling whites, reds, champagne and even port or
sherry. The day will include tastings at several Temecula wineries, a gourmet picnic lunch, and exploration of Old Town
Temecula. The trip begins at the Anaheim Marriot departing
at 9 a.m. and returning by 5 p.m. The trip costs US$125, and
includes round-trip bus transportation, guide service, private
and group wine tastings at multiple wineries throughout the
Temecula Valley, a gourmet picnic lunch, and all taxes and
gratuities.
Major League Baseball. The Los Angeles Angels of
Anaheim vs. Seattle Mariners. We have organized bus transportation and a block of seats for a game on Saturday evening, 29 May. Bus for game will depart Anaheim Marriott at
approximately 5 p.m. Cost: US$35, includes game ticket and
round-trip transportation to the Angel Stadium.
Technical Program
Organization of the Oral Sessions
Most of the AAPG and GSA oral theme sessions will
consist of 20-minute presentations (roughly 15 minutes
for talk and 5 minutes for questions/discussion). Most SPE
talks will be in 30-minute time slots. For the SPE sessions
(T30–T43), this may not be the final program. Please refer
to the program addendum at the registration booth for the
final SPE presentation listing. Additionally, any changes after
publication of this program will be posted at http://www.spe.
org/events/wrm/pages/schedule/tech_program/index.php.
Presentation Hardware and Software
In all sessions, only one laptop computer running
Windows XP operating system with PowerPoint 2007 software, one LCD projector, and one screen will be provided.
Speakers will not be able to use their own computer for presentations. All speakers should double-check their presentations,
especially speakers who built their talks on another platform
(e.g., Mac), by loading and running it on the computers in
the Speaker Ready Room to ensure it runs properly.
Uploading Your Presentations
Plan to upload your presentations via a USB drive or CD
in the Speaker Ready Room (Grand Salon D). For morning sessions, please have your presentations loaded by no
later than 7:15 a.m. on the morning of the talk, but loading
the presentation the afternoon before the talk is preferred.
Speaker Ready Room will open at 4 p.m. on Wednesday. For
afternoon sessions, please have your presentations loaded by
noon on the day of the talk. Speaker Ready Room volunteers
will be available to help with uploading your talk.
Poster Sessions
Poster presentations will take place in the Platinum
Ballroom (Platinum 5–6). For morning sessions, posters
should be displayed 8:30 a.m.–noon. Presenters should be
present between 9:30 and 11:30 a.m. For afternoon sessions,
posters should be displayed 1:30–5 p.m. Presenters should be
present between 2:30 and 4:30 p.m. All posters must fit on
8 ft x 4 ft display board using push pins or Velcro (provided).
Electrical connections and internet service are not available
in the poster area of the Ballroom.
For general information about the technical sessions
and symposia, contact the Technical Program co-chairs:
Jeff Knott (Cordilleran Section GSA) at jknott@
fullerton.edu and/or Hilario Camacho (Pacific Section AAPG)
at [email protected].
Field Trips
Ten field trips that portray the diversity of the regional
geology are planned in conjunction with our meeting. Unless
otherwise noted, all field trips will depart from and return to
the main lobby of the Anaheim Marriott. Specific information about the field trips was sent to the field trip participants.
For additional details, contact the field trip leader or the general field trip chair, Brady Rhodes at [email protected].
Field trip articles are being edited and published by Pacific
Section SEPM. Seven field trips will have articles in the published guidebook volume.
Pre-Meeting
Pliocene-Quaternary Tectonic Evolution of the Northern
Eastern California Shear Zone. Monday–Wednesday, 24–26
May 2010. Kurt Frankel, [email protected]; Nancye
Dawers, [email protected]; Plamen Ganev, ganev@
usc.edu; Eric Kirby, [email protected]; Jeff Lee, jeff@
geology.cwu.edu; Lewis Owen, [email protected]; Fred
Phillips, [email protected]; Jeff Unruh, [email protected].
Cost: US$320 (includes two breakfasts, three lunches, two
dinners, snacks, two nights’ accommodation, transportation,
and guidebook). Max.: 25; min.: 15.
The eastern California shear zone (ECSZ) extends for
>800 km through the Mojave Desert northward along the
western edge of the Basin and Range. This system of predominantly right-lateral faults is thought to accommodate nearly
25% of Pacific-North America plate boundary deformation.
This region has been the focus of much recent research
because of its importance in understanding Pacific-North
America plate boundary dynamics. This field trip will start
12 2010 GSA Abstracts with Programs and end in Anaheim, CA, making a loop through the northern ECSZ. The first day of the trip will explore active deformation along the Panamint Valley and Hunter Mountain
faults. The second day will explore dextral and extensional
faulting in Fish Lake Valley and Queen Valley. The final day
of the trip will include stops that investigate active faulting in the Volcanic Tableland, Round Valley, and the Coso
Range. This itinerary highlights most of the major tectonic
features in the northern ECSZ and will allow trip participants
the opportunity to discuss the most recent research on strain
distribution in the region.
Late Proterozoic, Paleozoic and Mesozoic Rocks and
Structures In The Victorville-Helendale Region, Mojave
Desert California. Tuesday–Wednesday, 25–26 May 2010.
Starts and ends at Marriott Hotel (meeting headquarters).
Howard Brown, [email protected]; Janis Hernandez,
[email protected]. Cost: US$270 (includes breakfast, 2 lunches, snacks and refreshments, 1 night
lodging, and transportation.). Max.: 18; min.: 10.
On this trip we will visit the Victorville region of the
Mojave Desert to see a variety of geologic features including: 1) Multiply folded and metamorphosed Late Proterozoic
and Paleozoic miogeoclinal rocks; 2) Folded Lower Jurassic
Fairview Valley Formation metasediments that unconformably overlie eroded Paleozoic rocks; 3) Middle Jurassic
Lower Sidewinder volcanic rocks; 4) Syn- and post-Lower
Sidewinder extensional deformation including the Sparkhule
Mountain slide which placed Paleozoic limestones and Early
Jurassic Fairview Valley Formation on top of younger lower
Sidewinder volcanics; 5) Younger Jurassic low angle extensional and compressional deformation; 6) Still younger intrusive rocks, gravity slides/breccia sheets, faulting and much,
much more.
Stops include easy to moderate hikes to reach outcrops or
overview points for discussion and arm waving. New geologic
mapping allows greater resolution of geologic details and has
allowed complexities not recognized by previous work to be
resolved. Numerous large-scale detailed maps will be displayed and discussed.
Anatomy of an Anachronistic Carbonate Platform:
The Lower Triassic of the Southwestern United States
and its Relationship to the Recovery from the PermianTriassic Mass Extinction. Tuesday–Wednesday, 25–26 May
2010. Adam Woods, [email protected]; David Bottjer,
[email protected]. Cost: US$185 (includes transportation
and lodging. Meals not included.). Max.: 15; min.: 10.
This field trip examines several classic localities that have
been the focus of research that has attempted to reconstruct
environmental conditions in the wake of the Permian-Triassic
mass extinction and determine the relationship between the
recovery interval and Mesozoic biotic trends. This field trip
will provide attendees with a complete picture of carbonate
environments following the Permian-Triassic mass extinction, ranging from deep, outer shelf environments to shallow
subtidal environments. Sites that will be visited include the
deep water facies of the Union Wash Formation at Darwin,
in order to examine seafloor calcium carbonate precipitates,
shallow water stromatolites from the Union Wash Formation
at Cerro Gordo, CA, and middle shelf facies and corresponding reefal stromatolites from the Virgin Limestone at Lost
Cabin Springs, NV.
Monterey Formation of the Los Angeles Basin. Sponsored
by the LA Basin Geological Society. Tuesday, 25 May 2010.
Depart 7 a.m., return 6 p.m. Richard J. Behl, [email protected];
Stefano Mazzoni, [email protected]. Cost: US$90.
Max.: 40; min.: 12.
The Miocene Monterey Formation is a distinctly siliceous
and organic-rich deposit with stratigraphic equivalents that
span much of coastal California and the Pacific Rim. It is
California’s primary petroleum source rock and an important reservoir in some areas. It also records key middle to
late Miocene climatic, oceanographic, and tectonic transitions. It has been well-studied in the Coast ranges of central
California, the Salinas basin, and Temblor range/San Joaquin
basin, however, it has been little studied in the highly
petroliferous Los Angeles basin. The Monterey and it stratigraphic equivalents – the Puente and Modelo formations –
underlie and source most of LA’s oil fields; however, they only
outcrop in the uplifted terrains that surround the basin. This
field trip will visit key localities of the Monterey Formation
in Newport Beach, Crystal Cove State Park and the Palos
Verdes Peninsula to examine some of the key lithofacies and
see how they differ from better-studied areas in California.
Sedimentology and Facies Architecture of Channelized
Slope System: Capistrano Formation, San Clemente,
Southern California. Sponsored by the LA Basin Geological
Society. Wednesday, 26 May 2010. Depart 7 a.m., return 6 p.m.
Kirt Campion; Stefano Mazzoni, [email protected].
Cost: US$90 (includes transportation, guidebook, lunch, and
snacks). Max.: 35; min.: 10.
Outcrops of the Capistrano Formation located in the
vicinity of San Clemente State Beach provide excellent
exposures of deep-water channels that were formed in a slope
setting and filled with a variety of turbidite lithofacies. The
Capistrano Formation is late Miocene to Pliocene in age and
unconformably overlies diatomaceous shales and mudstones
of the middle to late Miocene Monterey Formation. This set
of outcrops provides analog data for many seismically resolved
confined-channel complexes and provides insight into lithofacies distribution and architectural features at the bed, bed
set, channel and channel complex scale.
This trip focuses on the architecture of the Capistrano,
which consists of a number of channels and channel complexes, and the distribution of turbidite lithofacies within this
architectural framework. The sandstone-dominated system is
about 20 m thick and 1.3 km wide and serves as a model for
confined channels that typically are represented seismically
by a single cycle. The Capistrano is made up of laterally amalgamated channels that exhibit a change in net to gross ratio,
facies preservation, and bed architecture from the channel
margin to channel axis. Channel margin facies is low net to
gross (<50% net), non-amalgamated, thin-bedded, and dominated by low-concentration turbidites (Tbcde). In contrast,
the channel-axis facies is high net to gross (>90%), thickbedded, amalgamated, and dominated by traction deposition
of sand and gravel deposits.
We will walk along the base of sea cliffs to examine exposures; please bring comfortable shoes. You will need a small
pack for water and camera (no sampling is allowed, so leave
your hammers at home).
Post-Meeting
Geologic History, Eruptive Stratigraphy and Ongoing
Volcanic Unrest at Long Valley Caldera and Mammoth
Mountain. Sunday–Wednesday, 30 May–2 June 2010. Wes
Hildreth, [email protected]; David Hill, [email protected];
Brandon Browne, [email protected]; Jorge Vazquez,
[email protected]. Cost: US$410 (includes transportation
to/from Anaheim, 3 nights lodging at the Sierra Nevada
Aquatic Research Laboratory (SNARL) dormitory, meals
while at SNARL, and gondola tickets to Mammoth Mountain
summit). Max.: 20; min.: 8.
Eastern California possesses a rich volcanic history characterized most notably by the cataclysmic caldera-forming
eruption of Long Valley ~760,000 years ago and numerous
mafic scoria cones, silicic domes and their associated lavas
and pyroclastic deposits near Mammoth Mountain, Glass
Mountain and the Coso and Big Pine volcanic fields. The
stops on this trip will highlight a revised understanding of the
region’s volcanic history based on new results from Mammoth
Mountain and new studies of Holocene mafic eruptions in
the southern Inyo volcanic chain, as well as a review of classic localities where key features of the Bishop Tuff’s emplacement history are well-preserved. Stops will include the Chalk
Bluffs and Owens Gorge, Lookout Mountain, Deadman
Creek Dome and flow, Mammoth Mountain (flanks and summit), Horseshoe Lake, and the Big Pine Volcanic Field.
Exploring the Whittier and San Andreas Faults.
Sunday, 30 May. Start 7:30 a.m., return 5:30 p.m. Galen R.
Carlson, [email protected] ; Kris Weaver-Bowman,
KWeaverBowman @MtSac.edu. Cost: US$55 (includes transportation and guidebook). Max.: 25; min.: 8.
This field trip is specifically designed for 6th–12th grade
science teachers, but is open to anyone. We will visit several
locations along the San Andreas and Whittier faults where
we will see and interpret features produced by active faulting,
including scarps and offset drainages. We will also look at
where these and other local faults lie with respect to human
structures, and discuss some of the ways in which California
deals with faults that lie in the way of development. Each
field trip stop is bus-accessible and would make a great addition to classroom lessons on earthquakes and their impacts.
This field trip is a companion to the teacher workshop “When the
Classroom Shakes: Tools for Teaching K–12 Students about
Earthquakes in their Front Yard” being offered on Saturday, 29
May. However, these are two different events covering slightly different material, and one is not a prerequisite for the other.
Soledad and Plush Ranch Basins: Mid-Tertiary Extensional
Terrane Dismembered By The San Andreas Fault System.
Saturday–Monday, 29–31 May 2010. Raymond V. Ingersoll,
[email protected]; Eric Hendrix, edhendrix@missiongeo.
com; Ron Cole, [email protected]. Cost: US$255
(includes transportation, 2 nights lodging (double occupan-
cy), 2 lunches, snacks and drinks, and guidebook. Dinners or
breakfasts are not included.). Max.: 40; min.: 15.
This trip revisits two “classic localities” originally
identified by John Crowell, Perry Ehlig & their students
during the 1950’s through 1970’s as evidence for largemagnitude displacements along faults of the San Andreas
system. Subsequent detailed work on the sedimentary, volcanic & structural history and geochronology of these two
basins confirms synsedimentary crustal extension during the
mid-Cenozoic (26 – 20 Ma) transition from convergent to
transform tectonics. This trip will observe alluvial, rockslide,
lacustrine and volcanogenic deposits, which confirm similar
half-graben evolution of both basins, with similar crustal
extension direction (N-NW). Synsedimentary detachment
faulting has been identified in at least one of the two basins;
potential impacts of detachment evolution on sedimentation and subsequent basin deformation will be observed
and discussed. Possible geodynamic explanations for crustal
extension during the convergent-to-transform transition will
be presented. Finally, the relative importance of these offset
basins in understanding evolution of the SAF system will be
discussed.
Hydrogeology of Icehouse Canyon, San Gabriel
Mountains, California. Sunday, 30 May 2010. Jonathan A.
Nourse, [email protected]. Cost: US$90 (includes
transportation, parking passes, lunch, and snacks). Max.: 21;
min.: 10.
For hydrogeology and nature enthusiasts, Icehouse Canyon
with its Quaternary deposits, crystal-clear pools and redwoods
is one of Southern California’s true gems. This one-day
field trip explores the geologic reasons for flow variations in
Icehouse Creek. Gaining and losing reaches of the creek documented by many years of stream gauge records will be related
to vivid geologic controls that include: spring discharge from
water-saturated landslide deposits, bedrock constrictions of
alluvial aquifers, and infiltration into fault-bounded gravel
deposits. The morning itinerary involves a moderately strenuous 1.5 mile hike up Icehouse Canyon trail, with multiple
stops to view stream-gauging sites and perennial springs.
Afternoon stops will contrast Icehouse Canyon watershed
with the adjacent Upper San Antonio Canyon watershed
which records markedly different base-flow recession. We will
discuss likely reasons for this difference while exploring the
Quaternary and bedrock geology near San Antonio Falls and
Upper Manker Springs. This excursion takes place during the
peak of the runoff season when spring discharge and stream
flow are most dramatic.
Quaternary Geology of the San Bernardino Mountains
and their Tectonic Margins. Saturday–Tuesday, 29 May–1
June 2010. Doug Yule, [email protected]; Jonathan Matti,
[email protected]; James Spotila, [email protected]. Cost: US$260
(includes three nights lodging, meals (2B, 3L, 1D), transportation, and guidebook. Some meals are not included (1B,
2D). Trip participants will have an opportunity to purchase
these meals on their own as we travel. Max.: 30; min.: 15.
This trip visits key sites that illustrate the temporal and
spatial Quaternary geologic evolution of the San Bernardino
Mountains. The Quaternary record here reveals a compelling
14 2010 GSA Abstracts with Programs story of fault reorganization, uplift, and erosion related to
oblique convergence at the southern ‘Big Bend’ of the San
Andreas fault. The currently active and several abandoned
strands of the San Andreas fault bound the range on the
southwest. Here, the fault-bounded Yucaipa Ridge block experienced >5 mm/yr of denudation from 0.5 to 0.8 Ma. Other
structural blocks in the mountain range have experienced distinct uplift and erosion histories that will be explored. In San
Gorgonio Pass, an ongoing debate about the seismic hazard
facing southern California centers on whether through-going
rupture of the San Andreas system can occur here. The 1992
Joshua Tree-Landers-Big Bear earthquake sequence revealed
the significance of the fault system that bounds the eastern
margin of the range. To the north impressive thrust scarps of
the North Frontal fault bound the range but appear to have
last ruptured thousands of years ago. Important questions to
address on the field trip include (1) can tectonogeomorphic
features owing to local block adjustments be distinguished
from features owing to broader plate margin interactions,
(2) do tectonic structures along the Mojave Desert margin
of the range have similar time-space histories as structures
along the southeast margin of the range, and (3) what is the
evidence for a two-sided uplift history for the San Bernardino
Mountains within the broader San Andreas system?
Short Courses and Workshops
1. Introduction to U-Th-Pb Geochronology using a
Laser-Ablation Multicollector ICP Mass Spectrometer.
Wednesday, 26 May, 9 a.m.–5 p.m., Grand Salon A.
Cost: US$100, includes lunch and workbook. Limit: 25.
George Gehrels, [email protected]; Alex Pullen,
[email protected], Arizona LaserChron Center,
University of Arizona.
Participants are introduced to the fundamentals of U-ThPb geochronology and its application in the study of Earth
sciences. This course is ideal for graduate students but inclusive to all researchers interested in familiarizing themselves
with: the U-Th-Pb decay system; measurement methodologies; pitfalls; data analysis; igneous and detrital geochronology; and future directions. The course is focused on the use of
Laser-Ablation Multicollector Inductively-Coupled-Plasma
Mass Spectrometry in making rapid and accurate U-Th-Pb
isotopic measurements. Participants will be encouraged to
join in a synergistic discussion of projects and ideas.
2. Introduction to Geographic Information Systems
(GIS) using ArcGIS for Geological and Environmental
Science Applications. Co-sponsored by ESRI. Wednesday, 26
May, 9 a.m.–5 p.m., Grand Salon B. Cost: US$80, includes
lunch and publications. Limit: 20. Toni Fisher, tfisher@
esri.com, ESRI.
Participants are introduced to the use of GIS in geosciences and environmental-related applications through brief
lectures, demonstrations, and hands-on computer exercises.
Participants do not need experience with ArcGIS, but familiarity with the Windows OS would be helpful. A brief introduction to spatial concepts and GIS using ArcGIS, ArcMap,
and Spatial and 3D Analyst extensions will follow with the
creation of a project covering many analysis techniques (geo-
processing using Toolbox tools and ModelBuilder). Use of
Geodatabase Model schema and resources for accessing data
will be explored.
3. When the Classroom Shakes: Tools for Teaching
K–12 Students about Earthquakes in Their Front Yard.
Saturday, 29 May, 9 a.m.–3 p.m., Elite 1. No costs (but
must register for meeting) thanks to the generosity of the
Southern California Earthquake Center (SCEC) and the
Department of Geological Sciences at CSUF. Includes some
course materials. Does not include lunch; please bring a
bag lunch or plan to purchase your lunch at (or near) the
hotel. Limit: 30. Kristin Weaver Bowman, kweaverbowman@
mtsac.edu; Becca Walker, [email protected]; Annie Scott,
[email protected], Mt. San Antonio College; Robert
de Groot, [email protected], Southern California Earthquake
Center (SCEC).
Designed for middle and high school science teachers.
Participants in this workshop will learn how to bring local
earthquake geology and hazards into their classrooms and
explore standards-based classroom activities for teaching
earthquakes. All K–12 and pre-service teachers are welcome.
This workshop is a companion to the “Exploring the Whittier
and San Andreas Faults” being offered on Sunday, 30 May.
However, these are two different events covering slightly different
material, and one is not a prerequisite for the other.
4. Less Talk, More Action: Strategies that Improve
Learning by Engaging Students.
Saturday 29 May, 3:30 – 4:30 p.m., Elite 1. No costs.
Limit: 30. David Steer, [email protected], The University of
Akron.
This workshop capitalizes on the growing trend to introduce active learning into geoscience-related classes. Many
teachers and faculty are interested in such methods, but do
not know how or where to begin. This workshop introduces
participants to a schema for developing their own materials
and provide an opportunity to develop one or more of their
own activities. Participants will leave the workshop with
the pedagogical foundation and in-class learning resources
they need to better engage their students. Handouts will be
provided that guide participants through an evaluation-level
exercise for designing teaching and learning activities and for
constructing their own classroom activities.
5. Petrel Session 1—Basics and Data Visualization.
Wednesday, 26 May, 8 a.m.–noon, Grand Salon C.
Cost: US$100, includes workbook and course materials.
Limit: 24. Instructed by Schlumberger personnel.
Schlumberger’s Petrel software delivers collaborative
workflows with best in class technology and leading innovation that seamlessly unites the subsurface domains of geophysics, geology, geological modeling, reservoir engineering
and drilling. This morning session focuses on navigating and
working within a 3-D window in Petrel plus some hands-on
with other windows and visualization techniques in Petrel.
This session includes understanding the Petrel data structure
as well as using the gridding algorithms in Petrel for mapping or 2-D surface generation. Petrel experience is not a
requirement.
6. Petrel Session 2—Petrel Geostatistical Overview.
Wednesday, 26 May, 1–5 p.m., Grand Salon C. Cost: US$100,
includes workbook and course materials. Limit: 24. Instructed
by Schlumberger personnel.
This afternoon session takes the users through the basics
of facies and property modeling in Petrel with a focus on the
geostatistical methods available in the application. The students have an opportunity to work directly on 3-D geocellular
model in this session. This session presents participants with
basic understanding of variagrams and overview of geostatistical algorithms and menus for facies and property modeling.
Petrel experience is not a requirement and the Session 1
course is not a prerequisite for Session 2.
Student Workshops
Roy J. Shlemon Mentor Program in Applied Geoscience.
Cosponsored by the GSA Foundation. Contact Jennifer
Nocerino, [email protected]. 11:30 a.m.–12:30 p.m.
and 12:30 p.m.–1:30 p.m., Thursday, 27 May, Elite 1. The
Shlemon Mentor Programs are designed to extend the mentoring reach of individual professionals from applied geology to undergraduates and graduate students attending GSA
sectional meetings. Over free lunches, mentors and students
discuss professional opportunities and challenges that await
students after graduation. Every student will receive a free
ticket to the Shlemon Luncheon along with his/her badge;
however, space is limited. Learn more at www.geosociety.org/
mentors/shlemon.htm.
The John Mann Mentors in Applied Hydrogeology
Program. 11:30 a.m.–12:30 p.m., Saturday, 29 May, Elite 2.
The Mann Mentors in Applied Hydrogeology Program presents mentoring opportunities for undergraduate and graduate
students as well as recent graduates with a declared interest
in applied hydrogeology as a career to interact and network
with practicing hydrogeology professionals. This relaxed
but focused small-scale event features a free lunch for students and mentors. Every student will receive a free ticket
to the Mann Luncheon along with his/her badge; however,
space is limited. Learn more at www.geosociety.org/mentors/
mann.htm.
Student Awards
Cordilleran Section GSA will present cash awards for
best and runner-up graduate oral, graduate poster, and undergraduate poster presentations. Pacific Section SEPM will
have separately judged cash awards for best undergraduate
and graduate presentations. Students must be lead authors
and presenters.
Student Travel and Field Trip Grant Opportunities
Student travel and field trip grants are available from the
Cordilleran Section in cooperation with the GSA Foundation
for GSA-member student presenters and meeting attendees.
Visit the student page at http://www.geosociety.org/sectdiv/
cord/2010mtg/students.htm for information on student travel
and field trip grant opportunities. For more information,
please contact the Cordilleran Section secretary Rod Metcalf
at [email protected].
Exhibits
Exhibits are located in the Platinum 5-6 Ballroom. The
exhibits are open:
Thursday, 27 May........... noon–6 p.m.
Friday, 28 May................ 8 a.m.–5:30 p.m.
Saturday, 29 May............ 8 a.m.–noon
Exhibitors
American Association of Petroleum Geologist/Petroleum
Technology Transfer Council (AAPG/PTTC)
Geological Society of America (GSA) Bookstore
Pacific Section AAPG Bookstore
Society for Sedimentary Geology (SEPM) Bookstore
AERA Energy, LLC
California Division of Oil, Gas & Geothermal Resources
Canrig Drilling Technology Ltd.
Dynamic Graphics, Inc.
GeoCare Benefits Insurance Programs
Horizon Well Logging, Inc
IHS
Neuralog
Paragon Geophysical Services, Inc.
Geokinetics Petroleum Geo-Sciences (PGS)
Seismic Micro Technology
TGS
Bay Geophysical, Inc
16 2010 GSA Abstracts with Programs Schlumberger
Baker Hughes
California Geological Survey
DHI Services, Inc.
Well Analysis Corporation
GSA Foundation
NAGT-Far Western Section
California State University Fullerton - Department of
Geological Sciences
Knowledge Reservoir
Core Laboratories
Morgan Stanley Smith Barney
W.H Freeman & Company
Venoco Inc.
GSA Geology & Society Division/Geology and
Public Policy Committee
Computer Modeling Group, Ltd
PTS Laboratories
Weatherford
Additional Information
The local organizing committee for Cordilleran Section
GSA, Pacific Section AAPG and SPE are committed to
making this an exciting meeting. For additional information,
see the meeting web site at http://www.geosociety.org/sectdiv/
cord/2010mtg/events.htm. You can also contact the meeting
co-chairs: Phil Armstrong (Cordilleran Section GSA) at [email protected] or Curtis Henderson (Pacific Section
AAPG) at [email protected].
Schedule of Events
Event
Time
Location
Monday, 24 May
Morning
Field Trip:
Pliocene-Quaternary Tectonic Evolution of the Northern Eastern California
Shear Zone
7 a.m.
Marriott Lobby
Tuesday, 25 May
Morning
Field Trips:
Late Proterozoic, Paleozoic and Mesozoic Rocks and Structures in the
Victorville-Helendale Region, Mojave Desert California
7 a.m.
Marriott Lobby
Anatomy of an Anachronistic Carbonate Platform: The Lower Triassic of
the Southwestern United States and its Relationship to the Recovery
From the Permian-Triassic Mass Extinction
7 a.m.
Marriott Lobby
Monterey Formation of the Los Angeles Basin
7 a.m.
Marriott Lobby
Wednesday, 26 May
Morning
Field Trip:
Sedimentology and Facies Architecture of Channelized Slope System:
Capistrano Formation, San Clemente, Southern California
7 a.m.
Marriott Lobby
9 a.m.–5 p.m.
Grand Salon A
9 a.m.–5 p.m.
Grand Salon B
8 a.m.–noon
Grand Salon C
1–5 p.m.
Grand Salon C
Registration
4–8 p.m.
Marriott Main Lobby
Speaker Ready Room
4–8 p.m.
Grand Salon D
Workshop 1:
Introduction to U-Th-Pb Geochronology Using a Laser-Ablation
Multicollector ICP Mass Spectrometer
Workshop 2:
Introduction to Geographic Information Systems (GIS) Using ArcGIS for
Geological and Environmental Science Applications
Workshop 5:
Petrel Session 1—Basics and Data Visualization
Afternoon
Workshop 6:
Petrel Session 2—Petrel Geostatistical Overview
Event
Time
Location
Thursday, 27 May
Morning
Registration
7 a.m.–4 p.m.
Platinum Ballroom Foyer
Speaker Ready Room
7 a.m.–6 p.m.
Grand Salon D
Cordilleran GSA Board Meeting
7–8 a.m.
Gold Key I
AAPG HOD Breakfast
7–8 a.m.
Elite 1
Roy J. Shlemon Mentor Program in Applied Geoscience I
11:30 a.m.–
12:30 p.m.
Elite 1
Exhibit Set Up
8 a.m.–noon
Platinum 5-6
S2. Using Basin Analysis and Geochemistry to Reconstruct the
San Andreas Fault System: A Symposium in Honor of John Crowell,
Tor Nilsen, Tom Dibblee, and Perry Ehlig (Pacific Section SEPM)
8:40–11:10 a.m.
Platinum 2
T12. Biotic Response to Phanerozoic Environmental Change
(Pacific Section SEPM; The Paleontological Society)
8:30–11:30 a.m.
Platinum 9
T20. Detrital Zircon Studies in Western North America (Cordilleran
Section GSA)
8:30–11:30 a.m.
Platinum 3
T30. Plenary: Opportunities and Challenges in the Western North
American Region (Society of Petroleum Engineers (SPE))
8:30–10 a.m.
Platinum 7
T31. Arctic Operations/Permafrost Issues/Hydrates (Society of Petroleum
Engineers (SPE))
10:30 a.m.–
12:30 p.m.
Platinum 7
T32. Advances in Drilling and Completion Technology (Society of
Petroleum Engineers (SPE))
8:30 a.m.–noon
Platinum 8
T33. Reservoir Characterization I (Pacific Section, AAPG; Society of
8:30 a.m.–noon
Platinum 10
Exhibit Opening
noon
Platinum 5-6
Refreshments with Exhibitors
noon–1 p.m.
Platinum 5-6
Exhibits
noon–6 p.m.
Roy J. Shlemon Mentor Program in Applied Geoscience II
12:30–1:30 p.m.
Elite 1
Sedimentology/Stratigraphy/Paleontology
1:30–4:55 p.m.
Platinum 9
S1. Debating the Connections Between the Plutonic and Volcanic Rock
Record (Cordilleran Section GSA)
1:30–5 p.m.
Platinum 2
T3. Terrestrial and Marine Records of Late Quaternary Climate from
Western North America/Eastern Pacific: Developments, Comparisons,
and Directions (Cordilleran Section GSA)
1:30–4:30 p.m.
Platinum 3
T5. Active Tectonics of the Eastern California Shear Zone–Walker Lane
Belt (Cordilleran Section GSA)
1:30–4 p.m.
Platinum 1
T16. Miocene Tectonics and Structural Evolution of Coastal Southern
California (Pacific Section, AAPG; Society of Petroleum Engineers (SPE))
1:30–3:30 p.m.
Platinum 4
T34. EOR Technologies I (Society of Petroleum Engineers (SPE))
1:30–5 p.m.
Platinum 7
T36. Economic Uncertainty And Risk Analysis (Society of Petroleum
Engineers (SPE))
1:30–4:30 p.m.
Platinum 10
Oral Sessions:
Afternoon
Oral Sessions:
18 2010 GSA Abstracts with Programs Event
Time
Location
T19. Undergraduate Research in Geoscience (Posters) (Cordilleran
Section, GSA; Pacific Section, AAPG; Pacific Section, SEPM; and
Council of Undergraduate Research (CUR))
1:30 p.m.
Platinum 5-6
T20. Detrital Zircon Studies in Western North America (Posters)
(Cordilleran Section GSA)
1:30 p.m.
Platinum 5-6
Cordilleran GSA Business Meeting
5–6 p.m.
Gold Key 1
Pacific Section AAPG Executive Committee Meeting
5–6 p.m.
Elite 1
Evening Reception
6–8 p.m.
Platinum 5-6
Poster Sessions:
Friday, 28 May
Morning
Registration
7:30 a.m.–4 p.m.
Speaker Ready Room
7 a.m.–6 p.m.
Grand Salon D
Exhibits
8 a.m.–5:30 p.m.
Platinum 5-6
AAPG Luncheon and Awards Banquet
11:30 a.m.–
1:30 p.m.
Marquis NW
T1. Sierra Nevada Microplate-Basement and Basins I (Cordilleran
Section GSA)
8:30–noon
Platinum 2
T2. Tectonic Evolution of the Southern Big-Bend Region, San Andreas
Fault (Cordilleran Section GSA; Pacific Section, AAPG; Pacific Section
SEPM)
8–11:30 a.m.
Platinum 1
T21. Carbon Sequestration and Oil Fields (Pacific Section AAPG/Society
of Petroleum Engineers (SPE))
8–noon
Platinum 8
T34. EOR Technologies II (Society of Petroleum Engineers (SPE))
8:30–noon
Platinum 9
T37. Advanced Reservoir Modeling Concepts (Society of Petroleum
Engineers (SPE))
8:30–noon
Platinum 7
T38. California Monterey Reservoirs (Society of Petroleum Engineers
(SPE))
8:30–noon
Platinum 10
Sedimentology/Stratigraphy/Paleontology (Posters)
8:30–noon
Platinum 5-6
T3. Terrestrial and Marine Records of Late Quaternary Climate from
Western North America/Eastern Pacific: Developments, Comparisons, and
Directions (Posters) (Cordilleran Section GSA)
8:30–noon
Platinum 5-6
T6. New Insights into Tectonics of the Central California Coast Ranges—
The Link between Los Angeles and San Francisco (Posters) (Cordilleran
Section GSA; Pacific Section, AAPG; Pacific Section SEPM)
8:30–noon
Platinum 5-6
Oral Sessions:
Poster Sessions:
Event
Time
Location
noon–1:30 p.m.
Marquis NE
T1. Sierra Nevada Microplate-Basement and Basins II (Cordilleran
Section GSA)
1:30–4 p.m.
Platinum 2
T6. New Insights into Tectonics of the Central California Coast Ranges—
The Link between Los Angeles and San Francisco (Cordilleran Section
GSA; Pacific Section, AAPG; Pacific Section SEPM)
1:30–3:20 p.m.
Platinum 3
T7. Late Neogene Tectonics and Deformation Along Active Faults East
of and Including the San Andreas—San Jacinto Fault Zones (Cordilleran
Section GSA; Pacific Section, AAPG; Pacific Section SEPM)
1:30–4 p.m.
Platinum 1
T33. Reservoir Characterization II (Pacific Section, AAPG; Society of
1:30–6 p.m.
Platinum 4
T39. Tight Plays and Unconventional Reservoirs (Society of Petroleum
Engineers (SPE))
1:30–5 p.m.
Platinum 7
T40. Managing Heavy Oil Resources (Society of Petroleum Engineers
(SPE))
1:30–4:30 p.m.
Platinum 8
T41. Advances in Completion and Production Operations (Society of
1:30–5 p.m.
Platinum 10
T42. Social Responsibility, Health, Air and Water Quality and GHG
Emissions (Society of Petroleum Engineers (SPE))
1:30–3 p.m.
Platinum 9
T43. Society of Petroleum Engineers (Posters) (Society of Petroleum
Engineers (SPE))
1:30–5 p.m.
Platinum 5-6
T44. American Association of Petroleum Geologists (Posters)
(Pacific Section, AAPG)
1:30–5 p.m.
Platinum 5-6
T45. San Andreas and Walker Lane Neotectonics (Posters)
1:30–5 p.m.
Platinum 5-6
5:30–6:30 p.m.
Marquis NW/NE
Afternoon
SPE Luncheon
Oral Sessions:
Poster Sessions:
Keynote Address:
When the Mountains Come to Main Street: Helping California Live with
Natural Disasters, Lucile Jones, USGS
Saturday, 29 May
Morning
Registration
7:30 a.m.–noon
Speaker Ready Room
7 a.m.–1:30 p.m.
Grand Salon D
Exhibits
8 a.m.–noon
Platinum 5-6
8:30 a.m.–noon
Platinum 8
Special Session:
Easter Earthquake in Northern Baja
20 2010 GSA Abstracts with Programs Event
Time
Location
9 a.m.–3 p.m.
Elite 1
11:30 a.m.–
12:30 p.m.
Elite 2
Structural Geology/Tectonics I
8:30–10:20 a.m.
Platinum 4
T4. Advances in Understanding Magma Petrogenesis and Eruption
Dynamics at Basaltic Monogenetic Volcanoes (Cordilleran Section GSA)
9 a.m.–noon
Platinum 3
T11. New Insights into the Petrology of Mesozoic Cordilleran Batholiths I
8:30–10:30 a.m.
Platinum 2
T18. Managing Groundwater in the Cordillera I (Cordilleran Section,
GSA and Pacific Section, AAPG)
8:30–10 a.m.
Platinum 1
T29. The California Geological Survey I: Providing Scientific Products and
Professional Services to Californians for 150 Years
8:40–11:40 a.m.
Platinum 7
Structural Geology/Tectonics (Posters)
8:30 a.m.–noon
Platinum 5-6
T4. Advances in Understanding Magma Petrogenesis and Eruption
Dynamics at Basaltic Monogenetic Volcanoes (Posters) (Cordilleran
Section GSA)
8:30 a.m.–noon
Platinum 5-6
T10. Theory and Practice: Engineering Geology in the Cordillera (Posters)
8:30 a.m.–noon
Platinum 5-6
T11. New Insights into the Petrology of Mesozoic Cordilleran Batholiths
(Posters) (Cordilleran Section GSA)
8:30 a.m.–noon
Platinum 5-6
T18. Managing Groundwater in the Cordillera (Posters) (Cordilleran
Section, GSA and Pacific Section, AAPG)
8:30 a.m.–noon
Platinum 5-6
noon–1 p.m.
Platinum 7
Structural Geology/Tectonics II
1:30–4 p.m.
Platinum 4
T9. Enhancing Societal Relevance in Introductory Geoscience Education
1:30–4:30 p.m.
Platinum 3
T11. New Insights into the Petrology of Mesozoic Cordilleran Batholiths II
1:30–2:50 p.m.
Platinum 2
T18. Managing Groundwater in the Cordillera II (Cordilleran Section, GSA
and Pacific Section, AAPG)
1:30–3:10 p.m.
Platinum 1
T29. The California Geological Survey II: Providing Scientific Products and
Professional Services to Californians for 150 Years
1:30–4:30 p.m.
Platinum 7
noon–6 p.m.
Platinum 5-6
Workshop 3:
When the Classroom Shakes: Tools for Teaching K–12 Students about
Earthquakes in Their Front Yard
The John Mann Mentors in Applied Hydrogeology Program
Oral Sessions:
Poster Sessions:
Afternoon
A Special Lunchtime Talk:
Conflicts Between Josiah D. Whitney and William P. Blake, and the Fate
of the First California Geological Survey, Stephen Testa, California
Geological Survey.
Oral Sessions:
Exhibit Tear-down
Event
Time
Location
3:30–4:30 p.m.
Elite 1
Quaternary Geology of the San Bernardino Mountains and Their
Tectonic Margins
4:30 p.m.
Marriott Lobby
Soledad and Plush Ranch Basins: Mid-Tertiary Extensional Terrane
Dismembered by the San Andreas Fault System
5 p.m.
Marriott Main Lobby
5–6 p.m.
Elite 2
Workshop 4:
Less Talk, More Action: Strategies That Improve Learning by
Engaging Students
Field Trips:
Reception:
Friends of the California Geological Survey
Sunday, 30 May
Morning
Field Trips:
Exploring the Whittier and San Andreas Faults
7 a.m.
Marriott Lobby
Geologic History, Eruptive Stratigraphy and Ongoing Volcanic Unrest at
Long Valley Caldera and Mammoth Mountain
7:30 a.m.
Marriott Lobby
Hydrogeology of Icehouse Canyon, San Gabriel Mountains, California
7:30 a.m.
Marriott Lobby
22 2010 GSA Abstracts with Programs Technical Sessions
A no-smoking policy has been established by
the Programme Committee and will be followed
in all meeting rooms for technical sessions.
Meeting policy prohibits the use of cameras
or sound-recording equipment at technical
sessions and poster sessions.
Notice
In the interest of public information, the Geological Society of America provides a forum for the presentation
of diverse opinions and positions. The opinions (views) expressed by speakers and exhibitors at these sessions
are their own and do not necessarily represent the views or policies of the Geological Society of America.
Note index system
Numbers (3-4, 15-4) indicate session and order of presentation within that session.
* denotes speaker
THURSDAY, 27 MAY 2010
morning Oral
Technical Sessions
SESSION NO. 2
T12. Biotic Response to Phanerozoic Environmental Change
(Pacific Section SEPM; The Paleontological Society)
8:30 AM, Marriott Anaheim Hotel, Platinum 9
SESSION NO. 1
S2. Using Basin Analysis and Geochemistry to Reconstruct the
San Andreas Fault System: A Symposium in Honor of John Crowell,
Tor Nilsen, Tom Dibblee, and Perry Ehlig (Pacific Section SEPM)
Adam D. Woods, Nicole Bonuso, David J. Bottjer, and
Matthew E. Clapham, Presiding
8:30 AM Introductory Remarks
2-1
8:40 AM Baker, Jonathan L.*; Jiang, Ganqing; Zeiza, Adam: CARBON
ISOTOPIC FRACTIONATION ACROSS A LATE CAMBRIAN
CARBONATE PLATFORM: A REGIONAL RESPONSE TO
THE SPICE EVENT AS RECORDED IN THE GREAT BASIN,
WESTERN UNITED STATES
2-2
8:55 AM Clapham, Matthew E.*: REGIONAL-SCALE FAUNAL
CHANGES DURING EARLY PERMIAN CLIMATE
FLUCTUATIONS
2-3
9:10 AM Woods, Adam D.*; Beatty, Tyler W.; Zonneveld, J.-P.:
PRIMARY PRODUCTIVITY DURING THE EARLY TRIASSIC
BIOTIC RECOVERY IN THE WESTERN CANADA
SEDIMENTARY BASIN AND ITS RELATIONSHIP TO
PALEOENVIRONMENTAL CONDITIONS
2-4
9:25 AM Mata, Scott A.*; Bottjer, David J.: CONTROLS ON THE
DISTRIBUTION OF BENTHIC MICROBIAL MATS DURING
THE EARLY TRIASSIC AFTERMATH OF THE ENDPERMIAN MASS EXTINCTION: EXAMPLES FROM THE
SOUTHWESTERN UNITED STATES
2-5
9:40 AM McCoy, Jennifer, M.*; Woods, Adam D.: DIVERSITY OF
STROMATOLITES IN THE LOWER TRIASSIC VIRGIN
LIMESTONE (MOENKOPI FORMATION) NEAR BLUE
DIAMOND, NV
Raymond V. Ingersoll, Eric Hendrix, and Ronald B. Cole, Presiding
1-1
8:40 AM Saleeby, Jason*; Chapman, Alan D.; Kidder, Steven; Ducea,
Mihai N.: DISPERSAL OF SOUTHERN SIERRA NEVADA
BATHOLITH (SNB) CRUSTAL FRAGMENTS ACROSS AND
ALONG THE TRACE OF THE SAN ANDREAS FAULT (SAF)WHAT CONSTITUTES THE CENTRAL SALINIA BASEMENT
1-2
9:10 AM Powell, Robert E.*: BASEMENT, BASINS, AND TECTONICS:
EARLY EVOLUTION OF SAN ANDREAS FAULT SYSTEM IN
SOUTHERN CALIFORNIA
1-3
9:40 AM Ingersoll, Raymond V.*: RECONSTRUCTING THE
DILIGENCIA AND VASQUEZ BASINS ACROSS THE
SAN ANDREAS FAULT (SOUTHERN CALIFORNIA)
1-4
1-5
10:10 AM Dorsey, Rebecca J.*; Housen, Bernard A.; Spears, Amy L.F.;
Janecke, Susanne U.; Axen, Gary; McDougall, Kristin;
Shirvell, Catherine: LATE MIOCENE ONSET OF PLATEBOUNDARY STRAIN IN THE SALTON TROUGH REGION:
STRATIGRAPHIC EVIDENCE FROM SPLIT MOUNTAIN
GORGE, SOUTHERN CALIFORNIA
10:40 AM Janecke, Susanne U.*; DeMets, Charles: EARLY
PLEISTOCENE REORGANIZATION OF PLATE MOTION IN
THE SALTON-TROUGH-GULF OF CALIFORNIA
9:55 AM Break
2-6
10:10 AM Pietsch, Carlie*; Bottjer, David J.: UNDERSTANDING EARLY
TRIASSIC BENTHIC INVERTEBRATE DIVERSITY AND
ECOLOGY AND CORRESPONDING CARBON ISOTOPE
EXCURSIONS
2-7
10:25 AM Kelley, Neil P.*; Motani, Ryosuke; Jiang, Da-yong; Rieppel,
Olivier; Oster, Jessica: SUFFERING A SEA CHANGE: THE
SESSION NO. 2
EVOLUTION AND EXTINCTION OF TRIASSIC MARINE
REPTILES
2-8
10:40 AM Monarrez, Pedro M.*; Bonuso, Nicole: DAZED AND
CONFUSED: BIVALVE AND BRACHIOPOD OCCURRENCE
TRENDS FOLLOWING THE END-PERMIAN MASS
EXTINCTION
2-9
10:55 AM Scott, Eric*: BIOSTRATIGRAPHY AND NORTH AMERICAN
PLEISTOCENE MEGAFAUNAL EXTINCTIONS
11:10 AM Concluding Remarks
5-2
11:00 AM Moridis, George J.*; Reagan, Matthew T.: EVALUATION
OF TWO NORTH SLOPE, ALASKA, DEPOSITS FOR A
POTENTIAL LONG TERM TEST OF GAS PRODUCTION
FROM HYDRATES
5-3
11:30 AM Reagan, Matthew T.*; Moridis, George J.; Kowalsky, Michael
Brendon: THE EFFECT OF RESERVOIR HETEROGENEITY
ON GAS PRODUCTION FROM HYDRATE ACCUMULATIONS
IN THE PERMAFROST
5-4
12:00 PM Venepalli, Kiran Kumar*: STUDY ON PORE SCALE
DISTRIBUTION OF FROZEN WATER AND ITS EFFECT
ON RELATIVE PERMEABILITY OF OIL IN PERMAFROST
RESERVOIR ROCKS
SESSION NO. 3
T20. Detrital Zircon Studies in Western North America
George Gehrels and Alex Pullen, Presiding
SESSION NO. 6
T32. Advances in Drilling and Completion Technology (Society of
3-1
8:40 AM Malkowski, Matthew A.*; Hampton, Brian A.; Bradley, Dwight C.;
Gehrels, George E.: NEW PROVENANCE CONSTRAINT
FROM UPPER PALEOZOIC STRATA OF THE FAREWELL
TERRANE, SOUTHWEST ALASKA
Paul J. Durning and Michael Ernest Utt, Presiding
3-2
3-3
6-1
9:00 AM Kochelek, Evan J.*; Amato, Jeffrey M.: DETRITAL ZIRCON
AGES FROM THE VALDEZ GROUP INDICATE RAPID
LATEST CRETACEOUS DEPOSITION IN THE CHUGACH
ACCRETIONARY COMPLEX, SOUTHERN ALASKA
8:30 AM Fram, Joe H.*; Sims, Jackie C.; Mayer, Tiffany Crystal;
Sequera, Axzel: ADDRESSING HORIZONTAL STEAM
INJECTION COMPLETIONS CHALLENGES WITH
CHEVRON’S HORIZONTAL STEAM TEST FACILITY
6-2
9:20 AM Garver, John I.*; Enkelmann, Eva; Kveton, Kevin J.: UPLIFT
AND EXHUMATION OF THE CHUGACH-PRINCE WILLIAM
TERRANE, ALASKA, REVEALED THROUGH VARIABLE
ANNEALING OF FISSION TRACKS IN DETRITAL ZIRCON
9:00 AM Lee, Jung kun*: CATALYTIC PROPERTIES OF CLAY BASED
HYBRID MATERIALS FOR DRILLING OPERATIONS
CORRESPONDING AUTHOR’S COMPANY: UNIVERSITY OF
PITTSBURGH
6-3
9:30 AM Hallman, Tyler James*; MacDonald, Ron R.; Gerlitz, Jeff;
Hareland, Geir: THERMAL MODELING OF DRILLING INTO
STEAM CHAMBERS
9:40 AM Break
10:00 AM Break
10:00 AM Evenson, Nathan S.*; Henderson, Tiffany; Ancuta, Lenny;
Davidson, Cameron; White, Timothy S.; Wirth, Karl R.:
U-PB DETRITAL ZIRCON GEOCHRONOLOGY AND
PROVENANCE OF THE PALEOGENE-NEOGENE
KOOTZNAHOO FORMATION, SOUTHEAST ALASKA:
A SEDIMENTARY RECORD OF COAST MOUNTAINS
EXHUMATION
6-4
10:30 AM Cavender, Travis Wayne*; Schultz, Roger L.: METHOD FOR
MINIMIZING LINER EXPANSION ISSUES IN HORIZONTAL
THERMAL APPLICATIONS
6-5
11:00 AM Suri, Ajay*; Sharma, Mukul: AN IMPROVED LABORATORY
METHOD TO ESTIMATE FLOW INITIATION PRESSURES
AND RETURN PERMEABILITIES DURING FLOWBACK
3-5
10:20 AM Ancuta, Lenny*; Garver, John I.: DETRITAL ZIRCON FISSION
TRACK AGES OF THE PALEOGENE KOOTZNAHOO
FORMATION, SOUTHEAST ALASKA
6-6
11:30 AM Bai, Baojun*; Zhang, Jin; Zhang, Shicheng: DEVELOPMENT
AND FIELD PILOT OF A NOVEL VISCOELASTIC ANIONIC
SURFACTANT (VAS) FRACTURING FLUID
3-6
10:40 AM Paterson, Scott R.; Memeti, Vali*; Mundil, Roland: ICP-MS
AND TIMS ZIRCON DATING IN THE SIERRA NEVADA:
INITIAL IMPLICATIONS FOR TECTONIC AND MAGMATIC
PROCESSES
SESSION NO. 7
11:00 AM González-León, Carlos*; Solari, Luigi; Valencia, Victor; Lawton,
Timothy F.; Lopez-Martinez, Margarita; Gray, Floyd; Bernal,
Juan Pablo; Lozano Santacruz, R.: U-PB GEOCHRONOLOGY
OF LARAMIDE MAGMATISM IN NORTH-CENTRAL
SONORA, MEXICO
7-1
3-4
3-7
SESSION NO. 4
T30. Plenary: Opportunities and Challenges in the Western North
American Region (Society of Petroleum Engineers (SPE))
T32. Advances in Drilling and Completion Technology (Alternate)
(Society of Petroleum Engineers (SPE))
SESSION NO. 8
T33. Reservoir Characterization I (Pacific Section, AAPG; Society of
Sam Sarem and Fred Aminzadeh, Presiding
8-1
8:30 AM Pan, Yan*; Sullivan, Michael; Belanger, Dave: BEST
PRACTICES IN TESTING AND ANALYZING MULTILAYER
RESERVOIRS
8-2
9:00 AM Jianwei Wang, Wang*; Dou, Qifeng Dou: INTEGRATION OF
3D SEISMIC ATTRIBUTES INTO STOCHASTIC RESERVOIR
MODELS USING ITERATIVE VERTICAL RESOLUTION
MODELING METHODOLOGY
8-3
9:30 AM Dastan, Aysegul*; Tarantola, Albertt; Horne, Roland:
ROBUST WELL TEST INTERPRETATION USING
NONLINEAR REGRESSION WITH PARAMETER AND DATA
TRANSFORMATIONS
Behrooz Fattahi and Raj Upadhyay, Presiding
8:30 AM Round table discussion
SESSION NO. 5
T31. Arctic Operations/Permafrost Issues/Hydrates (Society of
Hareland, Geir*: DIRECTIONAL HOLE CLEANING
PROCESS REVIEW: A SYSTEMATIC VIEW
Abhijit Yeshwant Dandekar and Santanu Khataniar, Presiding
10:00 AM Break
5-1
8-4
10:30 AM Shad, Saeed*; Maini, Brij B.; Gates, Ian Donald: EFFECT
OF FRACTURE AND FLOW ORIENTATION ON TWO
10:30 AM Mathews, William Lloyd; Young, James P.*: ALASKAN HEAVY
OIL: FIRST CHOPS AT A VAST, UNTAPPED ARCTIC
RESOURCE
24 2010 GSA Abstracts with Programs SESSION NO. 11
PHASE FLOW IN AN OIL WET FRACTURE: RELATIVE
PERMEABILITY CURVES AND FLOW STRUCTURES
8-5
11:00 AM Mitra, Arijit*; Warrington, Daniel Scott; Sommer, Alan:
APPLICATION OF LITHOFACIES MODELS TO
CHARACTERIZE UNCONVENTIONAL SHALE GAS
RESERVOIRS AND IDENTIFY OPTIMAL COMPLETION
INTERVALS
8-6
11:30 AM Williams, Steve O.*; Solanki, Maxi; Batarseh, Samih Issa:
DEVELOPMENT OF PETROPHYSICAL STRESS
MODELS FOR CONVERSION OF CORE POROSITY AND
PERMEABILITY DATA FROM AMBIENT TO RESERVOIR
CONDITIONS: A NEW HYBRID APPROACH
EVOLUTION OF THE RIVER MOUNTAINS VOLCANIC SUITE
AND WILSON RIDGE PLUTON
10-3
2:15 PM Hildebrand, Robert S.*; Hoffman, Paul F.; Housh, Todd;
Bowring, Samuel A.: THE NATURE OF VOLCANO-PLUTONIC
RELATIONS IN THE GREAT BEAR MAGMATIC ZONE,
NORTHWESTERN CANADA
10-4
2:35 PM Hirt, William H.*: DEVELOPMENT OF A VERTICALLYSTRATIFIED DACITE-RHYOLITE MAGMATIC SYSTEM
WITHIN THE MOUNT WHITNEY INTRUSIVE SUITE, SIERRA
NEVADA, CALIFORNIA
10-5
2:55 PM Claiborne, Lily L.; Miller, Calvin F.*; Flanagan, Daniel M.;
Clynne, Michael A.; Wooden, Joseph L.: ACTIVE INTRUSIVE
COMPLEXES BENEATH ARC VOLCANOES: THE ZIRCON
RECORD OF MOUNT ST. HELENS
3:15 PM Break
1:30 PM, Marriott Anaheim Hotel, Platinum 9
10-6
3:30 PM Glazner, Allen F.*; Bartley, John M.; Coleman, Drew S.: THE
ROOM NON-PROBLEM
SESSION NO. 9
Shannon R. Leslie and R. Brown West, Presiding
1:30 PM Introductory Remarks
10-7
9-1
1:40 PM Pierce, David*; Awramik, S.M.: CRYOGENIAN MICROBIAL
FOSSILS FROM THE KINGSTON PEAK FORMATION
3:50 PM Deering, Chad D.*; Bachmann, Olivier: TRACE ELEMENT
INDICATORS OF SILICIC CUMULATES
10-8
9-2
2:00 PM McCall, Andrea M.*; Kodama, Kenneth P.: INCLINATION
CORRECTION FOR THE MOENAVE FORMATION AND
WINGATE SANDSTONE: IMPLICATIONS FOR NORTH
AMERICA’S APPARENT POLAR WANDER PATH AND
COLORADO PLATEAU ROTATION
4:10 PM Mills, Ryan D.*; Coleman, Drew S.: MODELING LARGEVOLUME FELSIC ERUPTIONS FROM TRACE-ELEMENT
GEOCHEMISTRY
4:30 PM Discussion
9-3
2:20 PM Amini, Sadraddin*: DIAPIRISM, MAGMATISM AND
MINERALIZATION IN THE HORMOZ ISLAND, PERSIAN
GULF, SOUTH IRAN
T3. Terrestrial and Marine Records of Late Quaternary Climate
from Western North America/Eastern Pacific: Developments,
Comparisons, and Directions (Cordilleran Section GSA)
9-4
2:40 PM Martindale, Steven G.*: PERMIAN STRATIGRAPHY IN THE
HEAD OF LORAY WASH, NORTHEASTERN NEVADA
3:00 PM Break
11-1
9-5
3:15 PM Stanton, Robert J. Jr.*; Alderson, John M.: LIMESTONE
SEDIMENTATION CONCURRENT WITH SUBMARINE
VOLCANISM IN THE CONEJO VOLCANICS, MIOCENE,
SANTA MONICA MOUNTAINS, SOUTHERN CALIFORNIA
1:30 PM Zimmerman, Susan Herrgesell*; Steponaitis, Elena A.;
Hemming, Sidney: IMPROVEMENTS ON THE DEGLACIAL
CHRONOLOGY AT MONO LAKE, CA FROM 14C-DATING
OF PROGRESSIVE LEACHES
11-2
9-6
3:35 PM Leslie, Shannon R.*; Miller, David M.; Wooden, Joe L.;
Vazquez, Jorge A.: STRATIGRAPHY, AGE, AND TECTONIC
SETTING OF THE MIOCENE BARSTOW FORMATION AT
HARVARD HILL, CENTRAL MOJAVE DESERT, CALIFORNIA
1:45 PM Liddicoat, Joseph C.*: LATE PLEISTOCENE GLACIATION
IN THE WESTERN U.S. GREAT BASIN AS RECORDED IN
MONO BASIN, CALIFORNIA
11-3
2:00 PM Oster, Jessica*; Montanez, Isabel P.; Sharp, Warren D.:
MODERN VARIABILITY IN CENTRAL SIERRA NEVADA
CAVE ENVIRONMENTS AND IMPLICATIONS FOR
CHANGES IN PALEO-PRECIPITATION
11-4
2:15 PM Reheis, Marith*; Miller, David M.; McGeehin, John P.: LATE
PLEISTOCENE SHORELINE FLUCTUATIONS OF LAKE
MANIX, MOJAVE DESERT: PALEOCLIMATE IMPLICATIONS
11-5
2:30 PM Starratt, Scott W.*; Barron, John A.; Wan, Elmira; Wahl,
David B.; Anderson, Lysanna: MARINE-TERRESTRIAL
CLIMATE CONNECTIONS: THE INFLUENCE OF THE
EASTERN PACIFIC OCEAN ON THREE MIDDLE TO HIGH
ELEVATION LAKES AND SAN FRANCISCO BAY
11-6
2:45 PM Behl, Richard J.*; Kennett, James; Afshar, Sara; Escobedo,
Diane K.; Hill, Tessa M.; Nicholson, Craig; Sorlien,
Christopher C.: ABRUPT AND MILLENNIAL-SCALE
CLIMATE AND OCEAN CHANGE SINCE THE MIDPLEISTOCENE TRANSITION IN SANTA BARBARA BASIN,
CALIFORNIA
9-7
3:55 PM McCuan, Daniel T.*; Negrini, Robert M.; Horton, Robert A.:
MAGNETIC MINERALOGY OF THE BB2 SERIES SEDIMENT
CORES FROM SUMMER LAKE, OR
9-8
4:15 PM McHargue, Tim*; Pyrcz, Michael J.; Sullivan, Morgan; Clark,
Julian; Levy, Marjorie; Fildani, Andrea; Posamentier, Henry;
Romans, Brian; Covault, Jacob A.: PREDICTING RESERVOIR
ARCHITECTURE OF TURBIDITE CHANNEL COMPLEXES: A
GENERAL MODEL ADAPTABLE TO SPECIFIC SITUATIONS
9-9
4:35 PM West, R. Brown*: LONGSHORE TRANSPORT AND SAND
SPIT CONSTRUCTION: HAVE WE GOTTEN IT WRONG ALL
THESE YEARS?
SESSION NO. 11
Matthew E. Kirby, Sarah Feakins, Kathleen R. Johnson, and Rob Negrini, Presiding
SESSION NO. 10
S1. Debating the Connections Between the Plutonic and Volcanic
Rock Record (Cordilleran Section GSA)
Drew S. Coleman and Olivier Bachmann, Presiding
10-1
1:35 PM Anderson, J. Lawford*; Paterson, Scott; Memeti, Valbone;
Zhang, Tao; Economos, Rita; Barth, Andrew P.; Pignotta,
Geoffrey; Mundil, Roland; Foley, Brad; Schmidt, Keegan L.:
EPISODIC DOWNWARD CRUSTAL FLOW DURING
TRIASSIC TO CRETACEOUS MAGMA SURGES IN THE
CENTRAL SIERRA ARC
10-2
1:55 PM Honn, Denise K.*; Smith, Eugene; Simon, Adam; Spell,
Terry L.: REDEFINING AN IGNEOUS SYSTEM: MAGMATIC
3:00 PM Break
11-7
3:15 PM Ferguson, Julie*; Johnson, Kathleen R.; Roy, Kaustuv;
Kennett, D. J.; Erlandson, Jon M.: SEASONAL RESOLUTION
SEA SURFACE TEMPERATURES FROM LOTTIA GIGANTEA
SHELL GEOCHEMISTRY
11-8
3:30 PM Kirby, Matthew E.*; Lund, S.P.; Patterson, William P.; Anderson,
Michael; Bird, Broxton W.: A 10,000 YEAR RECORD OF
PACIFIC DECADAL OSCILLATION (PDO)-RELATED
HYDROLOGIC VARIABILITY IN SOUTHERN CALIFORNIA
(LAKE ELSINORE, CA)
SESSION NO. 11
11-9
3:45 PM Englebrecht, Amy*; Ingram, Lynn; Byrne, Roger; Kienel,
Ulrike: A 2,000-YEAR VARVED RECORD OF HYDROLOGIC
CHANGE FROM ISLA ISABELA, SUBTROPICAL
NORTHEAST PACIFIC
11-10
4:00 PM Cheetham, Michael Ian*; Kirby, Matthew E.; Feakins, Sarah:
MULTI-DECADAL CLIMATE VARIABILITY IN SOUTHERN
CALIFORNIA OVER 2 MILLENNIA
11-11
4:15 PM Roach, Lydia D.*; Sessions, Alex L.; Cayan, Daniel C.; Charles,
Christoper D.; Anderson, R. Scott: HYDROGEN ISOTOPE
RATIOS OF LEAF WAX LIPIDS FROM SIERRA NEVADA
LAKE SEDIMENTS RECORD DECADAL HYDROCLIMATE
VARIABILITY DURING THE MEDIEVAL PERIOD
2:20 PM Break
13-4
2:30 PM Holk, Gregory J.*; Kelty, T.K.; Valenzuela, Gabriela; Searle,
Tiffany; Rodriguez, Aaron; Castro, Christopher; Hanson,
Eric; Vancil, Mia; Weaver, McKenzie; Brown, Arthur: THE
METAMORPHIC AND FLUID EVOLUTION OF THE ONLY
MAINLAND EXPOSURE OF THE CATALINA SCHIST:
GEORGE F CANYON, THE PALOS VERDES HILLS
13-5
2:45 PM Liddicoat, Joseph C.*: ASSESSMENT OF PALEOMAGNTIC
RESULTS FOR MIOCENE AND YOUNGER VOLCANIC AND
SEDIMENTARY ROCKS IN THE TRANSVERSE RANGES
AND VENTURA BASIN, COASTAL SOUTHERN CALIFORNIA
13-6
3:00 PM Yang, Wenzheng*; Hauksson, Egill: SEISMOTECTONIC
ANALYSIS OF SEISMICITY PATTERNS AND FOCAL
MECHANISMS IN THE EAST LOS ANGELES BASIN,
CALIFORNIA
13-7
3:15 PM Saenz, Joseph M.*; O’Neil, Thomas J.; Denison, Frank E.;
Fischer, Peter J.: STRATIGRAPHIC EVOLUTION OF THE
SANTA MARIA BASIN, OFFSHORE CALIFORNIA
SESSION NO. 12
T5. Active Tectonics of the Eastern California Shear Zone–Walker
Lane Belt (Cordilleran Section GSA)
Kurt L. Frankel and Plamen N. Ganev, Presiding
SESSION NO. 14
12-1
1:40 PM Hulett, Ashley*; McGill, Sally; Bryce, Colin; Herlihy, Rachelle;
Lopez, Amanda; Robles, Matthew; Stephens, Jonathan J.;
Swift, Mark; Velasquez, Christina; Ganev, Plamen N.; Dolan,
James: NEW HOLOCENE SLIP-RATE SITE ALONG
THE CENTRAL GARLOCK FAULT, SEARLES VALLEY,
SOUTHEASTERN CALIFORNIA
T34. EOR Technologies I (Society of Petroleum Engineers (SPE))
12-2
12-3
2:00 PM Caskey, S. John*; Goodman, Joshua T.; Green, Heather L.;
Niles, John H.; Wan, Elmira; Wahl, David B.; Olsen, Holly A.:
CONSTRAINTS ON POST-MIDDLE-PLEISTOCENE
OFFSETS AND NEW PERSPECTIVES ON PLIOPLEISTOCENE TECTONISM ALONG THE SOUTHERN
DEATH VALLEY FAULT ZONE
2:20 PM Stevens, Calvin H.*; Stone, Paul; Bishop, Kim M.; Blakely,
Richard J.: A NEW HYPOTHESIS FOR THE ORIGIN OF THE
POVERTY HILLS, OWENS VALLEY, CALIFORNIA
2:40 PM Break
12-4
3:00 PM Nagorsen, Sarah*; Lee, Jeff: FAULT KINEMATICS IN THE
WESTERN MINA DEFLECTION: FIELD STUDIES IN THE
ADOBE HILLS, CALIFORNIA
12-5
12-6
3:20 PM Hoeft, Jeffrey S.*; Frankel, Kurt L.: LATE PLEISTOCENE
RATES OF EXTENSION ON THE LONE MOUNTAIN
FAULT AND STRAIN DISTRIBUTION IN THE EASTERN
CALIFORNIA SHEAR ZONE-WALKER LANE
3:40 PM Surpless, Benjamin*: NEW CONSTRAINTS ON
QUATERNARY SLIP RATES OF THE WASSUK RANGE
FAULT SYSTEM, WESTERN NEVADA
SESSION NO. 13
T16. Miocene Tectonics and Structural Evolution of Coastal
Southern California (Pacific Section, AAPG; Society of Petroleum
Engineers (SPE))
Nate Onderdonk, Presiding
13-1
1:35 PM Legg, Mark R.*; Nicholson, Craig; Sorlien, Christopher C.:
MIOCENE OBLIQUE RIFTING OF THE SAN DIEGO TROUGH
REGION, CALIFORNIA CONTINENTAL BORDERLAND
13-2
1:50 PM Sorlien, Christopher C.*; Seeber, Leonardo; Campbell, Brian A.:
QUATERNARY SUBSIDENCE IN THE INNER CALIFORNIA
CONTINENTAL BORDERLAND: ECHO OF MIOCENE
CRUSTAL THINNING AND THRUST-FOLDING OF THE
NEAR-SHORE SLOPE
13-3
2:05 PM Francis, Robert D.*; Legg, Mark; Shafer, Luke R.; Castillo,
Chris M.: MIOCENE TO RECENT TECTONIC EVOLUTION
OF SAN PEDRO BASIN AND SANTA CATALINA ISLAND:
EVIDENCE FROM HIGH-RESOLUTION SEISMIC
REFLECTION IMAGES
26 2010 GSA Abstracts with Programs 1:30 PM, Marriott Anaheim Hotel, Platinum 7
Edward John Behm and Kristian Jessen, Presiding
14-1
1:30 PM Jamili, Ahmad Jamili*; Willhite, Paul; Green, Don W.:
MODELING GAS PHASE MASS TRANSFER BETWEEN
FRACTURE AND MATRIX IN NATURALLY FRACTURED
RESERVOIRS
14-2
2:00 PM Kuru, Ergun*; Trivedi, Japan: EFFECT OF ELASTICITY
DURING VISCOELASTIC POLYMER FLOODING A
POSSIBLE MECHANISM OF INCREASING THE SWEEP
EFFICIENCY
14-3
2:30 PM Barzin, Yalda*; Moore, Robert Gordon; Mehta, Sudarshan A.:
EFFECT OF INTERSTITIAL WATER SATURATION AND AIR
FLUX ON COMBUSTION KINETICS OF HIGH PRESSURE
AIR INJECTION (HPAI)
3:00 PM Break
14-4
3:30 PM Gao, Panqing*: FEASIBILITY INVESTIGATION OF CO2
MISCIBLE FLOODING IN SOUTH SLATTERY MINNELUSA
RESERVOIR, WYOMING
14-5
4:00 PM Delshad, Mojdeh*; Yuan, Changli; Wheeler, Mary Fanett:
PARALLEL SIMULATIONS OF COMMERCIAL SCALE
POLYMER FLOODS
14-6
4:30 PM Limkar, Parikshit*: NOVEL IN SITU COMBUSTION
TECHNIQUE USING A SEMI PERMEABLE COLLOIDAL
SYSTEM
SESSION NO. 15
T35. Mature Waterflood Management (Society of Petroleum
Engineers (SPE))
Keshav Narayanan and Zhengming Yang, Presiding
15-1
1:30 PM Izgec, Omer*; Sayarpour, Morteza; Shook, G. Michael:
OPTIMIZING VOLUMETRIC SWEEP EFFICIENCY IN
WATERFLOODS BY INTEGRATING STREAMLINES,
DESIGN OF EXPERIMENTS, AND HYDROCARBON F PHI
CURVES
15-2
2:00 PM Ahmadloo, Farid*; Asghari, Koorosh; Renouf, Gay: A NEW
DIAGNOSTIC TOOL FOR PERFORMANCE EVALUATION OF
MATURE HEAVY OIL WATERFLOODS: CASE OF WESTERN
CANADIAN HEAVY OIL RESERVOIRS
15-3
2:30 PM Lin, Yen Ting*; Ortega, Antonio I.; Nejad, Amir Mohammad;
Ershaghi, Iraj: WATERFLOOD TOMOGRAPHY: MAPPING
HIGH CONTRAST PERMEABILITY STRUCTURES USING
INJECTION/PRODUCTION DATA
3:00 PM Break
SESSION NO. 18
15-4
15-5
15-6
ICE AGE LIONS DURING THE LAST GLACIAL-INTERGLACIAL
CYCLE”
3:30 PM Lee, Kun Han*; Ortega, Antonio I.; Jafroodi, Nelia; Ershaghi,
Iraj: A MULTIVARIATE AUTOREGRESSIVE MODEL
FOR CHARACTERIZING PRODUCER PRODUCER
RELATIONSHIPS IN WATERFLOODS FROM INJECTION/
PRODUCTION RATE FLUCTUATIONS
18-2
4:00 PM Suri, Ajay*; Sharma, Mukul: A MORE COMPLETE MODEL
FOR INJECTION WELL TESTING THAT INCLUDES THE
EFFECTS OF SOLIDS DEPOSITION, TWO PHASE FLOW
AND INJECTION INDUCED FRACTURES
2 Unangst, Nathan A.*; Clapham, Matthew E.; Lopez, Shirley:
TAXONOMIC RE-EXAMINATION OF PERMO-CARBONIFEROUS
BRACHIOPODS FROM BOLIVIA: IMPLICATIONS FOR FAUNAL
CHANGE DURING THE LATE PALEOZOIC ICE AGE
18-3
4:30 PM Lee, Hyokyeong*; Yao, Ke thia; Okpani, Olu Ogbonnaya;
Nakano, A.; Ershaghi, Iraj: IDENTIFYING INJECTOR
PRODUCER RELATIONSHIP IN WATERFLOOD USING
HYBRID CONSTRAINED NONLINEAR OPTIMIZATION
3 Altman, Kathryn*; Teasdale, Rachel: USING ANALOG FLOW
EXPERIMENTS TO MODEL MORPHOLOGIES DEVELOPED
DURING EPISODIC DOME GROWTH: A CASE STUDY OF MOUNT
ST HELENS, 1980-1986
18-4
4 Cone, Allison J.*; Kathe, Kelly K.; Bonuso, Nicole: TURNOVER
RATES ASSOCIATED WITH THE MID-CARBONIFEROUS
BOUNDARY, BIRD SPRING FORMATION, ARROW CANYON,
NEVADA
18-5
5 Kieta, Andrew C.*; Nourse, Jonathan A.; Heaton, Daniel E.; Avant,
Travis B.; Kalighi, Azad; Wicks, Logan Edward: IMPACTS OF THE
FLOODS OF 1938, 1969 AND 2005 ON THE OLD MT.BALDY
ROAD, SAN GABRIEL MOUNTAINS CALIFORNIA
18-6
6 Lewis, Benjamin*; Browne, Brandon L.; Van Sickle, David; Vazquez,
Jorge A.: GEOLOGICAL AND PETROLOGICAL OBSERVATIONS
OF THE LONG CANYON DOME RHYOLITE, SIERRA NEVADA
18-7
7 Fassett, Laurry*; Kelly, Boyle; Shannon, Holt; Teasdale, Rachel;
Brown, David: MONITORING THE HYDROTHERMAL SYSTEM AT
THE LASSEN VOLCANIC CENTER, CALIFORNIA
18-8
8 Bonnar, Melissa S.*; Nourse, Jonathan A.: STRUCTURAL
ANALYSIS OF FOLDED PALEOPROTEROZOIC GNEISS
NEAR WEST FORK- NORTH FORK SAN GABRIEL RIVER
CONFLUENCE, CALIFORNIA
18-9
9 Hasten, Zachary E.L.*; Camp, Victor E.: TERTIARY VOLCANISM IN
THE SOUTHERN BUFFALO HILLS, SMOKE CREEK, NEVADA
SESSION NO. 16
T35. Mature Waterflood Management (Alternates) (Society of
16-1
Shirani mehr, Houtan*; Jafroodi, Nelia; Ghods, Ghods; Javaheri,
Mohammad; Kashani, Farnoush Banaei; Ershaghi, Iraj; Beierle,
Ryan; Shahabi, Cyrus: DATA DRIVEN MAPPING OF LIQUID
SATURATION IN WATERFLOODS USING INJECTION AND
PRODUCTION DATA
16-2
Siavoshi, Jamal*: MONITORING WATER FRONT ADVANCE
AND BILINEAR FLOW BEHAVIOUR ON PRESSURE
TRANSIENT TESTS IN HORIZONTAL WELLS
SESSION NO. 17
T36. Economic Uncertainty And Risk Analysis (Society of
Ahmed Badruzzaman and Dale Julander, Presiding
17-1
1:30 PM Chelmis, Charalampos*; Bakshi, A.; Seren, F. Burcu;
Prasanna, Victor; Gomadam, Karthik: INTELLIGENT MODEL
MANAGEMENT AND VISUALIZATION FOR SMART
OILFIELDS
17-2
2:00 PM Liu, Shuping*; Raghavendra, Cauligi Srinivasa; Yao, Ke thia;
Lenz, Tracy Lynn; Olabinjo, Lanre; Seren, F. Burcu; Seddighrad,
Sanaz; Babu, Dineshbabu C. Dinesh: FAILURE PREDICTION
FOR ARTIFICIAL LIFT SYSTEMS
17-3
2:30 PM Dougherty, E.L.*; Chang, Jincai: A METHOD TO QUICKLY
ESTIMATE THE PROBABLE VALUE OF A SHALE GAS
WELL
3:00 PM Break
17-4
3:30 PM Belhaj, Hadi Arbi*; Haroun, Muhammad Raeef; Lay, Terry:
INTEGRATED RISK ANALYSIS CRITERIA FOR MANAGING
EXPLORATION AND DEVELOPMENT OF OIL AND GAS
ASSETS
17-5
4:00 PM Wylde, Jonathan James*: QUANTIFYING THE FATE OF
HYDRATE INHIBITOR IN AN HPHT GAS CONDENSATE
SUBSEA TIEBACK
afternoon Poster
Technical Sessions
18-10
10 Lee, Daniel J.*; Sarna-Wojcicki, Andrei M.; Wan, Elmira; Wahl,
David B.; Knott, Jeffrey R.: MINOR AND TRACE ELEMENT GLASS
COMPOSITION OF LATEST PLEISTOCENE TEPHRA LAYERS
FROM THE WILSON CREEK FORMATION, MONO LAKE,
CALIFORNIA, USING INSTRUMENTAL NEUTRON ACTIVATION
18-11
11 Cronquist, Danny A.*; Camp, Victor: THE SMOKE CREEK DIKE
SWARM, NORTHWESTERN NEVADA
18-12
12 Diaz, Nathan*: LA-ICP-MS AS A HIGH PRECISION
IDENTIFICATION METHOD FOR THE TEPHRA LAYERS OF THE
WILSON CREEK FORMATION, MONO BASIN, CALIFORNIA
18-13
13 Bruns, Jessica J.*; Jessey, David R.: NEOGENE BASALTIC
VOLCANISM IN THE SOUTHERN OWENS VALLEY, CA:
IMPLICATIONS TO TECTONICS OF THE ECSZ
18-14
14 Carson, Mary L.*; Schiff, Caleb; Kaufman, Darrell S.: VARIABILITY
IN BIOLOGICAL PROXIES FOR UNDERSTANDING PALEOENVIRONMENTAL CHANGE AT PTARMIGAN LAKE, ALASKA
18-15
15 Epstein, Jordan David*; Davidson, Cameron; Wirth, Karl R.:
PALEOMAGNETISM AND GEOCHEMISTRY OF TERTIARY
INTRUSIONS AND FLOWS ASSOCIATED WITH THE
KOOTZNAHOO FORMATION NEAR KAKE, SOUTHEAST
ALASKA, AND IMPLICATIONS FOR THE ALEXANDER TERRANE
18-16
16 McHugh, Kelly*; Wypych, Alicja; Hart, William K.; Scarberry, Kaleb:
GEOLOGY AND PETROLOGY OF THE HAWKS VALLEY-LONE
MOUNTAIN VOLCANIC COMPLEX, SOUTHEASTERN OREGON
18-17
17 Rogers, Tamera L.*; Giaramita, Mario: PETROLOGY AND
GEOCHEMISTRY OF PILLOW BASALTS, EASTERN
ELK OUTLIER OF THE WESTERN KLAMATH TERRANE,
SOUTHWESTERN OREGON
18-18
18 Kathe, Kelly K.*; Cone, Allison J.; Bonuso, Nicole: DOCUMENTING
REGIONAL BRACHIOPOD ABUNDANCE AND DIVERSITY
ACROSS THE MISSISSIPPIAN-PENNSYLVANIAN BOUNDARY:
BIRD SPRING FORMATION, ARROW CANYON, NEVADA
18-19
19 Keefer, Emily*; Poletti, Juliana; Howard, Katlin; Chawla, Devika;
Fleishman, Suzanne; Jepson, Ryan; Mazza, Sarah; Rodenbough,
Elizabeth; Glazner, Allen: WIDESPREAD VOLCANIC ASH
COMPONENT IN SOILS OF EASTERN CALIFORNIA AND THE
ANCIENT BRISTLECONE PINE FOREST
SESSION NO. 18
T19. Undergraduate Research in Geoscience (Posters) (Cordilleran
Section, GSA; Pacific Section, AAPG; Pacific Section, SEPM; and
Council of Undergraduate Research (CUR))
1:30 PM, Marriott Anaheim Hotel, Platinum 5-6
Authors will be present from 2:30 to 4:30 PM
18-1
Booth #
1 Madan, Meena A.*; Psrothero, Donald R.; Sutyagina, Anastasiya:
“STASIS IN RANCHO LA BREA SABERTOOTHED CATS AND
SESSION NO. 18
18-20
20 Daubenmire, Emily*; Chinn, Logan; Kelty, T.K.; Genden, Ariunbold;
Sauermann, Robert; Dash, Batulzii: STRUCTURAL GEOLOGY OF
THE WEST DEREN AND DEREN FAULTS, SOUTH-CENTRAL
MONGOLIA
19-2
35 Ehret, Phillip*; Culbert, Kristan; Paterson, Scott; Cao,
Wenrong; Memeti, Vali; Schmidt, Keegan: COMPARISONS
OF DETRITAL ZIRCON AGES AND CHARACTERISTICS
OF METASEDIMENTARY PACKAGES IN THE SADDLEBAG
LAKE PENDANT, SIERRA NEVADA: IMPLICATIONS FOR
DEPOSITIONAL ENVIRONMENTS AND TECTONIC HISTORIES
19-3
36 Van Guilder, Emily*; Paterson, Scott; Memeti, Vali; Ehret, Phillip;
Gelbach, Lauren B.; Stanley, Ryan; Chang, Jonathan: DETRITAL
ZIRCON AGES FROM THE CALAVERAS COMPLEX, WESTERN
METAMORPHIC BELT (WMB), CALIFORNIA: IMPLICATIONS FOR
MESOZOIC TECTONICS AND CONTINENTAL GROWTH
19-4
37 Niemi, Nathan A.*: DILUTION OF DETRITAL ZIRCON
POPULATIONS AS A QUANTITATIVE MEASURE OF
FLUVIAL TRANSPORT DISTANCE AND DISCRIMINATOR OF
SEDIMENTARY VERSUS TECTONIC TRANSPORT ACROSS THE
DEATH VALLEY EXTENDED TERRANE
19-5
38 Gelbach, Lauren B.*; Paterson, Scott; Memeti, Vali; Van Guilder,
Emily; Stanley, Ryan; Chang, Jonathan; Zhang, Tao: ICP-MS DATING
OF ZIRCON IN THE IRON MOUNTAIN PENDANT: IMPLICATIONS
FOR SIERRAN TECTONICS
19-6
39 Godinez, Nicholas S.*; Kimbrough, David L.; Kohel, Chris:
STRATIGRAPHY AND PETROLOGIC EVOLUTION OF THE
OLIGOCENE-MIOCENE COMONDU GROUP NEAR BAHIA
CONCEPCION AND LORETO, BAJA CALIFORNIA SUR, MEXICO
19-7
26 Woodley, Steven R.*; Grove, Karen: INTERPRETING PLEISTOCENE
MARINE TERRACE DEPOSITS OVERLYING THE 82 KA WAVECUT PLATFORM, POINT REYES PENINSULA, MARIN COUNTY,
CALIFORNIA
40 Worthman, Caleb*; Amato, Jeffrey M.: DETRITAL ZIRCON AGES
FROM THE CHUGACH TERRANE: A STUDY OF THE McHugh
COMPLEX MELANGE AT SELDOVIA, ALASKA
19-8
27 Boyd, Kimberly Ann*; Dillon, David Byron; Kenyon, Scott B.; Casem,
Jacelyn; Nye, Jonathan; Stevens, Lora R.; Wechsler, Suzanne:
HEAVY METAL STEW: AN ANALYSIS OF THE WATER QUALITY
OF BARBARA’S LAKE, ORANGE COUNTY, CA
41 Reed, Michelle*; Perry, Kaysea; Johnston, Scott M.; Gehrels,
George E.: DETRITAL ZIRCON PROVENANCE OF
PRECAMBRIAN–CAMBRIAN MIOGEOCLINAL SEDIMENTARY
ROCKS, NEVADA–UTAH BORDER
19-9
42 Lovelock, Elizabeth C.*: EOCENE ZIRCONS AND FOSSIL FLORAS
FROM THE NORTHERN SIERRA NEVADA, CALIFORNIA
18-21
21 Keffer, Sean*; Liodas, Nate; Woods, Adam D.; Beatty, Tyler W.;
Zonneveld, J.-P.: EARLY TRIASSIC (DIENERIAN-SMITHIAN)
PALEOPRODUCTIVITY AND PALEOENVIRONMENTAL
CONDITIONS WITHIN THE NORTHERN WESTERN CANADA
SEDIMENTARY BASIN, BRITISH COLUMBIA, CANADA
18-22
22 Chinn, Logan*; Daubenmire, Emily; Kelty, T.K.; Genden, Ariunbold;
Sauermann, Robert; Dash, Batulzii: STRUCTURAL GEOLOGY
OF THE DEREN SEISMIC ZONE AND BÏRGÈD FAULT, SOUTHCENTRAL MONGOLIA
18-23
23 Wakefield, Ryan*; Woods, Adam D.; Beatty, Tyler W.; Zonneveld, J.-P.:
HOW QUICKLY DID PRIMARY PRODUCERS RECOVER FROM
THE PERMIAN-TRIASSIC MASS EXTINCTION? EARLIEST
TRIASSIC (GRIESBACHIAN) PRODUCTIVITY ESTIMATES
FROM THE PEDIGREE-RING BORDER-KAHNTAH RIVER AREA
(WESTERN CANADA SEDIMENTARY BASIN) NORTHWESTERN
ALBERTA AND NORTHEASTERN BRITISH COLUMBIA
18-24
18-25
18-26
18-27
18-28
24 Prior, Michael G.*; Arkle, Jeanette C.; Haeussler, Peter J.;
Armstrong, Phillip A.: CONSTRAINING THE EXHUMATION
HISTORY ALONG INFERRED FAULTS IN THE WESTERN
CHUGACH MOUNTAINS, ALASKA
25 Morrish, Shawn C.*; Butcher, Amber J.; Ritzinger, Brent T.; Wellington,
Kacie L.; Marshall, Jeffrey S.: TECTONIC GEOMORPHOLOGY AND
EARTHQUAKE HAZARDS OF THE NICOYA PENINSULA SEISMIC
GAP, COSTA RICA, CENTRAL AMERICA
28 Cates, Samantha*; Farthing, Heather; Burnett, Preston; Pianowski,
Laura; Glazner, Allen: SALINITY VARIATIONS IN MONO LAKE,
EASTERN CALIFORNIA, AND FORMATION OF TUFA TOWERS IN
MIXING ZONES BETWEEN LAKE WATER AND GROUNDWATER
18-29
29 Schlom, Tyanna M.*; Knott, Jeffrey R.: EARTHQUAKE MAGNITUDE
AND RECURRENCE FROM SCARP MORPHOLOGY, EUREKA
VALLEY FAULT ZONE, EASTERN CALIFORNIA
18-30
30 Gonzalez-Becuar, Elizard*; Perez-Segura, Efrén; Olguin-Villa,
Angel E.: THE PUERTA DEL SOL PLUTONIC SUITE, A RECORD
OF EOCENE TO MIOCENE PLUTONISM IN CENTRAL SONORA
18-31
31 Carpenter, David M.*; Armstrong, Phillip A.: GRAVITY
CONSTRAINTS ON BASIN GEOMETRY AND FAULT LOCATIONS
IN SOUTHERN CADIZ VALLEY, EASTERN CALIFORNIA SHEAR
ZONE
18-32
32 Gevedon, Michelle L.*; Bonuso, Nicole; Prior, Michael G.; Kathe,
Kelly K.; Monarrez, Pedro M.; Cone, Allison J.; Buchen, Chris:
A PALEOENVIRONMENTAL STUDY OF FAUNAL RESPONSE
WITHIN THE LATE CRETACEOUS HOLZ SHALE, SANTA ANA
MOUNTAINS, CALIFORNIA
18-33
PENDANT, WEST-CENTRAL SIERRA NEVADA BATHOLITH,
CALIFORNIA
33 La Blanc, Kathryn Elaine*; Knott, Jeffrey R.: USING REPEAT
PHOTOGRAPHY TO DOCUMENT LANDSCAPE CHANGE IN
DEATH VALLEY OVER THE LAST 100 YEARS
FRIDAY, 28 MAY 2010
morning Oral
Technical Sessions
SESSION NO. 20
T1. Sierra Nevada Microplate-Basement and Basins I
Jason Saleeby and Zorka Saleeby, Presiding
20-1
8:45 AM Kjos, A.R.*; Kimbrough, David L.; Mahoney, J. Brian: THE
BAHIA TORTUGAS FAULT OPHIOLITIC MELANGE,
BAJA CALIFORNIA SUR, MEXICO: A CORRELATIVE
TO CALIFORNIA-OREGON OPHIOLITE-ARC-FOREARC
ASSEMBLAGES?
20-2
9:05 AM Saleeby, Jason*; Saleeby, Zorka; Liu, Lijun; Maheo, Gweltaz:
MID-CRETACEOUS REGI0NAL EXHUMATION OF THE
SIERRA NEVADA-GREAT VALLEY BATHOLITH AND A
POSSIBLE TECTONIC DRIVING MECHANISM
20-3
9:25 AM Chapman, Alan D.*; Saleeby, Jason B.; Wood, David J.:
REGIONAL DISPLACEMENT ANALYSIS AND
PALINSPASTIC RESTORATION OF DISPERSED CRUSTAL
FRAGMENTS IN THE SOUTHERN SIERRA NEVADA,
CALIFORNIA
20-4
9:45 AM Lechler, Alex R.*; Niemi, Nathan A.: SEDIMENTOLOGIC
AND ISOTOPIC CONSTRAINTS ON PALEOCENE
SESSION NO. 19
T20. Detrital Zircon Studies in Western North America (Posters)
19-1
Booth #
34 Martin, Michael W.*; Clemens-Knott, Diane: A GEOCHRONOLOGIC
AND PROVENANCE STUDY OF THE GOLDSTEIN PEAK ROOF
PALEOELEVATIONS OF THE CENTRAL AND SOUTHERN
SIERRA NEVADA
10:05 AM Break
20-5
10:20 AM Blythe, Ann E.*; Longinotti, Nicole; Khalsa, Sopurkh: POST 20
MA EXHUMATION OF THE SOUTHERN SIERRA NEVADA/
TEHACHAPI MOUNTAINS, FROM FISSION-TRACK AND
(U-TH)/HE ANALYSES
20-6
20-7
20-8
10:40 AM Unruh, Jeffrey*; Hauksson, Egill: UPPER CRUSTAL
DEFORMATION ABOVE FOUNDERING LOWER
LITHOSPHERE, SOUTHERN SIERRA NEVADA
MICROPLATE, CALIFORNIA
11:00 AM Amos, Colin B.*; Kelson, Keith I.; Rood, Dylan H.; Simpson,
David T.; Rose, Ronn S.: ACTIVE INTERNAL DEFORMATION
OF THE SIERRA NEVADA MICROPLATE ON THE KERN
CANYON FAULT AT SODA SPRING, TULARE COUNTY,
CALIFORNIA
11:20 AM Saleeby, Zorka*; Saleeby, Jason: EROSIONAL STRIPPING
OF THE SOUTHEASTERN SAN JOAQUIN BASIN (SJB)
MARGIN OFF OF THE SOUTHERN SIERRA NEVADA
BASEMENT UPLIFT
SESSION NO. 22
T21. Carbon Sequestration and Oil Fields (Pacific Section AAPG/
Society of Petroleum Engineers (SPE))
William Barrett and Zuwa S. Omoregie, Presiding
22-1
8:00 AM Van Hollebeke, Philip*; Sandin, Nils: ADVANCES IN HIGH
RESOLUTION SEISMIC METHODS FOR CO2 ENHANCED
OIL RECOVERY (EOR) AND SEQUESTRATION
22-2
8:30 AM Ouenes, Ahmed*; Anderson, Thomas Carl; Klepacki,
Douglas; Robinson, Gary Charles; Bachir, Aissa; Boukhelf,
Boukhelf; Black, Brian J.; Stamp, Stamp: INTEGRATED
CHARACTERIZATION AND SIMULATION OF THE
FRACTURED TENSLEEP RESERVOIR AT TEAPOT DOME
FOR CO2 INJECTION DESIGN
22-3
9:00 AM Jordan, Preston*: BASIN WIDE PRESSURE CHANGES DUE
TO CO2 STORAGE: CALIFORNIA PRODUCTION AS A
REVERSE ANALOG
22-4
9:30 AM Kuo, Chia wei*; Perrin, Jean Christophe; Benson, Sally M.:
EFFECT OF GRAVITY, FLOW RATE, AND SMALL SCALE
HETEROGENEITY ON MULTIPHASE FLOW OF CO2 AND
BRINE
11:40 AM Discussion and Directed Question Session
SESSION NO. 21
10:00 AM Break
T2. Tectonic Evolution of the Southern Big-Bend Region,
San Andreas Fault (Cordilleran Section GSA; Pacific Section, AAPG;
Pacific Section SEPM)
22-5
10:30 AM Behzadi, Seyed*: COMPARISON OF CHEMICAL AND
HYSTERESIS CO2 TRAPPING IN THE NUGGET
FORMATION
22-6
11:00 AM Haroun, Muhammad Raeef*; Sarma, Hemanta Kumar;
Ghosh, Bisweswar: OPTIMIZING CO2 EOR REAL TIME
MANAGEMENT TO INCREASE “GREEN OIL” PRODUCTION
THE ELK HILL CASE STUDY
11:30 AM Delshad, Mojdeh*; Kong, Xianhui; Wheeler, Mary Fanett: A
CRITICAL ASSESSMENT OF CO2 INJECTION STRATEGIES
IN SALINE AQUIFERS
Doug Yule and James A. Spotila, Presiding
21-1
8:05 AM Brune, James N.*; Biasi, Glenn; Grant Ludwig, Lisa; Rood,
Dylan H.: ASSUMED BACKGROUND SEISMICITY AS
A PARTIAL EXPLANATION FOR DISCREPANCIES
BETWEEN PRECARIOUSLY BALANCED ROCKS AND 2008
CALIFORNIA HAZARD MAPS
22-7
21-2
8:25 AM Martin, Zachary*; Blythe, Ann E.: EXHUMATIONAL HISTORY
OF THE SAN JACINTO MOUNTAINS, FROM NEW APATITE
FISSION TRACK ANALYSES
T34. EOR Technologies II (Society of Petroleum Engineers (SPE))
21-3
21-4
21-5
8:45 AM Ricketts, J.W.*; Voyles, E.M.; Sainsbury, J.S.; Sutton, L..A.;
Girty, Gary H.: MIDDLE–LATE MIOCENE GROWTH OF
A DEPRESSION IN THE CHOCOLATE MOUNTAINS
ANTICLINORIUM, AS RECORDED BY THE BEAR CANYON
CONGLOMERATE, SE CALIFORNIA
9:05 AM McGill, Sally*; Weldon, Ray J. II.; Owen, Lewis A.:
LATEST PLEISTOCENE SLIP RATES ALONG THE
SAN BERNARDINO STRAND OF THE SAN ANDREAS
FAULT
9:25 AM Sainsbury, J.S.*; Ricketts, J.W.; Muela, K.K.; Girty, Gary H.:
THE CHOCOLATE MOUNTAINS ANTICLINORIUM:
MIOCENE GROWTH AND RE-ACTIVATION RECORDED IN
VOLCANICS AND ALLUVIAL GRAVELS, INDIAN PASS TO
CARRIZO WASH, SE CALIFORNIA
9:45 AM Break
21-6
10:00 AM Medina Luna, Lorena*; Yule, Doug; Rittenour, Tammy:
ANOMALOUS OSL APPARENT AGES OF THE BISKRA
PALMS ALLUVIAL FAN
21-7
10:20 AM Yule, Doug*: TESTING THE “SHAKEOUT” SCENARIO
EARTHQUAKE IN SAN GORGONIO PASS: FACT OR
FICTION?
21-8
10:40 AM Nicholson, Craig*; Hauksson, Egill; Plesch, Andreas: REVISED
3D FAULT MODELS FOR THE SOUTHERN SAN ANDREAS
FAULT SYSTEM EXTENDING FROM SAN GORGONIO PASS
TO THE SALTON SEA
21-9
11:00 AM Cooke, Michele L.*; Dair, Laura: 3D NUMERICAL
INVESTIGATIONS INTO THE EVOLUTION OF THE
SOUTHERN BEND BEND OF THE SAN ANDREAS FAULT
SESSION NO. 23
Serge Yervant Baghdikian and Baldev Gill, Presiding
23-1
8:30 AM Ahmed, Tarek*; Meehan, D. Nathan: CHARACTERIZING THE
PLUS FRACTION FOR EOS’ APPLICATIONS
23-2
9:00 AM Sheng, James J.*: EVALUATION OF THE EFFECT OF
WETTABILITY ALTERATION ON OIL RECOVERY IN
CARBONATE RESERVOIRS
23-3
9:30 AM Alvarado, Vladimir*; Behzadi, Seyed: SELECTION OF THREE
PHASE RELATIVE PERMEABILITY MODEL FOR MIXED
WET RESERVOIRS
10:00 AM Break
23-4
10:30 AM Nagineni, Venu Gopal Rao*; Hughes, Richard Gary; D’Souza,
David: EVALUATION OF CO2 INJECTIVITY FROM
WATERFLOOD VALUES
23-5
11:00 AM Saini, Dayanand*; Rao, Dandina Nagaraja: EXPERIMENTAL
DETERMINATION OF MINIMUM MISCIBILITY PRESSURE
BY GAS OIL IFT MEASUREMENTS FOR A GAS INJECTION
EOR PROJECT
23-6
11:30 AM Kalaei, M. Hosein*; Green, Don W.; Willhite, Paul: NUMERICAL
MODELING OF THE WATER IMBIBITION PROCESS IN
WATER WET LABORATORY CORES
SESSION NO. 24
T37. Advanced Reservoir Modeling Concepts (Society of
George J. Moridis and Allan Spivak, Presiding
24-1
8:30 AM Chen, Yan*; Oliver, Dean: PARAMETERIZATION
TECHNIQUES TO IMPROVE MASS CONSERVATION AND
DATA ASSIMILATION FOR ENSEMBLE KALMAN FILTER
SESSION NO. 24
24-2
24-3
9:00 AM Tabasinejad, Farshad*; Fraassen, Kees Cornelius Van; Barzin,
Yalda; Mehta, Sudarshan A.; Moore, Robert Gordon; Rushing,
Jay A.; Newsham, Kent E.: DENSITY OF HIGH PRESSURE
AND TEMPERATURE GAS RESERVOIRS: EFFECT OF
NON HYDROCARBON CONTAMINANTS ON DENSITY OF
NATURAL GAS MIXTURES
9:30 AM Rubin, Bary*: ACCURATE SIMULATION OF NON DARCY
FLOW IN STIMULATED FRACTURED SHALE RESERVOIRS
10:00 AM Break
24-4
10:30 AM Ghods, Ghods*; Jahangiri, Hamid Reza; Zhang, Dongxiao:
ASSISTED HISTORY MATCHING OF A WATERFLOODED
RESERVOIR USING EXTENDED AND UNSCENTED
KALMAN FILTERS
24-5
11:00 AM Khazaeni, Yasaman*; Mohaghegh, Shahab D.: INTELLIGENT
TIME SUCCESSIVE PRODUCTION MODELING
24-6
11:30 AM Gupta, Akhil*; Yin, Jichao Yin; Park, Han Young: A
HIERARCHICAL ASSISTED HISTORY MATCHING
APPROACH WITH GLOBAL AND LOCAL PARAMETER
UPDATES
1 Sanquini, Anne*; Metzger, Ellen P.; McLaughlin, Robert J.:
A PETROGRAPHIC LINK BETWEEN THE LATE CRETACEOUS
PIGEON POINT CONGLOMERATE AND FELSITIC VOLCANIC
ROCKS NEAR PESCADERO, CALIFORNIA
27-2
2 Keogh, Molly*; Dorsey, Rebecca: STRATIGRAPHIC ANALYSIS
OF LATE MIOCENE TO EARLY PLIOCENE (?) SEDIMENTARY
ROCKS, SW ISLA TIBURóN, SONORA, MEXICO
27-3
3 Rivera, Alexei A.*: ESTIMATION OF TRUE TAXONOMIC
LONGEVITIES FROM OBSERVED FOSSIL RANGES: A
COMPARISON OF TWO METHODS
27-4
4 Rivera, Alexei A.*: COPE’S RULE AND PHYLOGENETIC TRENDS
IN THE NAUTILOIDEA
27-5
5 McGuire, Terry*; Grove, Karen: THE PLIO-PLEISTOCENE MERCED
FORMATION IN NORTHERN CALIFORNIA: A WORLD-CLASS
EXAMPLE OF INTEGRATED SEA LEVEL AND TECTONIC
CONTROLS
27-6
6 Jackson, C.M.*; Ladinsky, T.C.; Graehl, N.A.; Caldwell, D.J.;
Mielke, J.L.; York, J.V.; Jackson, A.M.: ORIGIN AND AGE OF
PLEISTOCENE SHELLY MARINE DEPOSITS, TRINIDAD
HEADLANDS, HUMBOLDT COUNTY, NORTHWESTERN
CALIFORNIA, USA
27-7
7 Abeid, John A.*; Kimbrough, David L.; Abbott, Patrick L.: LATE
CRETACEOUS-EOCENE LANDSCAPE EVOLUTION AND
DRAINAGE REORGANIZATION ALONG THE SOUTHWEST EDGE
OF THE CORDILLERA; INSIGHT FROM VOLCANIC CLASTS
IN CONGLOMERATES OF THE CABRILLO FORMATION AND
POWAY-LA JOLLA GROUPS, SAN DIEGO COUNTY, CALIFORNIA
27-8
8 Carmichael, Chelsea N.*; Leggitt, V. Leroy: LACUSTRINE
MICROBIALITES FROM AN ACTIVE COLD WATER SPRING
MOUND: BRISCO, BRITISH COLUMBIA, CANADA
27-9
9 Kohel, Chris*; Kimbrough, David L.: FOREARC BASIN EVOLUTION
OF THE LATE JURASSIC-EARLY CRETACEOUS EUGENIA
FORMATION; NEW MAPPING IN THE VIZCAINO PENINSULA,
BAJA CALIFORNIA SUR
27-10
10 Beeler, Katherine R.; Lackey, Hilary Sanders*; Lackey, Jade Star:
DEPOSITION, DIAGENESIS, AND CEMENTATION HISTORY OF
PLEISTOCENE VOLCANICLASTIC SEDIMENTS IN LONG VALLEY
CALDERA, CA
SESSION NO. 25
T37. Advanced Reservoir Modeling Concepts (Alternate)
37-1
Dahaghi, Amirmasoud Kalantari*; Mohaghegh, Shahab D.:
NEW INSIGHT INTO INTEGRATED RESERVOIR
MANAGEMENT USING TOP DOWN, INTELLIGENT
RESERVOIR MODELING TECHNIQUE: APPLICATION TO A
GIANT AND COMPLEX OIL FIELD IN THE MIDDLE EAST
SESSION NO. 26
T38. California Monterey Reservoirs (Society of Petroleum
Engineers (SPE))
Steve Horner and Gary D. Lower, Presiding
26-1
8:30 AM Kovscek, Anthony Robert*; Peng, Jing: TEMPERATURE
INDUCED FRACTURE RECONSOLIDATION OF
DIATOMACEOUS ROCK DURING FORCED WATER
IMBIBITION
26-2
9:00 AM Frankiewicz, Theodore C.*; VanNostrand, Robert; Manning,
Robert: RECONFIGURING A CALIFORNIA PLATFORM
FOR OFFSHORE CRUDE DEHYDRATION AND WATER
DISPOSAL VIA INJECTION
26-3
9:30 AM Boles, James*; Horner, Steve; Garven, Grant: PERMEABILITY
ESTIMATES FOR THE SOUTH ELLWOOD FAULT
10:00 AM Break
26-4
10:30 AM Kovscek, Anthony Robert*; Vega, Bolivia; Urdaneta, Alfredo H.:
THE EFFECT OF TEMPERATURE AND OIL VISCOSITY
REDUCTION ON WATER IMBIBITION OF DIATOMITE
26-5
11:00 AM Urbancic, Theodore I.*; Bleakly, Douglas C.; Murer, Anthony S.;
McNeish, Greg R.; Prince, Marc: MONITORING OF
MICROSEISMICITY IN DIATOMITES
26-6
11:30 AM Urbancic, Theodore I.*; Baig, Adam; Murer, Anthony S.;
McNeish, Greg R.: CHARACTERIZING FRACTURE
DEVELOPMENT IN DIATOMITES WITH SEISMIC MOMENT
TENSOR INVERSION ANALYSIS
morning Poster
Technical Sessions
SESSION NO. 27
SESSION NO. 28
T3. Terrestrial and Marine Records of Late Quaternary Climate
from Western North America/Eastern Pacific: Developments,
Comparisons, and Directions (Posters) (Cordilleran Section GSA)
8:30 AM, Marriott Anaheim Hotel, Platinum 5-6
Authors will be present from 9:30 to 11:30 AM
30 2010 GSA Abstracts with Programs Booth #
28-1
11 King, Baird L.*; Kennedy, Martin; Kirby, Matthew E.: THE POST-LAST
GLACIAL MAXIMUM GLACIER RECORD OF THE TAMARACK
BENCH OF THE EASTERN ROCK CREEK DRAINAGE, EASTERN
SIERRA NEVADA MOUNTAINS, CALIFORNIA
28-2
12 Player, Gary F.*; McDonald, Blair: INDICATORS OF EARLY
PLEISTOCENE GLACIATION IN SOUTHWESTERN UTAH AND
ADJACENT STATES
28-3
13 Davies, Nigel*; Clark, Douglas H.: LATE HOLOCENE
FLUCTUATIONS OF THE MAMMOTH GLACIER, WIND RIVER
RANGE, WYOMING
28-4
14 Magary, Katharine L.*; Caskey, S. John: CONSTRAINTS ON
ORIGINAL ELEVATIONS OF HIGH-LEVEL LAKE MANLY
SHORELINES DURING RECENT PLUVIAL CYCLES, DEATH
VALLEY, CA
28-5
15 Garcia, Anna L.*; Knott, Jeffrey R.; Bright, Jordon; Mahan,
Shannon A.: GEOCHRONOLOGY AND PALEOENVIRONMENT OF
PLUVIAL HARPER LAKE, MOJAVE DESERT, CALIFORNIA
28-6
16 Padilla, Manuel*; Kirby, Matthew E.; Hiner, Christine; King, Baird:
INITIAL RESULTS FROM ZACA DRY LAKE REVEAL EVIDENCE
Booth #
27-1
SESSION NO. 30
FOR HOLOCENE CLIMATE CHANGE, SANTA BARBRA COUNTY,
CALIFORNIA
28-7
28-8
28-9
17 Knott, Jeffrey R.*; Liddicoat, Joseph; Coe, Robert S.:
PALEOMAGNETIC AND RADIOCARBON RECORD OF THE
SEARLES LAKE FORMATION AT POISON CANYON, SAN
BERNARDINO, CA
18 Pyke, Brittany N.*; Kirby, Matthew E.; Scholz, Christopher; Cattaneo,
Peter: SEISMIC REFLECTION DATA FROM LAKE ELSINORE,
SOUTHERN CA, DETAILS A NEW CLIMATE DRIVEN RECORD
FOR HOLOCENE LAKE LEVEL VARIATIONS
19 Peterson, Carlye D.*; Behl, Richard J.; Nicholson, Craig; Lisiecki,
Lorraine; Sorlien, Christopher C.: ORBITAL- TO SUB-ORBITALSCALE CYCLICITY IN SEISMIC REFLECTIONS AND SEDIMENT
CHARACTER IN EARLY TO MIDDLE PLEISTOCENE MUDSTONE,
SANTA BARBARA, CA
28-10
20 Rhodes, Nisa*; Kirby, Matthew E.; Bonuso, Nicole; Tulaczyk, Slawek;
Blazevic, Michael: AN INVESTIGATION OF SHAY’S DELTA
(BALDWIN LAKE, CA) AND ITS HOLOCENE DEPOSITIONAL
HISTORY
28-11
21 Torres, Mark*; Gaines, Robert: NEWLY DISCOVERED PALEOSOLS
FROM THE PALEOCENE GOLER FORMATION OF SOUTHERN
CALIFORNIA
28-12
22 Burns, Scott F.*: ANCIENT CATACLYSMIC FLOODS: ANCESTORS
OF THE MISSOULA FLOODS IN THE PACIFIC NORTHWEST, USA
28-13
23 Springer, Kathleen*; Manker, Craig: COOL WATER TUFAS AND
BLACK MATS: INDICATORS OF PALEOENVIRONMENTAL
CHANGE IN LATE PLEISTOCENE SPRING DISCHARGE
DEPOSITS OF THE UPPER LAS VEGAS WASH, NEVADA
28-14
24 McCabe-Glynn, Staryl*; Johnson, Kathleen R.; Berkelhammer, Max;
Sinha, Ashish: ASSESSING THE PALEOCLIMATE POTENTIAL OF
SPELEOTHEMS FROM THE SIERRA NEVADA MOUNTAINS: A
PRELIMINARY STUDY
28-15
25 Johnson, Kathleen R.*; Ferguson, Julie; Meyer, Laura; Acaylar,
Karla; dos Santos, Guaciara; Tripati, Aradhna: TESTING MODERN
CONTROLS ON SEASONAL 14C VARIATIONS IN SEAWATER DIC
AND MYTILUS CALIFORNIANUS SHELLS: THE POTENTIAL FOR
A NEW UPWELLING PROXY
THE NORTHERN SALINAS VALLEY GROUNDWATER BASIN,
CENTRAL CALIFORNIA COAST RANGE
29-7
32 Wiegers, Mark O.*: GEOLOGIC MAP OF THE MORRO BAY SOUTH
7.5’ QUADRANGLE
29-8
33 Rytuba, James*: GEOTHERMAL SYSTEMS IN THE PASO
ROBLES GROUNDWATER BASIN, CENTRAL COAST RANGES,
CALIFORNIA
29-9
34 Colgan, Joseph P.*; McPhee, Darcy K.: CRUSTAL STRUCTURE
ADJACENT TO THE SAN ANDREAS FAULT FROM CHOLAME
VALLEY TO THE NORTHERN CARRIZO PLAIN, CENTRAL
CALIFORNIA
29-10
35 Prothero, Donald R.*: MAGNETIC STRATIGRAPHY OF THE
MIOCENE-PLIOCENE ETCHEGOIN GROUP, WESTERN SAN
JOAQUIN BASIN, CALIFORNIA
29-11
36 Marshall, Courtney J.*; Sorlien, Christopher C.; Nicholson, Craig;
Behl, Richard J.; Kennett, James: SEDIMENTATION IN AN ACTIVE
FOLD AND THRUST BELT, SANTA BARBARA BASIN, CA:
SPATIAL AND TEMPORAL EVOLUTION OF SEDIMENTATION
FROM 1.0 MA TO PRESENT
29-12
37 Scheirer, Daniel*; Sweetkind, Donald; Langenheim, Victoria; Stanley,
Richard: CAN GRAVITY ANOMALIES BE USED TO MAP PREPLIOCENE SEDIMENTARY BASINS IN THE CENTRAL COAST
RANGES, CALIFORNIA?
29-13
38 Feigelson, Leah M.*; Prentice, Carol S.; Grove, Karen; Caskey, John;
Davis, Jerry; Ritz, Jeff: SLIP RATE ON THE SAN ANDREAS FAULT,
SAN FRANCISCO PENINSULA, CALIFORNIA
afternoon Oral
Technical Sessions
SESSION NO. 30
T1. Sierra Nevada Microplate-Basement and Basins II
Jason Saleeby and Zorka Saleeby, Presiding
SESSION NO. 29
T6. New Insights into Tectonics of the Central California Coast
Ranges—The Link between Los Angeles and San Francisco
(Posters) (Cordilleran Section GSA; Pacific Section, AAPG;
30-1
1:45 PM Busby, Cathy J.*; Hagan, Jeanette C.; Koerner, Alice A.;
Putirka, Keith; Pluhar, Christopher J.; Melosh, Benjamin L.:
BIRTH OF A PLATE BOUNDARY
30-2
2:00 PM Rosenberg, Jessica E.*; Glazner, Allen F.: IS PLIOCENE
MAGMATISM IN THE NORTHERN SIERRA NEVADA RANGE
LINKED TO LITHOSPHERIC DELAMINATION OR TO THE
ANCESTRAL CASCADE RANGE?
30-3
2:15 PM Cassel, Elizabeth J.*; Graham, Stephan A.; Maatta, Sara C.:
DEPOSITIONAL AGES, PROVENANCE, AND PALEODRAINAGE PATTERNS FROM DETRITAL ZIRCON
GEOCHRONOLOGY OF EOCENE-OLIGOCENE FLUVIAL
SEDIMENTS (“AURIFEROUS GRAVELS”) IN THE
NORTHERN SIERRA NEVADA, CALIFORNIA
30-4
2:30 PM Cecil, M. Robinson*; Ducea, Mihai N.; Reiners, Peter W.;
Gehrels, George E.; Mulch, Andreas; Allen, Charlotte M.;
Campbell, Ian H.: PALEOTOPOGRAPHY OF THE CENTRAL NORTHERN SIERRA NEVADA AND IMPLICATIONS FOR
UPLIFT AND TILTING OF THE SIERRAN BLOCK
2:45 PM Break
30-5
3:00 PM Figueroa, Andrea M.*; Knott, Jeffrey R.: TECTONIC
GEOMORPHOLOGY OF THE SOUTHERN SIERRA NEVADA
MOUNTAINS (CALIFORNIA): EVIDENCE FOR UPLIFT AND
BASIN FORMATION
30-6
3:15 PM Kleck, Wallace D.*: A PRELIMINARY STUDY OF THE
CENOZOIC HISTORY OF THE KERN RIVER, SIERRA
NEVADA MOUNTAINS, CALIFORNIA
3:30 PM Open Forum On Question Posed By Conveners: What
are the common and distinct features of landscape and
Booth #
29-1
26 Jachens, Robert C.*; Wentworth, Carl M.; Langenheim, Victoria;
Graymer, Russel W.; Simpson, Robert W.; Stanley, Richard; Colgan,
Joseph P.: A THREE-DIMENSIONAL GEOLOGIC MAP OF THE
CENTRAL CALIFORNIA COAST RANGES
29-2
27 Stanley, Richard*; Fleck, Robert J.; Wilson, Douglas S.; McCrory,
Patricia A.: NEW ISOTOPIC AGE FROM BASALT NEAR CARMEL,
CALIFORNIA, AND ITS TECTONIC SIGNIFICANCE
29-3
28 Watt, Janet T.*; Morin, Robert L.; Langenheim, Victoria: USING
POTENTIAL FIELDS TO REFINE BASIN AND FAULT GEOMETRY
IN SALINAS VALLEY, CALIFORNIA
29-4
29 Menotti, Tess*: INVESTIGATIONS INTO BURIAL HISTORY AND
PETROLEUM SYSTEM DEVELOPMENT IN THE SALINAS BASIN,
CALIFORNIA THROUGH 1-D MODELING
29-5
29-6
30 Sweetkind, Donald S.*; Langenheim, Victoria E.; Shumaker,
Lauren E.: CONFIGURATION AND LITHOLOGY OF MESOZOIC
BASEMENT BENEATH THE SANTA MARIA BASIN, CA FROM
ANALYSIS OF BOREHOLE DATA
31 Taylor, Emily M.; Sweetkind, Donald S.*; Garcia, Antonio F.;
Shumaker, Lauren E.: TERRAIN ANALYSIS AND GEOLOGIC
FIELD INVESTIGATIONS USED TO CONSTRAIN DRAINAGE
EVOLUTION AND BASIN-FILLING HISTORY WITHIN AND NEAR
SESSION NO. 30
basin evolution across the northern, central and southern
reaches of the Sierra Nevada Microplate, and what might
be the origins of these common or distinct features?
SESSION NO. 31
T6. New Insights into Tectonics of the Central California Coast
Ranges—The Link between Los Angeles and San Francisco
(Cordilleran Section GSA; Pacific Section, AAPG; Pacific
Section SEPM)
DESERT, CALIFORNIA: PALEOMAGNETISM AND 40AR/39AR
DATING OF THE MIOCENE PEACH SPRINGS TUFF
2:55 PM Break
32-5
3:15 PM Onderdonk, Nate*; Marliyani, Gayatri; Rockwell, Thomas K.;
McGill, Sally: PRELIMINARY RESULTS FROM MYSTIC
LAKE: A NEW PALEOSEISMIC SITE ALONG THE
NORTHERN SAN JACINTO FAULT ZONE
32-6
3:35 PM Mahan, Shannon A.*; Matti, Jonathan; Menges,
Christopher M.; Powell, Robert E.: A COMPILATION OF
OSL GEOCHRONOLOGY COLLECTED BY THE U.S.
GEOLOGICAL SURVEY FROM SOUTHERN CALIFORNIA:
WHAT THE AGES TELL US AND HOW THEY WILL BE USED
3:55 PM Discussion
Russell W. Graymer and Victoria Langenheim, Presiding
31-1
1:35 PM Langenheim, V.E.*; Jachens, R.C.; Graymer, R.W.;
Wentworth, C.M.; Colgan, J.P.; Stanley, R.G.: IMPLICATIONS
OF CUMULATIVE OFFSETS ALONG THE SAN GREGORIOHOSGRI FAULT, CALIFORNIA: WHY THE SANTA MARIA
BASIN MATTERS
31-2
1:50 PM Ernst, W.G.*; McLaughlin, R.J.; Clark, Joseph C.: U-PB AGE
OF THE PESCADERO FELSITE: LATE CRETACEOUS ARC
VOLCANISM IN THE WEST-CENTRAL CALIFORNIA COAST
RANGES?
SESSION NO. 33
T33. Reservoir Characterization II (Pacific Section, AAPG;
Tad Gladczenko and Hilario Camacho, Presiding
33-1
1:30 PM Doris, N.*; Henderson, J.M.; Skartvedt-Forte, Peggie:
INTEGRATING VINTAGE DATA WITH MODERN DATA TO
OPTIMIZE FIELD EVALUATION, WILMINGTON FIELD, CA
33-2
2:20 PM AbramsonWard, Hans*; Hanson, Kathryn; Greene, H. Gary;
Page, William D.; Lettis, William R.: PALEOSHORELINES
OFFSHORE OF THE SAN LUIS RANGE, SAN LUIS OBISPO
COUNTY, CENTRAL COASTAL CALIFORNIA
2:00 PM Little, Jeffrey D.*; Horner, Steve; Horkowitz, Jack;
Skartvedt-Forte, Peggie: A PRACTICAL APPROACH
TO PETROPHYSICAL MODEL CONSTRUCTION IN
ARKOSIC AND SUB-ARKOSIC SEDIMENTS OF THE
SESPE FORMATION USING LOG BASED GEOCHEMICAL
SPECTROSCOPY DATA
33-3
2:35 PM Nishenko, S.P.*; McLaren, M.K.; Page, W.D.; Langenheim, V.E.;
Watt, J.T.; Greene, H.G.; Rietman, J.D.; Lettis, W.R.; Angell, M.;
Kvitek, R.: SHORELINE FAULT ZONE, SOUTH-CENTRAL
COASTAL CALIFORNIA
2:30 PM Nichols, Jerry M.*; Grayson, Stephen T.; Little, Jeffrey D.:
RESERVOIR CHARACTERIZATION PROVIDES OPTIMIZED
COMPLETION STRATEGY IN THE MONTEREY SHALE OF
SOUTH BELRIDGE FIELD
33-4
2:50 PM Coppersmith, Ryan Thomas*: STRUCTURAL ANALYSIS
OF THE SAN SIMEON FAULT ZONE, CALIFORNIA:
IMPLICATIONS FOR TRANSFORM TECTONICS
3:00 PM Harris, John H.*; Grayson, Stephen T.; Zahner, Bob: FAULT
DELINEATION IN OIL BASED MUD AT WEST MONTALVO
FIELD USING A 3-D RESISTIVITY TOOL
33-5
3:30 PM Grayson, Stephen T.*; Prestridge, Andrew L.; Cavette,
Greg; Nelson, Michael P.; Swager, Lee; Kovac, Katherine:
CHARACTERIZATION OF A THIN BEDDED RESERVOIR IN
CALIFORNIA USING 3-D RESISTIVITY MEASUREMENTS
33-6
4:00 PM Perez, Enrique*; Kaproth, Bryan M.; Haines, Samuel H.;
Saffer, Demian: LABORATORY MEASUREMENTS OF
PERMEABILITY REDUCTION IN NATURALLY OCCURRING
SHEAR BANDS FORMED IN UNLITHIFIED SANDS
SESSION NO. 32
33-7
T7. Late Neogene Tectonics and Deformation along Active
Faults East of and Including the San Andreas—San Jacinto Fault
Zones (Cordilleran Section GSA; Pacific Section, AAPG; Pacific
Section SEPM)
4:30 PM Garven, Grant*; Jung, Byeongju; Boles, James R.:
A GEOHYDRODYNAMIC STUDY OF THE ROLE OF FAULTS
ON PETROLEUM MIGRATION IN THE CALIFORNIA
BORDERLAND BASINS
33-8
5:00 PM Kovac, K.M.*; Khan, Shahnawaz; Nelson, Michael P.;
Swager, Lee; Grayson, Stephen T.; Blume, Cheryl: GEOLOGIC
MODELING OF LAMINATED TURBIDITE SANDS OF AN
OFFSHORE OILFIELD
5:30 PM O’Brien, Charles*: RESERVOIR MODELING OF THE
BELRIDGE DIATOMITE
31-3
31-4
31-5
31-6
31-7
2:05 PM Titus, Sarah*; Crump, Sarah; McGuire, Zack; Horsman, Eric;
Housen, Bernard: PALEOMAGNETIC DATA FROM THE
RINCONADA FAULT IN CENTRAL CALIFORNIA: EVIDENCE
FOR OFF-FAULT DEFORMATION AND LONG-TERM CREEP
ALONG THE SAN ANDREAS FAULT
3:05 PM Graymer, R.W.*; Langenheim, V.E.; Rosenberg, L.I.;
Colgan, J.P.; Roberts, M.A.: NEW INSIGHTS INTO THE
TECTONICS OF THE CENTRAL CALIFORNIA COAST
RANGES FROM CROSS-SECTIONS BASED ON
DIGITAL GEOLOGIC MAPPING AND POTENTIAL-FIELD
GEOPHYSICS
Christopher M. Menges and David M. Miller, Presiding
33-9
32-1
1:35 PM Andrew, Joseph E.*: LARGE-MAGNITUDE EXTENSION
OF THE DEATH VALLEY DETACHMENT SYSTEM AND
EVOLUTION OF THE GARLOCK FAULT
SESSION NO. 34
32-2
1:55 PM Schmidt, Kevin M.*; Langenheim, Victoria; Hanshaw,
Maiana N.; Miller, David M.; Hillhouse, J.W.; Phelps, G.A.:
GEOLOGY AND GEOPHYSICS ILLUMINATE LATE
QUATERNARY OFFSET ALONG THE CADY FAULT WITHIN
THE EASTERN CALIFORNIA SHEAR ZONE, SOUTHERN
CALIFORNIA
32-3
32-4
2:15 PM Miller, D.M.*; Schmidt, K.M.; Langenheim, V.E.; Hillhouse, J.W.;
Reheis, M.C.; Leslie, S.R.: INTERACTIONS OF ACTIVE
SINISTRAL AND DEXTRAL FAULTS IN THE CENTRAL
MOJAVE DESERT, CALIFORNIA
2:35 PM Hillhouse, J.W.*; Turrin, Brent; Miller, David M.: NEW
CONSTRAINTS ON TECTONIC ROTATIONS IN THE MOJAVE
32 2010 GSA Abstracts with Programs T39. Tight Plays and Unconventional Reservoirs (Society of
Joe H. Fram and Charles H. Webb, Presiding
34-1
1:30 PM Nobakht, Morteza*; Mattar, Louis: SIMPLIFIED AND
RIGOROUS FORECASTING OF TIGHT/SHALE GAS
PRODUCTION
34-2
2:00 PM Jessen, Kristian*; Jamshidi, Marjan: IMPACT OF RESERVOIR
CHARACTERISTICS ON WATER PRODUCTION IN
ENHANCED COALBED METHANE OPERATIONS
SESSION NO. 40
34-3
2:30 PM Ghods, Ghods*; Zhang, Dongxiao: ENSEMBLE BASED
CHARACTERIZATION AND HISTORY MATCHING
OF NATURALLY FRACTURED TIGHT/SHALE GAS
RESERVOIRS
3:00 PM Break
37-4
3:30 PM Shuler, Patrick J.*; Tang, Yongchun; Tang, Hongxin: HEAVY
OIL PRODUCTION ENHANCEMENT BY VISCOSITY
REDUCTION
3:00 PM Break
37-5
34-4
3:30 PM Palmer, Ian D.*: THE PERMEABILITY FACTOR IN COALBED
METHANE WELL COMPLETIONS AND PRODUCTION
34-5
4:00 PM Wang, Jianwei*; Robinson, John R.; Thompson, John Webster;
Fan, Li: APPLICATION OF ADVANCED RESERVOIR
SIMULATION WORK FLOW IN TIGHT GAS RESERVOIRS
4:00 PM Akhimiona, Nosakhare*; Auffant, Ariel; Gorham, Timothy Lee;
Harrelson, Jonathan Preston: AN ANALYSIS OF THE
PERFORMANCE OF GRAVEL PACKS AND SLOTTED
LINERS IN HEAVY OIL OPERATIONS
37-6
4:30 PM King, James G.*; Demarchos, Andronikos S.; Buffington,
Neil: A RUN HISTORY OF NEW TECHNOLOGIES IN THE
BAKKEN PLAY: MULTILATERALS AND INCREASED STAGE
OPENHOLE PACKER/SLEEVE SYSTEMS
4:30 PM Mahadevan, Jagannathan*; Le, Duc Huu; McQueen,
Kenley H.: GEL DAMAGE REMEDIATION BY EVAPORATIVE
MECHANISMS: A LABORATORY INVESTIGATION
SESSION NO. 38
34-6
SESSION NO. 35
T41. Advances In Completion And Production Operations
(Alternates) (Society of Petroleum Engineers (SPE))
38-1
Yuan, Hong*; Zhou, Desheng: A NEW MODEL FOR
PREDICTING INFLOW PERFORMANCE OF FRACTURED
HORIZONTAL WELLS
38-2
Pan, Yi*; Zhangxin, John Chen; Xiao, Lizhi; Sun, Jian; Bao, Xia:
RESEARCH PROGRESS OF MODELLING ON COLD HEAVY
OIL PRODUCTION WITH SAND
T40. Managing Heavy Oil Resources (Society of Petroleum
Engineers (SPE))
Anthony Robert Kovscek and Tom Tang, Presiding
35-1
35-2
1:30 PM Kovscek, Anthony Robert*; Hascakir, Berna: SIMULATION OF
CYCLIC STEAM INJECTION INCLUDING THE EFFECTS OF
TEMPERATURE INDUCED WETTABILITY ALTERATION
2:00 PM Wu, Yongfu*; Hunky, Mohammed; Bai, Baojun; Norman,
Shari Dunn: AN EXPERIMENTAL STUDY OF ALKALINE
SURFACTANT FLOODING FOR ULTRA SHALLOW HEAVY
OIL RESERVOIRS
SESSION NO. 39
T42. Social Responsibility, Health, Air and Water Quality and GHG
Emissions (Society of Petroleum Engineers (SPE))
Mark A. Shemaria, Presiding
35-3
2:30 PM Babadagli, Tayfun*; Al Bahlani, Al Muatasim Mohammad:
EFFICIENCY ANALYSIS OF STEAM OVER SOLVENT
INJECTION IN FRACTURED RESERVOIRS (SOS FR)
METHOD FOR HEAVY OIL RECOVERY
39-1
1:30 PM Baghdikian, Serge*; Jepson, John J.; Holtz, Kimberley; Bock,
Lydia; Fayman, Jeffrey; Mader, Gerald: ENHANCEMENTS
TO GPS BASED SUBSIDENCE MONITORING AT THE
WILMINGTON OIL FIELD
3:00 PM Break
39-2
35-4
3:30 PM Ayodele, Oluropo Rufus*: TESTING AND HISTORY
MATCHING OF ES SAGD (USING HEXANE)
2:00 PM Esposito, Ariel*; Benson, Sally M.: REMEDIATION OF
POSSIBLE LEAKAGE FROM GEOLOGIC CO2 STORAGE
RESERVOIRS INTO GROUNDWATER AQUIFERS
35-5
4:00 PM Mohammadzadeh, Omidreza*; Rezaei, Nima; Chatzis, Ioannis:
FURTHER IMPROVEMENTS IN PORE SCALE STUDIES OF
SAGD PROCESS
39-3
2:30 PM Jahangiri, Hamid Reza*; Zhang, Dongxiao: OPTIMIZATION OF
CARBON DIOXIDE SEQUESTRATION AND ENHANCED OIL
RECOVERY IN OIL RESERVOIR
SESSION NO. 36
morning Poster
Technical Sessions
T40. Managing Heavy Oil Resources (Alternates) (Society of
36-1
Babadagli, Tayfun*; Ozum, Baki: BIODIESEL AS
SURFACTANT ADDITIVE IN STEAM ASSISTED RECOVERY
OF HEAVY OIL AND BITUMEN
36-2
Li, Weiqiang*; Mamora, Daulat Debataraja: NUMERICAL
SIMULATION OF THERMAL SOLVENT REPLACING STEAM
UNDER STEAM ASSISTED GRAVITY DRAINAGE (SAGD)
PROCESS
SESSION NO. 40
T43. Society of Petroleum Engineers (Posters) (Society of Petroleum
Engineers (SPE))
SESSION NO. 37
T41. Advances In Completion And Production Operations
40-1
1 Mondal, Satyajit*; Agarwal, Siddhartha; Mongrain, Joanna; Misra,
Debasmita: TIGHT GAS EXPLOITATION: A STOCHASTIC
MODELING STUDY OF A LOW SINUOSITY RIVER SYSTEM
40-2
2 Sheng, James J.*: NEW CONCEPTS OF THE OPTIMUM
MICROEMULSION PHASE TYPE AND THE OPTIMUM SALINITY
PROFILE IN SURFACTANT/POLYMER FLOODING
40-3
3 Aguilera, Roberto*; Rahmanian, Mohammad Reza; Solano, Nisael:
STORAGE AND OUTPUT FLOW FROM SHALE AND TIGHT GAS
RESERVOIRS
40-4
4 Paidin, Wagirin Ruiz*; Rao, Dandina Nagaraja: THE POTENTIAL
OF NCG ENHANCED SAGD APPLICATION IN US HEAVY OIL
RESERVOIRS
40-5
5 Odi, Uchenna*; Lane, Robert H.; Barrufet, Maria Antonieta:
ENSEMBLE BASED OPTIMIZATION OF EOR PROCESSES
40-6
6 Jabbari, Hadi*; Kharrat, Riyaz; Zeng, Zhengwen; Mostafavi,
Vahidreza; Emamzadeh, Abolghasem: A NEW SEMI ANALYTICAL
Stephen K. Cheung and Bradford R. Pierce, Presiding
37-1
1:30 PM Haroun, Muhammad Raeef*; Ghosh, Bisweswar; Pamukcu,
Sibel; Wittle, J.K.; Al Badawi, Manal Abdel Aziz; Chilingar, G.V.:
A NOVEL OILFIELD SCALE CONTROL APPROACH IN SITU
ION DIVERSION THROUGH ELECTROKINETICS
37-2
2:00 PM Ahmadi, Mohabbat*; Torres, David Enrique; Sharma, Mukul;
Linnemeyer, Harry; Pope, Gary Arnold: CHEMICAL
TREATMENT TO MITIGATE CONDENSATE AND WATER
BLOCKING IN CARBONATE GAS WELLS
37-3
2:30 PM Diaz, Brigida Meza*; Sawatzky, Ronald P.; Kuru, Ergun:
SAND ON DEMAND: AN APPROACH TO IMPROVING
PRODUCTIVITY IN HORIZONTAL WELLS UNDER HEAVY
OIL PRIMARY PRODUCTION PART II
Booth #
SESSION NO. 40
MODELING OF TOE TO HEEL AIR INJECTION IN IN SITU
COMBUSTION PROCESS
40-7
7 Mahadevan, Jagannathan*; Le, Duc Huu: PRODUCTIVITY LOSS IN
GAS WELLS DUE TO SALT DEPOSITION
40-8
8 Yousef, Ali A.*; Al Saleh, Salah; Al Kaabi, Abdulaziz Ubaid: FIELD
BRINE COMPOSITION IMPACT ON TERTIARY OIL RECOVERY
FROM CARBONATE RESERVOIRS AN EXPERIMENTAL STUDY
40-9
9 Babadagli, Tayfun*; Singh, Rajpreet: MECHANICS AND UP
SCALING OF HEAVY OIL BITUMEN RECOVERY BY STEAM
OVER SOLVENT INJECTION IN FRACTURED RESERVOIRS
(SOS FR) METHOD
40-10
40-11
40-12
40-13
40-14
40-15
40-16
10 Gil, Baldev Singh*: AN ANALYTICAL METHODOLOGY TO
DETERMINE OIL IN PLACE: AQUIFER INFLUX AND ULTIMATE
SWEEP EFFICIENCY OF A MATURE HEAVY OIL WATERFLOOD
IN THE WILMINGTON BASIN
11 Li, Xin*; Longmuir, Gavin; McMillen, Kenneth James; Duan, Shengkai:
INVESTIGATION OF OIL BY PASSED MECHANISMS FOR
IMPROVED OIL RECOVERY IN DEEPWATER GULF OF MEXICO
SESSION NO. 41
T44. American Association of Petroleum Geologists (Posters)
(Pacific Section, AAPG)
Booth #
41-1
24 Higley, Richard T.*: NEW OIL OPPORTUNITIES IN THE EASTERN
VENTURA BASIN
41-2
25 Olson, Deborah M.*; Howard, Thomas M.: FROM PAPER TO
BINARY: PROBLEMS AND SOLUTIONS IN CREATING AND
VERIFYING DIGITAL LOG DATABASES
41-3
26 He, Meng*: ONE-DIMENSIONAL BURIAL HISTORY MODEL
SHEDS NEW INSIGHTS INTO THE PETROLEUM SYSTEMS IN
THE VALLECITOS AREA AND OIL FIELD, SAN JOAQUIN BASIN,
CALIFORNIA
SESSION NO. 42
12 Jung, Jung*; Yang, Daegil: SIMULATION OF TIME LAPSE MINERAL
CARBONATION AND ISOTOPE FRACTIONATION OF INJECTED
CO2 IN AQUIFER: IMPLICATIONS FOR MONITORING CO2
SEQUESTRATION
T45. San Andreas and Walker Lane Neotectonics (Posters)
13 Babadagli, Tayfun*; Jafari, Alireza: CALCULATING EQUIVALENT
FRACTURE NETWORK PERMEABILITY OF MULTI LAYER
COMPLEX NATURALLY FRACTURED RESERVOIRS
14 El Shaari, Nabil Abdalla*; Fritz, Steven Arthur; Bergstrom, Jason:
IMPROVED WELL FRACTURE STIMULATION PERFORMANCE
THROUGH THE APPLICATION OF UNIQUE SOLID CHEMICAL
INHIBITORS
15 Al Otaibi, Ajab Mohammed*; Wu, Yu Shu: TRANSIENT BEHAVIOR
AND ANALYSIS OF NON DARCY FLOW IN POROUS AND
FRACTURED RESERVOIRS ACCORDING TO THE BARREE AND
CONWAY MODEL
16 Jiang, Haifeng*; Nuryaningsih, Lily; Adidharma, Hertanto: THE
EFFECT OF SALINITY OF INJECTION BRINE ON WATER
ALTERNATING GAS PERFORMANCE IN TERTIARY MISCIBLE
CARBON DIOXIDE FLOODING: EXPERIMENTAL STUDY
40-17
17 Li, Weiqiang*; Mamora, Daulat Debataraja: SIMULATION
INVESTIGATION OF SOLVENT CO INJECTION IN VAPOR AND
LIQUID PHASE TO REDUCE SHALE BARRIER IMPACT ON SAGD
PERFORMANCE
40-18
18 Cheng, Kun*; Wei, Yunan; Wu, Wenyan; Holditch, Stephen A.:
A NOVEL OPTIMIZATION MODEL FOR ANALYZING
PRODUCTION DATA
40-19
19 Zhai, Daoyuan*: AN INEQUALITY CONSTRAINED EXTENDED
KALMAN FILTER FOR CONTINUAL FORECASTING OF
INTERWELL CONNECTIVITIES IN WATERFLOODS
40-20
20 Al Shuwaikhat, Hisham Ibrahim*: ENERGY CONSERVATION AND
OIL PRODUCTION OPPORTUNITIES IN GHAWAR FIELD IN
SAUDI ARAMCO
40-21
21 Lane, Robert H.*; Seyidov, Murad: DEEP PLACEMENT GEL BANK
AS AN IOR PROCESS: MODELING, ECONOMIC ANALYSIS AND
COMPARISON TO POLYMER FLOODING
40-22
22 Fuentes Cruz, Gorgonio*; Velazquez, Rodolfo Gabriel Camacho;
Vasquez cruz, Mario Alberto: A UNIFIED APPROACH FOR
FALLOFF AND BUILDUP TESTS ANALYSIS FOLLOWING A
SHORT INJECTION/PRODUCTION TIME
40-23
23 Kalaei, M. Hosein*; Green, Don W.; Willhite, Paul: NUMERICAL
MODELING OF THE WATER IMBIBITION PROCESS IN WATER
WET LABORATORY CORES - POSTER
34 2010 GSA Abstracts with Programs 1:30 PM, Marriott Anaheim Hotel, Platinum 5-6
Booth #
42-1
27 Gooding, Margaret L.*: ANALYSIS OF SEISMIC ACTIVITY AND
POTENTIAL SEISMIC HAZARDS OF THE FONTANA SEISMIC
TREND IN SOUTHERN CALIFORNIA
42-2
28 Masana, Eulalia*; Rockwell, Thomas K.; Stepancikova, Petra:
COMBINING NEW AIRBORNE LIDAR DATA AND PROVENANCE
OF ALLUVIAL FAN DEPOSITS TO CONSTRAIN LONG-TERM
OFFSETS ALONG THE ELSINORE FAULT IN THE COYOTE
MOUNTAINS, IMPERIAL VALLEY, CALIFORNIA
42-3
29 Herbert, Justin*; Cooke, Michele L.: INTERSEISMIC DEFORMATION
OF THE SAN BERNARDINO REGION FROM GEOLOGICALLY
BASED MODELS
42-4
30 Hebert, Chris*; Schottenfeld, Mariel T.; Cooke, Michele L.; Herbert,
Justin: CLAYBOX SIMULATIONS OF THE EVOLUTION OF THE
SOUTHERN BIG BEND REGION OF THE SAN ANDREAS
42-5
31 Schottenfeld, Mariel T.*; Cooke, Michele: INVESTIGATION OF NEW
FAULT DEVELOPMENT WITHIN CONTRACTION BENDS IN A
CLAYBOX
42-6
32 Luo, Shangde*; Wu, Yi-Chen; Shen, Chuan-Chou; Palacios,
Carlos: DATING PALEO-SEISMIC/TECTONIC EVENTS BASED
ON U-SERIES DISEQUILIBRIUM IN EVAPORATES FROM THE
FAULT ZONES
42-7
33 Rittase, William M.*; Walker, J. Douglas; Kirby, Eric; McDonald, Eric;
Gosse, John: OFF-FAULT DEFORMATION, UPLIFT AND
SEDIMENTATION IN PILOT KNOB VALLEY, CALIFORNIA -PIECING TOGETHER COMPLEX STRUCTURAL AND KINEMATIC
PROCESSES BETWEEN THE GARLOCK FAULT AND PANAMINT
VALLEY FAULT
42-8
34 Danskin, Wesley R.*; Schug, David L.: MAPPING THE SAN DIEGO
FORMATION NEAR CHULA VISTA, CALIFORNIA
42-9
35 Menges, Christopher M.*; Matti, Jonathan C.; Langenheim,
Victoria E.; Mahan, Shannon A.; Hillhouse, John W.: COMPLEX
QUATERNARY DEFORMATION AMONG INTERSECTING
SETS OF STRIKE-SLIP FAULTS NEAR TWENTYNINE PALMS,
SOUTHERN CALIFORNIA
42-10
36 Guzman, Nathan E.*; Yule, Doug: GEOLOGY AND
GEOMORPHOLOGY OF THE INTERSECTING MISSION CREEK
AND BANNING FAULT STRANDS, SAN ANDREAS FAULT
42-11
37 Harvey, Janet C.*; Stock, Joann; Miller, David M.: THE LATE
NEOGENE DEFORMATION HISTORY OF THE SOUTH BRISTOL
MOUNTAINS FAULT ZONE
SESSION NO. 47
SATURDAY, 29 MAY 2010
SESSION NO. 45
T11. New Insights into the Petrology of Mesozoic Cordilleran
Batholiths I (Cordilleran Section GSA)
morning Oral
Technical Sessions
Doug Morton and Diane Clemens-Knott, Presiding
45-1
8:40 AM Morton, Douglas M.*; Alvarez, Rachel M.; Alcott, Alison;
Miller, Fred K.; cossette, Pamela: ANATOMY OF A 100 MA
SUTURE, NORTHERN PENINSULAR RANGES BATHOLITH
45-2
9:00 AM Holk, Gregory J.*: MAJOR AND TRACE ELEMENT
METASOMATISM BY SUBDUCTION-RELATED FLUIDS
ALONG THE EASTERN PENINSULAR RANGES
MYLONITE ZONE
SESSION NO. 43
Structural Geology/Tectonics I
Jonathan A. Nourse and Jeanette C. Arkle, Presiding
9:20 AM Break
43-2
9:00 AM Morgan, George J.*; Morgan, J.R.: POST PLIOCENE
DETACHMENT ON THE EASTERN SIDE OF THE COYOTE
MOUNTAINS, SALTON TROUGH, SOUTHERN CALIFORNIA
45-3
9:35 AM Barnes, Calvin G.*; Coint, Nolwenn; Allen, Charlotte M.: LATE
MIDDLE JURASSIC ‘RETRO-ARC’ MAGMATISM IN THE
KLAMATH MOUNTAIN PROVINCE
43-3
9:20 AM Haugerud, Ralph A.*; Kovanen, D.J.: DIRECT OBSERVATION
OF TILT ASSOCIATED WITH GLACIO-ISOSTATIC
REBOUND, WESTERN WHATCOM COUNTY, WASHINGTON
45-4
9:55 AM Coint, Nolwenn*; Barnes, Calvin G.: MULTIPLE MAGMA
BATCHES IN THE TILTED WOOLEY CREEK BATHOLITH,
KLAMATH MOUNTAINS, CALIFORNIA
43-4
9:40 AM Arkle, Jeanette C.*; Armstrong, Phillip A.; Haeussler, Peter J.:
FOCUSED EXHUMATION IN THE SOUTHERN ALASKA
SYNTAXIS
43-5
10:00 AM Page, Bryan R.*; Girty, Gary H.: ASSESSING THE
STATISTICAL SIGNIFICANCE OF MASS AND VOLUME
CHANGES IN THE DEVELOPMENT OF SAPROCK FROM
CORESTONE NEAR THE ELSINORE FAULT ZONE, SAN
DIEGO COUNTY, CALIFORNIA: POTENTIAL IMPLICATIONS
FOR GROUND SHAKING EVENTS
SESSION NO. 44
T4. Advances in Understanding Magma Petrogenesis and
Eruption Dynamics at Basaltic Monogenetic Volcanoes
SESSION NO. 46
T18. Managing Groundwater in the Cordillera I (Cordilleran Section,
Richard Laton, John Foster, Barry J. Hibbs, and Matthew Becker, Presiding
46-1
8:40 AM Hibbs, Barry J.*: HYDROGEOLOGIC FACTORS IN SELENIUM
LOADING TO SOUTHERN CALIFORNIA WATERSHEDS
46-2
9:00 AM Barker, Shelby R.*; Laton, Richard; Foster, John: AN
INVESTIGATION OF POTENTIAL SURFICIAL RECHARGE
IN THE LUCERNE VALLEY GROUNDWATER BASIN,
MOJAVE DESERT, CA
46-3
9:20 AM Kear, Jordan*: ROLES OF AQUIFER HYDRAULICS IN
OPTIMIZING ASR WELL PERFORMANCE
Brandon L. Browne and Nancy Riggs, Presiding
44-1
9:05 AM Browne, Brandon L.*; Vitale, Michelle; Campbell, Colin:
CONSTRAINTS ON THE DEVELOPMENT AND
EVOLUTION OF QUATERNARY SCORIA CONE PLUMBING
SYSTEMS IN THE SIERRA NEVADA: INSIGHTS FROM
CLINOPYROXENE-MELT GEOTHERMOBAROMETRY
9:20 AM Self, Stephen*; Ort, Michael H.; Amos, Robert C.:
INTERPRETATION OF THE C. AD 1075 ERUPTION OF
SUNSET CRATER, ARIZONA, USA
44-2
44-3
9:35 AM Carlisle, Catherine J.*; Mattox, Stephen; Colgan, Patrick M.;
Hon, Ken: PALEOMAGNETISM OF AN INFLATED LAVA
FLOW: KILAUEA, HAWAII
9:50 AM Poster Viewing
10:50 AM Return to Talks
44-4
11:00 AM Hanson, Sarah L.*: GEOCHEMISTRY AND AGE
DETERMINATIONS OF LAVA FLOWS IN THE
NORTHEASTERN SAN FRANCISCO VOLCANIC FIELD,
NORTHERN ARIZONA
44-5
44-6
11:15 AM Wypych, Alicja*; Hart, William K.: MID-MIOCENE SILICIC
VOLCANSIM IN THE IDAHO-OREGON-NEVADA REGION AS
A WINDOW INTO CONTINENTAL CRUST FORMATION AND
MODIFICATION
11:30 AM DeWolfe, Y. Michelle*; Gibson, Harold L.; Piercey, Stephen J.:
PEPERITIC TEXTURES AND FACIES ARCHITECTURE OF A
PALEOPROTEROZOIC BASALTIC ANDESITE INTRUSION,
FLIN FLON, MANITOBA, CANADA: EVIDENCE FOR
THE EMPLACEMENT OF A CRYPTOFLOW DURING THE
GROWTH OF A DOMINANTLY BASALTIC VOLCANO
SESSION NO. 47
T29. The California Geological Survey I: Providing Scientific
Products and Professional Services to Californians for 150 Years
John G. Parrish and Stephen M. Testa, Presiding
47-1
8:45 AM Parrish, John G.*: CALIFORNIA GEOLOGICAL SURVEY -STAYING RELEVANT AFTER 150 YEARS
47-2
9:00 AM Testa, Stephen M.*; Arcand, Will J.: HISTORY OF THE
CALIFORNIA STATE MINING AND GEOLOGY BOARD - 125
YEARS OF DEVELOPMENT AND IMPLEMENTATION OF
EARTH SCIENCE POLICY
47-3
9:20 AM Saucedo, George J.*; Wills, Christopher J.: GEOLOGIC
MAPPING AT THE CALIFORNIA GEOLOGICAL SURVEY –
HISTORY, EVOLUTION, AND METHODS
47-4
9:40 AM Wills, Chris J.*: DEVELOPING MAPS OF POTENTIAL
EARTHQUAKE SHAKING FOR CALIFORNIA
10:00 AM Break
47-5
10:20 AM Clinkenbeard, John P.*: THE CALIFORNIA GEOLOGICAL
SURVEY MINERAL RESOURCES PROGRAM - MINERAL
RESOURCES, MINERAL HAZARDS AND ENVIRONMENTAL
GEOLOGY
47-6
10:40 AM Miller, Russell V.*: MINERAL LAND CLASSIFICATION IN
THE CALIFORNIA GEOLOGICAL SURVEY’S MINERAL
RESOURCES PROGRAM
SESSION NO. 47
47-7
11:00 AM Pompy, James*: ORIGINS OF CALIFORNIA’S SURFACE
MINING & RECLAMATION ACT (SMARA)
47-8
11:20 AM Kustic, Tim*: A HISTORY OF CALIFORNIA’S DIVISION OF
OIL, GAS, AND GEOTHERMAL RESOURCES
morning Poster
Technical Sessions
GOL AND TöHöMIYN NUUR VALLEYS, CENTRAL MONGOLIA:
IMPLICATIONS FOR POTENTIALLY ACTIVE FAULTING
48-15
15 Kelty, T.K.*; Dash, Batulzii; Day, Paul P.; Rice, Karin; Daubenmire,
Emily; Chinn, Logan; Chavez, J.: EARTHQUAKE FAULTS OF
CENTRAL MONGOLIA: IMPLICATIONS FOR THE SEISMIC
SAFETY OF ULAANBAATAR
48-16
16 Dermond, Jeffrey A.*; Lee, Jeff: DUCTILE DEFORMATION
PATTERNS IN THE LOWER PLATE OF THE NORTHERN SNAKE
DETACHMENT: DEFORMATION TEMPERATURE, VORTICITY,
QUARTZ C-AXIS FABRIC PATTERN, AND FINITE STRAIN
STUDIES
SESSION NO. 48
SESSION NO. 49
T4. Advances in Understanding Magma Petrogenesis and
Eruption Dynamics at Basaltic Monogenetic Volcanoes (Posters)
Booth #
48-1
1 Soller, David R.; Haugerud, Ralph A.*; Richard, Stephen M.;
Thoms, Evan E.: NCGMP09 -- A DATABASE SCHEMA FOR
DIGITAL PUBLICATION OF GEOLOGIC MAPS
48-2
2 Brown, Howard J.*: GEOLOGIC MAP OF THE FAIRVIEW VALLEY
AREA, SAN BERNARDINO COUNTY, CALIFORNIA
48-3
3 Brown, Howard J.*; Hernandez, Janis L.: LATE PROTEROZOIC,
PALEOZOIC, AND MESOZOIC ROCKS AND GEOLOGIC
STRUCTURES IN THE VICTORVILLE AND HELENDALE
7.5’ QUADRANGLES WEST CENTRAL MOJAVE DESERT,
CALIFORNIA
48-2
4 Masana, Eulalia*; Rockwell, Thomas K.; Stepancikova, Petra:
COMBINING NEW AIRBORNE LIDAR DATA AND PROVENANCE
OF ALLUVIAL FAN DEPOSITS TO CONSTRAIN LONG-TERM
OFFSETS ALONG THE ELSINORE FAULT IN THE COYOTE
MOUNTAINS, IMPERIAL VALLEY, CALIFORNIA
48-5
5 Green, Joe*; Simila, Gerry: ANALYSIS OF THE MICROSEISMICITY
(1996-2007) OF THE SANTA MONICA MOUNTAINS AND
ASSOCIATED MALIBU COAST, SANTA MONICA-DUME, AND
SANTA MONICA BAY FAULTS
48-6
6 Anderson, Thomas H.*; Campbell, Patricia A.; Powell, Robert E.;
Molde, Brooke: IS THERE A CASE FOR A MAJOR LATE
JURASSIC SHEAR ZONE IN THE PENINSULAR RANGES?
48-7
7 Clay, Pamela Jamie*; Miller, Robert B.: TECTONIC IMPLICATIONS
OF DUCTILE SHEAR ZONES IN THE JURASSIC KEITHS
DOME PLUTON, NORTHERN SIERRA NEVADA BATHOLITH,
CALIFORNIA
48-8
8 Simila, Gerry*; Francis, Robert D.: HIGH RESOLUTION FAULT
KINEMATICS OF THE SAN PEDRO BASIN FAULT, CALIFORNIA
CONTINENTAL BORDERLAND
48-9
9 Sorlien, Christopher C.*; Braudy, Nicole; Cormier, Marie-Helene;
Davis, Marcy; De Bow, Sam; Deming, Jacob; Diebold, John;
Dieudonne, Nicole; Douilly, Roby; Gulick, Sean S.P.; Hornbach,
Matthew; Johnson, Harold; McHugh, Cecilia; Mishkin, Katherine;
Seeber, Leonardo; Steckler, Michael; Symithe, Steeve Julien;
Templeton, John; Wilson, Robert: THRUST-REACTIVATED
NORMAL FAULTS AND THRUST-FOLDING CALIFORNIA
BORDERLAND AND HAITI
48-10
10 Koster, Kelvin L.*: SPACED CLEAVAGE DEVELOPMENT AT
McCartney MOUNTAIN, MONTANA
48-11
11 Dutra, Steven M.*; Shulman, Deborah J.; Leech, Mary:
THERMOBAROMETRY OF ECLOGITE-FACIES SHEAR ZONES
IN THE LOFOTEN ISLANDS, NORWAY
48-12
12 LaFromboise, Eli*; Marshall, Jeff; Simila, Gerry; Protti, Marino;
Quintero, Ronnie: NEOTECTONICS OF THE NICOYA PENINSULA,
COSTA RICA
48-13
13 Hacker, Christopher*: INCISED MEANDERING STREAMS AS
INDICATOR OF TERTIARY-QUATERNARY REGIONAL UPLIFT IN
NORTHWEST THAILAND
48-14
14 Rice, Karin*; Kelty, T.K.; Sauermann, Robert; Dash, Batulzii:
GEOLOGICAL RECONNAISSANCE OF THE MALANGIYN
36 2010 GSA Abstracts with Programs 8:30 AM, Marriott Anaheim Hotel, Platinum 5-6
Booth #
49-1
17 Schreck, Beth A.*; Riggs, Nancy R.: COMPLEX CINDER CONE
ERUPTIVE SEQUENCE AT O’Neill CRATER, SAN FRANCISCO
VOLCANIC FIELD, ARIZONA
49-2
18 Smith, A.L.*; Mattioli, Glen S.; Storni, Natasha; Fryxell, J.E.; Salazar,
Joseph S.; Hulett, Ashley; Velasquez, Christina: COMPARISON OF
THE 1902 ERUPTION TO THE OTHER HISTORIC ERUPTIONS OF
SOUFRIERE, ST. VINCENT, LESSER ANTILLES
49-3
19 Vitale, Michelle*; Browne, Brandon L.: TEXTURAL AND
MINERALOGICAL OBSERVATIONS OF QUENCHED BASALTIC
INCLUSIONS IN LOW-SILICA ANDESITE FROM THE 2006
ERUPTION OF AUGUSTINE VOLCANO, ALASKA
49-4
20 Beach, Megan*; Riggs, Nancy R.: PHYSICAL VOLCANOLOGY OF
THE MULE CREEK RHYOLITE, ARIZONA AND NEW MEXICO
49-5
21 Vazquez, J.A.*; Woolford, J.M.; Zohar, A.; Nagy-Shadman, E.A.;
Champion, D.E.: TIMING OF LATE PLEISTOCENE VOLCANISM
AT BIG PINE VOLCANIC FIELD: INSIGHTS FROM VOLCANIC
STRATIGRAPHY, COSMOGENIC 36CL DATING, AND
PALEOMAGNETISM
SESSION NO. 50
T10. Theory and Practice: Engineering Geology in the Cordillera
Booth #
50-1
22 Vincett, James D.*: NEW EVIDENCE FOR THE TUNGSTEN HILLS,
NEAR BISHOP, CA, AS A LANDSLIDE DEPOSIT
50-3
24 Bell, Angie*; de la Fuente, Juan A.; Bell, Chad B.: APPLICATION OF
A DEBRIS FLOW POTENTIAL MODEL ON THE 2008 PANTHER
FIRE ON THE KLAMATH NATIONAL FOREST, NORTHERN
CALIFORNIA
50-4
25 Shaller, Philip J.*; Shrestha, Parmeshwar L.; Doroudian, Macan;
Hamilton, Douglas L.; Sykora, David W.: THE JANUARY 10, 2005 LA
CONCHITA LANDSLIDE
50-5
26 Behl, Richard J.*; Ta, Linda; Williams, Dana; Werner, Alison;
Bernardino, Melissa; Peterson, Randall; McCormick, Chelsea;
Nagy, Brian: GEOMORPHIC EXPRESSION OF A MIOCENE DIKE
COMPLEX, SAN JOAQUIN HILLS, CALIFORNIA, USA
50-6
27 Johnson, Philip L.*: THE HIDDEN COMPLEXITY OF A DEEPSEATED LANDSLIDE COMPLEX IN RICHMOND, CALIFORNIA
50-7
28 Fife, Donald L.*; Shlemon, Roy: PERALTA HILLS FAULT A
PREVIOUSLY UNRECOGNIZED ACTIVE TRANSVERSE RANGE
“BLIND THRUST” ORANGE COUNTY, CA
50-8
29 Colburn, Ivan P.*: GRAIN SIZE ANALYSIS AND MECHANICS
OF THE 2008 MOUNT WHITNEY FISH HATCHERY MUDFLOW
ON THE EASTERN SLOPE OF THE SIERRA NEVADA,
INDEPENDENCE, CALIFORNIA
SESSION NO. 53
50-9
30 Wagner, David L.*; DeRose, Margie: THE OAK CREEK MUDFLOWS
AND DEBRIS FLOWS OF JULY 12, 2008, OWENS VALLEY, INYO
COUNTY CALIFONRIA
50-10
31 Bishop, Kim M.*: EVIDENCE FOR A 45 km2 SIERRA NEVADA
LANDSLIDE, NORTHERN OWENS VALLEY, CALIFORNIA
Batholiths (Posters) (Cordilleran Section GSA)
51-1
51-2
45 Harris, Daniel B.*; Toro, Jaime; McDannell, Kalin T.: CRETACEOUS
TECTONIC AND MAGMATIC EVOLUTION OF THE BENDELEBEN
AND WINDY CREEK PLUTONS, SEWARD PENINSULA, ALASKA
SESSION NO. 52
T18. Managing Groundwater in the Cordillera (Posters)
(Cordilleran Section, GSA and Pacific Section, AAPG)
SESSION NO. 51
51-14
46 Higgins, Chris T.*; Churchill, Ronald K.; Downey, Cameron I.;
Fonseca, Milton C.: MAPS OF POTENTIAL MINERAL AND
MINING-CHEMICAL HAZARDS ALONG PARTS OF STATE
HIGHWAYS 128 AND 299 IN NORTHERN CALIFORNIA
52-2
47 Robards, Patricia*; Wilson, Alan Jr.; Clemens-Knott, Diane:
GROUNDWATER MAPPING IN THE IRVINE SUB-BASIN, ORANGE
CO., CA, USING STABLE ISOTOPE AND GENERAL MINERAL
COMPOSITIONS
Booth #
32 Clausen, Benjamin L.*; Morton, Douglas M.; Kistler, Ronald W.;
Lee, Cin-Ty A.: MAFIC-FELSIC MAGMA MIXING IN CONTINENTAL
CRUST FORMATION: AN EXAMPLE FROM LOW-INITIAL SR
GRANITOIDS OF THE NORTHWESTERN PENINSULAR RANGES
BATHOLITH, SOUTHERN CALIFORNIA
Booth #
52-1
33 Shaw, Stirling E.; Todd, Victoria R.*: A RECONNAISSANCE STUDY
OF GRANITE SUITES ACROSS SAN DIEGO COUNTY USING
176
Hf/177Hf FROM SINGLE ZIRCON GRAINS: EVIDENCE OF
MAGMA MIXING BETWEEN MANTLE-DERIVED AND CRUSTALDERIVED MELTS
52-3
48 Stevens, Lora R.*; Zahn, Eric F.; Hamilton, Andrew; Mull, Christopher:
RESTORING THE LOS CERRITOS WETLANDS: ASSESSMENT
OF TRACE METAL CONTAMINATION
52-4
51-3
34 Todd, Victoria R.*; Hernandez, Janis L.; Kimbrough, David L.;
Busch, Lawrence L.: THE ZONED RAMONA PLUTONIC COMPLEX,
SAN DIEGO COUNTY, CALIFORNIA: A MID-CRUSTAL MAGMA
CHAMBER BENEATH A CRETACEOUS STRATOVOLCANO?
49 Lane, Charles L.*; Dittmer, Eric; Elliott, William S. Jr.; Mason, Steve:
AN ANALYSIS OF SEDIMENTS IMPOUNDED AT GOLD RAY DAM,
JACKSON COUNTY, OREGON: INITIAL STEPS IN REMOVAL OF
A MAINSTEM DAM
52-5
51-4
35 Bender, E. Erik*: WIDESPREAD CRUSTAL CONTAMINATION
OF EARLY PROTEROZOIC MAGMAS: AN EXAMPLE FROM
THE FENNER GNEISS, PIUTE AND OLD WOMAN MOUNTAINS,
SAN BERNARDINO COUNTY, CALIFORNIA
50 Vargas, Luz; Hibbs, Barry J.*; Merino, Mercedes: ENVIRONMENTAL
ISOTOPES ASSESS GROUNDWATER FLOW AT AN ALLUVIAL
FAN/PLAYA MARGIN INTERFACE, MOJAVE DESERT
52-6
51 Erdelyi, Nasrin*; Kelliher, Mat; Hibbs, Barry J.: ANALYSIS
OF STABLE ISOTOPES AND RADIOISOTOPES ASSESS
GROUNDWATER FLOW AT DOS PALMAS PRESERVE AND
VICINITY, SALTON SEA AREA, CALIFORNIA
51-5
36 Ianno, Adam J.*; Paterson, Scott R.: LATE CRETACEOUS
GRANITOIDS IN THE MIDDLE TO LOWER CRUST, EASTERN
TRANSVERSE RANGES, CALIFORNIA: MAGMATIC EVOLUTION
IN A CRUSTAL COLUMN
51-6
37 Zhang, Tao*; Paterson, Scott; Pignotta, Geoffrey; Anderson, J.
Lawford; Memeti, Vali; Mundil, Roland: TEMPORAL AND SPATIAL
GEOCHEMICAL EVOLUTION OF MESOZOIC MAGMATISM IN
THE CENTRAL SIERRA ARC, CALIFORNIA
51-7
38 Gross, M. Benjamin*; Memeti, Vali; Krause, Joachim; Paterson,
Scott R.: MICROANALYSIS OF K-FELDSPAR MEGACRYSTS
AT THE EASTERN CATHEDRAL PEAK GRANODIORITE-HOST
ROCK BOUNDARY, SADDLEBAG LAKE PENDANT, SIERRA
NEVADA, CA
SESSION NO. 53
39 Seal, Elizabeth*; Clemens-Knott, Diane: MAGMA
DIFFERENTIATION AS RECORDED BY CHANGES IN MINERAL
STRATIGRAPHY WITHIN LAYERED MAFIC CUMULATES
(WESTERN SIERRA NEVADA BATHOLITH, CALIFORNIA)
53-1
1:40 PM Cao, Wenrong*; Paterson, Scott R.; Whitesides, Andrew;
Memeti, Vali; Miller, Robert B.: LATE-CRETACEOUS SHEAR
ZONES FORMED BY EMPLACEMENT, REGIONAL
DEXTRAL SLIP, AND STRAIN PARTITIONING AROUND
THE TUOLUMNE BATHOLITH: IMPLICATIONS FOR SHEAR
ZONE DEVELOPMENT IN ARCS AND CRETACEOUS
TECTONICS
53-2
2:00 PM Whitesides, Andrew*; Cao, Wenrong; Paterson, Scott R.;
Enriquez, Marcus; Ehret, Phillip; Culbert, Kristan; Gross, M.
Benjamin; Zhang, Tao; Memeti, Vali; Mundil, Roland:
TRANSITION FROM DUCTILE TO BRITTLE MOTION ON
THE NORTHERN EXTENSION OF THE EASTERN SIERRA
CREST SHEAR ZONE (ESCSZ) IN THE SADDLEBAG LAKE
PENDANT, CENTRAL SIERRA NEVADA, CA
53-3
2:20 PM Day, Paul P.*; Kelty, Thomas K.; Dash, Batulzii: GEOLOGY
AND SEISMIC POTENTIAL OF THE HUSTAIN FAULT,
CENTRAL MONGOLIA
2:40 PM Break
53-4
2:55 PM Bethel-Thompson, C.E.M.*; Sainbury, J.S.; Ricketts, J.W.; Girty,
Gary H.; Kimbrough, David L.: STRUCTURAL HISTORY OF A
SEGMENT OF THE PENINSULAR RANGES BATHOLITHS
(PRB), SOUTHERN CALIFORNIA: NEW EVIDENCE FOR
PRE-130 MA AND POST- TO SYN-116 MA DEFORMATION
51-8
51-9
40 Castellanos, Crystal*; Clemens-Knott, Diane: MINERALOGY
AND PETROGRAPHY OF THE POLYMETAMORPHIC KINGS
SEQUENCE, LAKE KAWEAH PENDANT, WEST-CENTRAL
SIERRA NEVADA BATHOLITH, CA
51-10
41 Melchiorre, Erik*; Lopez, Amanda: STABLE ISOTOPE RECORD
OF ARCHEAN AND CAMBRIAN SERPENTINIZING FLUID
COMPOSITION FROM STICHTITE (MG-CR CARBONATE
HYDROXIDE)
51-11
42 Melchiorre, Erik*; Velasquez, Christina: GEOCHEMICAL
FINGERPRINT OF PLACER GOLD FROM THE MIDDLE CAMP
DISTRICT, QUARTZSITE, AZ
51-12
43 Mallory, Marci*; Holk, Gregory J.; Larson, Peter B.; Cochrane, Matt:
A STABLE ISOTOPE AND PETROGENETIC STUDY OF THE
ALKALINE PENTICTON GROUP VOLCANIC SUITE: THE WHITE
LAKE BASIN, SOUTH-CENTRAL BRITISH COLUMBIA, CANADA
51-13
44 Knudsen, Duncan F.*: COMPARISON OF CRETACEOUS VS.
EOCENE GRANITOID INTRUSIONS IN NE WASHINGTON:
PETROLOGY AND AL-IN-HORNBLENDE BAROMETRY
afternoon Oral
Technical Sessions
Structural Geology/Tectonics II
Jonathan A. Nourse and Jeanette C. Arkle, Presiding
SESSION NO. 53
53-5
3:15 PM Nourse, Jonathan A.*; Irwin, James J.: TECTONIC AND
STRUCTURAL SETTING OF GOLD MINERALIZATION
IN THE SONORA-MOJAVE BELT: EXAMPLE FROM THE
JUAREZ-TAJITOS AREA
53-6
3:35 PM Sutton, Lauren A.*; Ricketts, J.W.; Sainsbury, J.S.; Gordon,
Erik M.; Hasten, Zachary E.L.; Girty, Gary H.: THE COPPER
BASIN FAULT: A NEWLY DEFINED REGIONAL REVERSE
FAULT IN THE LOWER COLORADO RIVER REGION,
SE CALIFORNIA: IMPLICATIONS FOR THE TIMING OF
INITIATION OF THE ECSZ
3:55 PM Concluding Remarks
SESSION NO. 54
T9. Enhancing Societal Relevance in Introductory Geoscience
Education (Cordilleran Section GSA)
55-2
2:00 PM Clemens-Knott, Diane*: REE-ISOTOPE STUDY OF MAFIC TO
FELSIC DIFFERENTIATION, STOKES MOUNTAIN REGION,
WESTERN SIERRA NEVADA BATHOLITH, CA
55-3
2:20 PM Lackey, Jade Star*; Cecil, M. Robinson; Windham, Cameron J.;
Frazer, Ryan E.; Bindeman, Ilya N.; Gehrels, George E.:
IGNITING THE SIERRAN ARC: EVOLVING OXYGEN AND
HAFNIUM ISOTOPE RATIOS IN THE BASS LAKE TONALITE
2:40 PM Discussion
SESSION NO. 56
T18. Managing Groundwater in the Cordillera II (Cordilleran Section,
Richard Laton, John Foster, Barry J. Hibbs, and Matthew Becker, Presiding
Elizabeth Nagy-Shadman, Martha A. House, and Bryan C. Wilbur, Presiding
56-1
1:40 PM Tobin, Benjamin W.*; Schwartz, Benjamin: ASSESSING
GROUNDWATER RESOURCES IN A MOUNTAIN SETTING
56-2
2:00 PM Guiltinan, Eric J.*; Becker, Matthew: USING HARMONIC
HYDRAULIC TESTS TO ESTIMATE FRACTURED BEDROCK
PROPERTIES AND PREDICT LOCAL HETEROGENEITY
56-3
2:20 PM Johnston, Luissa*; Kneeshaw, Tara A.: SPATIAL VARIABILITY
IN BIOGEOCHEMICAL PROCESSES AT THE SEDIMENTWATER INTERFACE IN A HYDROLOGICALLY DYNAMIC
RESERVOIR SYSTEM
54-1
1:40 PM Lozinsky, Richard P.*; Chamberlin, W. Sean: CREATING AN
EARTH SCIENCE COURSE THAT IS MORE RELEVANT TO
TODAY’S STUDENT
54-2
1:55 PM House, Martha A.*; Douglass, David N.: PHYSICAL
OCEANOGRAPHY FIELD EXPERIENCE AT PASADENA
CITY COLLEGE: INTRODUCING COMMUNITY COLLEGE
STUDENTS TO OCEANOGRAPHY, DATA AND THE
SOUTHERN CALIFORNIA COASTLINE
54-3
54-4
2:10 PM Nagy-Shadman, Elizabeth A.*: INCREASING STUDENT
AWARENESS OF DISAPPEARING NATURAL RESOURCES
IN INTRODUCTORY EARTH SCIENCE COURSES AT
PASADENA CITY COLLEGE
SESSION NO. 57
2:25 PM Sethi, Parvinder*: VIRTUAL REALITY FIELD-TRIPS FOR
STUDYING THE GEOLOGY OF NATIONAL PARKS: RECENT
ADVANCES & PEDAGOGY
54-5
2:40 PM Presiado, Rhea*: FROM SEA LEVEL RISE TO STREET VIEW:
SOCIALLY RELEVANT TEACHING USING GOOGLE EARTH
2:55 PM Break
54-6
3:10 PM Wilbur, Bryan C.*: JOLTING SOUTHERN CALIFORNIA INTO
PREPAREDNESS WITH EARTHQUAKE KITS
54-7
3:25 PM de Groot, Robert*; Springer, Kathleen; Brooks, Candace:
EARTHQUAKE AWARENESS AND PREPAREDNESS
EDUCATION IN CALIFORNIA – THE EPICENTER MODEL
54-8
3:40 PM Montoya, Marisa*; Henderson, Wayne G.: DOES
ENVIRONMENTAL EDUCATION PROVOKE
ENVIRONMENTALLY RESPONSIBLE BEHAVIOR?
54-9
3:55 PM Metzger, Ellen*; Sedlock, Richard: EARTH SCIENCE
TEACHER PROFESSIONAL DEVELOPMENT: LESSONS
LEARNED FROM TWO DECADES OF THE BAY AREA
EARTH SCIENCE INSTITUTE
4:10 PM Discussion
T29. The California Geological Survey II: Providing Scientific
Products and Professional Services to Californians for 150 Years
John G. Parrish and Stephen M. Testa, Presiding
57-1
1:30 PM Real, Charles R.*: HISTORICAL DEVELOPMENT OF
THE SEISMIC HAZARD ZONATION UNIT, CALIFORNIA
GEOLOGICAL SURVEY
57-2
1:50 PM Pridmore, Cynthia L.*: PRODUCTS OF THE SEISMIC
HAZARDS ZONATION UNIT, CALIFORNIA GEOLOGICAL
SURVEY (CGS)
57-3
2:10 PM Short, William R.*; Bedrossian, Trinda L.: CALIFORNIA
GEOLOGICAL SURVEY - ENVIRONMENTAL PROTECTION
AND PUBLIC SAFETY IN THE URBAN/WILDLAND
INTERFACE
57-4
2:30 PM Lancaster, Jeremy T.*; Spittler, Thomas E.; Short, William R.:
MODELING RELATIVE ALLUVIAL FAN FLOOD HAZARDS
FROM SURFICIAL GEOLOGIC MAPS
2:50 PM Break
57-5
3:10 PM Shakal, Anthony*: THE CALIFORNIA STRONG MOTION
INSTRUMENTATION PROGRAM
57-6
3:30 PM Haddadi, Hamid*; Stephens, Christopher; Shakal, Anthony;
Huang, Moh; Oppenheimer, David; Savage, William; Leith,
William; Parrish, John: CENTER FOR ENGINEERING
STRONG MOTION DATA (CESMD)
57-7
3:50 PM Arcand, Will J.*; Testa, Stephen M.: LEAD AGENCY
INTERACTIONS AND RELATED ROLES OF THE
CALIFORNIA STATE MINING AND GEOLOGY BOARD
57-8
4:10 PM Gius, Fred W.*: ASSESSING AND MANAGING THE EFFECTS
OF IN-STREAM MINING IN CALIFORNIA
SESSION NO. 55
Batholiths II (Cordilleran Section GSA)
Doug Morton and Diane Clemens-Knott, Presiding
55-1
1:40 PM Christe, Geoff*: U/PB AGES OF KETTLE ROCK AND MOUNT
JURA SEQUENCE VOLCANIC ROCK, EASTERN MESOZOIC
BELT, NORTHERN SIERRA NEVADA, CALIFORNIA: A
REVISED UNDERSTANDING OF THE AGE RELATIONSHIP
OF VOLCANISM, PLUTONISM, AND TECTONISM WITHIN
SUCCESSIVE JURASSIC ARC SEQUENCES
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Abstracts
Volume 42, No. 4
NOTICE
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provides this and other forums for the presentation of diverse opinions and
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Abstracts
Volume 42, No. 4
Abstracts to be presented at the meeting of the
Cordilleran Section
of the Geological Society of America and associated societies
and Pacific Section
American Association of Petroleum Geologists
with Western North America Regional Society of Petroleum Engineers
Anaheim, California
27–29 May 2010
Note indexing system
Numbers (2-4, 15-4) indicate session and order of presentation within that session.
Further information concerning the presented papers on which these abstracts are based
should be obtained by contacting the authors of the abstracts.
1-2
SESSION NO. 1, 8:40 AM
Thursday, 27 May 2010
S2. Using Basin Analysis and Geochemistry to
Reconstruct the San Andreas Fault System: A
Symposium in Honor of John Crowell, Tor Nilsen,
Tom Dibblee, and Perry Ehlig (Pacific Section SEPM)
Marriott Anaheim Hotel, Platinum 2
1-1
8:40 AM
Saleeby, Jason
[172747]
DISPERSAL OF SOUTHERN SIERRA NEVADA BATHOLITH (SNB) CRUSTAL FRAGMENTS
ACROSS AND ALONG THE TRACE OF THE SAN ANDREAS FAULT (SAF)-WHAT
CONSTITUTES THE CENTRAL SALINIA BASEMENT
SALEEBY, Jason, Tectonics Observatory, California Institute Technology, Mail Stop 100-23,
Pasadena, CA 91125-0001, [email protected], CHAPMAN, Alan D., Geological and
Planetary Sciences, California Institute of Technology, 1200 E. California Blvd, MC 100-23,
Pasadena, CA 91125, KIDDER, Steven, Division of Geological and Planetary Sciences,
California Institute of Technology, 1200 E. California Blvd, MC 100-23, Los Angeles, CA
91125, and DUCEA, Mihai N., Department of Geosciences, University of Arizona, Tucson,
AZ 85721
Analysis of the main Salinia basement indicates that it consists of crustal fragments that may be
correlated with various crustal levels of the southern SNB, and its disrupted continuation into the
Mojave batholith. The clearest correlations are between the San Emigdio-Tehachapi and Gabilan
Ranges. Mid-Cretaceous mid-to upper crustal eastern zone batholithic and metamorphic pendant
rocks of the main Gabilan massif correlate to the Pastoria plate, which sits above lower crustal
western zone Early Cretaceous SNB rocks of the San Emigdio-Tehachapi ranges along a folded
regional detachment fault of Late Cretaceous age. Through much of the San Emigdio range
the detachment completely cuts out the deep SNB plate and places Pastoria plate directly onto
underplated trench sediments of the Rand schist. The same relationship exists at the southern
end of the Gabilan’s where correlative mid-crustal granitoids sit tectonically on correlative schists
of Sierra de Salinas. Palinspastic restoration of the Pastoria-Gabilan plate based on regional
primary batholithic zonation patterns, and complementary crustal levels, places the allochthon
above the SE SNB northeast of Tehachapi Valley. Logan Quarry crystalline rocks, and several
other small slivers along the inner edge of Salinia correlate to basement inlier rocks nonconformably beneath Maastrichtian(?) to early Paleogene marine strata of the westernmost San Emigdio
range. These rocks constitute a fragment of the Sierra Foothills metamorphic belt that restores
to a detachment surface that forms the nonconformity at the base of the eastern Maricopa basin
Tertiary section. Utilizing primary batholithic zonation patterns, crustal levels and transport data
on the Salinas shear zone that bounds underplated trench sediments, the Santa Lucia-Sierra
de Salinas massif restores to western Mojave lower crust, beneath the site of the west Antelope
basin. Dispersal of the Salinia crustal fragments first involved SW-directed large magnitude extension of the southernmost SNB-western Mojave batholith above a shallow flat subduction segment
as underplated trench sediments were educted from the Late Cretaceous subduction zone in a
regional return flow channel. The trenchward displaced batholithic fragments were rendered liable
for further dispersal along the SAF system.
9:10 AM
Powell, Robert E.
[172997]
BASEMENT, BASINS, AND TECTONICS: EARLY EVOLUTION OF SAN ANDREAS FAULT
SYSTEM IN SOUTHERN CALIFORNIA
POWELL, Robert E., U.S. Geological Survey, Geology and Geophysics Science Center,
520 N Park Ave, Tucson, AZ 85719, [email protected]
Evolution of the San Andreas Fault system in southern California led to disruption of a basement
terrain comprising an array of distinctive crystalline rock bodies. Deforming basement blocks
shed debris into adjacent syn-tectonic basins that later were deformed, inverted, and subsequently replaced by successor basins as blocks shifted along the evolving plate-margin fault
system. Earliest plate-margin fault-related basins formed during Oligocene and early Miocene
and accumulated predominantly volcanic-volcaniclastic sequences in basins in southeasternmost
California and predominantly sedimentary sequences in the Plush Ranch, Diligencia, and western
Vasquez basins farther northwest. Paleogeologic reintegration achieved by simultaneous restoration of crystalline basement units, basinal lithostratigraphic packages, and clast provenance
connections reveals much about deformational style, magnitude, and evolution of faulting phases.
Sequential restoration of San Andreas displacements—including 160-180 km on the San Andreas
Fault, 40-45 km on the San Gabriel-San Andreas Fault northwest of Saugus, and 100 km on
the Clemens Well-Fenner-San Francisquito-San Andreas (CW-SA) Fault (Powell, 1993)—is only
part of this history. Prior to and during movement along the CW-SA Fault, a structural domain
between the proto-eastern Transverse Ranges block and the proto-San Gabriel Mts-Frazier Mtn
block defined a broad zone, eventually including the CW-SA Fault, that underwent greater dextral
shear than the bounding proto-blocks. In this zone, transtension was accompanied by significant
clockwise rotation and internal disruption. The age of volcanism indicates that transtension,
accompanied by hyperextension in the Chocolate-Orocopia Mts region, began before inception
of the CW-SA Fault. Coevolving NNW-trending right-oblique faults likely contributed to this transtensional deformation and continued moving after slip on the CW-SA Fault ceased. The earliest
evidence for right slip is represented by a displacement of about 25 km that occurred along a
pre- to syn- Diligencia-Plush Ranch fault, which projects northwestward toward the Russell Fault
(Yeats and others, 1989) and may be the southeastward continuation of that fault.
1-3
9:40 AM
Ingersoll, Raymond V.
[172892]
RECONSTRUCTING THE DILIGENCIA AND VASQUEZ BASINS ACROSS THE SAN ANDREAS
FAULT (SOUTHERN CALIFORNIA)
INGERSOLL, Raymond V., Earth and Space Sciences, University of California, Los Angeles,
CA 90095-1567, [email protected]
Recent work by a UCLA team confirms that a NW-SE-trending normal fault (the Diligencia fault)
bounds the northeast side of the Diligencia basin (present orientations): 1. Stratal thicknesses
increase toward the northeast. 2. Composition, grain size and paleocurrents of basal Diligencia
conglomerate are consistent with derivation from proximal granite, which outcrops to the northeast of the basin. 3. Basal Diligencia conglomerate lies in angular unconformity on Eocene
Maniobra Formation along the north side of the basin, without faults. 4. To the NW, the Diligencia
fault aligns with a monocline expressed by the Maniobra nonconformity on Mesozoic granite.
5. Geophysical surveys across the Quaternary alluvium along the northeast side of the basin
indicate a fault between exposed granite and covered sedimentary or volcanic strata.
When the Diligencia basin and Diligencia fault are unrotated 90° counterclockwise and the
Soledad basin is unrotated 45° counterclockwise (as indicated by paleomagnetic data), and
240 km of dextral slip across the San Andreas and closely related faults are removed, the following elements align (NW to SE): 1. Mesozoic granitoids, 2. monoclinal flexure of Maniobra - San
Francisquito nonconformity on granitoids, 3. Maniobra-Diligencia and San Francisquito - Vasquez
unconformity, 4. half grabens of Diligencia and Charlie Canyon sub-basins (although with opposite
polarities), 5. Orocopia detachment - Clemens Well - San Francisquito faults, and 6. OrocopiaPelona Schist antiforms.
The Diligencia basin probably did not connect directly with any of the Soledad sub-basins
(Charlie Canyon, Texas Canyon and Vasquez Rocks), but it formed in a structural setting similar to
SESSION NO. 1
that of Charlie Canyon sub-basin. This reconstruction refines, but does not refute the reconstructions of Bohannon (1975) and Crowell (1975).
1-4
10:10 AM
Dorsey, Rebecca J.
[173150]
LATE MIOCENE ONSET OF PLATE-BOUNDARY STRAIN IN THE SALTON TROUGH REGION:
STRATIGRAPHIC EVIDENCE FROM SPLIT MOUNTAIN GORGE, SOUTHERN CALIFORNIA
DORSEY, Rebecca J.1, HOUSEN, Bernard A.2, SPEARS, Amy L.F.2, JANECKE, Susanne U.3,
AXEN, Gary4, MCDOUGALL, Kristin5, and SHIRVELL, Catherine6, (1) Dept. of Geological
Sciences, 1272 University of Oregon, Eugene, OR 97403-1272, [email protected],
(2) Geology Department, Western Washington University, 516 High St, Bellingham, WA
98225-9080, (3) Geology, Utah State University, 4505 Old Main Hill, Utah State University,
Logan, UT 84322-4505, (4) Department of Earth & Environmental Science, New Mexico
Tech, 801 Leroy Place, Socorro, NM 87801, (5) U. S. Geological Survey, 2255 N. Gemini Dr,
Flagstaff, AZ 86001, (6) ExxonMobil, Houston, TX 77002
Two groups of models have been proposed for the age of the Pacific-North America plate boundary in the Salton Trough and Gulf of California (ST-GC): (1) plate-boundary strain became localized along the ST-GC at ~5-6 Ma and has accumulated ~300 km of dextral offset; or (2) plate
motion in the ST-GC initiated ~12-17 Ma and accumulated ~300-450 km of offset. Group-1
models equal or exceed the plate rate (~50 mm/yr), and Group-2 models underestimate it by ~3060%. Lack of consensus on this question poses a major obstacle to understanding the kinematic
evolution of the Pacific-North America plate boundary. Based on recent stratigraphic, paleomagnetic, and micropaleontologic analysis of late Miocene sedimentary rocks at Split Mt. Gorge, we
test the applicability of these models and propose an intermediate solution. The Elephant Trees
Conglomerate (Me) rests nonconformably on Cretaceous tonalite and is ~8.1 +/- 0.4 Ma at its
base in a local paleovalley. Me coarsens up from fluvial sandstone to boulder-rich debris-flow and
landslide deposits, onlaps tonalite, and is capped by a large rock-avalanche megabreccia. These
deposits filled a complex basin bounded by extension- or transtension-related uplifts that generated steep unstable local topography. The lower megabreccia is abruptly overlain by the marine
Fish Creek Gypsum and turbidites of the Latrania Fm, which record rapid marine incursion at
6.27 Ma (top of the C3An.2n subchron). Basal marine deposits of remarkably similar age (~6.36.5 Ma) are preserved in a narrow belt for ~600 km along the ST-GC, indicating that the plate
boundary was in its present position by or before 6.3 Ma. Thus we infer that deposition of Me in
a structurally active basin between ~8 and 6.3 Ma records early off-fault strain associated with
initiation of the paleo-San Andreas Fault in the ST-GC corridor. Alternatively, (1) the paleo-San
Andreas Fault could have been active prior to 8 Ma without causing any deformation in this area,
or (2) these deposits could record intraplate deformation prior to localization of the plate boundary in the Salton Trough. The lead author favors a model in which the Pacific-North America plate
boundary was established in the Salton Trough and Gulf of California at about 7-8 Ma, but the
alternatives are also plausible.
1-5
10:40 AM
Janecke, Susanne U.
[173237]
EARLY PLEISTOCENE REORGANIZATION OF PLATE MOTION IN THE SALTON-TROUGHGULF OF CALIFORNIA
JANECKE, Susanne U., Department of Geology, Utah State University, 4505 Old Main Hill,
Logan, UT 84322-4505, [email protected] and DEMETS, Charles, Department of
Geoscience, University of Wisconson, 1215 W Dayton St, Madison, WI 53706
Recent studies in the northern Salton Trough document initiation of the San Jacinto, San Felipe,
and southern and central (?) Elsinore fault zones within a few hundred thousand years of one
another in the early Pleistocene. The Imperial and Cerro Prieto faults probably replaced the paleoSan Andreas fault in the southern Salton Trough at about the same time (Pacheco et al. 2006).
Here, we examine whether these shifts signal a previously unrecognized change in the kinematics
of the Gulf of California at this time. From bathymetric and magnetic data from the southern Gulf
of California, we find evidence for a ~5° CCW change since 3.5 Ma in direction along the Tamayo
transform fault and across the Alarcon Rise, in accord with results reported by MacDonald et al.
(1979). From well-mapped marine magnetic anomalies adjacent to the Tamayo fracture zone,
we estimate that this change occurred between ~1.8 Ma and ~1.2 Ma, when the transforms first
evolved to an ocean-ocean geometry (1.8 Ma) or a volcanic ridge began to form along the possibly
leaky transform (1.2 Ma). Relatively constant spreading rates of 48±2 mm/yr across the Alarcon
rise and northernmost East Pacific rise since ~2.5 Ma appear to exclude a change in seafloor
spreading rates as a possible cause of the proposed kinematic reorganization. Evidence documented by Aragon, Martin and other workers for 3-14° coeval CCW rotations of faults in the central
and northern Gulf is also consistent with a possible CCW change in the direction of separation
across the Gulf of California-Salton Trough during the early Pleistocene. In the central Gulf, faultstrikes rotate as much as 7-14° (Aragon et al, 2005). Rocks adjacent to the Ballenas Transform in
the northern Gulf record a 1.8 Ma pulse of heating that probably reflect its initiation (Sieler et al.,
2009). This kinematic change affected the entire ~1300 km long Salton-Trough-Gulf of California
plate boundary. It was likely synchronous because the reorganization is the same age at the north
and south ends of the province, where it is well dated. Contrary evidence includes a small number
of transforms faults that exhibit opposite-sense (CW) rotations during this period.
T12. Biotic Response to Phanerozoic Environmental
Change (Pacific Section SEPM; The Paleontological
Society)
2-1
8:40 AM
Baker, Jonathan L.
[173640]
CARBON ISOTOPIC FRACTIONATION ACROSS A LATE CAMBRIAN CARBONATE
PLATFORM: A REGIONAL RESPONSE TO THE SPICE EVENT AS RECORDED IN THE
GREAT BASIN, WESTERN UNITED STATES
BAKER, Jonathan L., JIANG, Ganqing, and ZEIZA, Adam, Geoscience, University of
Nevada, Las Vegas, 4505 Maryland Parkway, Box 454010, Las Vegas, NV 89154-4010,
[email protected]
Geochemical models have proposed that the late Cambrian was characterized by a greenhouse
climate with high pCO2. Furthermore, stable-isotope analyses within the Great Basin have docu-
44 2010 GSA Abstracts with Programs mented a large carbon isotope (δ13Ccarb) excursion, known as the Steptoean Positive Carbon
Isotope Excursion (SPICE). This event has been documented globally, and is interpreted as
having resulted from enhanced organic carbon burial. Unless the size of carbon reservoirs in the
Cambrian ocean was significantly different from those of the Cenozoic, this forcing should have
resulted in a comparable excursion in organic carbon (δ13Corg). It is also predicted that increased
organic carbon burial would lower atmospheric CO2. Organic carbon isotope data are presented
here from Shingle Pass, Nevada and House Range, Utah. At Shingle Pass, δ13Corg values record
a positive excursion that roughly mirrors δ13Ccarb values at a similar magnitude, suggesting an
oceanographic control on the carbon isotope trend. In the House Range section, although δ13Corg
values show a rough positive shift associated with δ13Ccarb, the magnitude is smaller and values
show minor shifts across the excursion. We interpret this to reflect a larger chemoautotrophic
biomass contribution in the relatively deep water, semi-restricted basinal setting. The difference
between organic and inorganic carbon isotope values (Δ13C) averages 27-28 per mil across both
sections, but increases to 30 per mil at the peak of the excursion and falls to as low as 25 per
mil immediately after the Sauk II/III sequence boundary. We interpret the parallel but reduced
excursion in δ13Corg values did reflect the production changes temporally across the SPICE event.
During greenhouse conditions, Δ13C is less sensitive to changes in atmospheric CO2. Thus the
increased organic fractionation during the SPICE event may have rather been due to diminished
growth rates concomitant with sea level fall and a potential drop in atmospheric carbon dioxide.
2-2
8:55 AM
Clapham, Matthew E.
[173601]
REGIONAL-SCALE FAUNAL CHANGES DURING EARLY PERMIAN CLIMATE FLUCTUATIONS
CLAPHAM, Matthew E., Department of Earth and Planetary Sciences, University of
California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, [email protected]
The geographic distribution of a marine invertebrate taxon is influenced by its temperature tolerance and dispersal capability. As a result, paleobiogeographic patterns can provide an estimate of
relative paleotemperature and ocean circulation patterns to help constrain climate model results,
analogous to but potentially more sensitive than climate-sensitive sediments. I used a database
containing occurrences of more than 2750 marine invertebrate genera at 12,000 Permian fossil
localities to produce quantitative estimates of the climatic affinity of the marine fauna. For each
genus, the mean paleolatitude of its occurrences was calculated to provide an estimate of its
temperature sensitivity; the paleoclimate of a 1 degree by 1 degree bin was then estimated from
the mean temperature sensitivity value of all genera occurring that bin. The overall pattern closely
matches previous paleobiogeographic reconstructions and is able to quantify trends previously
recognized from qualitative approaches, such as the progressive cooling of Boreal regions from
the Sakmarian to Wordian. More subtle regional changes can also be reconstructed. Northern
hemisphere faunas from eastern Panthalassa have a cooler climate affinity than faunas from
similar paleolatitudes on the western margin, consistent with the expected influence of cool and
warm boundary currents. Temporal trends in western Laurentian faunas further indicate intensification or cooling of the southerly-flowing boundary current in the Middle Permian. Similar faunal
changes and climatic boundaries can be identified in the Cimmerian continents in Tethys and in
eastern Australia, placing constraints on paleotemperature changes and the location and intensity
of ocean currents during major Permian climate fluctuations.
2-3
9:10 AM
Woods, Adam D.
[173289]
PRIMARY PRODUCTIVITY DURING THE EARLY TRIASSIC BIOTIC RECOVERY
IN THE WESTERN CANADA SEDIMENTARY BASIN AND ITS RELATIONSHIP TO
PALEOENVIRONMENTAL CONDITIONS
WOODS, Adam D., Department of Geological Sciences, California State University, Fullerton,
800 North State College Blvd, Fullerton, CA 92834-6850, [email protected], BEATTY,
Tyler W., Consortia for Applied Basin Studies, Dept. of Geoscience, University of Calgary,
2500 University Drive N.W, Calgary, AB T2N 1N4, and ZONNEVELD, J.-P., Department of
Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB T6G 2E3, Canada
Biotic recovery following the Permian-Triassic mass extinction and its relationship to environmental conditions has been extensively studied over the past 2 decades, while the recovery of primary
producers, which is a critical element in any recovery, has received scant attention. Estimates
of primary productivity following the Permian-Triassic mass extinction are contradictory, with
δ13Corg isotopes suggesting that primary productivity returned within 50-100 ka, while stagelevel comparisons of chert and phosphorite abundances imply an extended productivity slump.
These differing results suggest that while productivity may have returned quickly, it remained
unstable. In order to gain a better perspective of when primary productivity returned from the
Permian-Triassic mass extinction, and its relationship to paleoenvironmental conditions (specifically paleoxygenation), major, minor, and trace element data is being collected from multiple outcrops and cores from across the Western Canada Sedimentary Basin (WCSB), which stretches
~1000km along the BC – AB border. Data has been collected from each of the 3 subbasins that
make up the WCSB (Opal Creek locality, Spray River Basin, southern AB; Cadomin locality,
Peace River Basin, central AB; Pedigree-Ring Border-Kahntah River area cores, Liard Basin,
northeastern BC). Results from Opal Creek and Cadomin demonstrate that productivity collapsed
at the P/T boundary, but quickly recovered in the early Griesbachian. Paleoproductivity remained
robust at the Opal Creek locality through the top of the section, while anoxic conditions receded
near the Dienerian-Smithian boundary. Paleoproductivity covaries positively with paleoxygenation
at the Cadomin locality following the early Griesbachian, suggesting that paleoxygenation may
have been at least partially related to organic input. Analysis of samples from the Liard Basin
have concentrated thus far on Smithian-aged rocks, and results indicate that productivity was
robust across the interval, with shifts in paleoxygenation related to sea-level variations. Ongoing
analyses from additional localities across the WCSB should further clarify productivity and paleoxygenation trends and their relationship to each other as well as macrofaunal trends during the
post-extinction recovery interval.
2-4
9:25 AM
Mata, Scott A.
[172933]
CONTROLS ON THE DISTRIBUTION OF BENTHIC MICROBIAL MATS DURING THE EARLY
TRIASSIC AFTERMATH OF THE END-PERMIAN MASS EXTINCTION: EXAMPLES FROM THE
SOUTHWESTERN UNITED STATES
MATA, Scott A. and BOTTJER, David J., Department of Earth Sciences, University of
Southern California, Los Angeles, CA 90089-0740, [email protected]
The expansion of microbial mats into marine subtidal settings has become a hallmark of the
Lower Triassic sedimentary record and has greatly influenced the understanding of the unusual
benthic and oceanographic conditions that persisted throughout the duration of Early Triassic
time. It has been shown by many workers that there are numerous significant pulses of microbial
carbonate in the form of stromatolitic and thrombolitic patch reefs that can be found in marine
subtidal settings in the aftermath of the end-Permian mass extinction, yet knowledge of the existence of benthic microbial mats in siliciclastic settings during this interval was lacking until only
recently. The discovery of wrinkle structures—microbial features comprised of mm-scale ridges,
pits, and troughs that commonly exhibit a patchy distribution and an irregularly meandering
SESSION NO. 2
morphology—by Pruss et al. (2004) in Lower Triassic storm-dominated shelf strata showed that
the microbialite record for this time was not restricted solely to carbonate environments.
It is now known that wrinkle structures occur in storm-dominated strata from the southwestern
United States, northern Italy, northern Pakistan, and northern Iraq. At each locality wrinkle structures are associated with subtidal storm deposits that often display hummocky or swaley crossstratification. In the southwestern United States, wrinkle structures are found within the Lower
Triassic Thaynes Formation and the Virgin Limestone Member of the Moenkopi Formation and are
found predominantly across marine flooding surfaces—stratal surfaces in which there is an abrupt
increase in water depth upsection—separating underlying nearshore sandstones from overlying
deeper-water siltstone and shale. Wrinkle structures provide profound insight into the nature of
the Early Triassic seafloor and suggest, by the presence of these benthic microbial mats, that during their formation a surface mixed-layer, which is a characteristic feature of most post-Cambrian
seafloors, was commonly non-existent during this unusual interval in Earth’s history.
2-5
9:40 AM
McCoy, Jennifer, M.
[173231]
DIVERSITY OF STROMATOLITES IN THE LOWER TRIASSIC VIRGIN LIMESTONE
(MOENKOPI FORMATION) NEAR BLUE DIAMOND, NV
MCCOY, Jennifer, M., Geological Sciences, California State University, Fullerton, 310 N.
Indian Hill Blvd, 153, Claremont, CA 91711, [email protected] and WOODS,
Adam D., Department of Geological Sciences, California State University, Fullerton,
800 North State College Blvd, Fullerton, CA 92834-6850
Numerous studies have attempted to shed light on environmental conditions that enabled the formation of anachronistic facies in the aftermath of the Permian-Triassic mass extinction. Unusual
carbonates, such as flat pebble conglomerates and large seafloor cements, and the proliferation
of microbialites are indicative of the presence of alkaline and anoxic seawater, and such hostile
environmental conditions would have hindered the post-extinction biotic recovery. The presence of
well developed, laterally extensive domal stromatolites in the Spathian Virgin Limestone Member
of the Moenkopi Formation near Blue Diamond, NV, supports the model of stressed environmental conditions along the shallow shelf. These stromatolites are stratigraphically lower than
those reported at Lost Cabin Springs, and are the earliest observed microbialites in the Virgin
Limestone.
Stromatolites occur in micritic limestone as laterally linked hemispheroids, isolated hemispheroids, and meter-scale lozenge-shaped masses. Laterally linked hemispheroids up to 20 cm
in diameter have well defined wavy laminae; in several samples, centimeter-scale fingering is
apparent. Isolated domes have a similar hemispherical shape and wavy laminae, but at a smaller
scale, <10 cm. Lozenge-shaped masses appear to be aggregates of columnar domes; polished
slabs of the stromatolite aggregates reveal closely packed decimeter-scale columns with constant
diameter. In all three forms, the appearance of layering is enhanced by the concentration of oxidized iron minerals (formerly pyrite?) along laminae.
Surrounding units include hummocky cross-stratified lime mudstone, beds of large (>3 cm)
oriented bivalve shells, and mudchip horizons, which are indicative of occasional storm events
and deposition in a subtidal environment. These stromatolites, therefore, represent an additional example of subtidal microbialite growth following the Permian-Triassic mass extinction.
Widespread microbialites are thought to represent the combination of a dampening of burrowing
and grazing behaviors in the wake of the extinction, coupled with environmental conditions that
likely enhanced the growth of microbial and abiotic calcium carbonate.
2-6
10:10 AM
Pietsch, Carlie
10:25 AM
Kelley, Neil P.
2-8
10:40 AM
Monarrez, Pedro M.
[173277]
DAZED AND CONFUSED: BIVALVE AND BRACHIOPOD OCCURRENCE TRENDS
FOLLOWING THE END-PERMIAN MASS EXTINCTION
MONARREZ, Pedro M. and BONUSO, Nicole, Department of Geological Sciences,
California State University, Fullerton, 800 N. State College Blvd, Fullerton, CA 92834-6850,
[email protected]
Studies suggest that survival taxa of mass extinctions go through greater attrition after extinction
events than during the extinction event itself, generally during the onset of recovery. An important
aspect of studying the recovery of a mass extinction is distinguishing the recovery fauna from
the survival fauna. Studying the occurrence intervals of taxa aids in determining the onset of the
recovery phase. This project focuses on comparing the dominant genera that occur in the Early
and Middle Triassic, i.e. bivalves and brachiopods, to distinguish survival and recovery genera
following the end-Permian mass extinction. For this study, we define survival genera as genera
that originated prior to the mass extinction and during the Early Triassic but died out before the
Middle Triassic. Recovery genera are defined as genera that disappeared during the mass extinction but reappeared during the Middle Triassic and persisted beyond (i.e., Lazarus Taxa) and
genera that originated following the mass extinction and persisted beyond the Middle Triassic.
Genera data were downloaded from the Paleobiology Database (PBDB) based on the following
criteria: genera occurring in marine environments with carbonate, siliciclastic or mixed lithologies,
environment zones ranging from marginal to shelf slope and basin, and only genera occurrences
in North America. Once our genera list was compiled, we used the Strauss and Sadler (1989)
method from the PBDB to plot genera range and calculate confidence intervals. This method
calculates confidence intervals on the endpoints of local stratigraphic ranges using a Bayesian
approach. The data set comprises 62 bivalve genera and 18 brachiopod genera. A total of 53% of
the bivalve genera originated during the Triassic (31% during the Early Triassic and 22% during
the Middle Triassic) while the remaining 47% of the genera originated during the Paleozoic. A total
of 61% of the brachiopod genera originated during the Triassic (33% during the Early Triassic and
28% during the Middle Triassic) while the remaining 39% originated during the Paleozoic. Genera
ranges reveal that 79% of bivalve and 61% of brachiopod genera are considered recovery genera.
This study suggests that the majority of surviving bivalve and brachiopod genera faced relatively
low attrition following the mass extinction.
[173280]
UNDERSTANDING EARLY TRIASSIC BENTHIC INVERTEBRATE DIVERSITY AND ECOLOGY
AND CORRESPONDING CARBON ISOTOPE EXCURSIONS
PIETSCH, Carlie, University of Southern California, Los Angeles, CA 90089, cp236@
cornell.edu and BOTTJER, David J., Department of Earth Sciences, University of Southern
California, Zumberge Hall 117, Los Angeles, CA 90089-0740
The end-Permian mass extinction resulted in the demise of ~90% of marine genera. Recent work
on the Early Triassic using carbon isotopes, ammonoids, conodonts, and some benthic fauna
shows that this supposed recovery period was almost as turbulent as the extinction itself. Carbon
isotope records from China, India, and Italy portray a global signal with major perturbations at
stage boundaries in the Early Triassic most likely resulting from rapid and widespread volcanic
eruptions of a magnitude that could alter environmental conditions. The coinciding nature of the
global cycles of extinction and radiation of ammonoids and conodonts with global carbon isotope
excursions as well as anachronistic microbialite and carbonate fan deposition, suggests that all
three are related. In order to investigate the ubiquity of the connection between the carbon signal
and biological changes, benthic diversity and ecology need to be more thoroughly investigated.
A literature review showed evidence for gradual increases in both taxonomic and guild diversity.
Taxonomic diversity increased from 26 genera in the Griesbachian to 66 genera by the Spathian.
The lack of evenness in the recovery suggests ecological stagnation: dominance of a few disaster
and opportunistic genera occupying only a few life habits. To better understand this turbulent
period, we investigated the Spathian-Anisian benthic communities of the Virgin Limestone. These
two Early to Middle Triassic stages were chosen for study because of a major carbon isotope
excursion that occurs at the boundary, which corresponds in magnitude to the excursion at the
end-Permian. Additionally, sequence stratigraphic analysis of the boundary finds beds of benthic
invertebrates in stratigraphic contact with anachronistic microbialite facies suggesting a close
proximity of an anoxic environment with more habitable ocean conditions. Patterns in benthic and
pelagic diversity, in relation to the Spathian-Anisian excursion, both point to environmental instability in the Early Triassic as the probable cause for the protraction of the biotic crisis.
2-7
We compiled species level taxonomic records at the stage level to explore patterns in marine
reptile diversity through time. Overall patterns of diversification were compared to published
trends of Triassic seawater chemistry based on measurements from marine invertebrate fossils
to explore possible links between changes in the Triassic oceans and marine reptile evolution. We
also grouped marine reptiles according to tooth shape, limb shape and tail shape to test for ecologically selective extinction based on habitat or dietary preferences.
Peak taxonomic and ecological diversity of marine reptiles in the Middle Triassic corresponds
to an interval characterized by relatively stable δ13C and δ18O values, as well as less radiogenic
87Sr/86Sr values, consistent with reduced sedimentary input, higher sea level and well oxygenated, temperate ocean conditions. The Late Triassic is characterized by pronounced δ13C and
δ18O fluctuations and increasingly radiogenic 87Sr/86Sr consistent with falling sea levels and
anoxic pulses. The step-wise extinction of marine reptile clades adapted to near-shore/benthic
environments may be linked to these changes. Only fully pelagic forms survived into the Jurassic.
Other marine organisms continued to thrive until the terminal Triassic extinction event suggesting
that marine reptiles may have been especially sensitive to fluctuations in sea-level and reduction
in nearshore habitat.
[173581]
2-9
10:55 AM
Scott, Eric
[173245]
BIOSTRATIGRAPHY AND NORTH AMERICAN PLEISTOCENE MEGAFAUNAL EXTINCTIONS
SCOTT, Eric, Division of Geological Sciences, San Bernardino County Museum,
2024 Orange Tree Lane, Redlands, CA 92374, [email protected]
Several scenarios have been proposed to explain the terminal Pleistocene large mammal extinction event in North America, including climate warming and/or cooling, overhunting by early
humans, disease, and bolide detonation or impact. Each of these premises seeks factors making
the end-Pleistocene deglaciation uniquely different from earlier such periods of climate change,
then infers that the observed difference is responsible for the extinction. Common to all of these
scenarios is the assumption that large mammals present in North America at the end of the
Pleistocene were also present in similar abundance, with similar geographic distributions, during
earlier, equally severe periods of climate change (e.g., ~125 ka BP). Consideration of biostratigraphic data negates this assumption. The genus Bison, index taxon for the Rancholabrean North
American Land Mammal Age (≤ 240 ka - ~10 ka BP), was numerically profuse and geographically
widespread in the later Pleistocene, particularly in the American West. Living bison are massive
grazing ruminants that dramatically impact biological communities; their Pleistocene forebears
were still larger. The presence of these animals constitutes a significant difference between later
Pleistocene and earlier large mammal faunas in North America. Further, the latest Pleistocene
species Bison antiquus was more widely distributed and present in greater profusion than earlier
species such as the larger B. latifrons south of the glacial ice. The increased abundance and
distribution of these large, aggressive, herd-dwelling ruminants through time in late Pleistocene
North America constitutes a critical distinction between end-Pleistocene communities and those
of all earlier, similarly intense glacial-interglacial transitions, particularly with respect to the potential of increased competition for available resources. Responses of the megafauna to changing
climatic conditions at the end of the Pleistocene were therefore unique. Extinction scenarios for
Pleistocene North America should avoid assuming a relatively static long-term faunal component,
and consider the potential impacts of non-human immigrant species on natives – particularly
when immigration and subsequent evolutionary trajectories are relatively close in time and space
with climate changes.
SUFFERING A SEA CHANGE: THE EVOLUTION AND EXTINCTION OF TRIASSIC
MARINE REPTILES
KELLEY, Neil P., Geology, University of California, Davis, 1 Shields Avenue, Davis, CA
95616, [email protected], MOTANI, Ryosuke, Geology, University of California, Davis,
One Shields Ave, Davis, CA 95616, JIANG, Da-yong, Geology, Peking University, Beijing,
100871, China, RIEPPEL, Olivier, Field Museum, 1400 S. Lake Shore Dr, Chicago, IL 606052496, and OSTER, Jessica, Geology, University of California, Davis, One Shields Avenue,
Davis, CA 95616
Secondarily marine reptiles occupied the top trophic levels of many Mesozoic marine ecosystems.
The first appearance of marine reptiles in the Spathian was synchronous with the stabilization of carbon isotopes and the end of the Early Triassic delayed recovery interval following the
Permo-Triassic mass extinction. Marine reptiles diversified rapidly during the Middle Triassic and
exhibited high morphological disparity in terms of dentition and body plan indicative of substantial
ecological diversity. Overall marine reptile taxonomic diversity declined in Late Triassic, apparently
well-before the terminal Triassic mass-extinction of other marine and terrestrial taxa. However, the
mechanisms behind this decline have not been scrutinized.
SESSION NO. 3
3-1
8:40 AM
Malkowski, Matthew A.
[173680]
NEW PROVENANCE CONSTRAINT FROM UPPER PALEOZOIC STRATA OF THE FAREWELL
TERRANE, SOUTHWEST ALASKA
MALKOWSKI, Matthew A., Geological Sciences, Michigan State University, 206 Natural
Science Building, East Lansing, MI 48824, [email protected], HAMPTON, Brian A.,
Dept. of Geological Sciences, Michigan State University, 206 Natural Science Building,
East Lansing, MI 48824-1115, BRADLEY, Dwight C., U.S. Geological Survey, 4210 University
Drive, Anchorage, AK 99508, and GEHRELS, George E., Department of Geosciences,
University of Arizona, Tucson, AZ 85721
Paleozoic strata of the Farewell terrane are exposed primarily in the Alaska Range of southwestern Alaska and throughout the foothills of west-central Alaska. Three, somewhat distinct stratigraphic successions make up the Farewell terrane and consist of (1) Neoproterozoic–Devonian
carbonate rocks of the Nixon Fork subterrane, (2) Cambrian–Devonian carbonate and siliciclastic
strata of the Dillinger subterrane, and (3) Devonian–Permian(?) siliciclastic strata of the Mystic
subterrane. Some of the more widespread units of the Mystic subterrane consist of Devonian(?)–
Pennsylvanian submarine fan deposits and a Permian marginal-marine to nonmarine fluvialdeltaic deposits.
New provenance data from Upper Paleozoic strata of the Mystic subterrane reveal a diverse
range of Precambrian and Paleozoic age detrital grains. Three U-Pb detrital zircon samples, collected from the Mystic Pass region of southwest Alaska yield primary age peaks between 300–
350 and 420–450 with smaller peaks between 1800–2000 Ma. A fourth and slightly older sample,
collected from near the Farewell Lakes-Sheep Creek region, yields a dominant peak at ~450 Ma
with minor peak at 600, and occurrences between 1000–2000 Ma. Modal composition trends from
these strata reveal pervasive occurrences of mono- and polycrystalline quartz, plagioclase, as
well as a very strong lithic volcanic component.
Provenance and faunal data from Neoproterozoic–Devonian strata of the Dillinger and Nixon
Fork subterranes have been used to suggest a Siberian-link for the Farewell terrane. However,
while the Mystic subterrane does share some provenance trends with Dillinger and Nixon Fork
strata, preliminary provenance data potentially suggest a link with Laurentia toward the end of the
Paleozoic. The relative abundance of lithic volcanic detritus in these strata may reflect the occurrence of a significant arc source area that was being exhumed throughout much of the depositional history of these strata.
3-2
9:00 AM
Kochelek, Evan J.
[172791]
DETRITAL ZIRCON AGES FROM THE VALDEZ GROUP INDICATE RAPID LATEST
CRETACEOUS DEPOSITION IN THE CHUGACH ACCRETIONARY COMPLEX,
SOUTHERN ALASKA
KOCHELEK, Evan J., Geosciences, New Mexico State University, Dept. Geological
Sciences/MSC 3AB, New Mexico State University PO Box 30001, Las Cruces, NM 88003,
[email protected] and AMATO, Jeffrey M., Department of Geological Sciences,
New Mexico State University, MSC 3AB, PO Box 30001, Las Cruces, NM 88003
Four volcanic litharenite (greywacke) samples from the Valdez Group were dated in a study of
the Late Cretaceous-Paleocene flysch facies of the Chugach terrane accretionary complex.
Petrography supports previous interpretation of an arc provenance for these marine turbidite
deposits. U-Pb detrital zircon ages were obtained using LA-MC-ICPMS; total number of analyses
per sample ranged from 50 to 100. Three samples were collected on a ~50 km transect of the
Valdez Group along Turnagain Arm southeast of Anchorage, Alaska. AnJ06 has a youngest
population of three grains with an age of 67±3 Ma (2s), a dominant Late Cretaceous population,
a very minor Triassic-Jurassic population, two Paleozoic and two Proterzoic grains. AnJ13 has
a population of six grains with an age of 68±2 Ma, a dominant Late Cretaceous population, a
significant Triassic-Jurassic population, two Paleozoic, and three Proterozoic grains. Ked24 has
a population of seven grains with an age of 68±2 Ma, a dominant Late Cretaceous population,
a significant Triassic-Jurassic population, eight Paleozoic and nine Proterozoic grains. AnJ40
was collected from near Mt. Magnificent which is mapped as part of the Valdez Group ~30 km
northeast of Anchorage and has an older population of seven grains with an age of 82±3 Ma, a
large (30% of grains) Late Cretaceous population but a more significant (46% of grains) TriassicJurassic population, one Paleozoic, and nine Proterozoic grains. We propose that based on
petrology, and the detrital zircon ages, the Coast orogen in British Columbia was the main source
of Late Cretaceous zircons in the Valdez Group flysch. These similar youngest ages constrain
the maximum depositional age on the ~50 km transect could indicate rapid, large volume deposition. These data indicate a gap of 15-20 m.y. between the McHugh complex mélange facies and
the Valdez Group may indicate a period of tectonic erosion between accretion of the McHugh
Complex and the Valdez Group.
3-3
9:20 AM
Garver, John I.
[173216]
UPLIFT AND EXHUMATION OF THE CHUGACH-PRINCE WILLIAM TERRANE, ALASKA,
REVEALED THROUGH VARIABLE ANNEALING OF FISSION TRACKS IN DETRITAL ZIRCON
GARVER, John I., Geology Department, Union College, 807 Union ST, Olin Center,
Schenectady, NY 12308, [email protected], ENKELMANN, Eva, Institut fur
Geowissenschaften, Universität Tubingen, Wilhelmstr. 56, Tubingen, Germany, and
KVETON, Kevin J., Chevron Indonesia, Sentral Senayan I, 14th Floor, Jl. Asia Afrika No. 8,
Jakarta, 10270, Indonesia
The Chugach-Prince William (CPW) terrane is a Mesozoic-Tertiary accretionary complex exposed
for ~2000 km in southern Alaska. Pervasive prehnite-pumpellyite metamorphism presents unique
challenges for thermochronolgy because many of these rocks lack primary datable phases. We
use variable thermal resetting of fission tracks in detrital zircon from sandstones of the CPW
terrane to understand the time-temperature history of these low-grade rocks. On Kodiak Island,
analysis of samples from the Maastrictian Kodiak Formation and the Paleocene Ghost Rocks,
shows they experienced a similar thermal history, and they record two distinct cooling events: one
at c. 60 Ma and one at c. 47 Ma: the latter population is more robust as it can only be comprised
of fully annealed zircon. The fraction of fully annealed grains in the younger population may sug-
46 2010 GSA Abstracts with Programs gest hotter Tmax for the Kodiak Formation. Other studies have shown that these units have vitrinite values (%Ro = 2.95 to 4.0) and fluid inclusions that suggest Tmax of 250-300°C and depths of
c. 10 km. The more outboard Eocene Sitkalidak Formation has not seen thermal annealing of zircon, and the populations of these grains reveal details of sediment provenance. In Prince William
Sound, about 375 km to the east, in and around Bainbridge Island, we dated 14 samples from the
Orca Group that show young ZFT reset ages between 30-40 Ma. Given the mineral assemblage
and vitrinite values from these samples (%Ro = 2.9-4.0), these rocks also experienced Tmax
between 250-300°C and depths of c. 10 km. In the main Chugach Range, some 260 km to the
east of PWS, we use detrital zircon from modern rivers confined to the CPW bedrock as a proxy
for the thermal evolution of this part of the terrane. These data show that most of these rocks
have young ZFT reset ages between 20 and 35 Ma. While low-grade metamorphism is common
here as well, locally these rocks experienced amphibolite-grade metamorphism. We ask whether
there is a spatial and temporal pattern of exhumation in the CPW related to translation, accretion,
and collision. These three locations show progressive younger reset ages from west to east. This
progression has implications for the locus of unroofing and the volume of material that must have
fed adjacent basins.
3-4
10:00 AM
Evenson, Nathan S.
[173246]
U-PB DETRITAL ZIRCON GEOCHRONOLOGY AND PROVENANCE OF THE PALEOGENENEOGENE KOOTZNAHOO FORMATION, SOUTHEAST ALASKA: A SEDIMENTARY RECORD
OF COAST MOUNTAINS EXHUMATION
EVENSON, Nathan S.1, HENDERSON, Tiffany2, ANCUTA, Lenny3, DAVIDSON, Cameron1,
WHITE, Timothy S.4, and WIRTH, Karl R.5, (1) Department of Geology, Carleton College,
One North College St, Northfield, MN 55057, [email protected], (2) Geosciences
Department, Trinity University, One Trinity Place, San Antonio, TX 78212, (3) Geology
Department, Union College, Schenectady, NY 12308, (4) Earth and Environmental Systems
Institute, The Pennsylvania State University, 217 EES Building, University Park, PA 16802,
(5) Geology Department, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105
Quartzo-feldspathic arenites of the Kootznahoo Formation in southeast Alaska contain detrital
zircon U-Pb age distributions dominated by plutonic zircon populations at 190-160, 95-85, and
65-50 Ma. These populations suggest derivation from the adjacent Coast Mountains Batholith
complex, and maximum depositional ages suggest that most of the Kootznahoo Formation in the
study area was deposited between 60-25 Ma. We use the Kolgomorov-Smirnov statistical test to
demonstrate a depositional affinity between the Kootznahoo Formation exposed in Little Pybus
Bay on Admiralty Island and the lower portion of the Kootznahoo stratigraphy in the Keku Straits
region to the south on Kupreanof Island. An abrupt influx of early Paleogene-aged zircons (65 to
50 Ma) implies that the initial un-roofing of the Coast Plutonic Complex, east of the Coast Shear
Zone, is captured within the lower part of the Kootznahoo stratigraphy between 60-50 Ma. Our
data also suggests the development of a depositional hiatus or erosional unconformity at about
50 Ma followed by sedimentation between 40 and 25 Ma. The development of this unconformity
may be due to uplift and subsidence driven by subduction of an oceanic ridge at approximately
50 Ma. A change in lithofacies from arkosic sandstones and conglomerate with plutonic clasts to
dominantly volcaniclastic sandstones and conglomerate with volcanic clasts occurs in the upper
most part of the section. This change coincides with a pronounced influx of 27-25 Ma zircons
most likely derived from volcanic rocks related to the Admiralty Island Volcanics.
3-5
10:20 AM
Ancuta, Lenny
[173265]
DETRITAL ZIRCON FISSION TRACK AGES OF THE PALEOGENE KOOTZNAHOO
FORMATION, SOUTHEAST ALASKA
ANCUTA, Lenny, Geology Department, Union College, 807 Union St, Schenectady, NY
12308, [email protected] and GARVER, John I., Geology Department, Union College,
807 Union ST, Olin Center, Schenectady, NY 12308
Arkosic and lithic sandstones of the Paleogene Kootznahoo Formation in the Keku Straits region
on Kupreanof Island and the Little Pybus Bay section on Admiralty Island in southeast Alaska
record the exhumation of distinct sources adjacent to the Admiralty trough. Fission Track (ZFT)
and U/Pb dating of detrital zircon have been used to understand sediment provenance, basin
evolution, and exhumation of flanking terranes. ZFT ages from the base of the section have component populations at ~55 and 67 Ma. ZFT age from the middle of the section have component
populations at 51 and 39 Ma. ZFT ages from the top of the stratigraphic section have three populations at 35, 48 and 69 Ma. We entertain the idea that sediment of the Kootznahoo Formation
record mixing of material from the Coast Plutonic Complex to the east and the Chugach terrane
to the west. The ZFT cooling ages from 51-55 Ma likely represent rapid exhumation of the Coast
Mountains, which flanks the Admiralty trough to the east. Upwards in the stratigraphy, the pattern
is more complicated because both younger and older cooling ages emerge. The young population
may represent the uplift and exhumation of the Chugach terrane along the western basin margin.
Garnet-bearing schist clasts in strata at the top of the section may have been eroded from the
Baranof Schist of the Chugach terrane. The 35-39 Ma ZFT population may show exhumation of
the Chugach terrane, which is known to have cooled dramatically in this interval. Exhumation
likely caused denudation of Chugach cover strata and produced the 69 Ma population. It is
unclear if the 48 Ma population is associated with continued exhumation of the Coast Mountains
or erosion of the Chugach. U/Pb ages through the section are consistent with a CPC source,
though these data cannot rule out exhumation of the Chugach because it most of these strata
are also inferred to have been derived from Coast Mountain Complex. ZFT ages from samples
taken adjacent to three dikes show a clear thermal resetting of three samples at 23 Ma, which
constrains the minimum depositional age of the Kootznahoo Formation.
3-6
10:40 AM
Memeti, Vali
[173651]
ICP-MS AND TIMS ZIRCON DATING IN THE SIERRA NEVADA: INITIAL IMPLICATIONS FOR
TECTONIC AND MAGMATIC PROCESSES
PATERSON, Scott R., Department of Earth Sciences, University of Southern California,
Los Angeles, CA 90089-0740, [email protected], MEMETI, Vali, Department of Earth and
Planetary Sciences, Washington University in St. Louis, 1 Brookings Dr, St. Louis, MO 631304862, [email protected], and MUNDIL, Roland, Berkeley Geochronology Ctr, 2455 Ridge Rd,
Berkeley, CA 94709-1211
LA-ICPMS geochronology of zircon populations in 54 new samples including 38 metasedimentary
samples, 14 volcanic samples, and two plutonic samples from the central and southern Sierra
Nevada are combined with 25 CA-TIMS zircon ages from several plutons intruding the above. We
are using these data to (1) determine the age and origin of metasedimentary and metavolcanic
packages in pendants in the Sierra Nevada batholith and terranes of the Western Metamorphic
belt; (2) evaluate proposed tectonic scenarios for the Sierra; and (3) investigate magmatic processes and the degree of host rock assimilation by granitoids.
Our preliminary results confirm the following: (1) Golconda and younger sedimentary packages
occur in the Saddlebag Lake pendant; (2) miogeoclinal strata are preserved in pendants from just
north of the Tuolumne Batholith to the Lake Isabella area, southern Sierra, (3) Jurassic marine
SESSION NO. 5
sequence(s) are recognized in pendants throughout the Sierra and may form an overlap assemblage on both of the above; (4) a belt of Cretaceous volcanic rocks is preserved in pendants along
the central axis of the Sierra, and overlie the marine Jurassic rocks; and (5) clastic metasedimentary units in the Calaveras Complex are no older than Jurassic.
We further examined Death Valley and Inyo Facies units as potential source regions for miogeoclinal rocks in Sierran pendants. Our preliminary comparison of zircon populations from the
Eureka quartzite in the Talc City Hills area with those in the May Lake pendant show considerable
overlap. Thus zircon populations from the Inyo and Death Valley facies strata are equally permissive as source regions. Since the Eureka Quartzite is missing in the Mojave Desert, a ≤200 km
amount of displacement along the Mojave-Snow Lake fault may be a more likely scenario.
Our new ages also indicate that Precambian zircon xenocrysts are largely absent in the dated
plutons although common in some nearby host rocks, whereas Mesozoic xenocrystic zircons do
locally occur in these plutons. Finally, even though aureole T’s range up to ~700 oC, LA-ICPMS
zircon ages are not reset in samples from these aureoles nor do they fall below the TIMS ages of
the intruding plutons.
3-7
11:00 AM
González-León, Carlos
[173129]
U-PB GEOCHRONOLOGY OF LARAMIDE MAGMATISM IN NORTH-CENTRAL SONORA,
MEXICO
GONZÁLEZ-LEÓN, Carlos, Instituto de Geología, UNAM, Estación Regional del Noroeste,
Apartado Postal 1039, Hermosillo, Sonora, 83000, Mexico, [email protected], SOLARI,
Luigi, UNAM, Centro de Geociencias, Juriquilla, Queretaro, 76230, Mexico, VALENCIA,
Victor, Valencia Geoservices, 3389 N River Rapids Dr, Tucson AZ, AZ 85712, LAWTON,
Timothy F., Geological Sciences/MSC 3AB, New Mexico State University, P.O. Box 30001,
Las Cruces, NM 88003, LOPEZ-MARTINEZ, Margarita, Lab. de Geocronologia, CICESE,
Km. 107, carr. Tij-Ensenada, Ensenada, Baja Calif, 83000, Mexico, GRAY, Floyd, United
States Geological Survey, 520 North Park Avenue, Tucson, AZ 85721, BERNAL, Juan Pablo,
UNAM, Instituto de Geología, México, Ciudad Universitaria, México, D.F, 04510, Mexico, and
LOZANO SANTACRUZ, R., UNAM, Instituto de Geología, Ciudad Universitaria, Mexico, D.F,
04510, Mexico
The Laramide magmatic arc is well represented in the Arizpe-Mazocahui quadrangle of northcentral Sonora where dioritic to granitic plutons intrude a rhyolitic-dacitic, andesitic and volcaniclastic succession assigned to the Tarahumara Formation. Measured stratigraphic columns indicate that this succession is at least 2-km-thick, and regionally extends to northern Sonora where it
grades laterally into the Campanian-Maastrichtian Cabullona Group. Consistent U-Pb ages range
from 76 to 70 Ma for this volcanic succession, whereas 40Ar/39Ar ages north of the quadrangle are
as young as ~60 Ma. The lowermost member of the Tarahumara Formation is a conglomerate and
rhyolitic succession that unconformably overlies thrusted and folded rocks of Proterozoic to early
Late Cretaceous age. The upper members are composed of rhyolitic to dacitic ash-flow tuffs, ashfall tuffs, andesitic flows and agglomerates, volcaniclastic sandstone and conglomerate. Several
large plutons younger than the Tarahumara range in age from 71 to 50 Ma (U-Pb), although four
apparent magmatic pulses around ~70, ~62, 56-53, and ~50 Ma are present. This magmatism
was high-K and calc-alkaline, and the plutonic rocks are metaluminous to strongly peraluminous,
exemplified by the muscovite-bearing El Babizo (70 Ma) and El Jaralito (55 Ma) granites.
The youngest tectonically deformed unit which the Tarahumara Formation unconformably overlies is the Cocóspera Formation, a syntectonic conglomerate from where an interbedded andesitic
flow yielded a ~93 Ma age (40Ar/39Ar hornblende; Lawton et al., 2009). These data constrain the
age of shortening between Cenomanian-Turonian to middle Campanian time, as the Tarahumara
postdates it. Nevertheless, the age-equivalent Cabullona Group, the basin-fill of the southernmost
basin of the belt of Laramide uplifts extending northward into the USA, is deformed by open folds,
suggesting northward migration of the deformational front with time. Other ~90 Ma ages assigned
to Tarahumara volcanism in southern Sonora may in fact represent a volcanic and sedimentary
succession correlative with the Cocóspera Formation, considering that most of the reported older
ages for the Tarahumara in that region cluster near 74 Ma.
T30. Plenary: Opportunities and Challenges in the
Western North American Region (Society of Petroleum
Engineers (SPE))
gas drive. Suitability of reservoir fluids for cold production is difficult to quantify due to high oil
viscosities & unconsolidated reservoir sands. Due to the surface environment, significant well construction and artificial lift design challenges also exist. Reservoir access, balanced with effective
solids transport along the wellbore are key considerations in for future CHOPS or horizontal well
development and needed to be better understood. Results, Observations, Conclusions A 2008
flow back to test the viability of CHOPS recovered the first significant quantities of 11‑12 API oil at
minimal drawdown and 5‑40% sand over a 3‑week period. In a separate appraisal well, PVT quality fluid samples were obtained from 2 additional sands with a drill‑stem test that provided crucial
information to characterize the reservoir. Based on the appraisal data gathering, the following conclusions can be made about developing the resource: 1.Exploitation of the resource is technically
possible using cold production techniques. 2.Formation permeability and dissolved gas suggest
that massive sand production may not be required for effective primary production. 3. Well design
& artificial lift must be centered on managing fluid viscosity and transporting produced solids.
Significance of Subject Matter. Understanding reservoir properties in unconsolidated, heavy oil
reservoirs is challenging, but essential in appraising the resource. Collecting quality data early in
is crucial to unlocking this large, unconventional resource.
5-2
5-3
[173776]
11:30 AM
Reagan, Matthew T.
[173777]
8:30 AM Round table discussion
T31. Arctic Operations/Permafrost Issues/Hydrates
10:30 AM
Young, James P.
[173775]
ALASKAN HEAVY OIL: FIRST CHOPS AT A VAST, UNTAPPED ARCTIC RESOURCE
MATHEWS, William Lloyd and YOUNG, James P., BP, Long Beach, CA 90802,
[email protected]
This paper describes a cold heavy oil production with sand (CHOPS) flow back and a multi‑zone
drill‑stem test undertaken to characterize a large, untapped, extra heavy oil resource on Alaska’s
North Slope for commercialization. Application Although the resource is found in multiple reservoir zones extending across the basin, initial appraisal focused on the deeper, less viscous oil in
the east which was believed to be suited to for “cold” production techniques that exploit solution
Moridis, George J.
THE EFFECT OF RESERVOIR HETEROGENEITY ON GAS PRODUCTION FROM HYDRATE
ACCUMULATIONS IN THE PERMAFROST
REAGAN, Matthew T., MORIDIS, George J., and KOWALSKY, Michael Brendon,
Lawrence Berkeley Laboratory, Long Beach, CA 90802, [email protected]
The quantity of hydrocarbon gases trapped in natural hydrate accumulations is enormous, leading
to significant interest in the evaluation of their potential as an energy source. Large volumes of gas
can be readily produced at high rates for long times from methane hydrate accumulations in the
permafrost by means of depressurization‑induced dissociation, and using conventional technologies and horizontal or vertical well configurations. Initial studies on the possibility of natural gas
production from permafrost hydrates assumed homogeneity in intrinsic reservoir properties and
in the initial condition of the hydrate‑bearing layers (either due to the coarseness of the model
or due to simplifications in the definition of the system). These results showed great promise for
gas recovery from Class 1, 2, and 3 systems in the permafrost. This work examines the consequences of inevitable heterogeneity in intrinsic properties, such and the porosity and permeability
of the hydrate‑bearing formation, as well as heterogeneity in the initial state of hydrate saturation. Heterogeneous configurations are generated through multiple methods: 1) through defining
heterogeneous layers via existing well‑log data, 2) through randomized initialization of reservoir
properties and initial conditions, and 3) through the use of geostatistical methods to create hetereogenous 2‑D and 3‑D fields that extrapolate from localized information. These extrapolations
use all available information and established geophysical methods to capture a range of deposit
properties and hydrate configurations. The results show that some forms of heterogeneity, such as
horizontal stratification, can assist in production of hydrate‑derived gas. However, more heterogeneous structures can lead to complex physical behavior within the deposit and near the wellbore
that may obstruct the flow of fluids to the well, necessitating revised production strategies. The
need for fine discretization is crucial in all cases to capture dynamic behavior during production.
5-4
5-1
11:00 AM
EVALUATION OF TWO NORTH SLOPE, ALASKA, DEPOSITS FOR A POTENTIAL LONG TERM
TEST OF GAS PRODUCTION FROM HYDRATES
MORIDIS, George J. and REAGAN, Matthew T., Lawrence Berkeley Laboratory, Long Beach,
CA 90802, [email protected]
As part of the effort to investigate the technical feasibility of gas production from hydrate deposits,
a long‑term field test (lasting 18‑24 months) is under consideration in a project led by the U.S.
Department of Energy. We evaluate two candidate depoits: the D‑Unit accumulation at the Mount
Elbert site, and the C‑Unit deposit at the PBU‑L106 site, both in North Slope, Alaska. Both deposits are bounded by impermeable shale top and bottom boundaries (Class 3), and are characterized by high intrinsic permeabilities, high porosity, high hydrate saturation, and a hydrostatic pressure distribution. The D‑unit deposit involves a single layer, is shallower, and is characterized by
a lower pressure and temperature than the deeper, warmer (and thicker deposit at the PBU‑L106
site, which is composed of two hydrate‑bearing strata separated by a shale interlayer. We investigate by means of numerical simulation involving fine grids the production potential of these two
deposits using both vertical and horizontal wells. We also explore the sensitivity of production to
key parameters such as the hydrate saturation, the formation permeability and porosity, the system heterogeneity, the boundary permeability, and the initial temperature. The results indicate that
the PBU‑L106 deposit has a distinct advantage as a candidate for the long‑term production test.
At either site, production from horizontal wells may be orders of magnitude larger than that from
vertical ones. Additionally, production increases with the formation permeability and porosity, with
the temperature of the deposit, with heterogeneity along the vertical axis (layered systems) and
with a decreasing permeability of the boundaries. The effect of the hydrate saturation on production is not monotonic, i.e., it appears to be optimal at medium levels (about 50%) and depends on
the time frame of production.
12:00 PM
Venepalli, Kiran Kumar
[173778]
STUDY ON PORE SCALE DISTRIBUTION OF FROZEN WATER AND ITS EFFECT ON
RELATIVE PERMEABILITY OF OIL IN PERMAFROST RESERVOIR ROCKS
VENEPALLI, Kiran Kumar, U of Alaska, Long Beach, CA 90802, [email protected]
Permafrost is a regular feature of extreme northern and southern terrain throughout the world,
its boundaries dictated by the laws of physics alone. The petroleum reservoir that could produce economically from a frozen ground preferentially contains oil, water, ice, and /or gas. This
four‑component system makes the reservoir much more complex than the regular conventional
three‑component system (oil, water, and/or gas). The reasons behind this can be analyzed in
macro and micro level.The former contributes to the very unusual conditions and the difficulties in
completing oil wells in permafrost grounds and the later investigates the effect of freezing of this
formation water on the relative permeability of each individuals of this four‑component system in
a frozen ground.This present study concentrates on this pore scale distribution of water and ice
using Nuclear Magnetic Resonance (NMR) and its effect on the relative permeability of oil. The
amount of unfrozen water in a frozen sample has been estimated using NMR and then performed
a laboratory study of fluid‑flux permeability measurements of samples, which were frozen below
zero centigrade and then, followed by thawing of the core. The effect of frozen water in the pore
space on the relative permeability is observed to estimate the production potential of the field. The
results experimentally proved the existence of liquid water below zero temperature and changes
in the relative permeability of oil while thawing. Further experiments are going on to investigate a
best production technique to increase the quantity of “Recoverable reserve” in this ice rich reservoir fields.
SESSION NO. 6
6-4
T32. Advances in Drilling and Completion Technology
6-1
8:30 AM
Fram, Joe H.
[173779]
ADDRESSING HORIZONTAL STEAM INJECTION COMPLETIONS CHALLENGES WITH
CHEVRON’S HORIZONTAL STEAM TEST FACILITY
FRAM, Joe H., SIMS, Jackie C., MAYER, Tiffany Crystal, and SEQUERA, Axzel, Chevron,
Long Beach, CA 90802, [email protected]
Steam injection profile control is a significant challenge for thermal recovery of heavy oil with
horizontal wells. There is no reliable commercially available method for controlling two‑phase
steam distribution in horizontal laterals and not even a commercial laboratory capable of testing such devices. To address this gap Chevron constructed a surface horizontal steam injection
test facility in the Kern River Field located outside of Bakersfield, California. This facility is used
for testing commercial and proprietary devices for improving control of steam distribution along
a lateral in a horizontal well. The horizontal steam test facility is capable of testing the capabilities of a wide range of full sized down hole completion equipment (tubing and liner flow control
devices tubing liner and annulus/liner isolation devices and logging equipment) at the surface
under precise controlled conditions. This paper discuss the need for horizontal steam injection
wells and steam distribution control. The current “State‑of‑the‑Art” of horizontal steam injection
completions or more accurately the lack of steam profile control currently available. It will discuss
the three areas critical for controlling the steam profile along a lateral: 1) liner‑open hole 2) liner
and 3) tubing‑liner. It will also discuss the capabilities of the test facility, initial test results and a
possible pathway to field deployment of promising technology.
6-2
9:00 AM
Lee, Jung kun
[173780]
CATALYTIC PROPERTIES OF CLAY BASED HYBRID MATERIALS FOR DRILLING
OPERATIONS CORRESPONDING AUTHOR’S COMPANY: UNIVERSITY OF PITTSBURGH
LEE, Jung kun, University of Pittsburgh, Long Beach, CA 90802, [email protected]
In this presentation, we will introduce our recent research to explore transition metal oxide nanoparticles to remove harmful byproducts of the drilling operation. One of potential hazards in drilling operations originates from gas‑phase byproducts. A typical gas endangering drilling facilities
and workers is H2S that is poisonous as well as flammable. H2S is produced by bacteria in confined water and oil where the influx of air is very limited. High concentration H2S causes coma,
collapse and death of oil field workers. In addition, H2S in the drilling fluids erodes and embrittles
drilling bits, strings, and rigs, leading to a decrease in their mechanical strength and lifetime. To
prevent environmental contamination and protect health of oil field workers, it is desired that the
constituents of the drilling fluids filter poisonous gas‑phase byproducts that are produced during
oil drilling process. For this purpose, we have studied hybrid particles consisting of micro‑size
bentonite particles and iron oxide nanoparticles with large surface area and evaluate the effect of
transition metal oxide nanoparticles on scavenging harmful underground gas such as H2S. The
kinetics of scavenging reaction was affected by several parameters such as particle size and pH,
which needs systematic research to maximize the efficiency of the scavenging reaction. When
the iron oxide nanoparticles were employed, the reaction would be substantially faster due to
their large surface area. But, then distribution and collection of nanoparticles in a mud pit are not
easily controlled because the size of nanoparticles is too small compared with other constituents
of the drilling fluids. We have developed the Fe nanoparticle‑clay hybrid particles that possess
high chemical reactivity of the nanoparticles and easy processability of the clay particles. Newly
developed Fe nanoparticle‑clay hybrid particles were found to effectively decompose the pollutants and purify water.
6-3
9:30 AM
Hallman, Tyler James
[173781]
THERMAL MODELING OF DRILLING INTO STEAM CHAMBERS
HALLMAN, Tyler James, RPS Energy, Long Beach, CA 90802, [email protected],
MACDONALD, Ron R., APA, Long Beach, CA 90802, GERLITZ, Jeff, Suncor, Long Beach,
CA 90802, and HARELAND, Geir, U of Calgary, Calgary, AB T6G 2R3, Canada
On occasion SAGD wells need to be drilled into or close to steam chambers. When drilling such
wells the drilling fluid temperature may become excessively high, endangering personnel and
exceeding the borehole stability, bottom hole assembly or drilling fluid temperature limitations. The
drilling was simulated to predict the resulting wellbore, mud return, and formation temperatures.
The transient thermodynamic model was created with commercial software, calibrated by matching predicted temperatures with actual drilling data from several cold wells. The calibrated model
was used to predict the formation temperature of several hot wells. The wellbore temperature
during the drilling of several generic wells was also evaluated. This model may be used to ensure
the mud temperatures are not prohibitively high during future drilling operations. The mud return
temperature was predicted to within B11B0C of the actual. The formation temperature was predicted to approximately B120B0C when drilling into wells with formations of 50 to 200B0C. The
generic drilling scenarios modeled demonstrate that it is possible for the mud to return to surface
at temperatures exceeding 100B0C resulting in the water component of the mud flashing to
steam. When entering a hot wellbore, tripping in slowly while circulating may be required to avoid
returning excessively high temperature mud to surface. Mud coolers may be required to prevent
the mud temperature from climbing too high. A small number of SAGD wells have been drilled
into steam chambers. The model allows this limited experience to be expanded. The model may
be used for planning of future drilling operations by predicting mud temperatures in a variety of
drilling scenarios especially with regards to safety concerns. In addition the need for employment
of mud coolers or specific trip procedures can be evaluated. The approximate accuracy of the
simulation software employed is also demonstrated.
48 2010 GSA Abstracts with Programs 10:30 AM
Cavender, Travis Wayne
[173782]
METHOD FOR MINIMIZING LINER EXPANSION ISSUES IN HORIZONTAL THERMAL
APPLICATIONS
CAVENDER, Travis Wayne and SCHULTZ, Roger L., Halliburton, Long Beach, CA 90802,
[email protected]
Heavy oil is found in many parts of the world, but because of its high viscosity, traditional methods have been incapable of producing these wells. Thermal recovery methods have been used
to exploit heavy oil and bitumen reservoirs, but they can create severe expansion problems on
liner and production tubular equipment. This is particularly a problem in the case of horizontal
sand face completion configurations used in steam flood, cyclic steam and steam‑assisted gravity drainage (SAGD) applications. With the increasing demand for energy, however, the industry
has renewed its attention to finding solutions to the problems currently experienced with heavy
oil production. This paper will present different wellbore configurations that are used with various thermal recovery methods, and particularly, the use of thermal expansion devices. Many
single lateral and multi‑lateral horizontal heavy oil wells have been produced initially using the
cold heavy‑oil‑production‑with‑sand (CHOPS) method of recovery where liner expansion is not
a concern. However, with proper up‑front planning and engineering, these wells can be converted to thermal‑enhanced oil recovery (EOR) producers with the addition of thermal expansion
devices placed within the liner assembly during initial completion. These expansion devices are
engineered to activate with elevated temperatures once the thermal operation begins and do not
require mechanical activation or well intervention. Since these devices are deployed with the liner
assembly, they also have the capability to handle compression, tension and torque loading across
the liner during the deployment phase. This technology can be deployed with the slotted liner/
sand‑screen applications, or be used with production or concentric tubing configurations. In addition to helping resolve expansion problems, the enhanced safety and economic benefits provided
by the devices will be discussed.
6-5
11:00 AM
Suri, Ajay
[173783]
AN IMPROVED LABORATORY METHOD TO ESTIMATE FLOW INITIATION PRESSURES AND
RETURN PERMEABILITIES DURING FLOWBACK
SURI, Ajay and SHARMA, Mukul, University of Texas, Long Beach, CA 90802,
[email protected]
The flow initiation pressure (FIP) is used as an estimate of the differential pressure required
between the reservoir and the well to initiate production. The standard method to measure FIP
uses a constant flowback rate. However this method is incorrect and results in much higher estimates for FIP. An improved flowback method that closely represents a constant drawdown in the
field is applied, to measure the FIP. In addition the permeability during flowback is measured at
these increasing steps of differential pressures, resulting in a spectrum of return permeabilities
as a function of drawdown. Two types of drilling fluids (sized calcium carbonate and bentonite)
are used on porous media ranging in permeability from 4 to 1500 md. Both single‑phase and
two‑phase experiments are conducted in lab‑simulated open‑hole and perforated completions
to measure the FIP and the return permeability spectra. Small values for FIP are found in all the
experiments (considerably smaller than presented in the literature with the constant flowback rate
method). The small values of FIP suggest that the pressure gradients are sufficient in the field to
initiate production especially if the well are vertical but may not initiate production in horizontal
wells or if the over‑balance was very high during drilling (>500 psi). The FIP and the return permeability are controlled by the cleanup of the internal filter cake. A Bingham fluid in a network of
pores is used to model the cleanup of the internal filter cake. The model as well as the experiments indicates that very large pressure gradients are required to cleanup the entire internal
filter cake. However, a pressure gradient of 10 psi / inch during production is needed to keep skin
factor < 1 for open‑hole completed wells drilled with an over‑balance of ~ 100 psi.
6-6
11:30 AM
Bai, Baojun
[173784]
DEVELOPMENT AND FIELD PILOT OF A NOVEL VISCOELASTIC ANIONIC SURFACTANT
(VAS) FRACTURING FLUID
BAI, Baojun, ZHANG, Jin, and ZHANG, Shicheng, Missouri U of Science and Tech,
Long Beach, 90802, [email protected]
A novel fracturing fluid called VAS (anionic surfactant type) has been successfully developed
and applied in both oil and gas wells in China oilfield. VAS can not only eliminate matrix damage
induced by fracturing fluid absorbing onto the formation which is usually negatively charged, but
it also can lower the water‑sensitive and water‑lock damage to the formation. This paper presents
the rheology, leakoff and conductivity of this fluid system together with its case histories. The stimulation mechanisms of this novel VAS fracturing fluid are also analyzed. Results, Observations,
Conclusions: This novel VAS fracturing fluid inherits all merits of traditional VES (surfactant type)
hydraulic fluid, but gets rid of the wettability reversal induced by VES. The novel VAS fracturing
fluid mainly consists of an anionic surfactant, EDTA, KCl, and KOH. Each major additive of the
fracturing fluid system has the functions to initiate fracture, transport sand and enhance production. Field pilot tests demonstrate that the wells using VAS as a fracturing fluid had much higher
production rate and longer stabilized effective life than those using Guar gum as a fracturing fluid.
Applications: Until February 2009, this novel fracturing fluid had been successfully applied to 16
wells in Nanyang oilfield with a total increased oil production of 9,373 tons. It also had successfully applied to 4 wells in Changqing gasfield with an average AOF of 15.53C_‑104 m3/d after
fracturing stimulation. Technical Contributions: The novel hydraulic fluid can significantly reduce
hydraulic fluid damage on formation and proppant bed due to the involvement of anionic surfactant. This novel VAS fracturing fluid has been used successfully in fracturing operation of Nanyang
oilfield and Changqing tight gas reservoirs. Lessons and experiences to develop and apply the
novel fracturing fluid will be illustrated.
SESSION NO. 8
SESSION NO. 7
T32. Advances in Drilling and Completion Technology
(Alternate) (Society of Petroleum Engineers (SPE))
7-1
Hareland, Geir
8-3
[173862]
DIRECTIONAL HOLE CLEANING PROCESS REVIEW: A SYSTEMATIC VIEW
HARELAND, Geir, U of Calgary, Calgary, AB T6G 2R3 Canada, [email protected]
Hole cleaning is one of the most important processes that needs to be monitored and controlled
during a drilling operation. Some shortcomings in drilling operations such as low mud rate, low
rotational speed or wrong mud system may cause less lift or drag forces and interrupt the cuttings
transportation. The best way of facing an industrial problem is to deal with it as a combination in a
physical‑systematical model. This paper reviews all different types of hole cleaning studies since
1972. One of the advantages of this review is that the drilling process has been looked upon in a
systematic method approach. Output and internal states vectors are related to the input vectors.
This form of a modeling is obtained by physical rules and relations of the parameters. Concepts
of a systematic analysis are defined for drilling operations such as classification of drilling parameters and defining observability and controllability of internal states in a drilling procedure. Hole
cleaning as an internal state has been represented by different parameters such as bed thickness
or cuttings concentration over the years. Generally all previous studies on hole cleaning can be
divided into four categories: ‑ Sensitivity analysis of hole cleaning: Variation of an internal state
by changing a combination of inputs. ‑ Hole cleaning modeling: Systematic presentation of physical relation of inputs and internal states. ‑ Hole cleaning monitoring: Estimation of internal states
using measured data. ‑ Controlling the hole cleaning: Desirable internal state value by changing
inputs. In addition to a complete survey on previous studies on hole cleaning, this paper defines
a new systematic‑physical framework to investigate the drilling operation. Applying such a framework for drilling procedures, any tool or combination of different methods of data analysis, modeling, monitoring and controlling of the procedure can be applied for drilling operational analysis.
8:30 AM
Pan, Yan
[173785]
BEST PRACTICES IN TESTING AND ANALYZING MULTILAYER RESERVOIRS
PAN, Yan, SULLIVAN, Michael, and BELANGER, Dave, Chevron, Long Beach, 90802,
[email protected]
Layered formations are the norm rather than exception among oil and gas reservoirs. Knowing
the individual layer properties is important for making development strategies. It plays a significant role in secondary recovery. This paper presents best practices in the design, execution,
and analysis of multilayer pressure transient tests in the “super‑giant” Tengiz oil field in western
Kazakhstan. Our experiences prove that the use of multilayer testing and analysis techniques
result in a lower level of uncertainty in layered reservoir characterization than can be obtained
by the simpler commingled pressure transient test alone. The formations in the platform area of
Tengiz consist of multiple zones with different reservoir pressures and cross flow often occurs
during shut‑in periods. In some cases, the impact from different layer pressure and skin distribution could result in 100% difference in individual layer permeability estimations. To reduce the
uncertainty, a Selective Inflow Performance (SIP) production logging technique is used to measure the bottom‑hole pressures and flow contributions of individual layers during a commingled
pressure transient test. Pulsed Neutron Capture logs also provide information about stimulation
effectiveness (skin) in each zone. Then a robust step by step analysis method developed to utilize
all these data and information is applied to obtain individual layer properties. The best practices of
using this methodology and the associated uncertainty are discussed in this paper. The challenge
in characterization of layered reservoirs lies in the large number of unknown parameters. The
approach described in this paper resolves enough of these unknowns in a systematic fashion that
a more direct solution is obtained with resultant lower uncertainty. By sharing our testing experiences in Tengiz we hope to provide means and ideas for petroleum engineers to face the challenge and reduce the uncertainty in the development and management of multilayered reservoirs.
8-2
9:00 AM
Jianwei Wang, Wang
[173786]
INTEGRATION OF 3D SEISMIC ATTRIBUTES INTO STOCHASTIC RESERVOIR MODELS
USING ITERATIVE VERTICAL RESOLUTION MODELING METHODOLOGY
JIANWEI WANG, Wang and DOU, Qifeng Dou, Schlumberger, Long Beach, CA 90802,
[email protected]
At early stages of field development, there is generally no sufficient well data available to predict
reasonable reservoir property distributions. Integrating densely distributed seismic attributes as
a secondary constraint can significantly improve the accuracy of reservoir models and reduce
uncertainties. However, one challenging problem facing is scale difference between seismic and
well log. Geostatistical modelers encounter both upscale and down‑scale issues. We illustrate an
iterative vertical resolution modeling methodology to compromise both seismic and log resolutions, and a new geostatistical modeling technique for generating better reservoir models. Vertical
variogram analyses on log data were conducted to determine an upper‑limit vertical resolution
for each geological zone. Under this vertical resolution, the heterogeneity of log properties can
be preserved. Different 3D reservoir models with different scales were built. Log porosities were
upscaled and seismic acoustic impedances were sampled (down‑scaled) into these models.
A correlation coefficient between log porosity and acoustic impedance for each zone in each
model was calculated. Within the upper limit of the log resolution, the best vertical scale that
compromises both log and seismic scales was decided based on the best correlation. Horizontal
9:30 AM
Dastan, Aysegul
[173787]
ROBUST WELL TEST INTERPRETATION USING NONLINEAR REGRESSION WITH
PARAMETER AND DATA TRANSFORMATIONS
DASTAN, Aysegul1, TARANTOLA, Albertt2, and HORNE, Roland1, (1) Stanford University,
Long Beach, CA 90802, [email protected], (2) Institut de Physique du Globe de Paris,
Long Beach, 90802
Nonlinear regression used in well test interpretation is a relatively well‑established technique.
However, sensitivity to noise, unacceptably wide confidence intervals, and dependency on starting guess make this widely‑used technique vulnerable to issues commonly observed in real data
sets. In this work, we show significant improvements in nonlinear regression by using transformations on the parameter space and the data space. In addition to providing more accurate results
(narrower confidence intervals), faster convergence, and reduced sensitivity to starting guesses,
our technique also provides noise reduction and data compression. The approach is directly
applicable to other techniques developed for reservoir modeling and analysis, including multifractured horizontal wells, deconvolution, derivative analysis, and permanent downhole gauges.
The logarithm of permeability has been used in some applications for parameter estimation and
it is known to improve the performance. In this work, we derive Cartesian transformation formulas
for common well test parameters and show that the transformed parameters provide significant
performance improvement. Cartesian transformed parameters provide faster convergence, more
accuracy, and wider tolerance to starting guesses. In the second part of this paper we discuss
wavelet transformations of the data set. The wavelet transform makes it possible to realize certain
interpretation operations simultaneously, including compressing and denoising the data. We show
that the wavelet transform handles complicated and long data sets with many data points (e.g.
coming from permanent downhole gauges) without loss of information. For the wavelet transform,
it is possible to use only a few wavelet coefficients and achieve the same converged result as
when using all the data. Our significant new contributions are: 1. Novel nonlinear regression algorithms that are faster, and more robust to poor initial guesses. 2. Analysis of massive data sets
from permanent downhole gauges without loss of information. 3. Inherent noise removal during
pressure transient analysis.
8-4
T33. Reservoir Characterization I (Pacific Section,
AAPG; Society of Petroleum Engineers (SPE))
8-1
variogram analysis was then conducted based on densely sampled correlated acoustic impedances. This method overcame the common difficulty in conducting horizontal variogram analysis
using aerially sparse log data and provided a better quantitative estimate of spatial correlation.
Sequential Gaussian Simulation coupled with Collocated Co‑kriging was then used to populate
porosity. The methodology was applied to the Gullfaks field in North Sea. The workflow described
yielded a reservoir model much improved over conventional stochastic modeling methods and
greatly reduced uncertainties on porosity distribution away from wells. The chief technical contribution is the presentation of an iterative vertical resolution modeling methodology that compromises both seismic and log resolutions to integrate seismic into reservoir model.
10:30 AM
Shad, Saeed
[173788]
EFFECT OF FRACTURE AND FLOW ORIENTATION ON TWO PHASE FLOW IN AN OIL WET
FRACTURE: RELATIVE PERMEABILITY CURVES AND FLOW STRUCTURES
SHAD, Saeed, MAINI, Brij B., and GATES, Ian Donald, U of Calgary, Calgary, AB 90802,
Canada, [email protected]
Naturally fractured reservoirs are among the most complex reservoirs for heavy oil production.
A series of laboratory experiments were done to study/visualize the complexity of co‑current
water‑heavy‑oil flow in a fracture by using a Hele‑Shaw cell. In these experiments, the effect of
fracture and flow orientation, fluid properties and different forces on relative‑permeability curves
and flow structures have been evaluated. Application: Flow in fractures and relative‑permeabilities
are not well understood. It is obvious that inaccurate relative‑permeability curves lead to large
errors in recovery prediction. The results of this study can be applied in reservoir characterisation
and numerical simulations. Fracture flow regime maps can be used for reservoir management
and production optimization. Results: New relative‑permeability model that accounts for flow and
fracture orientation has been proposed and compared to other published models. Flow structure
for different flow and fracture orientations were compared each other and with published ones.
The results reveal complexity involved in fracture dominated flow and high interference between
phases that can only be modeled by using the proposed model. Results show that oil‑water
relative‑permeability is not just function of saturation but also fluid and fracture properties, orientation and flow pattern. In contrast with many studies, two‑phase flow in continuous and discontinuous forms was observed. Flow maps derived in this research include numerous new experimental
data. Significance: This paper reveals the significance of relative‑permeability curves in reservoir
characterization and its complexity. The visualized two‑phase flow structure in the fracture and
the transition between the flow regimes provides more understanding of fracture flow dynamics.
Given that numerical/analytical reserve and recovery prediction depends strongly on relative
permeability, the results of this study help us to simulate and predict flow in fractured reservoir
rock more accurately.
8-5
11:00 AM
Mitra, Arijit
[173789]
APPLICATION OF LITHOFACIES MODELS TO CHARACTERIZE UNCONVENTIONAL SHALE
GAS RESERVOIRS AND IDENTIFY OPTIMAL COMPLETION INTERVALS
MITRA, Arijit, WARRINGTON, Daniel Scott, and SOMMER, Alan, Baker Hughes Inc,
Long Beach, CA 90802, [email protected]
Unconventional shale gas reservoirs are economically viable hydrocarbon prospects and their
development has rapidly increased in North America. These reservoirs must be routinely drilled
horizontally and hydraulically fracture stimulated to maximize production rates. Identification of
the different chemostratigraphic units or lithofacies that make up these reservoirs is crucial for
devising completion strategies because some lithofacies are more favorable to gas recovery in
terms of their organic content and geomechanical characteristics. Lithofacies are indicative of
eustatic changes during deposition and are typical geo‑markers related to the preservation and
amount of accumulated TOC for a given basin. Gas content is related to TOC and varies according to lithofacies. Based on the mineralogical and TOC content, some lithofacies are favorable for
gas production (e.g., siliceous lithofacies) and the geomechanical properties of these lithofacies
often possess low fracture gradients that are conducive to forming extensive fracture fairways
for recovery of gas. Other lithofacies can be fracture barriers and zones of fracture propagation
attenuation (e.g., carbonate lithofacies). A shale gas facies expert system was developed with
the goal of chemostratigraphically characterizing different shale plays and utilizing an integrated
petrophysical reservoir evaluation approach to identify optimal completion intervals. This system
can aid operators design selective completion strategies, which can potentially reduce fracturing
expenses and optimize well productivity. The expert system incorporates a combination of density,
neutron, acoustic, nuclear magnetic resonance and geochemical logging measurements. This
system first characterizes the lithofacies based on their geochemical makeup and then the most
favorable and unfavorable zones are flagged using a simple “stop‑light” approach based on the
petrophysical and geomechanical properties. This paper presents facies models for the Barnett
SESSION NO. 8
Shale, the Haynesville Shale, the Marcellus Shale, the Woodford Shale, and the Eagle Ford Shale
applied to a case study well in each of these plays.
8-6
11:30 AM
Williams, Steve O.
[173791]
DEVELOPMENT OF PETROPHYSICAL STRESS MODELS FOR CONVERSION OF CORE
POROSITY AND PERMEABILITY DATA FROM AMBIENT TO RESERVOIR CONDITIONS: A
NEW HYBRID APPROACH
WILLIAMS, Steve O., SOLANKI, Maxi, and BATARSEH, Samih Issa, AERA, Bakersfield,
Correction of ambient measured core data to reservoir conditions poses a major challenge in the
optimal use of historical core data in reservoir description and exploitation. The use of such data
in any form of reservoir evaluation without appropriate correction to reservoir conditions will result
to some degree of uncertainty in reserves determination and flow performance predictions. Core
data from the Ventura avenue field was used for this development. This field is structurally complex and consists of a turbidite sand sequence that is shaly, thinly bedded and laminated. Porosity
and permeability values are low and variable. This paper presents a new hybrid approach that
uses the numerical or error minimization techniques to approximate the non‑linear and double
exponential relationship of porosity and permeability versus stress and takes into account the
shaly and laminated sand variability, microscopic pore throat attributes and resultant stress patterns inherent in the Ventura Core data. This approach eliminates the use of average parameters
that is more favored in homogenous reservoirs. It also examines and compares with other existing
methodologies in the industry. The result is promising and shows a more improved and accurate
porosity and permeability conversion stress model.
SESSION NO. 9, 1:30 PM
9-1
1:40 PM
Pierce, David
[173658]
CRYOGENIAN MICROBIAL FOSSILS FROM THE KINGSTON PEAK FORMATION
PIERCE, David, 1717 East College Avenue, Lompoc, CA 93436-4940, [email protected]
and AWRAMIK, S.M., Department of Earth Science, University of California, Santa Barbara,
CA 93106
New microbial fossils expand the diversity and range of previously reported occurrences from
the Cryogenian Kingston Peak Formation, Death Valley, eastern California. Fossil-bearing, black,
microcrystalline chert in dolostone intervals is stratigraphically bracketed by diamictite. Striated
clasts below and an apparent lodgment till in depositional contact with the Noonday Dolomite
above indicate glaciation. There is little support for an age more precise than probably 750 to
650 Ma.
A microbial-microfacies succession is recorded in relict textures: (1) fragmented microbial mat
forms oncoid nuclear bodies, (2) filamentous and coccoid microbes resembling cyanobactia
occupy oncoid cortex laminations, (3) vase shaped microfossils, planktonic visitors, are sparsely
captured in micritized oncoids, (4) late euendolithic fossils, probable eukaryotes, have modified
oncoid grains, (5) filamentous and coccoid fossils populate the oncoid supporting matrix, and
(6) microbes occupy fracture porosity associated with karsting.
Large oncoids occur near and at the top of a recognizable carbonate interval, a candidate cap
carbonate based on C and O isotopes. Recently located Kingston Range spanning exposures,
commonly comprised of oncolite unconformable over underlying silty dolostone, are up to 17.5 m
thick compared to typical cap carbonates at <15 m.
Black chert replacing cm sized oncoids situated at the base of the oncolite bed contain the best
preserved microbial fossils. Thinsections show that relict carbonate textures record a diagenetic
sequence parallel to and consistent with alteration of limestones described by Zempolich (1988)
for the Crystal Spring Formation and Corsetti et al. (2003) for the Johnnie Formation. Troxel and
others have described a tectonic setting for the Kingston Peak Formation where normal faulting
runs concurrently with glaciation and periodic quiet water carbonate shelf deposition. Meteoric
water and marine pore water mixing in the subsurface provides a mechanism for early silicification. The preserved microbial detail provides a unique window on life in Cryogenian times.
9-2
2:00 PM
McCall, Andrea M.
[172951]
INCLINATION CORRECTION FOR THE MOENAVE FORMATION AND WINGATE SANDSTONE:
IMPLICATIONS FOR NORTH AMERICA’S APPARENT POLAR WANDER PATH AND
COLORADO PLATEAU ROTATION
MCCALL, Andrea M., Earth & Environmental Sciences, Lehigh University, 31 Williams Drive,
Bethlehem, PA 18015, [email protected] and KODAMA, Kenneth P., Earth and
Environmental Sciences, Lehigh University, 31 Williams Dr, Bethlehem, PA 18015-3188
The ~ 201 Ma paleopole for North America has been observed in two widely different locations,
one paleopole is determined from the Mesozoic rift basins in the northeastern US (67ºN, 93.8ºE
[Kent & Olsen, 2008]) and one from the Colorado Plateau (CP) (59.8ºN, 75.3ºE [Molina-Garza
et al., 2003]). The paleopole from the CP is determined from the Latest Triassic/Earliest Jurassic
Moenave Formation and Wingate Sandstone (M&W) of northern Arizona and southern Utah. The
discrepancy in paleopole positions has been explained by Kent & Olsen (2008) as due to large
amounts of clockwise vertical axis rotation of the CP (13.5º) combined with inclination shallowing of the paleomagnetism; however, structural and geologic data indicate less than 5º of vertical
axis rotation for the CP (Gordon et al., 1984; Cather, 1999; Molina-Garza et al., 2003). Inclination
shallowing has been corrected for the sedimentary rocks of the northeastern US rift basins, but
has not been corrected for the sedimentary rocks from the CP. We resampled the M&W, collecting
5-8 samples from 14 sites that were thermally demagnetized. The formation mean (D = 358.7º,
I = 12.2º, a95 = 6.6º) is statistically the same as Molina-Garza et al.’s mean direction. We have
corrected the inclination of the M&W rocks to determine if the corrected M&W paleopole from the
CP, when unrotated about an Euler pole local to the CP to reconcile the paleopole longitude difference, still has a paleopole latitude difference with the coeval northeastern US paleopole. Based
on isothermal remanence anisotropy measurements, the M&W rocks on the CP have experienced
inclination shallowing of their paleomagnetic remanence, which changed the M&W paleopole by
only ~ 3º northwards. When the inclination shallowing corrected paleopole is rotated 11.5º about
an Euler pole local to the CP, the longitudes come into agreement, but there is still a difference
~ 6º in paleopole latitude, although it is not statistically significant. Inclination shallowing cannot
reconcile the difference in longitude between the paleopoles. The amount of vertical axis rotation
50 2010 GSA Abstracts with Programs needed to bring the paleopole longitudes into agreement is somewhat smaller than suggested by
Kent & Olsen, but still large enough to be inconsistent with the geological observations.
9-3
2:20 PM
Amini, Sadraddin
[173663]
DIAPIRISM, MAGMATISM AND MINERALIZATION IN THE HORMOZ ISLAND, PERSIAN GULF,
SOUTH IRAN
AMINI, Sadraddin, Earth and Space Sciences, UCLA ( University of California Los Angeles),
3806 Geology Building, Los Angeles, CA 90095-1567, [email protected]
Hormoz island is situated within the Persian Gulf in southern Iran. It is a salt-gypsum diapir that
comprises diverse rock types ranging in age from pre-Cambrian to recent. It is part of a group
of diapirs in Iran that are present in older (500-800 Ma) rocks known as the south Zagros group,
(including Hormoz). This contrasts with the younger (or Great Kavir group) of diapirs in exclusively Tertiary rocks. Combined, the diapirs in Central Iran (Great Kavir) and south of Zagros
form a prominent province on a global scale with over 500 occurrences known or suspected. The
Hormoz diapir is unusual in many respects because of its recent tectonic activity, and unusual
low- and high-temperature mineralization that formed deposits of gypsum, anhydrite, calcite,
dolomite, hematite, hydro-hematite, goethite, pyrite, kaolinite, halite, as well as augite, hornblende, ilmenite, apatite, and feldspar. The role of magmatism (presently undated) in the context
of diapirism remains yet to be resolved.
9-4
2:40 PM
Martindale, Steven G.
[173310]
PERMIAN STRATIGRAPHY IN THE HEAD OF LORAY WASH, NORTHEASTERN NEVADA
MARTINDALE, Steven G., Public Works, Orange County, 1152 East Fruit Street, Santa Ana,
The head of Loray Wash, located in a Southern Pacific Railroad excavation in the southern Leach
Mountains, immediately north of State Hwy 30, NE Nevada, contains a structurally deformed
succession of Permian marine sedimentary rocks. A previous worker named an undesignated
thickness of these rocks the Loray Fm. This was reported as the type locality for the Loray Fm - a
succession of yellow-tan gypsiferous silts and thin bioclastic limestones in the head of Loray
Wash, in conformable contact with the underlying Fm.
Subsequent stratigraphic correlations into this area and detailed geologic mapping show
the Permian stratigraphy here as including the upper approximately 30 m of the Grandeur Fm
(Leonardian) of the Park City Group, overlain by approximately 33 m of the Meade Peak Tongue
of the Phosphoria Fm (Leonardian), in turn overlain nearby by the lower approximately 300 m of
the Murdock Mountain Fm (Leonardian? to Guadalupian). The Loray Fm of the previous worker at
this locality is considered by this author to be the Grandeur Fm.
The Grandeur Fm in Loray Wash consists of dolomitic sandstone, less calcareous sandstone
and minor bioclastic limestone. Gypsiferous silts and a conformable contact with the underlying
formation noted by the previous worker for the type section for the Loray Fm are absent in Loray
Wash. The contact between the base of the Loray Fm, or the Grandeur Fm of this author, and
the underlying formation is actually located 3.2 km to the NW. Due to discrepancies between the
discription of the type section and the actual lithologies exposed there, and due to the absence of
the base of the Loray Fm of the previous worker, or Grandeur Fm of this author, and also considering the stratigraphic correlations presented here, Loray Wash is considered as an inappropriate
locality for the type section of the Loray Fm. Although a type section cannot be changed, future
work on location and description of an appropriate typical section for the Loray Fm would be helpful for support of usage of the name by others in NE Nevada and NW Utah.
9-5
3:15 PM
Stanton, Robert J.
[173010]
LIMESTONE SEDIMENTATION CONCURRENT WITH SUBMARINE VOLCANISM IN THE
CONEJO VOLCANICS, MIOCENE, SANTA MONICA MOUNTAINS, SOUTHERN CALIFORNIA
STANTON, Robert J. Jr and ALDERSON, John M., Department of Invertebrate Paleontology,
Nat History Museum of Los Angeles County, 900 Exposition Blvd, Los Angeles, CA 90007,
[email protected]
Fossiliferous carbonate and terrigenous deposits are intercalated with submarine flows of the
Conejo Volcanics in the central Santa Monica Mountains. The limestones are skeletal lime grainstone to wackestone and contain volcanic clasts ranging in size from silt to boulders. They occur
on flow surfaces as lenses and as matrix within volcanic pebble to cobble conglomerate, and
within flows as fillings in primary fissures and as neptunian dikes. Hard-substrate taxa, notably
barnacles, oysters, serpulids, and regular echinoids are characteristic of the limestone, in contrast to the soft-substrate and infaunal taxa characteristic of Cenozoic strata of the Pacific Coast
in general.
Clastic strata occur above or lateral to limestone lenses, or as separate beds. Their biota is
distinctly different from that in the limestones with infaunal bivalves, inarticulate brachiopods, and
vascular plant debris as characteristic components; the dominant limestone taxa are absent or
much less abundant. Both types of sediment are mass-flow deposits.
Oxygen-isotopic analysis indicates that the organisms making up the limestones grew at a temperature of approximately 15º C. The biota is indicative of warm-temperate to sub-tropical climate
at the southern end of the modern Californian molluscan province. The present equivalent location based on both isotopic and provincial results is off northwestern Baja California. The biota is
referred to the barnamol association of temperate carbonates.
Limestone is very rare in the Cenozoic of the Pacific Coast because high relief along the
convergent plate margin generated abundant terrigenous sediment that accumulated at a much
higher rate than skeletal carbonate, particularly for temperate carbonates, which accumulate at an
order of magnitude slower rate than do tropical carbonates. Limestones in the Conejo Volcanics
form time horizons that define local sea-floor topography resulting from volcanic accumulation and
concurrent sea-floor subsidence.
9-6
3:35 PM
Leslie, Shannon R.
[173619]
STRATIGRAPHY, AGE, AND TECTONIC SETTING OF THE MIOCENE BARSTOW FORMATION
AT HARVARD HILL, CENTRAL MOJAVE DESERT, CALIFORNIA
LESLIE, Shannon R.1, MILLER, David M.1, WOODEN, Joe L.2, and VAZQUEZ, Jorge A.3,
(1) U.S. Geological Survey, 345 Middlefield Road MS 973, Menlo Park, CA 94025, sleslie@
usgs.gov, (2) USGS-Stanford Ion Microprobe Laboratory, Stanford University, Stanford, CA
94305, (3) U.S. Geological Survey, 345 Middlefield Road MS 910, Menlo Park, CA 94025
Our detailed geologic mapping and geochronology of the Barstow Formation at Harvard Hill, CA,
help to constrain Miocene paleogeography and tectonics of the central Mojave Desert. The study
area is 30 km east of Barstow, CA and near the eastern boundary of a WNW-trending Miocene
basin. A northern strand of the Quaternary ENE-striking, sinistral Manix fault divides the Barstow
Formation at Harvard Hill into two distinct lithologic assemblages. Strata north of the fault consist
of: a green rhyolitic tuff, informally named the Shamrock tuff; lacustrine sandstone; partially silicified thin-bedded to massive limestone; and alluvial sandstone to pebble conglomerate. Strata
SESSION NO. 10
south of the fault consist of: lacustrine siltstone and sandstone; a rhyolitic tuff dated at 19.1 Ma
(U-Pb); rock-avalanche breccia deposits; partially silicified well-bedded to massive limestone; and
alluvial sandstone and conglomerate.
Our U-Pb zircon dating of the Shamrock tuff yields a peak probability age of 18.7 ± 0.1 Ma.
Distinctive outcrop characteristics, mineralogy, remanent magnetization, and zircon geochemistry
(Th/U) suggest that the Shamrock tuff represents a lacustrine deposit of the regionally extensive
Peach Spring Tuff (PST) pyroclastic density current. When Shamrock tuff zircon age data are
combined with zircon age analyses from three well-characterized PST samples, the peak probability age is 18.7 ± 0.1 Ma, thus providing new insight into the age of zircon crystallization in the
PST rhyolite.
Results of our field studies show that Miocene strata at Harvard Hill mostly accumulated in a
shallow lacustrine environment; the rock-avalanche breccias near the base of the exposed section
indicate proximity to a steep basin margin, perhaps just after basin initiation. Our geochronology
demonstrates that deposition of the Barstow Formation at Harvard Hill extended from before
~19.1 Ma until well after ~18.7 Ma, similar to timing of Barstow Formation lake deposition in the
Calico Mountains but at least 3 million years older than comparable facies in the Mud Hills type
section. These observations are consistent with either of two paleogeographic models: westward
transgression of lacustrine environments within a single large basin, or sequential development of
geographically distinct eastern and western sub-basins.
9-7
3:55 PM
McCuan, Daniel T.
[173255]
MAGNETIC MINERALOGY OF THE BB2 SERIES SEDIMENT CORES FROM SUMMER
LAKE, OR
MCCUAN, Daniel T., NEGRINI, Robert M., and HORTON, Robert A., Department of Geology,
California State University, Bakersfield, 9001 Stockdale Highway, Bakersfield, CA 93311,
[email protected]
Three oriented piston sediment cores were retrieved in the Fall of 2009 with the purpose of
resolving the question surrounding the existence of the Mono Lake Excursion. Prior to paleomagnetic analysis the sediments were analyzed to determine the magnetic mineralogy of the Summer
Lake, OR sediments, including the possible presence of greigite, a magnetic mineral that would
likely be responsible for an overprinted signal. This research builds on the original B&B core taken
from the same location in 1992, whose mineralogy was tentatively determined by reflective light
microscopy to be magnetite (Fe3O4), titanomagnetite (Fe3-xTixO4). and greigite (Fe3S4).
Samples were taken from areas of low, medium, and high susceptibility and the magnetic
minerals were separated from the rest of the sediment using a shaped glass tube and neodymium-based magnets. The magnetic separates were then subjected to both XRD and SEM/EDX
analysis. The XRD analysis strongly suggests that the primary magnetic mineral is a magnetiteseries spinel of the magnesioferrite-magnetite solid solution series. Diffraction peaks attributed
to greigite were not present in the x-ray scan. The SEM analysis first focused on detecting
sulfur using an EDS element-mapping program. Rare areas of significant sulfur content were
subjected to further investigation leading to the discovery of several spinel group shaped iron
sulfides that may be greigite. These particles were found to be sub-micron in size and extremely
rare. Subsequent analyses focused on identifying elemental constituents of the most common
magnetic minerals associated with a volcanic provenance and grain-sizes that ranged from 0.1 to
20 µm. Based on semiquantitative elemental weight percents in the mineral grains large enough
to analyze (>5 µm), the dominant magnetic mineralogy of the Summer Lake sediments was found
to be consistent with (titano)magnetite containing an appreciable amount of magnesium substitution. Magnetic grains large enough to observe (>0.1 µm), but too small to analyze, (<5 µm) had
similar morphologies to the (titano)magnetites.
9-8
4:15 PM
McHargue, Tim
[173634]
PREDICTING RESERVOIR ARCHITECTURE OF TURBIDITE CHANNEL COMPLEXES: A
GENERAL MODEL ADAPTABLE TO SPECIFIC SITUATIONS
MCHARGUE, Tim1, PYRCZ, Michael J.2, SULLIVAN, Morgan2, CLARK, Julian3, LEVY,
Marjorie3, FILDANI, Andrea3, POSAMENTIER, Henry2, ROMANS, Brian3, and COVAULT,
Jacob A.3, (1) Department of Geological and Environmental Sciences, Stanford University,
450 Serra Mall, Stanford, CA 94305, [email protected], (2) Chevron ETC, 1500
Louisiana Street, Houston, TX 77002, (3) Chevron ETC, 6001 Bollinger Canyon Rd,
San Ramon, CA 94583
Observations from numerous examples of turbidite channel systems in diverse settings and
multiple basins have been summarized as a series of rules. These rules provide a useful basis
for constructing predictive, detailed, 3-dimensional, event-based models of turbidite reservoirs.
Interaction of the various rules allows for the development of a wide range of possible channel
architectures, but the succession of architectures tend to follow a recurring pattern with 4 stages:
1) System-scale erosion; 2) Amalgamation of channel elements with lateral offset during a low
rate of aggradation; 3) Disorganized stacking of channel elements during a moderate rate of
aggradation; and 4) Organized stacking of channel elements during a high rate of aggradation.
Depending on the proportion of sand in the system, some stages may be diminished in volume
relative to the other stages, or even absent. Sand-rich systems tend to be dominated by stages
1 and 2 whereas stages 3 and 4 are more prominent in mud-rich systems. Similarly, gradient
appears to influence the proportion of the 4 stages with stages 1 through 4 predominating in
proximal areas of high gradient whereas stages 2 through 3 predominate in distal areas of low
gradient. The 4 stages can develop with or without the presence of outer levees, but prominent
outer levees imply abundant mud and high rates of aggradation which favor the development of
stage 4 – organized stacking. Lateral accretion can occur in a variety of settings but is particularly common in mud-rich systems during stage 4. Uncertainty and variability can be addressed
through multiple realizations of event-based models that account for uncertainties in the prevalence of stages or architectures and rules within each stage. Also, these event-based models can
be conditioned to constraining data such as wells or seismic images. This has been demonstrated
to work well specifically in sparse data settings common to deepwater reservoirs.
9-9
4:35 PM
West, R. Brown
[173717]
LONGSHORE TRANSPORT AND SAND SPIT CONSTRUCTION: HAVE WE GOTTEN IT
WRONG ALL THESE YEARS?
WEST, R. Brown, Geology, East Los Angeles College, 1301 Avenida Cesar Chavez,
Monterey Park, CA 91754, [email protected]
Textbook sandspit construction involves the growth of the spit in the dominant down drift direction. One might expect to deduce the dominant direction of longshore transport from the orientation of a sand spit across a bay mouth, rivermouth, or other coastal reentrant. One would
expect, in the case of coastal California, to find sand spits pointing south across many coastal
reentrants due to the dominant southerly flow of longshore currents. This is, however, not the
case. While many spits point south, few in this orientation are found in a natural state. Especially
in Southern California those southward pointing spits are anchored with rip-rap or some other
artifice. Whereas along the Northern California coast there are numerous spits in a natural state,
the majority of which point north in defiance of the deductively reasoned textbook explanation.
Several examples from the north coast provide clues to a possible explanation, with the Mad
River providing key evidence suggesting that spits do indeed grow up drift. Does this mean that
spits do not grow down drift? Of course not, but their growth in the updrift direction is clearly
related to interaction or competition between river and wave actions. The simplest explantion is
found where the sole aggregate along a stretch of beach is clearly derived from the river associated with said spit. In these cases wave action promotes aggradation on the down drift bank of
the river at its mouth and consequently the channel migrates up drift and the spit grows up drift
trapping the river between spit and seacliff or other backshore anchor such as a dune field. The
spit may grow as far as a nearby headland as was the case for the Mad River before its progress
was halted by our own. A groin was built to prevent its northward migration, but a swale marks its
former path well north of the groin that now turns its mouth prematurely to the sea. A model will
be presented in demonstration of this interpretation.
S1. Debating the Connections Between the Plutonic
and Volcanic Rock Record (Cordilleran Section GSA)
10-1
1:35 PM
Anderson, J. Lawford
[173290]
EPISODIC DOWNWARD CRUSTAL FLOW DURING TRIASSIC TO CRETACEOUS MAGMA
SURGES IN THE CENTRAL SIERRA ARC
ANDERSON, J. Lawford1, PATERSON, Scott1, MEMETI, Valbone1, ZHANG, Tao1,
ECONOMOS, Rita2, BARTH, Andrew P.2, PIGNOTTA, Geoffrey3, MUNDIL, Roland4,
FOLEY, Brad5, and SCHMIDT, Keegan L.6, (1) Department of Earth Sciences, University of
Southern California, Los Angeles, CA 90089-0740, [email protected], (2) Department of
Earth Sciences, Indiana University Purdue University Indianapolis, Indianapolis, IN 46202,
(3) Department of Geology, University of Wisconsin - Eau Claire, 105 Garfield Ave, Eau
Claire, WI 54702, (4) Berkeley Geochronology Ctr, 2455 Ridge Rd, Berkeley, CA 947091211, (5) Department of Geology and Geophysics, Yale University, New Haven, CT 065208109, (6) Division of Natural Science, Lewis - Clark State College, 500 8th Ave, Lewiston,
ID 83501
The Cinko, Jackass, Soldier, and Saddlebag lakes areas of the central Sierra region of California
have significant downward displacement of Mesozoic volcanic rocks during episodes of Triassic,
Jurassic, and Cretaceous pluton intrusion. Plutons and intruded metavolcanics share down-dip
foliations and lineations. Host rocks record rotations to steep dips and strains up to 75% shortening and >100% extension.
In the Cinko Lake area, the Harriet Lake (102 Ma) and Fremont Lake (< 95 Ma) granodiorite
plutons are intruded into slightly older metavolcanics (102-107 Ma; all radioisotopic ages quoted
here are U-Pb zircon). Hornblende-plagioclase rims yield estimates of 684-726°C at 2.6 kb for the
Fremont intrusion and 684-698°C at 2.5 kb for the Harriet Lake, corresponding to emplacement
depths of 9-10 km.
The ~97 Ma Jackass Lakes pluton intrudes metavolcanics with ages ranging 98-103 Ma.
Hornblende-plagioclase thermobarometry indicate emplacement at 3.0 kb (11 km) at 681°C.
In the Soldier Lake region, the 86 Ma Cathedral Peak, the 97 Ma Soldier Lake, and the 165 Ma
Green Lake plutons intrude metavolcanics with ages of 177-220 Ma. Pluton emplacement pressure lowers with age, including 3.2 kb (12 km) at 731°C for the Green Lake pluton and 2.3-2.4 kb
(9 km) at ~696 °C for the Soldier Lake and the Cathedral Peak.
In the Saddlebag Lake area, the 221 Ma Saddlebag quartz diorite intrudes metavolcanics of the
Koip sequence with ages of 232 Ma and younger.
Host units achieved peak mid- to high-amphibolite grade near plutons based on mineral assemblages. We are currently collecting plutonic and metamorphic P-T data for the Saddlebag area,
but for Cinko and Soldier lake regions, hornblende-plagioclase thermometry yields metamorphic
temperatures of 640-717°C, exhibiting near thermal equilibration with adjacent plutons and geothermal gradients in excess of 70°C/km. In areas, host units descended to depths of 11 or greater
kilometers prior to or during subsequent pluton emplacement.
Others have suggested downward flow of host rock during rise of magma in the central (Tobisch
et al., 2000) and southern (Saleeby, 1990; Saleeby et al., 2007) Sierras suggesting that this may
be a major, Sierra-wide event. We therefore propose that this regional downward flow may be a
batholith-scale geodynamic process in response to magma surges in arcs.
10-2
1:55 PM
Honn, Denise K.
[172867]
REDEFINING AN IGNEOUS SYSTEM: MAGMATIC EVOLUTION OF THE RIVER MOUNTAINS
VOLCANIC SUITE AND WILSON RIDGE PLUTON
HONN, Denise K., Geoscience, University of Nevada, Las Vegas, 4505 S. Maryland Pkwy,
PO Box 4010, Las Vegas, NV 89154, [email protected], SMITH, Eugene, Geoscience,
University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV 89154-4010,
SIMON, Adam, Department of Geoscience, University of Nevada, Las Vegas, 4505 Maryland
Pkwy, Las Vegas, NV 89154-4010, and SPELL, Terry L., Department of Geoscience, Univ of
Nevada-Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154
A new model for the evolution of igneous systems is based on the linked River Mountains volcanic
suite and Wilson Ridge pluton of Nevada and Arizona. Evidence for this link includes new field
work, U/Pb zircon geochronology, major and trace element geochemistry, whole rock Sr and Nd
isotopes, and in situ plagioclase chemistry. Faulting and uplift from Basin and Range extension
expose both the volcanic and plutonic sections, allowing us to expand the definition of igneous
systems and our understanding of how they evolve. The River Mountains volcanic suite - Wilson
Ridge pluton igneous system is the result of continuous bimodal magmatism and formed in three
stages. Early and late stages of the system preserve bimodal magmas as separate intrusions,
lavas, and dikes. Early hypabyssal units (14.91 ± 0.37 to 13.55 ± 0.42 Ma) and late stage dikes
and lavas (13.64 ± 0.43 to 12.95 ± 0.32 Ma) are basalt and rhyolite. During the middle stage,
bimodal magmas coalesced to form a magma chamber of intermediate composition. In contrast,
the main phase of the system (13.94 ± 0.38 to 13.42 ± 0.23 Ma) is the result of extensive magma
mixing and comingling producing quartz monzonite in the pluton and dacite in the volcanic suite.
Mafic enclaves in the main phase of the pluton are largest and most abundant near the base,
where feeder dikes entered the magma chamber. Enclaves occur near the margins of the pluton,
but become smaller and less abundant towards the interior, where mixing was more thorough.
Magma mixing models reproduce trends in major, trace elements, and Sr and Nd isotopes. A
large component of assimilation of crustal material also explains 87Sr/86Sr (0.7076 to 0.7107)
SESSION NO. 10
and 143Nd/144Nd (0.51225 to 0.51206) values for the entire system. Major element EPMA
transects across plagioclase grains demonstrate a difference between volcanic and plutonic
magmatic records. Volcanic plagioclase grains preserve smaller increments of this history than
plutonic grains. On average, An numbers in volcanic grains only vary up to 15 mol.%. In comparison, plutonic grains vary up to 30 mol.%. The truncated growth of volcanic grains at the time of
eruption translates to less variation in major element chemistry across volcanic grains compared
to plutonic grains. This new data give a more complete understanding of systems with incomplete
preservation and exposure.
10-3
2:15 PM
Hildebrand, Robert S.
[173052]
THE NATURE OF VOLCANO-PLUTONIC RELATIONS IN THE GREAT BEAR MAGMATIC ZONE,
NORTHWESTERN CANADA
HILDEBRAND, Robert S., 1401 N. Camino de Juan, Tucson, AZ 85745, bob@
roberthildebrand.com, HOFFMAN, Paul F., 3271 Wicklow St, Victoria, BC V8X 1E1,
Canada, HOUSH, Todd, Department of Geological Sciences, The University of Texas
at Austin, Jackson School of Geosciences, 1 University Station, C1100, Austin, TX
78712, and BOWRING, Samuel A., Dept. of Earth, Atmospheric and Planetary Sciences,
Massachusetts Institute of Technology, Cambridge, MA 02139
The connection between the volcanism and plutonism has been of interest to geologists since
they realized that plutons were once low viscosity magma. Despite numerous studies involving
thousands of chemical and isotopic analyses the connection has proven difficult to resolve and is
still obscure, largely because there are few places that have enough relief to expose the critical
relations. The Great Bear magmatic zone, a Paleoproterozoic continental arc located in northern
Canada’s Wopmay orogen, provides an informative field setting to resolve some of these issues
because the rocks are generally non-metamorphosed and were broadly folded such that calderas,
stratovolcanoes, and a wide variety of plutons are exposed in oblique cross-section on limbs of
shallowly-plunging folds in an area of subdued topographic relief.
Early mafic plutons intruded co-magmatic pillow basalt piles as thin sheets with aspect ratios of
10-15. Plutons of intermediate composition, temporally and spatially associated with porphyritic
andesitic stratocones, have flat or slightly domical roofs and flat floors, zoned alteration haloes,
and have aspect ratios in the range of 5-10. Dominantly granodioritic to monzogranitic plutons
that cut thick sequences of ignimbrite are generally sheet-like bodies with aspect ratios of 10-20,
except where they intrude calderas and form resurgent plutons. Many, if not all, of the ignimbrite
sheets are compositionally zoned, but the plutons, despite compositional variations nearly as
large as the zone as a whole, are generally not zoned in an obviously systematic manner.
After each eruption type, magmas of similar composition and texture rose into the volcanic
suprastructure to form sheet-like plutons. The plutons, which appear broadly comagmatic with
their wallrocks, cannot have fed them because they cut them and are thus demonstrably younger.
We suggest that following eruption and partial evacuation of compositionally zoned magma
chambers, the chambers were re-energized, perhaps by influx of additional magma, and rose into
their own eruptive products. The cycle of eruption, with the partial evacuation of chambers and
subsequent rise of remaining magma to even higher levels in the crust explains why it is generally
so difficult to link volcanic eruptions to specific plutons.
10-4
2:35 PM
Hirt, William H.
[173293]
DEVELOPMENT OF A VERTICALLY-STRATIFIED DACITE-RHYOLITE MAGMATIC SYSTEM
WITHIN THE MOUNT WHITNEY INTRUSIVE SUITE, SIERRA NEVADA, CALIFORNIA
HIRT, William H., Natural Sciences, College of the Siskiyous, 800 College Avenue, Weed,
Some ash-flow tuffs that preserve dacite-rhyolite compositional transitions are interpreted as the
erupted contents of stratified reservoirs in which rhyolitic magmas overlie the dacitic “mushes”
from which they segregated. The youngest member of the Mount Whitney Intrusive Suite (MWIS)
may preserve a plutonic record of such a compositionally-stratified system.
The MWIS was emplaced between 90 and 83 Ma near the eastern edge of the Sierra Nevada
batholith and its youngest member, the Whitney pluton, intrudes both older members and wall
rocks warmed by them. The pluton grades from marginal granodiorite at low elevations to granite
in its upper central part, and mass balance calculations indicate the granite can derived from the
granodiorite by modest fractionation of hb + pl + mt. Alkali-feldspar megacrysts comprise 6-11%
of the body and are coarser towards its center. Evidence of repeated resorption and growth of
Ba-rich zones in the megacrysts indicates open-system behavior during which influxes of hotter
magma are inferred to have selectively dissolved small alkali-feldspar crystals and led to coarsening. The inward coarsening of megacrysts suggests that the longest history of recharge occurred
near the center of the Whitney pluton where it would have promoted differentiation by episodically
raising temperature and lowering crystallinity.
Field relations, chemistry, and megacryst textures suggest that relatively slow cooling at the
center of the suite held the lower dacitic part of the Whitney pluton above its rigid percolation
threshold long enough (104-105 years) for melt to segregate and form the overlying granite. A
coupled thermal-deformational model of the MWIS agrees with similar models in predicting that
intrusion at an average rate greater than 10-3 m3/m2/yr would have been required to sustain a
differentiable reservoir at the center of the Whitney pluton.
10-5
2:55 PM
Miller, Calvin F.
[173124]
ACTIVE INTRUSIVE COMPLEXES BENEATH ARC VOLCANOES: THE ZIRCON RECORD OF
MOUNT ST. HELENS
CLAIBORNE, Lily L.1, MILLER, Calvin F.1, FLANAGAN, Daniel M.2, CLYNNE, Michael A.3,
and WOODEN, Joseph L.4, (1) Earth and Environmental Sciences, Vanderbilt University,
Nashville, TN 37235, [email protected], (2) Department of Earth and
Environmental Sciences, Vanderbilt University, Nashville, TN 37235, (3) Volcano Hazards
Team, USGS, Menlo Park, CA 94025, (4) Stanford University, Stanford, CA 94305
U-Series disequilibria and U-Pb SHRIMP ages of zircons from 24 samples spanning the nearly
300 kyr eruptive history of Mount St. Helens (MSH) reveal that an active intrusive complex
underlies the volcano. Here magmas repeatedly stall or are left behind following eruptions and
are stored, experiencing cooling and crystallization and periodic rejuvenation of portions that are
mixed into young, hot magmas traversing the intrusion, and erupted. All samples have multiple
zircon age populations, including ages at least 150 kyr and up to 300 kyr older than their eruption age. Age groups, which range from approximately 6 to 600 ka, are present in most but not
all, samples. Ti-in-zircon thermometry and zircon saturation calculation suggests that much of
the zircon growth was from highly fractionated melts and at low temperatures, requiring that the
common MSH dacitic compositions would have been immobile crystal mushes by the time zircon
saturation was reached. The geochemistry of the various magmas indicates that they are lower
crustal melts and the relatively young ages of the major phases in erupted magmas indicate
that they move rapidly from generation to eruption, and thus are not the products of segregation
from the stalled magmas that are growing the zircons. However, this active plutonic body must
contribute some material to the erupting magmas, as the presence of zircon in many erupted
52 2010 GSA Abstracts with Programs units requires that mushes or perhaps even rocks have repeatedly melted, been rejuvenated, and
some portion of these melts and the zircons they contain incorporated into erupting magmas.
The portions of the MSH intrusive body, then, that have not experienced any rejuvenation or
zircon+melt extraction may be the unerupted equivalents of the volcanic rocks, while the portions
that have undergone repeated rejuvenation and have contributed material to erupting magmas
would likely be more like crystal cumulate residues. This intrusive component of the system is
mostly cryptic in the volcanic record, with the exception of the zircons that survive the reheating
events and mix into the lower crustal melts before eruption.
10-6
3:30 PM
Glazner, Allen F.
[173181]
THE ROOM NON-PROBLEM
GLAZNER, Allen F.1, BARTLEY, John M.2, and COLEMAN, Drew S.1, (1) Geological
Sciences, Univ. of North Carolina, Chapel Hill, NC 27599-3315, [email protected], (2) Geology
and Geophysics, Univ. of Utah, Salt Lake City, UT 84112
A long-standing enigma in petrology and structural geology has been the “room problem.” Making
space for a magma body the size of a large pluton is indeed a problem, but this reflects the venerable “big tank” model in which a pluton represents crystallization of a magma body of the same
size. We argue that there generally is no room problem because most plutons are intruded in
small increments over durations long enough that space is made by familiar processes at uniformitarian rates.
A large and growing body of geochronological, field, geochemical, geophysical, and experimental results indicates that most plutons are composite and were assembled over durations on the
order of 106 years. This time scale accords with InSAR-determined rates of non-eruptive volcanic
inflation (~106-107 m3/yr) and with the ~107 year life spans of major volcanic centers. Geophysical
surveys have failed to image big magma chambers under active volcanic centers. Although large
ignimbrite eruptions indicate that big tanks do form, they reflect transient periods of high power
input relative to heat loss. Field relations traditionally interpreted in terms of huge, bottomless,
molar-shaped plutons are equally consistent with incremental pluton growth by crack inflation.
Crack-seal pluton growth accords with volcano geodesy which records short-lived pulses of rapid
surface uplift (crack inflation) and subsidence (increment cooling). It accounts for the fact that
wall-rock inclusions--regardless of size and density--are generally rare, unsorted, and concentrated near pluton margins; such xenoliths were likely never engulfed in or sank through magma.
Sharp, discordant pluton roofs are typically the upper limits of crack systems into which numerous magma increments intruded to form the pluton. Incremental pluton growth by crack-seal
eliminates major inconsistencies between conventional interpretations of volcanic and plutonic
phenomena and renders the “room problem” largely irrelevant.
10-7
3:50 PM
Deering, Chad D.
[173066]
TRACE ELEMENT INDICATORS OF SILICIC CUMULATES
DEERING, Chad D., Earth and Space Sciences, University of Washington, Seattle, WA
98195, [email protected] and BACHMANN, Olivier, Earth Space Sciences,
University of Washington, Box 351310, Seattle, WA 98195-1310
If fractional crystallization coupled with some crustal assimilation (AFC) is the dominant process
for generating evolved magmas in the Earth’s crust, large quantities of igneous cumulates must
be present in the rock record. However, despite some reported occurrences, intermediate to silicic
rocks characterized by an unambiguous crystal accumulation signature have remained elusive.
The signature is expected to be subtle in viscous silicic magmas, and sensitive criteria need to
be developed to test whether these cumulates are truly rare or difficult to discern. We propose
models that use specific trace element concentrations and ratios (Zr, Ba, Eu/Eu*, Zr/Hf) within
a well-constrained framework for the physical extraction of liquid from crystals (mostly occurring between 50 and 70 vol% crystals) to identify silicic cumulates. The results of these models
indicate that crystal accumulation (or melt extraction) has occurred in multiple natural examples
around the world (both in plutonic and volcanic realms). However, these examples were selected
because they represent conditions that are most favorable (high amount of melt extraction, wellconstrained initial liquid compositions) for unambiguously identifying cumulate residue; in many
cases, we show that the trace element signature for crystal accumulation will remain largely concealed. In addition, the different liquid lines of descent related to the various tectonic settings on
Earth (dry-reduced in hot spots-divergent margins and wetter-more oxidizing in arc environments)
will lead to different trace element evolution and each criterion must be applied on a case-to-case
basis. Despite these limitations, the undeniable but subtle presence of silicic cumulates in the
mid- to upper-crust lends support to the idea that igneous differentiation is dominantly driven by
melt extraction from crystalline reservoirs.
10-8
4:10 PM
Mills, Ryan D.
[172755]
MODELING LARGE-VOLUME FELSIC ERUPTIONS FROM TRACE-ELEMENT
GEOCHEMISTRY
MILLS, Ryan D. and COLEMAN, Drew S., Department of Geological Sciences, University of
North Carolina, CB# 3315, Chapel Hill, NC 27599-3315, [email protected]
The existence of large bodies of felsic magma in the upper crust is inferred from ignimbrites estimated to represent eruptions of 100’s to 1000’s of km3, but the origin of the magmas is debated.
One prominent model involves fractional crystallization of an intermediate magma, resulting in
crystals and a complementary felsic melt. Compaction can segregate the liquid from the crystals
once crystals account for ~50% of the system, and extraction of a fraction of the liquid from the
system is hypothesized to yield silicic ignimbrites.
Felsic igneous rocks, including large felsic ignimbrites, have highly fractionated whole rock
chemistry (e.g. negative Eu anomalies) that is not seen in intermediate igneous rocks envisioned
to be their parent magmas. Intermediate igneous rocks are also not chemically complementary
to the fractionated felsic magmas (e.g. positive Eu anomalies). Thus, a fractional crystallization
model for the creation of felsic magma in the upper crust requires that a portion of the fractionated
felsic liquid remain in the system after eruption. Crystallization of the resulting system, consisting
of unerupted felsic liquid and crystals, produces intermediate plutonic rocks with neither a fractionated, nor complementary, chemistry. An important variable in this model is the fraction of liquid
that must be left behind to mask the chemical signature of melt extraction from the crystal mush.
We used the Eu deficiency (conc. of the Eu anomaly in ppm) and erupted volume of felsic
ignimbrites as starting parameters for predicting the Eu excess and volume of the associated
plutonic rocks. Results suggest that a system with ~50% crystals that erupts more that 25% of
the liquid fraction will leave behind a pluton with a chemical signature that is not consistent with
data for plutonic rocks. Because >75% of the felsic liquid must remain in the system, magma
fluxes > 0.02 km3/yr are required to build chambers capable of generating even moderately sized
ignimbrites on timescales of 200-300 ka (U/Pb zircon age ranges of large ignimbrites). Calculated
intrusive:extrusive ratios are >20, far greater than typical estimates. Although calculated magma
flux rates are in agreement with rates calculated for super eruptions, at these flux rates it is difficult to fractionally crystallize a system due to the near constant heat input.
SESSION NO. 11
T3. Terrestrial and Marine Records of Late Quaternary
Climate from Western North America/Eastern
Pacific: Developments, Comparisons, and Directions
11-1
1:30 PM
Zimmerman, Susan Herrgesell
[172959]
IMPROVEMENTS ON THE DEGLACIAL CHRONOLOGY AT MONO LAKE, CA FROM
14C-DATING OF PROGRESSIVE LEACHES
ZIMMERMAN, Susan Herrgesell, Center for Accelerator Mass Spectrometry, Lawrence
Livermore National Laboratory, P.O. Box 808, L-397, Livermore, CA 94550, zimmerman17@
llnl.gov, STEPONAITIS, Elena A., Department of Environmental Science, Barnard College,
New York, NY 10027, and HEMMING, Sidney, Department of Earth and Environmental
Sciences and Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964
The dramatic expansion of the Great Basin lakes at the end of the last glacial period is wellknown but poorly understood, in part because of difficulties in dating the time and duration of the
expanded lakes. At Mono Lake the final highstand is marked by the sequence of Ashes 1-2-3-4,
readily-identifiable in deep lake sediments as high as 50-60 m above average late-Pleistocene
levels. Carbonate 14C dates and 40Ar/39Ar on rhyolitic ashes in the Wilson Creek Formation sediments both have complications, and for the high-precision and –accuracy required to correlate
global changes, improved chronological constraints are required.
We have built on previous progressive leaching experiments to separate and radiocarbon date
the oldest carbon in a sample, on the premise that all younger carbon is contamination added
after the time of the original precipitation. After weighing carbonate into a sealed vial, the vial is
evacuated, phosphoric acid is added, and the vial attached to the graphitization rig. Using variable
concentrations of acid, sampling intervals, and amounts of heat, we have dated multiple steps
on ostracodes, thinolite, and gastropods. The results show that surface area-to-volume ratio is
the most important factor in separating multiple steps: thinolite crushed to >300 microns can be
controlled easily, while ostracodes are quite thin and delicate, making the reaction much more
difficult to control.
Eleven steps on a thinolite fan from above Ash 1 show an increase of more than 2000 years
from first to last step, and ~400 year increase over a lightly-leached bulk sample. A weighted
mean of the final ages, 10,920 +/-20 14C yrs BP, minus a 1000-year reservoir effect, calibrates
to 11,300 +/- 70 cal yr BP, close to the end of the Younger Dryas interval recorded in Hulu cave
(11,470 +/- 100 ka). Several sets of leaches on one ostracode sample yielded 4000- to 7000-year
differences between first and last leach steps and 3500 years between the oldest leach and a
bulk sample date. Calibration of the oldest leach age corresponds to 13,900+/-170 cal yr BP (with
1 ka reservoir correction). These results suggest that both the cold Younger Dryas and the warm
Bolling-Allerod were extremely wet. Future work will increase the number of reliably-dated carbonates, and clarify the relation of the Mono Lake highstand to global climate changes.
11-2
1:45 PM
Liddicoat, Joseph C.
[173708]
LATE PLEISTOCENE GLACIATION IN THE WESTERN U.S. GREAT BASIN AS RECORDED
IN MONO BASIN, CALIFORNIA
LIDDICOAT, Joseph C., Department of Environmental Science, Barnard College,
Columbia University, New York, NY 10027, [email protected]
Beginning nearly a decade ago, research in the Mono Basin, CA, has been impetus for reinterpretation of late Quaternary glaciations in the western U.S. Great Basin (Zimmerman et al.,
2006). The renewed interest followed publication of Ar/Ar dates for several volcanic ash layers
(Kent et al., 2002) in the Wilson Creek Fm that indicate the ashes near the base of the section
were erupted from the Mono Craters perhaps 67,000 years ago (Zimmerman et al., 2006). That
age led to a suggestion that the Mono Lake Excursion (MLE) is older by nearly 8,000 years than
previously proposed (Benson et al., 2003), and that the MLE might not be a separate one of the
paleomagnetic field but instead is the Laschamp Excursion (LE) that is dated at about 40,000
years B.P. (Guillou et al., 2004)(Kent et al., 2002). However, the recent discovery of the MLE and
LE in cored sediment from Pyramid Lake, NV (Benson et al., 2008), and subsequent Ar/Ar dating
of several of the volcanic ashes in the Wilson Creek Fm (Cassata et al., 2010) indicate that the
two excursions indeed are separate events in the paleomagnetic record. On the assumption that
the base of the Wilson Creek Fm at its type locality along Wilson Creek is about 67,000 years
old and not about 38,000 years old that previously was the age assignment based on Carbon-14
dating of ostracodes, a match of the relative paleointensity in the formation to the Global
PaleoIntensity Stack (GLOPIS)(Laj et al., 2004) has resulted in a reinterpretation of the paleoclimate record in the Mono Basin (Zimmerman et al., 2006). Possible evidence that the Wilson
Creek Fm might not be 67,000 years old at its base comes from a comparison of the stratigraphic
intervals between volcanic ash layers that are exposed on opposite sides of the Mono Basin—at
the South Shore Cliffs and at Wilson Creek. The relative spacing is very similar for all the ash
layers except between two near the bottom of the sections where there is more than a fivefold
difference (decrease) at the type section; at Wilson Creek the interval between ash layers 16 and
17 is 20 cm but at the South Shore Cliffs the interval is 108 cm (Zimmerman et al., 2006). For the
20 cm of lacustrine silt at Wilson Creek to represent nearly 30,000 years of geologic time is not
consistent with deposition rates for other large Pleistocene pluvial lakes (Bonnevillle, Lahontan,
Searles) in the Great Basin.
11-3
2:00 PM
Oster, Jessica
calibrated stable isotopic and trace element time series for speleothems from Moaning and
McLean’s Caves.
Monthly measurements of cave air temperature, humidity, and pCO2 in Black Chasm demonstrate that the cave is ventilated in the winter months, when cold, dense surface air sinks into the
cave. Cave drip water δ18O and δD are correlated with rainwater stable isotopes and display more
negative values during the wet winter months, and less negative values during the summer and
fall. Cave drip water δ13C, Mg/Ca, and Sr/Ca are higher in the dry summer and fall, suggesting
that prior calcite precipitation occurs in the epikarst at these times.
Monitoring data from Black Chasm provides a modern framework for interpreting paleoclimate
proxy data from Moaning and McLean’s Caves where such monitoring programs cannot be
implemented. Speleothem isotopic and geochemical proxy records from these caves document
changes in Sierra Nevada precipitation that are approximately coeval with Greenland temperature changes for the periods 16.5 to 8.8 ka and 67 to 56 ka. From 16.5 to 8.8 ka, the Moaning
Cave stalagmite proxies record drier and possibly warmer conditions, signified by elevated δ18O,
δ13C, [Mg], [Sr], and [Ba] and more radiogenic 87Sr/86Sr, during Northern Hemisphere warm periods (Bølling, early and late Allerød) and wetter and possibly colder conditions during Northern
Hemisphere cool periods (Older Dryas, Inter-Allerød Cold Period, and Younger Dryas). From 67 to
56 ka, the McLean’s Cave stalagmite displays elevated δ18O and δ13C suggesting drier conditions
during the interstadials of MIS 4 and early MIS 3 (IS 18, 17, and 16) documented in Greenland
ice cores. The linkages between northern high-latitude climate and precipitation in the Sierra
Nevada suggested here could indicate that, under conditions of continued global warming, this
drought-prone region may experience a reduction in Pacific-sourced moisture.
11-4
2:15 PM
Reheis, Marith
[173047]
LATE PLEISTOCENE SHORELINE FLUCTUATIONS OF LAKE MANIX, MOJAVE DESERT:
PALEOCLIMATE IMPLICATIONS
REHEIS, Marith, U.S. Geological Survey, Box 25046, MS 980, Denver Federal Center,
Denver, CO 80225, [email protected], MILLER, David M., U.S. Geological Survey,
345 Middlefield Road MS 973, Menlo Park, CA 94025, and MCGEEHIN, John P.,
US Geological Survey, 12201 Sunrise Valley Drive, Reston, VA 20192
Marine and ice cores provide highly detailed proxy records of past climate conditions and suggest global teleconnections. However, recent records from cave speleothems in the western U.S.
compared with lake-level proxies suggest that continental interiors may respond to multiple drivers
that influence climate conditions at the scale of the geographic region. Previously published work
on pluvial lake levels in the western U.S. during marine isotope stage (MIS) 3 suggests that lakes
rise in response to warm phases of the Dansgaard-Oeschger (D-O) cycles, in agreement with
wetter warmer periods in the Santa Barbara Basin marine record. In contrast, two speleothem
records in south-central Arizona and southeastern New Mexico record cool wet periods coincident with cool D-O phases. These conflicting records may be reconciled by an hypothesis that
regional climate was influenced by the Pacific Ocean for the more western parts of the western
U.S., and by the Atlantic Ocean, as mediated by the Gulf of Mexico, for the more eastern regions
of the Sonoran and Chihuahuan desert area. Lake Manix, the main terminal lake for the Mojave
River in south-central California until about 25 cal ka, lies between the speleothem locations and
the Santa Barbara Basin. This lake, which was likely shallow due to previous sediment loading,
achieved multiple highstands during MIS 3 and early MIS 2. Our preliminary lake-level curve,
constrained by >40 calibrated 14C ages on Anodonta shells, indicates rapid fluctuations between
45 and 25 ka and at least 8 highstands within 10 m of the 543-m upper threshold for Lake Manix.
Correlations of Manix highstands with ice, marine, and speleothem records suggest that some
highstands coincide with colder D-O phases, whereas others coincide with warmer phases. Thus
Lake Manix, and hence runoff from the Transverse Ranges, may have responded alternately to
southerly displacement of Pacific winter storm tracks during colder D-O phases and to increased
moisture transport from the North Pacific off southern California during the warm D-O phases.
11-5
2:30 PM
Starratt, Scott W.
[173050]
MARINE-TERRESTRIAL CLIMATE CONNECTIONS: THE INFLUENCE OF THE EASTERN
PACIFIC OCEAN ON THREE MIDDLE TO HIGH ELEVATION LAKES AND SAN FRANCISCO
BAY
STARRATT, Scott W.1, BARRON, John A.1, WAN, Elmira2, WAHL, David B.2, and
ANDERSON, Lysanna3, (1) U.S. Geological Survey, 345 Middlefield Rd, Menlo Park, CA
94025-3591, [email protected], (2) U.S. Geological Survey, 345 Middlefield Rd, MS-975,
Menlo Park, CA 94025, (3) Environmental Earth System Science, Stanford University,
450 Serra Mall, Stanford, CA 94305
Evidence for a strong connection between the North Pacific Ocean and climate of the western
U.S. is found in paleoclimate records from middle and high elevation lakes in California and
Nevada, as well as San Francisco Bay.
Medicine Lake (2036 m), in northwestern California, is presently a closed-basin lake that
receives most of its water from seasonal snowpack. Comparison with the record from ODP Site
1019, off northern California, demonstrates a significant connection between coastal precipitation
and lake level throughout the Holocene. Swamp Lake (1554 m) is a small, middle elevation lake
in the northwestern corner of Yosemite National Park. Much of the ~19,000 year record is varved,
providing a high-resolution record. Multiple proxies record changes in lake level and productivity
during the Medieval Climate Anomaly and Little Ice Age that may allow us to evaluate the impact
of Pacific climate patterns such as ENSO and PDO. Located in the Ruby Mountains in northeastern Nevada, Favre Lake (3029 m) is affected by a more complicated set of atmospheric conditions than either of the previously discussed lakes. Preliminary results show some similarities to
both Pacific and Rocky Mountain climate records.
San Francisco Bay receives fresh water from more than 40% of California, and therefore provides a record of climate variability over much of the state. Marsh records from the northern bay
correspond well with other records of shorter duration allowing a synthesis of late Holocene precipitation records, which indicates that moisture is controlled by conditions in the Pacific Ocean.
[173674]
MODERN VARIABILITY IN CENTRAL SIERRA NEVADA CAVE ENVIRONMENTS AND
IMPLICATIONS FOR CHANGES IN PALEO-PRECIPITATION
OSTER, Jessica, Geology, University of California, Davis, One Shields Avenue, Davis,
CA 95616, [email protected], MONTANEZ, Isabel P., Department Geology, University
of California, Davis, CA 95616, and SHARP, Warren D., Berkeley Geochronology Center,
Berkeley, CA 94709
Speleothem-bearing caves developed in the central Sierra Nevada foothills, California, offer an
excellent opportunity to investigate the response of fracture-dominated cave systems to precipitation changes on seasonal to glacial-interglacial timescales. Here, we present the results of
three years of cave water and air measurements at Black Chasm Cavern coupled with U-series
SESSION NO. 11
11-6
2:45 PM
Behl, Richard J.
[173618]
ABRUPT AND MILLENNIAL-SCALE CLIMATE AND OCEAN CHANGE SINCE THE MIDPLEISTOCENE TRANSITION IN SANTA BARBARA BASIN, CALIFORNIA
BEHL, Richard J.1, KENNETT, James2, AFSHAR, Sara1, ESCOBEDO, Diane K.1, HILL,
Tessa M.3, NICHOLSON, Craig4, and SORLIEN, Christopher C.5, (1) Geological Sciences,
California State University Long Beach, 1250 Bellflower Blvd, Department of Geological
Sciences, Long Beach, CA 90840, [email protected], (2) Earth Sciences, University of
California Santa Barbara, Webb Hall, University of California Santa Barbara, Santa Barbara,
CA 93106, (3) Dept of Geology, Univ of California Davis, One Shields Ave, Davis, CA 95616,
(4) Marine Science Institute, University of California, Santa Barbara, CA 93106-6150,
(5) Institute for Crustal Studies, University of California Santa Barbara, Santa Barbara,
CA 93106
We have discovered evidence for abrupt ocean/climate change and millennial-scale oscillations
distributed through the past ~735 kyr in Santa Barbara Basin, California. As part of an integrated
seismic acquisition and piston coring campaign in 2005, we acquired thirty-two 2-11 m long piston
cores that provide ~2-9 kyr high-resolution windows into past climate behavior. High-frequency climatic oscillation is recorded in 8 of these cores by variations in massive to laminated sedimentary
fabric, oxygen and carbon isotopes, % total organic carbon, % carbonate, % biogenic silica, abundance of redox and productivity sensitive elements, or planktonic foraminiferal assemblages. In
general, warm interstadials are represented by laminated, organic-rich sediment deposited under
highly productive surface waters. During this interval, rapid decadal-scale climatic/oceanographic
transitions occur within different climatic states, such as, MIS 3-like intermediate conditions,
deglacial transitions, and glacial episodes. To date, no Dansgaard-Oeschger-like interstadials
have been found to occur during otherwise fully interglacial conditions. These results indicate that
the California margin has been sensitive to climatic forcing and experienced rapid climatic fluctuations since at least the Mid-Pleistocene Transition when predominance of 41-kyr climate cycles
shifted to a 100-kyr climate cycle regime. Sedimentation rates are of sufficient magnitude (70-130
cm/kyr) to obtain data at sub-decadal sample intervals, permitting analysis of the rate of change
and climate/ocean phasing at human time scales. We were able to obtain these cores by identification of distinctive seismic stratigraphic horizons related to climatic and sea-level fluctuations on
deep-penetration industry multichannel seismic (MCS) reflection data and in high-resolution MCS
and towed chirp data acquired during 2005 and 2008 research cruises. These horizons were
mapped in 3D to seafloor outcrop, where they are accessible to piston coring. Ages of horizons
and cores were determined by interpolation between ODP Site 893, a previously published 1-Ma
horizon, dated tephra, biostratigraphic markers, and climate states and transitions identified from
oxygen isotope records from the recovered cores.
11-7
3:15 PM
Ferguson, Julie
[173177]
SEASONAL RESOLUTION SEA SURFACE TEMPERATURES FROM LOTTIA GIGANTEA
SHELL GEOCHEMISTRY
FERGUSON, Julie1, JOHNSON, Kathleen R.1, ROY, Kaustuv2, KENNETT, D. J.3, and
ERLANDSON, Jon M.3, (1) Dept. of Earth System Science, University of California, Irvine,
3206 Croul Hall, Irvine, CA 92697-3100, [email protected], (2) Ecology, Behavior &
Evolution, Univ of California, San Diego, La Jolla, CA 92093, (3) Department of Anthropology,
Univ of Oregon, Eugene, OR 97403-1218
Producing seasonal-resolution records of past sea surface temperature is important if we are
to better understand the role of seasonality and interannual climate modes, such as the El Niño
Southern Oscillation (ENSO), in controlling mean climate on diverse timescales. Such records
would be of particular use along the west coast of North America where seasonal upwelling and
ENSO events have significant effects on the regional climate and ecology. However, finding suitable seasonal-resolution archives of climate information has proved difficult outside the range
of tropical surface corals. At mid-to-high latitudes, marine mollusk shells provide an archive with
significant potential. Using a New Wave Micromill, successive samples were drilled from the
cross sections of modern Lottia gigantea (Owl limpet) shells from the California coastline and
analysed to produce stable isotope (δ18O and δ13C) and trace element (Mg/Ca, Sr/Ca) profiles.
These profiles are then compared with nearby instrumental records of seawater temperature
and salinity. The oxygen isotope composition of the shells accurately record absolute sea surface
temperatures and capture more than 80% of the full seasonal range. Trace element ratios in Lottia
gigantea shells are more complex but are also investigated in an attempt to identify useful trace
element proxies of environmental variables. Finding and dating sequences of marine mollusk
shells spanning long periods of time is difficult due to sea-level change and the destructional
nature of most coastal environments. It is possible to avoid these problems by using the shells
of marine mollusks collected for food by humans in North America during the Holocene and left
behind in middens. Fossil Lottia gigantea shells dating from 10,000 years B.P. to recent, obtained
from archaeological sites on San Miguel and Santa Rosa Islands off California, were analysed to
produce snapshots of past sea surface temperature seasonality.
11-8
3:30 PM
Kirby, Matthew E.
[172944]
A 10,000 YEAR RECORD OF PACIFIC DECADAL OSCILLATION (PDO)-RELATED
HYDROLOGIC VARIABILITY IN SOUTHERN CALIFORNIA (LAKE ELSINORE, CA)
KIRBY, Matthew E., Geological Sciences, California State University, Fullerton, 800 N.
State College Blvd, Fullerton, CA 92834, [email protected], LUND, S.P., Department of
Earth Sciences, University of Southern California, Los Angeles, CA 90089, PATTERSON,
William P., Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon,
SK S7N 5E2, Canada, ANDERSON, Michael, Environmental Sciences, University of
California, Riverside, 218 Sciences Lab I, Riverside, CA 92521, and BIRD, Broxton W.,
Geology and Planetary Science, University of Pittsburgh, 200 SRCC Building, 4107 O’Hara
St, Pittsburgh, PA 15260
High-resolution, complete terrestrial records of Holocene climate from Southern California are
scarce. Moreover, there are no records of Pacific Decadal Oscillation (PDO) variability – a major
driver of decadal-to-multi-decadal climate variability for the region - older than 1000 years. Recent
research on Lake Elsinore, however, has shown that the lake’s sediments hold excellent potential
for paleoenvironmental analysis and reconstruction. New 1cm contiguous grain size data reveal a
more complex Holocene climate history for Southern California than previously recognized at the
site. A modern comparison between the 20th century PDO index, lake level change, San Jacinto
River discharge, and percent sand suggests that sand content is a robust, qualitative proxy for
PDO-related, hydrologic variability at both multi-decadal-to-centennial as well as at event (i.e.,
storm) timescales. A depositional model is also proposed to explain the sand-climate proxy. The
sand-hydrologic proxy data reveal nine intervals of wet (+PDO) and dry (-PDO) climate throughout the Holocene. Percent total sand values >1.5 standard deviation above the 150-9800 cal yr
BP average are frequent between 9800 and 3300 cal yr BP (n=41), but they are rare from 3300
to 150 cal yr BP (n=6); this disparity is interpreted as a change in the frequency of exceptionally
wet (high discharge) years and/or changes in large storm activity. A comparison to other regional
hydrologic proxies (10 sites) shows occasional similarities across the region (i.e., 6 of 9 Elsinore
wet intervals are present at >50% of the comparison sites). Only the Little Ice Age interval is
54 2010 GSA Abstracts with Programs interpreted consistently across the region as uniformly wet (8 of 10 sites). A comparison to ENSO
reconstructions indicates little, if any, correlation to the Elsinore data suggesting that ENSO variability is not the predominant forcing of Holocene climate in Southern California.
11-9
3:45 PM
Englebrecht, Amy
[173075]
A 2,000-YEAR VARVED RECORD OF HYDROLOGIC CHANGE FROM ISLA ISABELA,
SUBTROPICAL NORTHEAST PACIFIC
ENGLEBRECHT, Amy1, INGRAM, Lynn1, BYRNE, Roger2, and KIENEL, Ulrike3,
(1) Earth and Planetary Science, University of California Berkeley, Berkeley, CA 94720,
[email protected], (2) Geography, University of California Berkeley, Berkeley,
CA 94702, (3) Helmholtz Centre PotsdamGFZ, German Research Centre for Geosciences,
Potsdam, D-14473, Germany
The persistence and recurrence of dominant climate periodicities remains a concern in predicting
future variations across the Pacific Basin. We reconstructed a 2,000-year record of changes in
water availability from the oxygen isotope composition of a continuous varved sequence from Isla
Isabela, a small volcanic island in the subtropical northeast Pacific. Comparing the oxygen isotope (δ18O) record to the observed Pacific Decadal Oscillation (PDO) index, we found that shifts
toward more elevated δ18O corresponded to negative phases of the PDO, indicating that these
phases are marked by increased evaporation and/or decreased precipitation at Isabela Crater
Lake. Wavelet analysis of the δ18O record indicates that strength in the dominant PDO periodicities is intermittent over the past 2,000 years, with the greatest strength in the PDO bands appearing from AD 1200 to 1400 and 1850 to 1900. Our record suggests that the PDO has changed
several times in the past two millennia, and is both a critical and nonstationary component of
climate variability in the subtropical Pacific.
11-10
4:00 PM
Cheetham, Michael Ian
[173270]
MULTI-DECADAL CLIMATE VARIABILITY IN SOUTHERN CALIFORNIA OVER 2 MILLENNIA
CHEETHAM, Michael Ian1, KIRBY, Matthew E.2, and FEAKINS, Sarah1, (1) Department
of Earth Sciences, University of Southern California, 3501 Trousdale Pkwy, Los Angeles,
CA 90089-0740, [email protected], (2) Geological Sciences, California State University,
Fullerton, 800 N. State College Blvd, Fullerton, CA 92834
There is a keen interest in understanding the frequency and severity of droughts and floods in
southern California, although annually resolved millennial high resolution records are rare. We
have recently recovered two 9m sediment core from Zaca Lake, CA. This site, located within
50 km of the Santa Barbara Basin, is ideal for terrestrial-marine paleoclimate comparisons. The
sediments span the past 2 millennia with a sedimentation rate of c. 0.3 cm/yr. The age model is
based upon 9 radiocarbon dates, an historical event in 1938, and the 137Cs peak in 1963; further
age control from first appearances of non-native pollen in the nineteenth and twentieth century
will be added. Euxinic bottom waters and mm-scale color laminations imply minimal bioturbation.
Elemental abundance analyzed at up to 2 mm resolution by scanning XRF yields quasi-annual
resolution. Ti, Rb and Zn covary extremely closely, and together with grain size analysis is indicative of detrital input, associated with unusually wet conditions. Ti is diagenetically immobile, unlike
other elements (eg Fe, Mn) and not scavenged by minerals produced in the water column (eg Ca,
Sr). Detrital inputs were unusually high around 100, 200, 400, 1130, 1200, 1400 and 1600 AD.
We identify major regional floods that extend to the Santa Barbara basin as well as numerous
additional climate events, providing a new archive of wet-dry cycles in heavily populated southern California.
11-11
4:15 PM
Roach, Lydia D.
[173211]
HYDROGEN ISOTOPE RATIOS OF LEAF WAX LIPIDS FROM SIERRA NEVADA LAKE
SEDIMENTS RECORD DECADAL HYDROCLIMATE VARIABILITY DURING THE
MEDIEVAL PERIOD
ROACH, Lydia D., Geosciences, Scripps Institution of Oceanography, University of California
San Diego, 9500 Gilman Dr, Mail Code 0208, La Jolla, CA 92037-0208, [email protected],
SESSIONS, Alex L., Geological and Planetary Sciences, Caltech, MC 100-23, 1200 E.
California Blvd, Pasadena, CA 91125, CAYAN, Daniel C., Climate Sciences, Scripps
Institution of Oceanography, University of California San Diego, 9500 Gilman Dr, Mail Code
0224, La Jolla, CA 92037-0224, CHARLES, Christoper D., Geosciences, Scripps Institution
of Oceanography, University of California San Diego, 9500 Gilman Dr, Mail Code 0244,
La Jolla, CA 92037-0244, and ANDERSON, R. Scott, Center for Environmental Sciences &
Education, Northern Arizona University, Flagstaff, AZ 86011
Persistent drought is one of the greatest risks of climate change facing the western United States.
Highlighting this risk is evidence from paleo hydrologic reconstructions that during the medieval
period (~900-1400 AD) this region was witness to droughts of greater duration than any experienced in recorded history. However, much remains to be learned about these “mega-droughts,”
including their impact on precipitation and snowpack in the Sierra Nevada Mountain range, which
currently serve as a crucial source of fresh water to southern California. Stable hydrogen isotope
ratios (δD) of plant leaf wax lipid compounds preserved in lake sediments show promise as a
proxy for recording past hydroclimate variability in the Sierra Nevada Mountains. Previous work
demonstrates that the δD of these compounds reflects that of lake water and/or shallow ground
water--reservoirs both fed by local precipitation. Lake sediment δD can therefore reflect the processes that determine δD of meteoric water, including temperature, humidity, moisture source and
storm track. We have measured δD of aquatic and terrestrial plant leaf wax fatty acids extracted
from a suite of sediment cores collected at Swamp Lake (elevation: 1553m), in Yosemite National
Park, along the Sierra Nevada crest. Measurements at annual to interannual resolution were
made for two time periods: the 20th century and the 12th-15th centuries. Comparison of 20th century
results with instrumental records of Sierra Nevada hydroclimate reveals a significant relationship
at decadal scales between Swamp Lake leaf wax lipid δD variability and wintertime precipitation,
April 1st snow water content and Palmer Drought Severity Index (PDSI). In agreement with these
relationships, medieval δD variability, which ranges on the order of 30‰, mimics that of regional
tree ring PDSI reconstructions at decadal frequencies. This δD record provides an independent
means of capturing decadal scale hydroclimate variability and offers a unique perspective on the
mega-drought intervals in the Sierra Nevada Mountains.
SESSION NO. 12
T5. Active Tectonics of the Eastern California Shear
Zone–Walker Lane Belt (Cordilleran Section GSA)
12-1
1:40 PM
Hulett, Ashley
[173145]
NEW HOLOCENE SLIP-RATE SITE ALONG THE CENTRAL GARLOCK FAULT, SEARLES
VALLEY, SOUTHEASTERN CALIFORNIA
HULETT, Ashley1, MCGILL, Sally1, BRYCE, Colin1, HERLIHY, Rachelle1, LOPEZ, Amanda1,
ROBLES, Matthew1, STEPHENS, Jonathan J.1, SWIFT, Mark1, VELASQUEZ, Christina1,
GANEV, Plamen N.2, and DOLAN, James2, (1) Geological Sciences, California State
University, San Bernardino, 5500 University Parkway, San Bernardino, CA 92407, huletta@
csusb.edu, (2) Dept of Earth Sciences, Univ of Southern California, 3651 Trousdale Ave,
Los Angeles, CA 90089
The Garlock fault is a left-lateral fault about 250 km long that extends northeastward and eastward along the northern margin of the Mojave Desert. Geodetic studies imply that present-day
elastic strain accumulation is primarily occurring along northwest-striking, right-lateral faults both
north and south of the Garlock fault and that very little left-lateral strain is accumulating across
the Garlock fault. Nonetheless, the Garlock fault is a through-going structure with abundant evidence for Holocene slip. Along the stretch of fault east of Trona Road, in Searles Valley, numerous
incised channels and alluvial fans of apparent Holocene or latest Pleistocene age are offset tens
of meters. For this study we present mapping of an offset alluvial fan located about 4.2 km east of
Trona Road. The offset fan is best reconstructed by restoring 58 ± 8 meters of left-lateral slip. The
slightly incised east edge of the fan provides the sharpest offset marker, but the crest of the fan
and the tapered west edge of the fan appear to be offset the same amount. We dug a 2-m deep
pit on the center of the fan a few tens of meters north of the fault and collected samples for Be-10
and optically stimulated luminescence (OSL)dating. Because the measured offset applies to the
constructional crest and depositional west edge of the fan, the surface exposure age of the fan
from the Be-10 depth profile and the burial age of the uppermost fan deposits from OSL samples
65 and 80 cm deep, will provide a close (rather than a maximum) estimate of the time required
to accomplish the 58 meters of offset. This site may thus provide an important new Holocene slip
rate for the central Garlock fault.
12-2
2:00 PM
Caskey, S. John
[173247]
CONSTRAINTS ON POST-MIDDLE-PLEISTOCENE OFFSETS AND NEW PERSPECTIVES ON
PLIO-PLEISTOCENE TECTONISM ALONG THE SOUTHERN DEATH VALLEY FAULT ZONE
CASKEY, S. John1, GOODMAN, Joshua T.2, GREEN, Heather L.3, NILES, John H.1,
WAN, Elmira4, WAHL, David B.4, and OLSEN, Holly A.4, (1) Department of Geosciences,
San Francisco State University, 1600 Holloway Ave, San Francisco, CA 94132, caskey@
sfsu.edu, (2) FUGRO William Lettis and Associates, 1777 Bothelo Drive, Suite 262, Walnut
Creek, CA 94596, (3) Nevada Bureau of Mines and Geology, University of Nevada, Reno,
Reno, NV 89557, (4) U.S. Geological Survey, 345 Middlefield Rd, MS-975, Menlo Park,
CA 94025
New mapping and tephrochronology along the Southern Death Valley fault zone (SDVFZ) provide constraints on Pleistocene offsets and insights into post~3.3 Ma tectonism in Southern
Death Valley (SDV). In the Confidence Hills (CH), initial movement along the right-lateral SDVFZ
was preceded by intensive northeast-vergent, fault-propagation folding of the Confidence Hills
Formation (CHF). This earlier folding resulted in ~0.6 km of shortening between 1.2-0.9 Ma.
The intensive (~2 mm/yr), short-lived episode of shortening reflects northeast motion of the
Owlshead Mountains (OM) block that was likely accommodated by coeval left-lateral slip on the
Wingate Wash fault. Right-lateral offset of previously-folded CHF (~2.6-1.2 Ma) and unconformable capping gravel (≤0.9 Ma) are identical (~600 m), showing movement on the SDVFZ began
after 0.9 Ma in the CH and yielding a well-constrained, average slip rate of ~0.7 mm/yr. Previous
flower-structure models for the CH are problematic because: 1) earlier northeast-vergent folds
require blind thrusts that are rooted southwest of the SDVFZ; and 2) slip along the SDVFZ trace
began after earlier folding. Constraints on net offset (~420 m) along the SDVFZ northeast of the
Noble Hills (NH) are based on shortening of Pliocene strata across a persistent restraining step
over. Elsewhere in the area, the most prominent traces of the fault are expressed as small pressure ridges involving ≤0.64 Ma deposits. Field relations show that at least one previously mapped
SDVFZ strand in the central NH is actually a subvertical depositional contact that lies in the
steep-to-overturned forelimb of a large, northeast-vergent, fault-propagation fold involving ~500 m
of conformable ≥3.3 Ma strata. Hence, intensive northeast-vergent contraction that extends the
length of the NH likely began after 3.3 Ma. The conformable Pliocene strata contain clasts from
both the OM to the north and the Avawatz Mountains to south, which brings into question previous interpretations of large-magnitude, right-lateral offset of these deposits. We view northeastvergent contraction throughout SDV as being driven by clockwise rotation of the northeast Mojave
block and resultant northeast-directed block movements north of the Garlock fault, not as secondary shortening along strands of the SDVFZ.
12-3
2:20 PM
Stevens, Calvin H.
12-4
3:00 PM
Nagorsen, Sarah
[173169]
FAULT KINEMATICS IN THE WESTERN MINA DEFLECTION: FIELD STUDIES IN THE ADOBE
HILLS, CALIFORNIA
NAGORSEN, Sarah and LEE, Jeff, Central Washington University, 400 East University Way,
Ellensburg, WA 98926, [email protected]
The Adobe Hills, CA are located within the western Mina deflection, a right-stepping zone of faults
that connect the northern eastern California Shear zone (ECSZ) to the south with the Walker
Lane Belt (WLB) to the north. The Pliocene fault slip history in this region has not been studied in
detail, but is critical for understanding the kinematics of fault slip transfer. To address this issue,
we completed detailed mapping and kinematic studies in the Adobe Hills to test a fault slip kinematic model whereby <1.0 mm/yr of dextral fault slip from the northern ECSZ was transferred into
the western Mina deflection. The Adobe Hills are underlain by 11.1-11.7 Ma (Gilbert et al., 1968)
welded and unwelded latite ignimbrite, tuffaceous sandstone, a number of 2.7-4.2 Ma (Gilbert et
al., 1968) phyric basalt flows, and basalt cinder cones. Sinistral and normal faults cut and offset all
units except the cinder cones. The cinder cones exhibit either no evidence for offset or evidence
for a few meters of sinistral offset, suggesting they were emplaced during the waning stages of
faulting. ENE-striking sinistral faults dominate the area and either cut older normal faults or curve,
via a left-step, into a normal fault geometry. Evidence for sinistral faulting includes ENE-trending
linear valleys; left-stepping extensional and right-stepping compressional stepovers; sinistrally
offset normal faults, ridgelines, and contacts; and alternating scarp-facing directions along strike.
A minimum estimate for sinistral offset across the Adobe Hills is 2100 ± 100 m. Evidence for
normal faulting includes NNW-trending linear valleys and vertically offset basalt flows. Because
of the absence of vertically offset marker beds, scarp height, ranging from 10s of meters to ~100
meters, yields a minimum vertical displacement across normal faults. If basalt lavas in the Adobe
Hills are the same age as those to the east (2.7-4.2 Ma), these ages combined with our sinistral
offset measurements indicate a minimum sinistral slip rate of 0.5-0.8 mm/yr across this part of
the western Mina deflection. This rate is within error of the 0.8-0.4 mm/yr fault slip rate predicted
to have been transferred northward from the dextral White Mountains fault zone, northern ECSZ,
into the western Mina deflection (Lee et al., 2009).
12-5
3:20 PM
Hoeft, Jeffrey S.
[173077]
LATE PLEISTOCENE RATES OF EXTENSION ON THE LONE MOUNTAIN FAULT AND STRAIN
DISTRIBUTION IN THE EASTERN CALIFORNIA SHEAR ZONE-WALKER LANE
HOEFT, Jeffrey S., Earth and Atmospheric Sciences, Georgia Institute of Technology,
311 Ferst Dr, Atlanta, GA 30332-0340, [email protected] and FRANKEL, Kurt L.,
School of Earth and Atmospheric Sciences, Georgia Institute of Technology, 311 Ferst Drive,
Atlanta, GA 30332
Late Pleistocene displacement along the Lone Mountain fault suggests the Silver Peak-Lone
Mountain (SPLM) extensional complex is an important structure in accommodating and transferring strain within the eastern California shear zone (ECSZ) and Walker Lane. Using geologic and
geomorphic mapping, differential global positioning system surveys, and terrestrial cosmogenic
nuclide (TCN) geochronology, we determined rates of extension across the Lone Mountain fault
in western Nevada. The Lone Mountain fault is the northeastern component of the SPLM extensional complex, and is characterized by a series of down-to-the-northwest normal faults that offset
the northwestern Lone Mountain and Weepah Hills piedmonts. We mapped eight distinct alluvial
fan deposits and dated three of the surfaces using 10Be TCN geochronology, yielding ages of
~17 ka, ~92 ka, and ~142 ka for the Q3b, Q2c, and Q2b deposits, respectively. The ages were
combined with scarp profile measurements across the displaced fans to obtain minimum rates of
extension; the Q2b and Q2c surfaces yield an extension rate between 0.1and 0.2 mm/yr and the
Q3b surface yields a rate of 0.2 to 0.4 mm/yr, depending on the dip of the fault. Active extension
on the Lone Mountain fault suggests that it helps partition strain off of the major strike-slip faults
in the northern ECSZ and transfers deformation around the Mina Deflection northward into the
Walker Lane. Combining our results with estimates from other faults accommodating dextral shear
in the northern ECSZ reveals an apparent discrepancy between short- and long-term rates of
strain accumulation and release. If strain rates have remained constant since the late Pleistocene,
this could reflect transient strain accumulation, similar to the Mojave segment of the ECSZ.
However, our data also suggest an increase in strain rates between ~92 ka and ~17 ka, and
possibly to present day, which may also help explain the mismatch between long- and short-term
rates of deformation in the region.
[172620]
A NEW HYPOTHESIS FOR THE ORIGIN OF THE POVERTY HILLS, OWENS VALLEY,
CALIFORNIA
STEVENS, Calvin H., Geology, San Jose State University, 1 Washington Square, San Jose,
CA 95192-0102, [email protected], STONE, Paul, U.S. Geol Survey, 345 Middlefield
Road, MS 973, Menlo Park, CA 94025, BISHOP, Kim M., Geological Sciences, California
State University, Los Angeles, 5151 State University Dr, Los Angeles, CA 90032, and
BLAKELY, Richard J., US Geological Survey, 345 Middlefield Rd, MS 989, Menlo Park,
CA 94025
The Poverty Hills are a 13 km2 block of Jurassic plutonic rocks and upper Paleozoic sedimentary
rocks rising 300 m above the alluvium of Owens Valley south of Big Pine. Several conflicting
hypotheses have been offered to explain the origin of these topographically anomalous hills.
These include an origin as (1) a landslide mass derived from the Sierra Nevada to the west; (2) a
landslide mass derived from the Inyo Mountains to the east; or (3) a transpressional bedrock uplift
related to a left step in the dextral strike-slip Owens Valley fault at the north end of the hills. None
of these hypotheses, however, is fully consistent with the results of recent studies that show the
following: (a) brecciation and other evidence of landsliding are widespread in the Poverty Hills;
(b) rocks of the Poverty Hills match those of the Inyo Mountains much more closely than those of
the Sierra Nevada; (c ) dextral movement on the Owens Valley fault is not transferred along a left
step at the north end of the Poverty Hills as previously proposed, but instead is transferred along
a right step to the front of the White Mountains near the south end of the hills; and (d) the Poverty
Hills have evidently been uplifted since deposition of granitic boulders that now rest on high hills
underlain by Paleozoic sedimentary rocks. An alternative hypothesis, therefore, is needed.
We suggest the following sequence of events to explain the origin of the Poverty Hills. (1) Prior
to late Cenozoic opening of Owens Valley, the rocks that form the Poverty Hills lay 5 km to the
southeast at the north end of the Santa Rita Flat pluton in the Inyo Mountains where matching
rocks are found. (2) As part of the Sierra Nevada structural block, the Poverty Hills rocks were
rifted 8 km northwest as the valley opened. (3) These rocks were then buried by alluvium from the
high Sierra. (4) Later the rocks were uplifted as part of a north-trending horst between the Fish
Springs and Red Mountain faults where elevated granitic basement is now exposed. (5) Finally,
the Poverty Hills rocks were displaced as a landslide mass 3 km eastward from the horst to their
present position. This interpretation is consistent with the anomalous position of the hills east of
the Fish Springs fault on steep magnetic and gravity gradients that define the boundary between
the horst and the deep Owens Valley to the east.
12-6
3:40 PM
Surpless, Benjamin
[173025]
NEW CONSTRAINTS ON QUATERNARY SLIP RATES OF THE WASSUK RANGE FAULT
SYSTEM, WESTERN NEVADA
SURPLESS, Benjamin, Geosciences, Trinity University, 1 Trinity Place, San Antonio, TX
78212, [email protected]
The Wassuk Range fault system is among the most active in the Basin and Range province. Late
Quaternary slip across the east-dipping, high-angle range-bounding normal fault of the range has
produced fault scarps that cut alluvium at many locations along the eastern range front. At the
mouth of Penrod Canyon, in the central Wassuk Range, a large, abandoned alluvial fan displays a
well-defined escarpment striking approximately N30°E at a right-step in the NNW-striking rangefront fault system. This escarpment displays eroded wave-cut benches created by late Pleistocene
lake-level highstands, and well-preserved Holocene fault scarps subparallel and proximal to the
base of the escarpment suggest that this segment of the range-bounding fault system remains
active today.
The abandoned upper alluvial surface displays 40 meters throw relative to the active alluvial
surface on the hanging wall of the normal fault. This value is assumed to be the minimum throw
SESSION NO. 12
across the fault since the alluvial surface was truncated, because past and present alluvial deposition on the hanging wall have buried the correlative upper alluvial surface exposed on the footwall. Cosmogenic nuclide 10Be concentrations from two large boulders on the abandoned alluvial
fan surface yield surface exposure ages of 91 +/- 12 ka and 106 +/- 15 ka. These ages give the
maximum age for the latest deposition on the upper surface of the alluvial fan. Based on the measured fault throw and these exposure ages, the time-averaged slip rate along this fault segment
is approximately 0.4 mm/year. This Late Pleistocene-Holocene value is the same as an estimate
based on previous paleoseismic work for the last 5000 years of fault motion and is slightly lower
than the estimated time-averaged slip rate since the Late Pliocene of 0.5 – 0.75 mm/year. These
data imply a relatively constant rate of extensional deformation along the range-bounding fault
system of the central Wassuk Range since the Late Pliocene.
T16. Miocene Tectonics and Structural Evolution of
Coastal Southern California (Pacific Section, AAPG;
13-1
1:35 PM
Legg, Mark R.
[173146]
MIOCENE OBLIQUE RIFTING OF THE SAN DIEGO TROUGH REGION, CALIFORNIA
LEGG, Mark R., Legg Geophysical, 16541 Gothard Street, Suite 107, Huntington Beach,
CA 92647, [email protected], NICHOLSON, Craig, Marine Science Institute, University
of California, Santa Barbara, CA 93106-6150, and SORLIEN, Christopher C., Institute for
Crustal Studies, University of California Santa Barbara, Santa Barbara, CA 93106
Northwest oblique rifting and rotation of the Western Transverse Ranges (WTR) crustal block
created the Inner-Borderland Rift during Miocene development of the Pacific-North America plate
boundary. The San Diego Trough region occupies the southern third of this segmented continental
rift, where tilted crustal blocks and volcanic highland rift geometry is still preserved. Two major
phases of oblique rifting are recognized. First, subducted lower crust and upper mantle rocks
(Catalina Schist) were rapidly exhumed along the Thirtymile Bank and related detachment faults.
San Onofre Breccia along the mainland coast and offshore islands records this initial rifting. MidMiocene volcanic flows, volcaniclastic and other sedimentary sequences covered the exposed
detachment at the seafloor of the widening rift. A granodiorite pluton on Santa Catalina Island,
~19 Ma, records early volcanism within the rift, whereas widespread volcanic rocks, ~16-18 Ma,
record a major magmatic episode. A volcanic archipelago developed along the rift axis defined
by a suite of major calderas stretching from Santa Catalina Island through Catalina Basin to the
Fortymile Bank and Navy Bank volcanic highlands. The Glendora and Conejo volcanic complexes
of the WTR were part of this initial Miocene volcanic province, but subsequently transrotated away
from the rift axis. A second extensional phase, possibly associated with later oblique rifting of the
Outer Borderland block, disrupted the original detachment surfaces within the rift by high-angle
faulting to deeper levels of detachment creating horst block ridges like Thirtymile Bank and adjacent half-graben basins like the San Diego Trough. The Thirtymile Bank detachment fault was further segmented by high-angle faulting near the coast as the Coronado Bank block was westwardtilted and separated from the mainland. Mid-Miocene and older rocks on Islas Los Coronados are
tilted from 25° to 35° down to the west like correlative strata imaged within the upper Coronado
Bank block. Basalt flows that bracket San Onofre Breccia sequences within the Rosarito Beach
basin and derived from the Thirtymile Bank uplift, constrain timing of this later stage to post 16.115.5 Ma. As rifting ceased, the late Miocene San Diego Trough region was further sheared by
major high-angle right-slip fault zones.
13-2
1:50 PM
Sorlien, Christopher C.
[172568]
QUATERNARY SUBSIDENCE IN THE INNER CALIFORNIA CONTINENTAL BORDERLAND:
ECHO OF MIOCENE CRUSTAL THINNING AND THRUST-FOLDING OF THE NEAR-SHORE
SLOPE
SORLIEN, Christopher C., Institute for Crustal Studies, University of California
Santa Barbara, Santa Barbara, CA 93106, [email protected], SEEBER, Leonardo,
Seismology Geology and Tectonophysics, Lamont-Doherty Earth Observatory, 61 Route
9W, PO Box 1000, Palisades, NY 10964-8000, and CAMPBELL, Brian A., Department
of Geological Sciences, 101 Geology Building, University of Missouri, Columbia, MO
65211-1380
Extinction or subduction of the Pacific-microplate spreading centers resulted in extreme Miocene
extension of offshore southern California as the Pacific Plate diverged from the North American
Plate. This extension facilitated the clockwise rotation or the western Transverse Ranges, denuding the Catalina terrane of the Inner Borderland. High pressure accretionary rocks of the Catalina
schist now exposed on submerged ridges and Catalina Island were uplifted tens of km. The
main reason the Borderland is mostly submerged is that thinned crust eventually stands lower.
Most thinning and volcanism occurred during early and middle Miocene time and initial rapid
subsidence should have occurred shortly thereafter. Miocene subsidence and deposition in the
Inner Borderland Santa Monica and northern San Pedro Basins, and beneath the Gulf of Santa
Catalina (offshore San Clemente-San Diego) was localized to half grabens above low-angle
normal faults. The current basins had previously been relatively high-standing footwalls of certain
of these Miocene faults. Subsidence of the modern basins initiated, reorganized, or accelerated
after Miocene time as existing basins inverted to become the Santa Monica Mountains, and
Long Beach to San Diego shelf and slope. Tectonic denudation and rock uplift of the Catalina
Schist may have contributed to a 10 million year delay in regional subsidence of parts of the
Inner Borderland.
A late episode of subsidence beneath the Gulf of Santa Catalina is suggested by Quaternary
angular unconformities reminiscent of wave-cut platforms that now are at depths from 500 m to
more than 1 km. Progressive tilting of turbidites from Long Beach to San Clemente City show that
if the outer shelf has no vertical motion, the slope must be subsiding with rates increasing SW
towards the basin. This tilting is at a much larger scale than expected from restraining or releasing
double bends on strike-slip faults and suggest a contribution from regional blind thrust faults. Such
faults have been proposed, but generally with SW dip and wide offshore limbs being back limbs.
We propose instead that NE-dipping low-angle Miocene normal faults along the base of the slope
have been reactivated as blind (oblique?) thrust faults. Progressive tilting is thus on the forelimb
of the related folds.
56 2010 GSA Abstracts with Programs 13-3
2:05 PM
Francis, Robert D.
[173300]
MIOCENE TO RECENT TECTONIC EVOLUTION OF SAN PEDRO BASIN AND SANTA
CATALINA ISLAND: EVIDENCE FROM HIGH-RESOLUTION SEISMIC REFLECTION IMAGES
FRANCIS, Robert D.1, LEGG, Mark2, SHAFER, Luke R.1, and CASTILLO, Chris M.1,
(1) Department of Geological Sciences, California State Univ Long Beach, 1250 Bellflower
Blvd, Long Beach, CA 90840, [email protected], (2) Legg Geophysical, 16541 Gothard St,
Suite 107, Huntington Beach, CA 92647
Seismic imaging reveals two major sediment sequences in San Pedro Basin, suggesting a twostage history for the basin and its surrounding uplift features, extending from Mohnian time to the
present. Approximate dating of the sediments is derived from industry wells on San Pedro Shelf
and sequence dating in Santa Monica Basin, carried into San Pedro Basin by means of newly
acquired high-resolution seismic images. The deformed deeper sequence is imaged to depths
up to 2 km below the 900 m deep seafloor. The late Quaternary upper sequence is relatively
undeformed.
A narrow, multi-sequence sediment package underlies the Catalina Shelf, and probably surrounds Santa Catalina Island entirely. The new seismic profiles show the package resting on probable schist basement. A gently-sloping surface on the basement has an outer edge resembling
that of a wave cut terrace, currently at a depth of 400-500 m subsea. A working hypothesis is that
this surface is associated with the 600 ka stillstand; if so, the subsidence rate would have been
about 1/2 to 1 mm/y. Several benches (in multibeam bathymetry images; Cal State Monterey Bay)
have been eroded into the surface of the package (seafloor).
These data suggest that the island has been subsiding for approximately the last 600,000
years, which more or less corresponds to the second stage of San Pedro Basin history. That the
area is subsiding is consistent with the lack of well-defined terraces on the island itself. In contrast, Palos Verdes Peninsula, with its many terraces, has been uplifting for at least 600,000 years.
Thus San Pedro Basin is asymmetric.
The first stage of San Pedro Basin history was markedly different than the second, with significant uplift of Catalina, and small to moderate uplift of Palos Verdes and the adjoining San Pedro
shelf. Onlapping strata along the NE margin of the basin, adjacent to Palos Verdes, are younger
than those along the Catalina margin.
The San Pedro Basin fault cuts across the basin, has seafloor expression, and has offset both
sequences. Other faults in the region show restraining geometries in uplift areas such as Palos
Verdes, Catalina, and Lasuen Knoll. Possible interaction between San Pedro Basin fault and
these other faults, and implications for the apparent changes in uplift rates in different locales are
currently under study.
13-4
2:30 PM
Holk, Gregory J.
[173213]
THE METAMORPHIC AND FLUID EVOLUTION OF THE ONLY MAINLAND EXPOSURE OF THE
CATALINA SCHIST: GEORGE F CANYON, THE PALOS VERDES HILLS
HOLK, Gregory J.1, KELTY, T.K.2, VALENZUELA, Gabriela1, SEARLE, Tiffany1, RODRIGUEZ,
Aaron3, CASTRO, Christopher4, HANSON, Eric5, VANCIL, Mia6, WEAVER, McKenzie7,
and BROWN, Arthur8, (1) Department of Geological Sciences, California State Univ Long
Beach, 1250 Bellflower Blvd, Long Beach, CA 90840, [email protected], (2) Department of
Geological Sciences, CSULB, 1250 Bellflower Blvd, Long Beach, CA 90840, (3) El Camino
College, Torrance, 90506, (4) Long Beach City College, Long Beach, CA 90808,
(5) Lakewood High School, Lakewood, CA 90713, (6) University of California, Berkeley,
Berkeley, CA 94720, (7) Humboldt State University, Arcata, CA 95521, (8) Geologic
Consultant, Seal Beach, CA 90740
The Catalina Schist at George F Canyon in the Palos Verdes Hills was metamorphosed to
produce lawsonite-blueschist, epidote-blueschist, greenschist and possibly epidote-amphibolite
rocks. Our samples contain no amphibolite facies rocks. Outcrops are highly deformed and reflect
multiple episodes of tight folding, but foliation patterns define an antiform at the lower canyon.
Discontinuities in foliation and lineation directions from N45°E to N135°E between the upper
and lower canyon suggest the presence of a fault within the schist. Microtextures in thin section
indicate recrystallization of quartz during metamorphism under ductile conditions. A mapped
isograd reveals that the blueschist facies rocks are structurally below the greenschists, suggesting
the preservation of an inverted thermal gradient. The nature of this isograd is poorly understood.
Lawsonite blueschists (low-T blueschist, 250-400°C, > 8 kb) have quartz+white-mica+lawsonite+
chlorite assemblages. Epidote blueschists (high-T blueschist, 400-500°C, > 9 kb) have mineral
assemblages of quartz+white-mica+glaucophane+epidote. Greenschists (350-500°C, 2-8 kbar)
contain quartz+white-mica+feldspar+chlorite±epidote±actinolite. Most samples are quartz-rich
and likely had siliceous sandstone or graywacke protoliths, but some mafic talc-bearing schists
were found. Late calcite veins and alteration are common and most likely formed during Miocene
exhumation. Chlorite (–65.3‰ to –63.5‰), muscovite (–57.4‰ to –52.2‰), amphibole (–55.4‰
to –54.3‰), glaucophane (–65.9‰ to –57.7‰), and talc (–60.5‰) δD values indicate equilibrium with high-D/H metamorphic waters (~ –20‰) at T ~ 450°C. These waters overlap those
of Cretaceous seawater. Shear zones in the over-riding continental crustal plate (e.g. Eastern
Peninsular Ranges Mylonite Zone) may have served as paths of fluid expulsion. These mainland
exposures of Catalina Schist share a common subduction zone-related tectonometamorphic
history with the better-studied exposures of Catalina Schist on Santa Catalina Island (e.g., Bebout
and Barton, 1993). This study is the first known use of the PIMA portable infrared spectrometer to
identify hydrous and carbonate minerals formed during metamorphism.
13-5
2:45 PM
Liddicoat, Joseph C.
[173627]
ASSESSMENT OF PALEOMAGNTIC RESULTS FOR MIOCENE AND YOUNGER VOLCANIC
AND SEDIMENTARY ROCKS IN THE TRANSVERSE RANGES AND VENTURA BASIN,
COASTAL SOUTHERN CALIFORNIA
LIDDICOAT, Joseph C., Department of Environmental Science, Barnard College,
Columbia University, New York, NY 10027, [email protected]
Beginning with the pioneering study by Blackie and Yeats (1976) of cored Pliocene and
Pleistocene marine sediment (Pico Formation, renamed the Fernando Formation) in the Saticoy
Oil Field, subsequent work by investigators at UC, Santa Barbara, in the 1970s and 1980s
(Luyendyk, 1991; references therein) and others (Prothero, 2001) has resulted in a wealth of
paleomagnetic data for volcanic, terrestrial, and marine rocks in the Transverse Ranges and
Ventura Basin. Those data record nearly 90 degrees of clockwise rotation in the ranges and
basin since the Miocene (Hornafius, 1985; Luyendyk, 1991) and a magnetostratigraphy that
has been used for geochronologic investigations in a region where exploration and recovery of
hydrocarbons of economic importance continues. Besides the paleomagnetic data that have been
accepted, other paleomagnetic data are anomalous such as those for the Miocene Monterey
Formation exposed at South Mountain near Santa Paula, CA, that record southeasterly declination and negative inclination that is shallow by nearly 35 degrees when compared to the inclination of an axial dipole field; both are contrary to the large clockwise rotation described above
where the mean inclination is shallow by only about 15 degrees (Liddicoat, 2001). I will review the
collective paleomagnetic data for Miocene and younger sediments that have been studied in the
SESSION NO. 14
Ventura Basin to assess their utility in geologic, paleontologic, and paleoclimatic investigations in
coastal Southern California.
13-6
3:00 PM
Yang, Wenzheng
[173097]
SEISMOTECTONIC ANALYSIS OF SEISMICITY PATTERNS AND FOCAL MECHANISMS IN
THE EAST LOS ANGELES BASIN, CALIFORNIA
YANG, Wenzheng and HAUKSSON, Egill, Seismological Laboratory, California Institute
of Technology, 1200 E. California Blvd., MS 252-21, Pasadena, CA 91125, wenzheng@
gps.caltech.edu
The eastern edge of the Los Angeles basin (eastLA) abuts the Whittier fault and the Puente and
Chino Hills. The seismicity patterns that are complex along the Whittier fault imply the presence
of slip partitioning, with predominantly strike-slip faulting along the Whittier fault. A broad zone of
thrust faulting exists to the west of the Whittier fault, extending from the Peralta Hills fault into the
Whittier Narrows. Similarly, a zone of mixed strike-slip and thrust faulting exists to the east of the
Whittier fault. In contrast, with increasing depth, the spatial distribution of earthquakes becomes
more lineated in the north-south direction and the spatial heterogeneity of stress gradually
decreases. The results of the stress drop inversion show that stress drop increases with depth.
The two moderate-sized earthquakes, the 1987 ML 5.9 and the 2008 Mw5.4 Chino Hills that
occurred close to the bottom of seismogenic zone, both exhibited high stress drop. Stress field
inversion from focal mechanisms results show that the trend of the maximum principal stress
strikes north-south. The spatial variations in the stress field, depth distribution of seismicity, and
stress drops are consistent with a regional decollment near the bottom of the seismogenic zone.
With abundant earthquake data recorded by the Southern California Seismic Network (SCSN) in
the eastLA region, we systematically analyze seismicity and focal mechanisms from earthquakes
over a broaden range of magnitudes that occurred during the last twenty years. We use the
wavefrom based relocation methods to relocate the seismicity. We determine focal mechanisms
by using both first motions and P/S amplitude ratios. We also invert focal mechanism data for a
spatially/temporally varying stress field. We use an iterative-stacking method to calculate seismic
stress drop from P- wave spectrum.
13-7
3:15 PM
Saenz, Joseph M.
[173004]
STRATIGRAPHIC EVOLUTION OF THE SANTA MARIA BASIN, OFFSHORE CALIFORNIA
SAENZ, Joseph M., Oxnard College, 4000 Rose Avenue, Camarillo, CA 93012, jsaenz@
vcccd.edu, O’NEIL, Thomas J., Oxnard College, 4000 Rose Avenue, Oxnard, CA 93030,
DENISON, Frank E., Frank Denison Geology (Consultant), 867 Hartglen Avenue, Westlake
Village, CA 91361, and FISCHER, Peter J., Department of Geological Sciences, California
State Univ, Northridge, 18111 Nordoff Street, Northridge, CA 91330
Interpretive stratigraphic columns based on detailed descriptions of 73 well logs were used to
understand the relative effects of active tectonics on Mesozoic to Cenozoic stratigraphy in the
Santa Maria Basin (SMB), offshore California. The study confirms that the Hosgri-PurisimaLompoc Fault system plays a major role in the regional Cenozoic tectonics and sedimentations. A
working model is that the offshore SMB initially formed as an Oligocene forearc basin that evolved
into a rift basin during early-middle Miocene, with basin-bounding faults reactivated by PlioceneQuaternary transpression.
Using selected well data, 73 stratigraphic columns were constructed from mud and electric
logs, lithologic summaries, and paleontological information. Mud logs provided detailed information for lithologic analyses. Formation boundaries were determined by correlating electric and
mud logs, and micropaleontological reports. Micropaleontologic interpretations were based upon
nanofossil zonations for 50 wells. Summaries included geologic ages, lithologic subdivisions,
depositional environments, and microfossil determinations. Stratigraphic columns were integrated
into a tectonic and sedimentation model that was constructed into isochore thickness maps for
the Monterey, Sisquoc, and Foxen Formations and Quaternary deposits. Isochore thickness and
fault maps were used to assess the activity on structural highs and lows, and to locate faults
along linear trends of tightly-spaced contours.
Results of this investigation show that the offshore SMB subsided rapidly from early into late
Miocene. By late Miocene, an orthogonal component of compression initiated in response to a
shift in motion between the Pacific-North American plates with strike-slip motion concentrated
along dextral fault systems. Controlled by active tectonism, compressional structures formed
along the Hosgri Fault system and the thickest accumulations of Monterey, Sisquoc, and Foxen
Formations formed in two depocenters. The two depocenters migrated and evolved through the
history of the basin, contributing to significant lateral variability in the thickness of stratigraphic
units. The southern depocenter was located west of the Hosgri Fault zone, and southwest of Point
Arguello. The northern depocenter formed off Point Sal.
in the fracture and the second with carbon dioxide flow. The matrix was a chalk. The resident fluid
in the porous matrix was a mixture of methane and pentane. In the nitrogen diffusion experiments,
liquid and vapor phases were initially present, while in the carbon dioxide experiment the matrix
was saturated with a liquid phase. Calculated results match the experimental data, including
recovery of each component, saturation profile, and pressure gradient between matrix and fracture. The simulation reveals the presence of countercurrent flow inside the block. Diffusion was
the main mass‑transfer mechanism between matrix and fracture during nitrogen injection. In the
carbon dioxide experiment, diffusion and convection were both important.
14-2
14-3
T34. EOR Technologies I (Society of Petroleum
Engineers (SPE))
14-1
1:30 PM
Jamili, Ahmad Jamili
[173792]
MODELING GAS PHASE MASS TRANSFER BETWEEN FRACTURE AND MATRIX IN
NATURALLY FRACTURED RESERVOIRS
JAMILI, Ahmad Jamili, WILLHITE, Paul, and GREEN, Don W., U of Kansas, Long Beach,
KS 90802, [email protected]
Gas injection in naturally fractured reservoirs maintains the reservoir pressure, and increases oil
recovery primarily by gravity drainage and to a lesser extent by mass transfer between the flowing
gas in the fracture and the porous matrix. Although gravity drainage has been studied extensively, there has been limited research on mass‑transfer mechanisms between the gas flowing
in the fracture and fluids in the porous matrix. This paper presents a mathematical model which
describes the mass transfer in one dimension between a gas flowing in a fracture and a horizontal
matrix block. The model accounts for diffusion and convection mechanisms in both gas and liquid
phases in the porous matrix. The injected gas diffuses into the porous matrix through gas and liquid phases causing the vaporization of oil in the porous matrix which is transported by convection
and diffusion to the gas flowing in the fracture. Compositions of equilibrium phases are computed
using the Peng‑Robinson EOS. The mathematical model was validated by comparing calculations
to two sets of experimental data reported in the literature (reference), one involving nitrogen flow
Kuru, Ergun
[173793]
2:30 PM
Barzin, Yalda
[173795]
EFFECT OF INTERSTITIAL WATER SATURATION AND AIR FLUX ON COMBUSTION
KINETICS OF HIGH PRESSURE AIR INJECTION (HPAI)
BARZIN, Yalda, MOORE, Robert Gordon, and MEHTA, Sudarshan A., U of Calgary,
Calgary, AB 90802, Canada, [email protected]
High Pressure Air Injection (HPAI) in deep light oil reservoirs has received notable attention in
the last three decades after its first successful field application in 1979. Kinetics of the oxidation
reactions associated with HPAI are known to be the most crucial mechanism which control the
overall performance of air injection processes; however, they are not fully explored for light oils
yet. This paper describes the results of an experimental study conducted to characterize some
main parameters which impact the reaction kinetics of light oil oxidation/combustion in HPAI.
Vaporization of oil has been reported in the literature as a mechanism associated with kinetics of
air injection processes; however, the parameters controlling the vapor phase oxidation/combustion have not been included in the studies of oxidation kinetics. Interstitial water saturation plays
an important role on heat transfer and consequently the reaction kinetics. However, there is no
reported data in literature investigating this factor. This study aims to shed light on these unknown
aspects of light oil air injection (HPAI). Several oxygen and nitrogen injection experiments have
been performed on recombined light oil and also a pure oil component sample in a 45cm long,
ramped temperature oxidation reactor. Experiments were run in presence and absence of interstitial water at two different levels of injection flux. Chromatographic analysis of the product gas
stream, simulated distillation of the produced oil and determination of the mass of solid residue
on the post‑test core were performed for each experiment. An endothermic vaporization front was
observed to precede the thermal front in low flux air injection tests. Interstitial water saturation had
a major impact on formation and extent of endothermic vaporization front. The tests which were
run on recombined samples with no water barely developed a distinct distillation wave.
14-4
2:00 PM
EFFECT OF ELASTICITY DURING VISCOELASTIC POLYMER FLOODING A POSSIBLE
MECHANISM OF INCREASING THE SWEEP EFFICIENCY
KURU, Ergun, U of Alberta, Edmonton, AB T6G 2R3, Canada, [email protected] and
TRIVEDI, Japan, U of Alberta, Long Beach, AB 90802, Canada
Effect of Elasticity during Viscoelastic Polymer Flooding ‑ A Possible Mechanism of Increasing the
Sweep Efficiency It has been long believed that the visco‑elasticity of polymer solution improves
the displacement efficiency, but the individual effect of shear viscosity and the first normal stress
have not been distilled for single polymer solution. In this study, the effect of visco‑elasticity of
fluids on the sweep efficiency in the polymer flood operation is investigated via injection of two
polymeric fluids having identical shear thinning characteristics but very different elastic characteristic. Blends of a water‑soluble resin (Polyoxyethylene) with different molecular weight distribution
(MWD) and similar average molecular weight were prepared. The Polyox blends were then used
to prepare aqueous polymer solutions, which had similar shear viscosity but significantly different
elastic characteristics. A series of experiments were performed by injecting two blends of polymer
solutions in a special core holder designed to simulate radial flow through a sand pack ‑ saturated
with mineral oil. Injection was done through perforated tubing located at the center and producing
through two production tubing located at the periphery. Effect of injection rate on displacement
efficiency for both polymer blends was also studied within the shear rate range of field applications. Since both fluids have the same shear viscosity but different elastic properties, it was possible to see the effect of fluid elasticity on the displacement efficiency alone at various injection
rates. Experimental results indicated that sweep efficiency of a polymer based fluid could be
effectively improved by adjusting the MWD of the polymer at constant shear viscosity and concentration of the polymer. The fluid with higher elasticity exhibited significantly higher resistance to
flow through porous media than that of the fluid with lower elasticity resulting into higher displacement efficiency and lower residual oil saturation.
3:30 PM
Gao, Panqing
[173794]
FEASIBILITY INVESTIGATION OF CO2 MISCIBLE FLOODING IN SOUTH SLATTERY
MINNELUSA RESERVOIR, WYOMING
GAO, Panqing, U of Wyoming, Long Beach, WY 90802, [email protected]
Chemical floods are challenged by the low permeability and high salinity in many special
reservoirs due to the sensitivities of chemical injections. The large range of permeability and
non‑sensitive to salinity of CO2 miscible injection makes it become more and more popular in
the past decades. The Slattery Minnelusa A is a low permeability and high salinity sandstone
reservoir. Currently, the water cut and oil rate are getting close to the economic limits after near
two decades of water injection. It is necessary to figure out a way to stabilize the oil output. In this
research, the technical feasibility of CO2 miscible injection was investigated in the Slattery. Both
experimental and numerical simulations were employed in the methodology research. The minimum miscibility pressure (MMP) of CO2/Slattery oil was determined with the slim‑tube method
as a precondition. The reservoir simulations were performed to estimate the field scale flooding
efficiency of both the pure gas (PGI) and water alternating gas (WAG) injections. The research
validated the feasibility of the CO2 miscible flooding in the Slattery. Two disadvantages of current production system, the unfavorable well pattern and reservoir pressure, were presented and
analyzed. Solutions were also suggested to improve the CO2 injection. The results of the field
scale simulations showed the PGI injection was more suitable in Slattery. Simulation predictions
were also fully employed to optimize injection parameters. This investigation is an excellent opportunity to: (1) demonstrate the method to assess the potential of a CO2 miscible flood in the South
Slattery field, (2) show that this should be of reference value to many other similar reservoirs.
14-5
4:00 PM
Delshad, Mojdeh
[173796]
PARALLEL SIMULATIONS OF COMMERCIAL SCALE POLYMER FLOODS
DELSHAD, Mojdeh, YUAN, Changli, and WHEELER, Mary Fanett, U of Texas at Austin,
Austin, TX 90802, [email protected]
Despite advances in numerical techniques and computer hardwares, numerical modeling of
large scale polymerfloods remains a challenge. A low order finite difference scheme with coarse
grids, used as standard practice in oil industry, tends to smear the front and mask the benefit of
SESSION NO. 14
polymer solutions whereas the finer grids require excessive computer times. A polymer module
is added to in‑house simulator to benefit from parallel capability and efficient algorithms for
fine grid field‑scale simulations. Application The simulator can be used for reliable predictions
of large scale polymerflood performances. The impact of elastic properties of commonly used
hydrolyzed polyacrylamide (HPAM) on oil recovery improvement can also be evaluated. Results,
Observations, and Conclusions Polymers are added to water to improve the sweep efficiency in
heterogeneous formations by reducing the water mobility. Polymer properties modeled are dispersion, adsorption, aqueous phase permeability reduction, shear thinning and shear thickening, and
inaccessible pore volume. Aqueous phase property modified is viscosity that depends on salinity,
polymer concentration, and shear rate. Polymer solutions exhibit non‑Newtonian behavior where
the viscosity decreases as the shear rate increases. However, recently applied large HPAM molecules on the order of 20 MM molecular weight exhibit shear thickening behavior where above a
critical shear rate the viscosity increases. Field‑scale simulations of polymerflood are performed
using very fine grid and the results are compared with the commonly used grid resolutions.
Significant of Subject Matter Polymerflooding is a mature technology to economically recover
additional oil from medium to heavy oil reservoirs. A comprehensive polymer model coupled with
fine grid simulations is required to accurately evaluate the field‑scale polymer flood performances.
The biggest contribution is the capability of making commercial scale simulations of polymer flood
with ultra large number of gridblocks and parallel capability on a cluster of PCs.
14-6
4:30 PM
Limkar, Parikshit
[173797]
NOVEL IN SITU COMBUSTION TECHNIQUE USING A SEMI PERMEABLE COLLOIDAL
SYSTEM
LIMKAR, Parikshit, DELFT U OF TECHNOLOGY, Amsterdam 90802 Netherlands,
[email protected]
In‑situ combustion is a thermal enhanced oil recovery process. The technique is based on the
principle of reducing a viscosity of oil by heating it in a reservoir itself. This paper presents a novel
technique about the wet in‑situ combustion process, which makes use of in‑situ hydrocarbons for
causing a premature spontaneous combustion within a reservoir. This technique uses a semi‑
permeable colloidal sap, which has two virtual compartments in it, one store the fixed volume of
fuel gas and the other compartment which allows only crude oil to enter it and occupy certain
fixed volume. Once the compartment that is meant for crude oil is filled to its marked capacity,
it provokes the ignition of the crude with the help of fuel gas and results in burning of crude oil
creating combustion front which results in the formation of heat, water vapor and CO2. Results:
With the help of this technology, a pre‑mature spontaneous ignition is induced in reservoir. It also
produces a sufficient amount of coke in HTO and an ample volume of oxygen to burn the deposited coke, which gives rise to a self‑sustained combustion front. Conclusion: 1) Due to this novel
technique, period of LTO is reduced and that of HTO is increased, thus, the heat which is generated at the interface, is used at its maximum efficiency, to heat up a cold heavy oil, sweeping the
oil reservoir with maximum efficiency, unlike the case with conventional wet in‑situ combustion
process. 2) As the fuel gas, that is stored in the colloidal sap, has certain fixed volume, it limits
and controls the sustainment of the combustion front, thus avoiding the wastage.
T35. Mature Waterflood Management (Society of
1:30 PM
Izgec, Omer
[173798]
OPTIMIZING VOLUMETRIC SWEEP EFFICIENCY IN WATERFLOODS BY INTEGRATING
STREAMLINES, DESIGN OF EXPERIMENTS, AND HYDROCARBON F PHI CURVES
IZGEC, Omer, SAYARPOUR, Morteza, and SHOOK, G. Michael, Chevron, Long Beach,
Waterflooding is by far the most commonly used method to improve oil recovery. Success of a
waterflood depends on its ability to sweep remaining oil efficiently. Incorrect or insufficient design
may lead to increases in cost associated with water cycling and poor sweep. Most waterflood
management is restricted to classical surveillance methods or sensitivity studies centered on
finite difference simulation. Classical surveillance methods fail to account for subsurface heterogeneity, while optimizing sweep via conventional modeling is time consuming in big waterfloods
with large number of wells or a relatively high‑resolution numerical grid. We propose a practical
and efficient approach for rapid and full‑field optimization of waterfloods. Our method focuses on
optimizing volumetric sweep efficiency using streamlines. We introduce two new concepts: the
Hydrocarbon F‑Phi Curve and Dynamic Lorenz Coefficient (DLC). We show that these concepts
can be easily derived from streamline simulation and can be used for optimum waterflood management. The DLC serves as a unique measure of the flow ‑ or dynamic ‑ heterogeneity, and we
show that minimizing DLC results in optimal volumetric sweep efficiency. The method is straightforward: we evaluate the sensitivity of DLC to variations in operating conditions in a design of
experiment (DoE) study, and then select the conditions that minimize DLC. The main advantages
of our method are its speed, flexibility to start optimizing at any arbitrary time regardless of the
history, and ability to handle large problems. The new approach requires running a streamline
simulator only a few time steps, so multi‑million cell models are optimized in minutes. We verified
our approach with several synthetic examples. These examples showed that a 1,000,000 cell,
complex reservoir with 13 wells, and 29 completions can be optimized in less than 45 minutes.
Finally, a field application validates our approach.
15-2
2:00 PM
Ahmadloo, Farid
[173799]
A NEW DIAGNOSTIC TOOL FOR PERFORMANCE EVALUATION OF MATURE HEAVY OIL
WATERFLOODS: CASE OF WESTERN CANADIAN HEAVY OIL RESERVOIRS
AHMADLOO, Farid1, ASGHARI, Koorosh1, and RENOUF, Gay2, (1) U of Regina, Regina,
SK 90802, [email protected], (2) Saskatchewan Research Council, Regina, SK 90802
Waterflooding is traditionally considered as the least favorable recovery method in heavy oil reservoirs. Despite this common belief, there have been reported cases of successful waterfloods with
recovery factors as high as 40% in Western Canada. On this basis, a comprehensive statistical
study was conducted to determine the effects of various reservoir and operational parameters on
the performance of waterfloods and potential differences of heavy oil waterfloods with medium oil
waterfloods. Collected database in this study includes 120 operational and reservoir parameters
2:30 PM
Lin, Yen Ting
[173890]
WATERFLOOD TOMOGRAPHY: MAPPING HIGH CONTRAST PERMEABILITY STRUCTURES
USING INJECTION/PRODUCTION DATA
LIN, Yen Ting1, ORTEGA, Antonio I.2, NEJAD, Amir Mohammad1, and ERSHAGHI, Iraj2,
(1) U of Southern California, Los Angeles, CA 90089, [email protected], (2) U of Southern
California, Los Angeles, CA 90802
The paper presents a novel analytical method to detect the existence and orientation of high
contrast permeability channels between injection and production wells in a waterflood. Unlike
regular transmission tomography where complete response measurements are taken from all the
angles, we have developed new algorithms to image the high contrast permeability structure by
using production /injection data. The viewing angle is restricted from injectors to producers. The
main advantage is this technique can be applied without significantly affecting daily operation
and provide a consistency check with results from other methods. There have been suggestions
made in the literature to use tracer or pressure transient data for imaging heterogeneous reservoirs (D.W. Vasco 1999, A. Al‑Ghamdi 1996). In our approach, we show the response times at the
producers can be estimated by monitoring gross production rates, given that known time‑varying
injection rates are applied. We propose a mixture model to characterize the response time, where
multiple candidates of high contrast permeability channels are assumed to be the initial estimated
structure. Our algorithm iteratively modifies the length, orientation and location of each high/low
anomalous permeability structure to match the measured response time. Instead of providing a
single solution for the location of high/low permeability channels, our method provides several
possible estimates and make it possible to check with known geophysical properties. To validate
our approach, we used a commercial simulator to test a 5‑spot waterflood and a line drive. In the
first case, we tested a five spot from a low permeability reservoir with a centrally located producer
that has been hydraulically fractured to enhance its productivity. Then we tested a single fracture
with 45 degree orientation located between rows of producers and injectors. Results show our
method can provide very accurate estimates of fracture orientation.
15-4
15-1
for 177 waterfloods in Alberta and Saskatchewan. Statistical analysis of collected database and
15 different performance indices based on studied injection‑production history was conducted
using partial least square technique. This study revealed the significance of operational parameters on performance of heavy oil waterfloods. It also provided a ranking of various operational and
reservoir parameters on performance of waterfloods which were used for dimension reduction
of input parameters. In the next step, artificial neural network technique was applied to develop
performance predictive models based on selected parameters after dimension reduction. Error
analysis of developed neural network models showed average absolute error of 17% from calculated performance indices based on production and injection history of studied waterfloods. This
paper provides details of successful application of partial least square approach and neural network for developing a new diagnostic tool for evaluation and prediction of performance of waterfloods in heavy oil reservoirs based on more than 50 years experience of heavy oil waterflooding
in Western Canada. The developed tool in this study uses combination of 38 easily obtainable
operational and reservoir parameters to predict the performance of heavy oil waterfloods.
3:30 PM
Lee, Kun Han
[173800]
A MULTIVARIATE AUTOREGRESSIVE MODEL FOR CHARACTERIZING PRODUCER
PRODUCER RELATIONSHIPS IN WATERFLOODS FROM INJECTION/PRODUCTION RATE
FLUCTUATIONS
LEE, Kun Han, ORTEGA, Antonio I., JAFROODI, Nelia, and ERSHAGHI, Iraj, U of Southern
California, Los Angeles, CA 90802, [email protected]
Recently, a new research trend has focused on building reliable signal processing models to characterize communications among wells in waterfloods, using only injection/production data. Among
these we can cite Capacitance Model (CM) descried by Yousef et al. (SPE95322) and our previous work: finite‑impulse‑response (FIR) model (SPE121353). In these approaches, the producers
are often assumed to be independent of each other and to be only influenced by nearby injectors.
We present an improved approach based on a multivariate autoregressive model with extra‑inputs
(M‑ARX), which models the interaction among all injectors and producers (including producer
to producer interactions) in a region‑of‑interest (ROI), using a set of linear differential/difference
equations and solved by quadratic programming techniques. By coupling all injection/production
rates in the ROI, the ARX model outperforms other models in terms of prediction, while keeping
the number of unknown parameters relatively small compared to the FIR model. More importantly, when the rates of some producers change significantly, e.g., shutting‑in of a producer, the
ARX model does not have to be modified to handle the changes, while other models need to
be re‑trained. Our evaluation, under various scenarios using bench type simulated performance
data, shows that under similar number of parameters, the ARX model outperforms CM in terms
of prediction ability (within average of 65% lower prediction‑error). We also show a case study for
a waterflood case in California to demonstrate the superiority of the ARX model. Compared to
the Compensated Capacitance Model (CCM) by Kaviani et al. (SPE117856), which also captures
producer‑producer relationships, our approach is more general because the ARX model allows
coupling all rate information available (injection/production rates) in the ROI, but CCM can only
handle the special case of shutting in a producer.
15-5
4:00 PM
Suri, Ajay
[173801]
A MORE COMPLETE MODEL FOR INJECTION WELL TESTING THAT INCLUDES THE
EFFECTS OF SOLIDS DEPOSITION, TWO PHASE FLOW AND INJECTION INDUCED
FRACTURES
SURI, Ajay and SHARMA, Mukul, University of Texas, Long Beach, CA 90802,
[email protected]
Step‑rate injection well tests and production logging tools (PLT) are used to measure the
injectivity, fracturing pressure and injection profile in an injection well. These measurements
are significantly influenced by two‑phase flow, solids deposition and creation of any injection
induced fracture in an injection well. The standard injection well test does not include two‑phase
flow, solids deposition and injection induced fractures but rely only on single‑phase pressure
transient equation with a constant skin. Applications A comprehensive injection well test simulator is developed that adds the effect of solids deposition and fracture growth to an approximate
two‑phase pressure transient solution for more accurate interpretation of injection well tests. The
presented model can be used for 1) low step‑rate injection tests under matrix injection to confirm
the reservoir permeability, formation thickness, and initial skin; and 2) high step‑rate injection tests
under fracturing conditions to predict the minimum horizontal stress, induced fracture lengths and
injection profile expected during a water‑flood. Results, Observations, and Conclusions Since
most injectors are fractured, it is shown through model results that injectivity tests are affected
in a significant way by solids deposition and transience in the injection induced fracture lengths
(ex. creation of an induced fracture or opening and closing of existing hydraulic fracture). A case
study is presented where BHP and injectivity for an actual injection well is matched. Technical
Contributions Standard injection well test can not model the dynamic skin created in an injection
SESSION NO. 17
well due to solids deposition and fracture growth when injecting above the fracture gradient. For
the first time a more complete injection well test model is developed based on Gringarten’s infinite
conductivity fracture model with two‑phase flow approximation for an injection well along with
solids deposition and changing injection induced fracture lengths.
15-6
4:30 PM
Lee, Hyokyeong
[173802]
IDENTIFYING INJECTOR PRODUCER RELATIONSHIP IN WATERFLOOD USING HYBRID
CONSTRAINED NONLINEAR OPTIMIZATION
LEE, Hyokyeong, YAO, Ke thia, OKPANI, Olu Ogbonnaya, NAKANO, A., and ERSHAGHI,
Iraj, U of Southern California, Los Angeles, CA 90802, [email protected]
A key barrier to optimal field management, i.e., maximizing oil production and reducing operational cost, is the understanding of underlying structure of the field, which continuously changes
over time. Analyzing readily available injection and production data to identify injector‑producer
relationships (IPR) offers a convenient way to this understanding. The capacitance‑resistive model
(CRM) provides an intuitive and straightforward way to characterize IPR through production and
injection rate fluctuations (Sayarpour et al, 2007). However, it requires a large number of model
parameters. The number of parameters increases quadratically with number of production and
injection wells in the reservoir. For fields consisting of hundreds of wells identifying IPR among
the wells is challenging. Moreover, there is no analytical solution for solving the parameter values due to the nonlinear time constant parameters of the CRM and the constraints. This paper
presents a new method, a hybrid constrained nonlinear optimization (HCNO), for estimating the
optimal parameter values of a nonlinear predictive model. HCNO is optimization‑based algorithm
such that it estimates the optimal values of the model parameters satisfying the constraints.
HCNO separates the connectivity and time constant parameters of CRM then uses two different
optimization algorithms. A constrained nonlinear optimization algorithm is applied to estimating
the time constant parameters, and subsequently the connectivity parameters are estimated by
a constrained linear optimization algorithm with the estimated time constant parameters. The
co‑optimization is performed at each iteration, which leads to faster convergence. HCNO is tested
on several synthetic oil fields. The result showed that the search time and the prediction error by
HCNO were significantly less than those of estimating the parameters as a whole by solely constrained nonlinear optimization. The identification of IPR by the optimal parameter estimation will
help field engineersB!B/ decision making process in optimizing waterflooding.
SESSION NO. 16
T35. Mature Waterflood Management (Alternates)
16-1
Shirani mehr, Houtan
[173803]
DATA DRIVEN MAPPING OF LIQUID SATURATION IN WATERFLOODS USING INJECTION
AND PRODUCTION DATA
SHIRANI MEHR, Houtan1, JAFROODI, Nelia1, GHODS, Ghods1, JAVAHERI, Mohammad1,
KASHANI, Farnoush Banaei1, ERSHAGHI, Iraj1, BEIERLE, Ryan2, and SHAHABI, Cyrus1,
(1) U of Southern California, Los Angeles, CA 90802, [email protected], (2) Montana Tech,
Los Angeles, MT 90802
Mapping spatial distribution of oil and water saturations in a waterflood can help in recognizing
sweet‑spots for infill wells. Common methods of reservoir simulation and pressure pulse techniques rely on pressure and rate data for interwell transmissibilities estimation and storativities
leading to indirect estimation of saturation. We propose an innovative data‑driven approach that
enables categorization of liquid saturation in waterfloods solely based on injection and production data. Particularly, our approach enables 1)prediction of the gross production rates of the
producers and 2)mapping of the average liquid saturation among injector‑producers in a waterflood based on the predicted production rates. Accordingly, we have implemented our approach
as a two‑step process. First, we derive the injection allocation factors to predict the production
rates at the producers given the injection rate schedule. Without loss of generality, we assume
a linear relationship between production and injection rates which is modeled using Multiple
Linear Regression analysis. Next, we form and solve a system of equations based on the transmissibility equations to categorize nature of liquid saturation between injector‑producer pairs.
Areas where water saturation is high are detected from estimated tranmissibilities derived from
allocation factors. Finally, we need to categorize and map water saturation distribution between
injector‑producers across the waterflood. To this end, we first normalize the transmissibility values
among wells.We then categorize the saturation regimes from the normalized values and develop
areal distribution of sweet‑spots by indicator kriging of the estimated oil saturation categories.
Consequently,our approach offers a low‑cost, fast and scalable technique without requiring reservoir simulation. We have successfully tested our approach with synthetic waterfloods with two
different patterns (five‑spot and linear) in various scales. We have verified our results by comparing saturation categories with those predicted by the commercial simulator.
16-2
Siavoshi, Jamal
[173804]
MONITORING WATER FRONT ADVANCE AND BILINEAR FLOW BEHAVIOUR ON PRESSURE
TRANSIENT TESTS IN HORIZONTAL WELLS
SIAVOSHI, Jamal, Husky Energy, Calgary, AB 90802 Canada, [email protected]
Transient well testing has been a robust tool for reservoir characterization for a long term because
it provides valuable information about dynamic reservoir properties as well as reservoir boundaries. Until recently many horizontal wells have been drilled. As they are a good producer, there
has been a little incentive to shut in a horizontal well for pressure transient analysis. Traditional
well test analysis for horizontal wells is based on using an analytical model embedding early
vertical radial flow followed by a linear flow and late pseudo radial flow regimes. Apparently, most
researchers expect early radial and/or linear flow to appear. However, field examples of pressure
build up tests for horizontal wells demonstrate a unique bilinear flow behaviour. Also, long pressure build up tests with weeks of shut in‑time conducted in horizontal wells show the influence of
nearby water injectors on pressure behaviour. Using new techniques, one can monitor water front
movement in a water flooded reservoir over production time. All pressure transient tests prove a
dominant behaviour of bilinear flow as well as water front movement. Analysis and interpretation
of these field examples are based on few years of production and water injection hsitory, reservoir
simulation and well location associated with field geology in order to prove this new interpretation
technique. A numerical well testing was also used to demonstrate the applicability of this technique and proved that water front from nearby injectors moved towards producers over production
time. This paper presents incorporation of analytical and numerical well testing to identify bilinear
flow model and water front movement model. This approach can be used for a better water flooding management in a reservoir in order to avoid early water breakthrough. Also, dominant bilinear
flow behaviour on pressure transient data addresses a new analytical model for horizontal wells.
T36. Economic Uncertainty And Risk Analysis
17-1
1:30 PM
Chelmis, Charalampos
[173805]
INTELLIGENT MODEL MANAGEMENT AND VISUALIZATION FOR SMART OILFIELDS
CHELMIS, Charalampos1, BAKSHI, A.2, SEREN, F. Burcu2, PRASANNA, Victor1, and
GOMADAM, Karthik1, (1) U of Southern California, Long Beach, CA 90802, ershaghi@
usc.edu, (2) Chevron, Austin, CA 90802
Simulation models that represent a variety of what‑if scenarios are commonly used as an aid
to decision making for oilfield development and operations. Engineers create multitude models
to explore a design space that represents uncertainty of information and alternate operational
strategies. As the composition of asset teams changes over the lifetime of asseta and new modeling requirements emerge, it becomes important for asset teams to be able to quickly “mine”
the legacy model set to understand the distribution of the models in the design space, and also
to know if a particular scenario was already modeled in the past or if a new model needs to be
created. Further, it is important for asset teams to understand the impact of changes between
deferent models for the best operational strategy to be chosen. We describe a technique to analyze arbitrarily large set of simulation models, identify similarities and differences between model
parameters, and automatically cluster the models based on similarity in an n‑dimensional design
space. The objective is twofold: to create a smart browse, search and visualization capability over
a legacy model catalog in a non legacy manner and to try to reverse engineer the original intent
of the modeler by detecting which models can be represented as variations of same underlying
templates. We demonstrate the application of our algorithm to a set of IPM models. However, our
use of a standard, non‑proprietary network model abstraction as an intermediate representation
means that our analysis technique can be applied to asset models created using a variety of
modeling and simulation tools. The broader significance of this work is in the context of knowledge
management for smart oilfields, specifically focused on extracting meaningful information from
legacy simulation models, and making this information available and useful to the asset team.
17-2
2:00 PM
Liu, Shuping
[173880]
FAILURE PREDICTION FOR ARTIFICIAL LIFT SYSTEMS
LIU, Shuping1, RAGHAVENDRA, Cauligi Srinivasa, YAO, Ke thia2, LENZ, Tracy Lynn,
OLABINJO, Lanre, SEREN, F. Burcu3, SEDDIGHRAD, Sanaz, and BABU, Dineshbabu C.
Dinesh, (1) Bakersfield, 93306, [email protected], (2) U of Southern California,
Los Angeles, CA 90802, (3) Chevron, Austin, CA 90802
Predicting a well failure before it occurs can dramatically improve performance and reduce operating cost. It potentially can provide operators enough lead time to adjust operating parameters
to avert failures, or to schedule maintenance to minimize downtime and to avoid unplanned
repairs. This paper presents a failure prediction framework and corresponding failure prediction
algorithms for rod pump artificial lift systems. It adapts state‑of‑the‑art data mining approaches to
learn pre‑failure dynamic record patterns by comparing known failure cases against normal cases
in the training data. Then, it applies these patterns to testing cases for failure prediction. In this
framework, each well is represented by a set of attribute value time series. These attribute values
include dynamometer card area, peak/min surface loads, stroke length and so on. Multiple training records are generated from these time series by segmentation using a specific time window
(e.g. 14 day) that is statistically determined by cross‑correlation and autocorrelation analysis of
the raw data. Then, multiple features are extracted from these segments using robust polynomial
regression. Next, in order to cover more feature space and to adjust the training process avoid
the bias caused by limited training samples, we use “random peek” mechanism which randomly
selects one sample from each testing well and labels them as normal to improve the performance.
We use moving average approach to predict failures by sliding a time window from beginning to
the end of all testing data by wells and extract their features. The data set from this paper is taken
from a real‑world asset using rod pump artificial lift systems. The results show that the failure
prediction framework is capable of capturing future rod pump and tubing failures. Furthermore,
this framework shows good potential for different event predictions.
17-3
2:30 PM
Dougherty, E.L.
[173807]
A METHOD TO QUICKLY ESTIMATE THE PROBABLE VALUE OF A SHALE GAS WELL
DOUGHERTY, E.L. and CHANG, Jincai, Maraco Inc, Long Beach, CA 90802,
[email protected]
Producing shale gas requires intensive drilling and massive fracturing. Faced with rapid rate
decline, limited funds and gas price fluctuations, deciding on number of wells to drill is problematic. First and foremost, a fast and reliable estimate of the probable range of a new well’s value
is needed. This paper demonstrates an evaluation method that integrates uncertain key factors ‑ price, costs, rate, reserves ‑ to give a probable value range. As a less expensive alternate
to simulations, several authors have applied various PDA* (FMB** & production type‑curves)
methods to analyze performance and forecast future production of CBM, shale and tight gas
wells. We give test results from some of these methods using selected parameter estimation
techniques. Comparisons to simulated and field data are given. A range of possible future gas
prices are computed from predictive models. These are combined with production forecasts, and
probable development and operating costs in a stochastic economic model to obtain profitability
estimates. Unconventional gas wells are an important addition to US energy supplies. This paper
refines the tools necessary to deal with the uncertainties of these supplies in this troubled economic environment.
SESSION NO. 17
17-4
3:30 PM
Belhaj, Hadi Arbi
[173808]
INTEGRATED RISK ANALYSIS CRITERIA FOR MANAGING EXPLORATION AND
DEVELOPMENT OF OIL AND GAS ASSETS
BELHAJ, Hadi Arbi, The Petroleum Institute, Calgary, AB 90802, Canada, ershaghi@
usc.edu, HAROUN, Muhammad Raeef, U of Southern California, Los Angeles, CA 90802,
and LAY, Terry, Dalhousie University, Canada, Halifax, NS 90802, Canada
Current petroleum industry practice (as reported by Beucher et. al.1 and Bratvold and Begg2 etc.
AAPG 2008) adopts schemes that aim at separating risk into two main categories; subsurface risk
that includes resource size, production rate, and access cost and surface risk that demonstrates
total expenditure, facilities delivery, delays, performance, oil/gas revenues and costs. A recent
SPE review (Bartvold el al SPE RE 2009) of decision making in the petroleum industry shows
great dependence on VOI (Value of Information), to manage risk. VOI cannot stand alone as a
decision making tool. There are also shortcomings in the use of Monte Carlo simulation. In this
paper, we introduce an integrated approach for handling risk associated with oil and gas exploration as well as development of mature reservoirs through EOR and IOR. Test case includes a
major asset in Abu Dhabi selected due to its varying reservoir settings. The proposed approach
basically, integrates uncertainty elements that may create “business risk” causing “business
impact”. This solution methodology breaks down each risk parameter to sub‑parameters. Critical
and non critical sub‑parameters are broken down to even more detailed pieces of risk components, down to the smallest fragments of risk. Thereafter, a down‑to‑top risk analysis technique
is adopted to reach to target NCF (Net Cash Flow). Proposed is a tool for risk analysis modeling
criteria related to exploration of oil and gas, and development of mature fields. In particular, it
focuses on comprehension and inclusion and negates lumping/dropping of any risk parameter.
This is not only because petroleum industry is surrounded by lots of uncertainties and therefore
carries a huge risk, but also because other economies are revolving and highly dependent on this
industry. In many cases, ignored risk parameters, that once thought non‑critical, turned to business disasters.
17-5
4:00 PM
Wylde, Jonathan James
[173891]
QUANTIFYING THE FATE OF HYDRATE INHIBITOR IN AN HPHT GAS CONDENSATE
SUBSEA TIEBACK
WYLDE, Jonathan James, Clariant Oil Services, The Woodlands, TX 77831,
[email protected]
This case history details the passage of hydrate inhibitor after being injected at a subsea well
head in an HPHT gas‑condensate tieback. Produced gas and fluids were routed through in‑field
flow lines, gathering at a subsea manifold 44 km from the platform before passing through a
pipeline to the platform. Industrial methylated spirit (IMS) was the selected hydrate inhibitor and
was used to protect the pipeline on a cold start after depressurization. There was very little data
on the phase‑partitioning of IMS, and quantities could end up at the oil terminal where they would
have a serious effect on processing and product quality. This paper summarizes the management
of using large quantities of IMS (30 m3). Results from a series of injection trials at the oil terminal
have been summarized and show how partitioning of IMS occurred through the gas, condensate
and oil process. The paper then goes on to explain how this proved crucial in risk assessing
the impact and use of IMS on the platform. The data has been used to improve the model (CPA
equation of state and HYSYS) data sets and details of this have also been included. Extensive
sampling exercises performed offshore when injecting and processing IMS (necessary in order
to meet export requirements) have also been included and lead to details of phase‑partitioning
behavior through the platform process plant. Such considerations are rarely made, nor lengths
taken to understand the exact partitioning and fate of a chemical when injected offshore, as well
as on arrival at the terminal. The implications in this instance were significant and therefore the
exercise was necessary. The results show that exact quantification is very elusive and that relying
on models and standard principles can be very misleading and potentially damaging.
18-2
BTH 2
Unangst, Nathan A.
[173244]
TAXONOMIC RE-EXAMINATION OF PERMO-CARBONIFEROUS BRACHIOPODS FROM
BOLIVIA: IMPLICATIONS FOR FAUNAL CHANGE DURING THE LATE PALEOZOIC ICE AGE
UNANGST, Nathan A.1, CLAPHAM, Matthew E.1, and LOPEZ, Shirley2, (1) Department
of Earth and Planetary Sciences, University of California, Santa Cruz, 1156 High Street,
Santa Cruz, CA 95064, [email protected], (2) Sergeotecmin, La Paz, 14976, Bolivia
The Late Carboniferous to Early Permian brachiopod fauna from the Copacabana Formation
(northern Bolivia) spans an entire glacial episode during the late Paleozoic ice age, but investigating the effects of glacial-interglacial climate change on the marine communities is difficult because
the fauna is poorly understood. Many genera have not been formally described in decades, and
little is known about their paleogeographic affinities. New collections were made from the lower
Copacabana Formation (Upper Carboniferous) at Ancoraimes and the middle Copacabana
Formation (Lower Permian) at Yaurichambi. The brachiopods were then described taxonomically, and using these new taxa assignments faunal counts were conducted. The two localities
share many taxa in common, although different taxa were abundant at each site. Kozlowskia,
Phricodothyris, Stereochia, and Composita were most common at both localities, but several genera that are uncommon at Ancoraimes, such as Rhipidomella, Reticulariina, and Neochonetes,
are very rare at Yaurichambi. Within-sample genus richness decreased, from 8.7 genera per
sample in the Late Carboniferous at Ancoraimes to 7.2 genera per sample at Yaurichambi, and
several less common taxa do not appear or appear in very low numbers at Yaurichambi. Further,
taxa such as Costatumulus, Waagenoconcha, and Hoskingia, typical of cooler climates in
Gondwana, increased in numbers across the interval, implying decreasing water temperatures
and diversity in subtropical marine environments during the Late Carboniferous onset of the late
Paleozoic ice age.
18-3
BTH 3
Altman, Kathryn
[172608]
USING ANALOG FLOW EXPERIMENTS TO MODEL MORPHOLOGIES DEVELOPED DURING
EPISODIC DOME GROWTH: A CASE STUDY OF MOUNT ST HELENS, 1980-1986
ALTMAN, Kathryn, Geological & Environmental Sciences, CSU, Chico, Chico, CA 959290205, [email protected] and TEASDALE, Rachel, Geological & Environmental Sciences,
CSU Chico, Chico, CA 95929-0205
From 1980 to 1986 the dacite dome at Mount St. Helens was emplaced as a series of 17 events,
identified by different growth rates, volumes, height to diameter ratios, emplacement rates and
morphologies (Swanson, 1989). Rates of emplacement characterize three periods with fastest growth between October 18, 1980 and the end of 1981, intermediate growth rates between
March 1982 and March 1984 and slowest growth until the end of the emplacement events in 1986
(Swanson, 1989). The shape of the dome changed from 1980 to 1986 as a function of magma
viscosity, tensile strength of the hot core, and thickness of the outer shell (Swanson, 1989). The
height to diameter ratios (h:d) recorded throughout the growth of the dome have been used to
quantify the changes in the shape of the dome. The dome was flatter during the first period of
emplacement then by June 1981, the dome to steepened (Swanson, 1989). Analog models
presented here aim to reproduce the emplacement of the domes based on observations and
data recorded at Mount St. Helens from 1980 to 1986. Flow experiments use a slurry of PEG
(poly-ethelyne glycol) mixed with kaolin powder that is pumped into a tank of cold water (Fink and
Griffiths, 1998). PEG is liquid at room temperature and solidifies in the cold water. Kaolin powder,
added to the PEG, increases the PEG viscosity to be comparable to dacite domes. Observed
and recorded data from Mount St. Helens are used to constrain analog flow model parameters
such as slope, effusion rate, and PEG viscosity in an attempt to recreate the dome morphologies
observed in the 1980 to 1986 episodes. Dome morphologies in experiments vary with the crustal
thickness developed during experiments. The thickness of dome crust increases when the difference between water temperature and the slurry are large. Dome crust thickness controls the h:d
ratio, which are used here to characterize dome morphology. The h:d ratio of experiments are
very close to those measured at Mount St. Helens, so are considered good representations of
dome growth events. Ongoing work investigates multiple episodes of dome emplacement using
solid structures in the tanks to represent previously emplaced dome edifices.
18-4
T19. Undergraduate Research in Geoscience (Posters)
(Cordilleran Section, GSA; Pacific Section, AAPG;
Pacific Section, SEPM; and Council of Undergraduate
Research (CUR))
TURNOVER RATES ASSOCIATED WITH THE MID-CARBONIFEROUS BOUNDARY,
BIRD SPRING FORMATION, ARROW CANYON, NEVADA
CONE, Allison J., Geological Sciences, California State University, Fullerton, 800 N. State
College Blvd, Fullerton, CA 92831, [email protected], KATHE, Kelly K., Geological
Sciences, California State University, Fullerton, 800 N. State College Blvd, Fullerton,
CA 92834, and BONUSO, Nicole, Department of Geological Sciences, California State
Univeristy, Fullerton, 800 N State College Blvd, Fullerton, CA 92834-6850
Extinction and recovery patterns characteristic of Paleozoic marine life changed in the MidCarboniferous. Particularly, diversification and rates of evolutionary turnover slowed. This distinctive interval coincided with a change from greenhouse to icehouse climate regimes. Many
paleocommunities reorganized at this climate transition causing a second order mass extinction.
We examined specimens from the Global Stratigraphic Type Section for the Mid-Carboniferous
boundary in the Bird Spring Formation, Arrow Canyon Nevada to reveal how much of the turnover
is due to lower origination rate, extirpations (displacement), immigration, and/or actual extinction.
Over 200 specimens from the Mississippian and Pennsylvanian have been identified to genus
level and taxonomic ranges were determined using the Paleobiology Database. Our results suggest that the regional patterns are much more complex than previously thought.
Marriott Anaheim Hotel, Platinum 5-6
18-1
BTH 1
Madan, Meena A.
[172891]
“STASIS IN RANCHO LA BREA SABERTOOTHED CATS AND ICE AGE LIONS DURING THE
LAST GLACIAL-INTERGLACIAL CYCLE”
MADAN, Meena A.1, PROTHERO, Donald R.2, and SUTYAGINA, Anastasiya2, (1) Earth
and Environmental Science, University of California, Irvine, 204 Aldrich Hall, Irvine, CA
92697, [email protected], (2) Geology, Occidental College, 1600 Campus Rd, Los Angeles,
CA 90041
One of the great puzzles of evolutionary biology is how organisms remain static in the face of
dramatic climatic changes, contradicting the “Galapagos finch” model of organisms that are constantly changing in response to their environment. Such stasis was documented in Pleistocene
mammoths as early as 1863 by Darwin’s friend, Hugh Falconer, and is widely recognized among
most Pleistocene large mammals. We examined the two common felids, the saber-toothed cat
Smilodon fatalis, and the Ice Age lion, Panthera atrox, from the Rancho La Brea tar pits in the
Page Museum in Los Angeles. We measured large samples (more than 100 of each element) of
several dimensions of the most common bones (typically leg or foot bones) from all the pits with
good radiocarbon dates. Even though pollen, plants, snails, and isotopic studies provide evidence
of dramatic climatic and vegetational change from the previous interglacial (40 ka-20 ka) to the
peak glacial (20 ka-15 ka) to the glacial-interglacial transition (15 ka-10 ka) to the Holocene, none
of these taxa show any statistically significant differences in size or shape of their bones from
one level to the next. Such dramatic stasis has been documented among all the common La Brea
mammals and birds over the late Pleistocene-Holocene, despite dramatic climatic changes. This
casts doubt on the responsiveness of birds and mammals to environmental change, and suggests
that intrinsic rather than extrinsic factors are more important in evolution.
BTH 4
BTH 5
Cone, Allison J.
Kieta, Andrew C.
[173165]
[173305]
IMPACTS OF THE FLOODS OF 1938, 1969 AND 2005 ON THE OLD MT.BALDY ROAD,
SAN GABRIEL MOUNTAINS CALIFORNIA
KIETA, Andrew C.1, NOURSE, Jonathan A.2, HEATON, Daniel E.3, AVANT, Travis B.4,
KALIGHI, Azad1, and WICKS, Logan Edward5, (1) Department of Geological Sciences,
California State Polytechnic University, 3801 W. Temple Avenue, Pomona, CA 91768,
[email protected], (2) Geological Sciences Department, Cal Poly Pomona University,
Pomona, CA 91768, (3) Department of Geological Sciences, San Diego State University,
San Diego, CA 92182, (4) Department of Geological Sciences, New Mexico State University,
Las Cruces, NM 88003-8001, (5) Geological Sciences, Cal Poly Pomona, 3801 West Temple
Ave, Pomona, CA 91768
Six members of Cal Poly Pomona’s GIS Applications course conducted a detailed field survey to
deduce the history of interaction between old Mt. Baldy road and various Holocene flood channels
of lower San Antonio Creek. The original road, situated on active alluvium, provided access to
Mt. Baldy village prior to completion of a new road along the west canyon wall in 1955. We utilized
hand-held Garmin GPS receivers and ArcGIS software to map various paved road segments
affected by the floods of 1938, 1969, and 2005. We walked approximately 4 miles of the canyon
between Shinn Road and Mt Baldy School, noting places where bridges, pavement and culverts
SESSION NO. 18
have been buried, undercut or annihilated by historic landslides and floods. Waypoints and field
observations were integrated with ArcMap software to create a multi-layered color-coded map.
The 1957 Mt. Baldy topographic quadrangle and Google Earth satellite photos provided base
images for geo-referencing.
Floods associated with the 2005 record rainfall season scoured away sediments or heavily
vegetated soil to uncover previously buried portions of the old Mt. Baldy Road. We encountered
photogenic crosscutting relationships in which the oldest paved road segments are overlain by
1938 flood deposits, and younger road segments are eroded and locally buried by 1969 flood
deposits. The two generations of road (pre-1938 and pre-1969) may be distinguished by different
methods of road construction. In some places damaged segments of the pre-1938 road were
simply repaved, whereas in other cases the younger road was routed on the opposite side of the
canyon. There are several localities where 1969 flood deposits are covered by landslide deposits
associated with an intense rainstorm of January 7-11, 2005 (26.14 inches total, with 16.52 inches
precipitation recorded between January 8 and 9). Unstable canyon walls previously weakened by
the wildfire of 2003 contributed sediment for this debris flow event. The dramatic field relationships
in Lower San Antonio Canyon provide an excellent natural laboratory for studying the interactions
between natural hazards and human infrastructure. Precise constraints on the timing of historical disturbances make this site ideal for field trips involving Engineering Geology and Natural
Disasters courses.
18-6
BTH 6
Lewis, Benjamin
[173311]
GEOLOGICAL AND PETROLOGICAL OBSERVATIONS OF THE LONG CANYON DOME
RHYOLITE, SIERRA NEVADA
LEWIS, Benjamin1, BROWNE, Brandon L.1, VAN SICKLE, David1, and VAZQUEZ, Jorge A.2,
(1) Department of Geological Sciences, California State University, Fullerton, 800 N. State
College Blvd, Fullerton, CA 92834, [email protected], (2) U.S. Geological Survey,
345 Middlefield Road MS 910, Menlo Park, CA 94025
Long Canyon Dome (LCD, 2880 m elevation) is located at the northern edge of Long Canyon in
California’s south central Sierra Nevada, approximately 30 km west of the northern limit of the
Coso Volcanic Field. LCD is situated within a few kilometers of 3 other rhyolitic domes that erupted
more than 2 ma known as Monache Mtn, Templeton Mtn, and Little Templeton Mtn (Bacon and
Duffield, 1981). Previously dated sanidine crystals (Bacon and Duffield, 1981) and 238U-230Th
and U-Pb dating of LCD zircons supports the 185 ka eruption age from Bacon and Duffield (1981).
Geologic mapping indicates that LCD is composed of at least two separate lobes of porphyritic
rhyolite lava, which are distinguishable based on vesicularity and biotite abundance. The larger
lobe, measuring ~35 x 106 m3 in volume, contains sanidine (10 vol%), plagioclase and quartz
(5 vol% each), and traces of biotite, magnetite, ilmenite, allanite and rutile. Exposed on the westernmost edge of this larger lobe of rhyolite is a 12-m-thick outcrop of jig-sawed rhyolite fragmental
debris characterized by black and glassy obsidian flakes interbedded with 15-25-cm-thick lenses
of clast-supported blocky and poorly vesicular pumice clasts ranging in diameter from 2-25 cm,
indicating that LCD was initially emplaced under thick glacial ice. The smaller eastern lobe
accounts for ~15 x 106 m3 of rhyolite and contains equivalent amounts of sanidine, plagioclase,
quartz, allanite and oxides as the larger western lobe, but approximately double the abundance of
biotite and is more vesicular. Geothermometry calculations of magnetite-ilmenite and Ti-in-Zircon
(Watson et. al, 2006) yield pre-eruptive temperatures of 676-723°C and 664-789°C, respectively,
however more analyses are needed in order to statistically evaluate if differences exist in pre-temperatures for the different rhyolite lava lobes. LCD is partially enclosed by a poorly consolidated
tuff ring composed of blocky pumice fragments, ash and accidental lithics. Extending away from
LCD to the north lies a 12 x 104 m2 area devoid of virtually any plant material due to the poorly
sorted nature of the pyroclastic flow deposit that was emplaced during the LCD eruption there.
18-7
BTH 7
Fassett, Laurry
[173643]
MONITORING THE HYDROTHERMAL SYSTEM AT THE LASSEN VOLCANIC CENTER,
CALIFORNIA
FASSETT, Laurry, KELLY, Boyle, SHANNON, Holt, TEASDALE, Rachel, and
BROWN, David, Geological and Environmental Sciences, CSU, Chico, Chico, CA
95929-0205, [email protected]
This work reports on new monitoring efforts to trace short-term changes within the hydrothermal system of the Lassen Volcanic Center (LVC), located at the southern end of the Cascades
Volcanic Arc in northern California. The original main edifice of the LVC was Mount Brokeoff
(Mt. Tehama), which has been glaciated as well as hydrothermally altered. Our work is founded
on the idea that as magmatic activity of the system changes, the temperature of the hydrothermal
systems will also vary, along with CO2 concentration emitted by the magmatic system. Two sites
have been targeted at LVC: Sulfur Works in the central part of the complex, and Boiling Springs
Lake southeast of the main edifice. Campbell Scientific data loggers are used for continuous water
temperature measurements. Water temperatures have been measured at both sites since 2007.
Sulfur Works temperatures are typically around 75-90 C with decreased water temperatures during spring and early summer, consistent with snow melt events and is generally lowest in mid-June
(76 C). Boiling Springs Lake temperatures are generally between 60 C and 70 C with similar temperature decreases to 40-50 C during the spring. 18O/16O of water samples collected from Sulfur
Works range from -3.61 to -5.26. Lake water at Boiling Springs Lake ranges only from 1.35 to 1.38
and a single measurement of fumarole water is -6.86. These values are consistent with previous
results of Sorey and Ingebritsen (1984) who report that 18O/16O becomes lighter further from the
volcanic center, suggesting that water from Sulfur Works is more closely connected to the magmatic system than is Boiling Springs Lake. CO2 gas emissions are also monitored to characterize
the bubbling fumaroles at Sulfur Works and lake water at Boiling Springs Lake. CO2 gas samples
are collected using 300ml evacuated Giggenbach bottles with 50ml of 4M NaOH. Sulfur Works
gas concentrations are 8,150 ppm of CO2 and Boiling Springs Lake contains 3,475 ppm of CO2.
Each of these sites varies independently from each other in water temperature and composition.
18-8
BTH 8
Bonnar, Melissa S.
[173653]
STRUCTURAL ANALYSIS OF FOLDED PALEOPROTEROZOIC GNEISS NEAR WEST FORKNORTH FORK SAN GABRIEL RIVER CONFLUENCE, CALIFORNIA
BONNAR, Melissa S., Geological Sciences Department, Cal Poly University, Pomona,
Pomona, CA 91768, [email protected] and NOURSE, Jonathan A., Geological
Sciences Department, Cal Poly Pomona University, Pomona, CA 91768
We studied a section of complexly folded Paleoproterozoic gneiss exposed in pristine riverwashed outcrops near the junction of the West Fork and North Fork San Gabriel Canyon. Folded
rock types include banded quartzofeldspathic gneiss, amphibolite and augen gneiss (1.69 Ga;
Premo et al., 2007), intruded by leucogratic granitic and pegmatite dikes. Most folds are tight to
isoclinal with moderately dipping axial planes that appear to be uniformly oriented at outcrop
scale. However, observed gross differences in foliation orientation between the south and north
areas suggest that the section may be folded at map scale. We took systematic measurements of
foliation, axial plane orientation and fold hinges to test a hypothesis that two episodes of folding
are recorded in this area.
The gneisses display a profound flattening fabric, developed under amphibolite grade, in which
various marker units and granitic dikes form tight to isoclinal, recumbent folds. We compiled the
structural data on Stereonets to deduce patterns and to compare orientations of structural elements between the southern and northern areas. Foliation measurements generally correspond
to sheared limbs of tight or isoclinal folds, and have a moderate degree of scatter. Axial plane
orientations are more tightly clustered and reflect average foliation trends in a given outcrop area.
In the southern area, axial planes and foliations dip moderately SE and fold hinges plunge gently
SE or E. Farther north the structural elements appear to be shifted systematically in map view
such that axial planes and foliation dip moderately E or NE and fold hinges plunge ENE. This
pattern is consistent with map-scale open folding of the older flattening fabric along a hinge that
plunges gently east.
The earlier folding event associated with the flattening fabric post-dated 1.69 Ga intrusion
of the granite protolith to the augen gneiss. Leucogranite veins intruded across augen gneissbanded gneiss contacts share similar fold geometries. Two generations of Tertiary dikes (Late
Oligocene(?) rhyolite porphyry and Middle Miocene(?) basaltic andesite) crosscut the complexly
folded Precambrian section. These dikes do not appear to be systematically rotated during the
second folding event which we speculate may be driven by convergence related to the Paleocene
Vincent thrust.
18-9
BTH 9
Hasten, Zachary E.L.
[173679]
TERTIARY VOLCANISM IN THE SOUTHERN BUFFALO HILLS, SMOKE CREEK, NEVADA
HASTEN, Zachary E.L., Geological Sciences, San Diego State University, 5500 Campanile
Drive, San Diego, CA 92118, [email protected] and CAMP, Victor E., Geological
Sciences, San Diego State Univ, 5500 Campanile Dr, San Diego, CA 92182-1020
Tertiary volcanism in the Pacific Northwest is recorded in an extensive history of eruptions from
varied tectonomagmatic environments associated with the Cascade volcanic arc, back-arc extension, and hotspot initiation. All three of these environments were active in the tri-state region of
southern Oregon, northern Nevada, and northeastern California in the middle Tertiary. Here, in
northwestern Nevada, we describe a previously undocumented succession of fissure-fed lavas
exposed in the Smoke Creek drainage of the southern Buffalo Hills. The chemistry of these lavas
rules out their association with the hotspot-related Steens Basalt, but is more consistent with an
older group of Oligo-Miocene volcanic rocks that erupted very near the eastern boundary of the
ancestral Cascades. Our intent here is to examine the geochemical characteristics of these lavas
to determine if they are more consistent with a genesis associated with arc volcanism or with
back-arc extension. The Smoke Creek section includes more than 500 m of lava with more than
60 distinct lava flows that vary from aphyric to moderately plagioclase-phyric. They are typically
thin (less than 5 m) with moderately developed lower colonnades and brecciated flow tops. We
analyzed 42 samples from both flows and feeder dikes for major- and trace elements using XRF.
These lavas differ from typical arc lavas in that they are largely basaltic trachyandesites falling
along a mildly alkaline trend of differentiation, consistent with similar Oligo-Miocene lavas found
across the breadth of southeastern Oregon and adjacent Neveda. However, the Smoke Creek
lavas also fall within the Western Cascades field of Fe-depletion and they display moderate LILE/
HFS ratios and small Nb-troughs on MORB-normalized trace-element plots. Such characteristics
are consistent with the generation of basalts derived from a hydrated mantle source followed
by the modification of these melts by fractional crystallization of magnetite and/or hornblende.
Although the mildly alkaline signature of the Smoke Creek lavas is consistent with volcanism in
a back-arc setting, the petrogenesis of these lavas also appears to involve a hydrous component
associated with mid-Tertiary subduction beneath the Western Cascades volcanic arc.
18-10
BTH 10
Lee, Daniel J.
[173690]
MINOR AND TRACE ELEMENT GLASS COMPOSITION OF LATEST PLEISTOCENE TEPHRA
LAYERS FROM THE WILSON CREEK FORMATION, MONO LAKE, CALIFORNIA, USING
INSTRUMENTAL NEUTRON ACTIVATION
LEE, Daniel J.1, SARNA-WOJCICKI, Andrei M.2, WAN, Elmira3, WAHL, David B.3, and
KNOTT, Jeffrey R.1, (1) Department of Geological Sciences, California State University,
Fullerton, 800 N. State College Blvd, Fullerton, CA 92831, [email protected],
(2) U.S. Geological Survey, 345 Middlefield Rd, Menlo Park, CA 94025, (3) U.S. Geological
Survey, 345 Middlefield Rd, MS-975, Menlo Park, CA 94025
At the type locality along Wilson Creek, northwest of Mono Lake, California, the Pleistocene
Wilson Creek Formation is composed of mudstones interbedded with 19 tephra layers ranging in
age from 32,000 to 13,000 years old (uncalibrated 14C ages). The eruptive source of the rhyolitic
Wilson Creek tephra layers are the nearby Mono Craters, south of Mono Lake. One thick, basaltic
ash bed near the top of the section was erupted from Black Point, at the north shore of the lake.
The rhyolitic tephra layers are found as far east as Utah and are potentially valuable marker beds
for the Pleistocene of the western United States. Ash bed #15 is also associated with the Mono
Lake paleomagnetic excursion. However, the distribution of individual Mono Craters tephra layers is difficult to assess because the major-element composition of the glass shards are very
similar; however, a trend in Ca and Fe allows differentiation of groups of tephra layers.. In this
study, we calculated similarity coefficients (SC) for the major-element concentrations measured
by electron microprobe and minor and trace-element concentrations measured by instrumental
neutron activation analysis (INAA) for each tephra layer. The SC for elements (Si, Al, Fe, Ca, Ti),
SC ranged from 0.99 to 0.82). In several cases, an SC of 1.0-0.93 is generally the range for replicate analyses. The SCs for elements (Sc, Mn, Rb, Cs, La, Ce, Sm, Tb, Yb, Lu, Hf, Th; including Fe
[measured by microprobe]) ranged from 0.98-0.81. For ash bed #15, the major element data show
that #15 shards have SC of >0.93 when compared to seven other Wilson Creek tephra layers.
Using the INAA-measured minor and trace element concentrations, #15 has a SC <0.93 when
compared to all the other Wilson Creek tephra layers. In addition, the light rare-earth fractionation
of #15, shown by plots of SmN vs. LaN/SmN is unique. Using the minor and trace element data,
we correlate the Bridgeport Creek (SC=0.94) and Rush Creek (SC=0.94) ash layers with Wilson
Creek #19 (SC=0.94) and the Carson Sink (SC=0.96) and Upper Wilson Creek ash E (SC=0.95)
layers with Wilson Creek #15.
18-11
BTH 11
Cronquist, Danny A.
[173702]
THE SMOKE CREEK DIKE SWARM, NORTHWESTERN NEVADA
CRONQUIST, Danny A., Geology, SDSU, Department of Geological Sciences, San Diego
State University, San Diego, CA 92181, [email protected] and CAMP, Victor, Department
of Geological Sciences, San Diego State University, San Diego, CA 92182
The Smoke Creek dike swarm is a previously undocumented system of north-trending feeder
dikes that is best exposed in the Smoke Creek drainage in the southern Buffalo Hills of northwestern Nevada. The dike swarm extends over a north-south distance of 6 km and occupies
an area of at least 12 km2. At its maximum density, the swarm contains 16 dikes/km. Individual
dikes can reach 1.75 km in length and vary in width between0.5 and 2.0 m. They are typically
SESSION NO. 18
basaltic trachyandesites, with subordinate basaltic dikes, that are identical in composition to the
~500-m-thick succession of thin lava flows that they intrude in the Smoke Creek region. Local
vents with abundant bomb- and lapilli-size scoria fragments are partially buried and interbedded
within this sequence of lava flows, suggesting that the fissure-filling intrusions were flow-feeding
dikes that erupted at the surface periodically to form linear vent systems in the form of aligned
scoria cones.
The Smoke Creek flow-and-dike complex is buried to the north by Miocene-to-Pliocene highalumina olivine tholeiites. The stratigraphic position of the Smoke Creek lavas, together with
their overall mildly alkaline to calc-alkaline chemistry, suggests that they are equivalent in age to
Oligo-Miocene lavas found elsewhere in the Cascade back-arc region of the northern Basin-andRange Province. As such, the Smoke Creek dike swarm may be part of a much larger swarm that
has been identified as far north as Abert Rim in southern Oregon, over a north-south distance
of 220 km (Scarberry et al., 2009). Although recent studies suggest that significant Basin-andRange extension did not begin in this area until after ~12 Ma (e.g., Colgan et al., 2004), the
identification of such an extensive system of dikes suggests that a much older period of regional
east-west extension was the prevailing stress regime in the back-arc region of southern Oregon
and northern Nevada during the Oligo-Miocene.
18-12
BTH 12
Diaz, Nathan
[173705]
LA-ICP-MS AS A HIGH PRECISION IDENTIFICATION METHOD FOR THE TEPHRA LAYERS
OF THE WILSON CREEK FORMATION, MONO BASIN, CALIFORNIA
DIAZ, Nathan, Geological Sciences, California State University Fullerton, 800 N. State
College Blvd, Fullerton, CA 92834, [email protected]
The Wilson Creek (WC) Formation of the Mono Basin in eastern California consists of lacustrine
silt and sand beds interbedded with 19 tephra layers. The WC family of tephra are composed of
intra-volcanic eruptions from the Mono Craters, which span 100 - 13 ka, and have highly similar
major-element compositions, as determined by electron microprobe analysis. The eastern-most
extent of WC tephra is currently Utah, demonstrating their potential as late Pleistocene chronomarkers for the western United States. Further, Wilson Creek ash #15 or WC-15 is closely associated with the Mono Lake paleomagnetic excursion, extending the usefulness of this tephra as a
regional time-line. Previous work has shown the Wilson Creek tephra layers are distinguishable by
minor and trace-element compositions as measured by instrumental neutron activation analysis
(INAA). In this study, minor and trace element concentrations from volcanic glass shards of 18
WC tephra layers were analyzed by laser ablation inductively-coupled-plasma mass spectrometry
(LA-ICP-MS). Results show that higher concentration trace elements are more accurate using
LA-ICP-MS. Our results also show that Ba and Sr concentrations for WC-15 clearly distinguish
this tephra layer from the other WC tephra layers.
18-13
BTH 13
Bruns, Jessica J.
[172152]
NEOGENE BASALTIC VOLCANISM IN THE SOUTHERN OWENS VALLEY, CA: IMPLICATIONS
TO TECTONICS OF THE ECSZ
BRUNS, Jessica J. and JESSEY, David R., Geological Sciences, California Polytechnic
University-Pomona, Pomona, CA 91768, [email protected]
Neogene basaltic volcanism occurs at four locations in the Owens Valley; the Big Pine field south
of Independence, the Darwin field 40 miles to the southeast on the Darwin Plateau, the Coso field
north of Ridgecrest, CA and the Ricardo field in the El Paso Mountains. Big Pine basalts range in
composition from ne normative alkali basalt to Q normative tholeiitic basalt. Basalts of intermediate composition (olivine tholeiites) are rare. Olivine and its alteration product, iddingsite, are rare
phenocrystic phases. Darwin basalts span a similar range in composition, but are characterized
by a larger population of olivine tholeiites. Olivine is a common modal mineral, as is iddingsite.
The Coso field is characterized by bimodal basalt-rhyolite volcanism. Basalts are primitive ne/ol
normative alkali basalts with prominent phenocrysts of olivine. The Ricardo volcanic field is also
bimodal, but the basalts are Q normative tholeiites. Iddingsite and calcium siderite have replaced
olivine, leaving only scattered remnants of the latter. Owens Valley magmatism spans the transition from the late Miocene-Pliocene “Basin and Range” extension to Pliocene-Recent dextral
shear with tectonic setting having a significant influence on basalt composition. Basalts that are
the products of extension (Ricardo) are tholeiites while those emplaced in regions of transtension or oblique slip related to dextral shear (Coso) are dominantly alkali basalts. The Big Pine
volcanics underwent a compositional change from older tholeiites to Recent alkali basalts. This
may be related to changes in the regional stress pattern from Basin and Range extension to the
current regime of right-oblique slip. Darwin basalts do not fit the established pattern. Isotopic and
trace element data suggest Coso magmas reached the surface quickly utilizing conduits created
by transtension and did not interact with continental crust. In contrast, Ricardo volcanics were
emplaced during a period of pure extension resulting in tholeiitic basalts. The more evolved and
silica-saturated basalts (Ricardo) represent assimilation of crustal rocks during periods of ponding
at shallow levels within the crust.
18-14
BTH 14
Carson, Mary L.
[172822]
VARIABILITY IN BIOLOGICAL PROXIES FOR UNDERSTANDING PALEOENVIRONMENTAL
CHANGE AT PTARMIGAN LAKE, ALASKA
CARSON, Mary L., SCHIFF, Caleb, and KAUFMAN, Darrell S., School of Earth Sciences
and Environmental Sustainability, Northern Arizona University, Flagstaff, AZ 86011,
[email protected]
Arctic lakes can provide records for understanding the influence of modern warming trends in the
context of long-scale environmental change. Biogenic silica (BSi) is a measure of diatom abundance in lakes and reflects lake productivity. Total organic matter (OM) is a sum of aquatic biota
and input of terrestrial biological material from the watershed. A 0.62-m-long (07-PT-1A) surface
core and a 2.66-m-long percussion core (08-PT-02) were retrieved from 6.5-m-deep Ptarmigan
Lake (61° 1’ 52” N, 145° 43’ 24” W, 705 m asl) in south-central Alaska, and BSi and OM were
determined for the last ~3600 years. Plutonium dating and three radiocarbon ages were used to
develop a sediment age-depth relationship for both cores. A wet alkaline extraction method was
used to determine BSi. OM was determined through loss-on-ignition analyses. Low but measurable BSi ranged from 0.1-2.9% and OM from 3.2-5.6%.
The instrumental period (1910-2006 AD) is represented by 39 samples from the upper 10 cm
of 07-PT-1A (one sample per 2.5 years). In this interval, OM is correlated with January temperature (r=0.42, p=0.038 (adjusted for autocorrelation)), October temperature (r=0.38, p=0.023),
October precipitation (r=0.44, p=0.009) from Valdez, Alaska (~10 km south of Ptarmigan Lake),
and winter (Oct-Mar) Aleutian Low (AL) intensity (r=0.44, p=0.004) in the North Pacific. A strong
AL is generally associated with warmer wetter winters in this region, possibly leading to increased
spring runoff, avalanching and a greater input of terrestrial OM into lakes. BSi and modern climate
records are not correlated, but there is a general increase in BSi during the period.
Prior to the instrumental period, changes in OM are not consistent with other regional records
of AL strength, indicating that long-term controls on OM at Ptarmigan Lake may be different. OM
displays an overall increase from ~2480 BP to the present, and two spikes in OM are observed in
62 2010 GSA Abstracts with Programs the record between the onset of the Medieval Warm Period (MWP) at ~960 BP and near the end
of the Little Ice Age (LIA) ~100 BP. These spikes suggest a rapid pulse of OM. BSi values generally decline from ~2920 BP until an increase is observed during the MWP. An overall decline in
BSi during the LIA is observed. An increase in OM during the LIA, while BSi declined, suggests
that additional influences on OM should be investigated.
18-15
BTH 15
Epstein, Jordan David
[172846]
PALEOMAGNETISM AND GEOCHEMISTRY OF TERTIARY INTRUSIONS AND FLOWS
ASSOCIATED WITH THE KOOTZNAHOO FORMATION NEAR KAKE, SOUTHEAST ALASKA,
AND IMPLICATIONS FOR THE ALEXANDER TERRANE
EPSTEIN, Jordan David1, DAVIDSON, Cameron1, and WIRTH, Karl R.2, (1) Department
of Geology, Carleton College, One North College St, Northfield, MN 55057, epsteinj@
carleton.edu, (2) Geology Department, Macalester College, 1600 Grand Avenue, Saint Paul,
MN 55105
Major and trace element geochemistry of basaltic sills, dikes, and flows from 16 sites associated
with the Paleogene-Neogene Kootznahoo Formation near Kake, Alaska plot in the “within-plate”
or “ocean-floor” fields on the Ti-Zr-Y diagram of Pearce and Cann (1973). The mean in-situ characteristic remnant magnetism (ChRM) of 50 cores from 8 sites with MAD <7.0° and A95 <10° is
D =331.3° ± 7.07°, I = 66.5° ± 3.1, A95=3.1, k = 43.95. Applying a structural correction based on
the local strike and dip of the Kootznahoo Formation, the mean corrected direction for all sites
is D = 339.0° ± 10.7°, I =76° ± 2.4°, A95 = 2.4°, k = 70.75, which suggests a moderate 20.6°
± 9.8° of vertical axis counterclockwise rotation and no displacement when compared with a
North American pole at ~23 Ma, the approximate crystallization age of the gabbros and basalts
(Haeussler et al., 1992). However, close inspection of the paleomagnetic results from this study
combined with previously published paleomagnetic data from Haeussler et al. (1992) show systematic regional differences in directions that suggest local tilting and vertical-axis rotations vary
across the region from no vertical axis rotation up to 46.3° ± 8.3° counterclockwise rotation at
some locations. This suggests Neogene deformation in the Alexander terrane east of the Queen
Charlotte and Clarence Strait faults could be locally significant and should be considered when
determining paleomagnetic directions for older rocks in the region.
18-16
BTH 16
McHugh, Kelly
[172957]
GEOLOGY AND PETROLOGY OF THE HAWKS VALLEY-LONE MOUNTAIN VOLCANIC
COMPLEX, SOUTHEASTERN OREGON
MCHUGH, Kelly1, WYPYCH, Alicja1, HART, William K.1, and SCARBERRY, Kaleb2,
(1) Geology, Miami University, 114 Shideler Hall, Oxford, OH 45056, mchughkc@
muohio.edu, (2) Geosciences, Colorado State University, 322 Natural Resources Bldg,
Fort Collins, CO 80523
Located at the transition between the Basin and Range and High Lava Plains provinces, the
Hawks Valley - Lone Mountain area (HVLM) of southeastern Oregon exemplifies regional relationships between extensional tectonics and magmatism. Volcanism and faulting since ~16.6 Ma has
created a complex region optimal for field-based studies aimed at investigating factors controlling
the formation and modification of intracontinental lithosphere. Geologic mapping at the 1:24,000
scale sponsored by the USGS EDMAP Program documents episodes of NW and NNE oriented
normal fault development and bimodal volcanism. The NW trending faults produced a large
150 km2 graben feature exposing predominantly trachyte to rhyolite lavas. Quaternary basalts
erupted from small vents and fissures within this graben and are displaced by NNE-trending
faults. These structures locally intersect and displace the prominent NW-striking faults. Collectively
these features are associated with mafic and silicic vents thereby providing age constraints on the
deformation and evidence of the control exerted by regional stress patterns on magma transport
and eruption.
Numerous 16.4±0.2 Ma silicic units (trachyte-trachydacite-rhyolite) emanating from as many
as eight local vents are distinguished based on field relationships, petrography, and major/trace
element geochemistry. Resorbed alkali feldspar and resorbed and complexly-zoned plagioclase
indicate that magma mixing and/or crustal assimilation were important petrogenetic processes.
Geochemical parameters support these observations and require a major role for crystal fractionation in the evolution of the HVLM silicic materials. The HVLM’s structural complexities and
its proximity to exposures of temporally equivalent Steens flood basalt eruptive loci suggests that
basaltic input into the crust stimulated local melt production, the establishment of multiple small
upper-level magmatic systems along regional lithospheric weaknesses, and open system differentiation leading to the silicic suite. After a more than 15 m.y. hiatus, local HVLM volcanism resumed
with the eruption of 0.9-0.5 Ma low-K, high-Al olivine tholeiite (HAOT) lavas characteristic of the
High Lava Plains region and of relatively shallow basalt melt generation processes.
18-17
BTH 17
Rogers, Tamera L.
[172974]
PETROLOGY AND GEOCHEMISTRY OF PILLOW BASALTS, EASTERN ELK OUTLIER OF THE
WESTERN KLAMATH TERRANE, SOUTHWESTERN OREGON
ROGERS, Tamera L., 2076 E Yosemite Ave, Merced, CA 95340, [email protected]
and GIARAMITA, Mario, Department of Physics and Geology, California State University
Stanislaus, One University Circle, Turlock, CA 95382
A previously unmapped 150 x 96.5 x 30 m quarry exposure of pillow basalts averaging 1 m in
diameter was discovered in the eastern Elk outlier (EO) of the western Klamath terrane (WKT),
SW Oregon. The EO lies ~ 50 km west of the WKT and consists primarily of metasediments of
the Late Jurassic Galice Formation cut by Early Cretaceous diorite intrusives. Sheeted dikes
and basaltic pillows in a serpentinite-matrix mélange are present in the western EO. Pillows
were analyzed petrographically and geochemically to characterize tectonic affinity and test correlation with the rocks of the western EO and the Josephine ophiolite (JO). The pillows lie 8 km
south of Powers, OR (lat. N45°48.64’; long. W124°4.65’), 386 m west of the Coquille River fault
where Tertiary sediments crop out to the east. Pillows appear mildly flattened and some reveal
keels indicating they are overturned. Hyaloclastite breccia commonly rims larger pillows with
small faults and veins throughout. Grain size grades from ~ 1.5 mm in cores to altered-glass chill
zones at the rinds. Cores reveal plagioclase microphenocrysts up to 13 mm in length in a matrix
of plagioclase, augite, and secondary sphene having intergranular texture. Additional secondary
minerals include albite(?), calcite, quartz, chlorite, pyrite, pumpellyite(?) and prehnite(?). Pillow
basalt 21B (50.8. wt% SiO2) and 21D (50.6 wt% SiO2), collected near the base and top of the
exposed pillows, were chosen for XRF and ICP-MS analysis performed at the Geoanalytical Lab,
WSU. Samples 21B (331 ppm Cr, 28.89 ppm Y) and 21D (315 ppm Cr, 31.32 ppm Y) plot in the
MORB field on a Cr-Y diagram. Both have MORB-like Ti-V ratios of ~27. Th/Yb vs Ta/Yb for 21B
(0.07, 0.05) and 21D (0.07, 0.06) and La/Sm vs TiO2 for 21B (0.98, 1.349) and 21D (0.98, 1.449)
are MORB like. Both samples are LREE-depleted and slightly HREE-depleted at ~ 20 x chondrite,
and are MORB-like on a MORB normalized trace element plot except for a possible slight Th-Ta
anomaly suggesting a possible minor slab component in the lavas. The pillows were erupted on
the sea floor at a spreading center, possibly a back-arc basin. Geochemically, they appear similar
to MORB like pillows of the western Elk outlier except for the minor slab signal. They are similar in
SESSION NO. 18
some respects to the upper pillows of the JO and might represent basement to the Galice in the
Elk outlier of the WKT.
18-18
BTH 18
Kathe, Kelly K.
[173009]
DOCUMENTING REGIONAL BRACHIOPOD ABUNDANCE AND DIVERSITY ACROSS
THE MISSISSIPPIAN-PENNSYLVANIAN BOUNDARY: BIRD SPRING FORMATION,
ARROW CANYON, NEVADA
KATHE, Kelly K.1, CONE, Allison J.1, and BONUSO, Nicole2, (1) Geological Sciences,
California State University, Fullerton, 800 N. State College Blvd, Fullerton, CA 92834,
[email protected], (2) Department of Geological Sciences, California State
Univeristy, Fullerton, 800 N State College Blvd, Fullerton, CA 92834-6850
We presently are living through the “modern biodiversity crisis” caused by climate change.
Examining past taxonomic patterns across major environmental perturbation provides a much
needed perspective on how biotas might respond to future climate transitions. During the middle
Carboniferous, a global climate transition from warmer greenhouse conditions to cooler icehouse
conditions took place at the Mississippian-Pennsylvanian boundary. Many paleocommunities reorganized at this transition causing a second order mass extinction. The purpose of this research
is to document the faunal patterns before and after the boundary interval. The Shannon Diversity
Index was used to determine the alpha diversity within the samples to measure the taxonomic
richness, and rank-abundance curves (RAC) were used to assess the ecological response of
organism across the boundary. We found that the global climate change associated with the
Mississippian-Pennsylvanian boundary interval forced marine fauna to reorganize locally, causing
a drop in diversity and a change in dominant taxa through time.
18-19
BTH 19
Keefer, Emily
[173032]
WIDESPREAD VOLCANIC ASH COMPONENT IN SOILS OF EASTERN CALIFORNIA AND THE
ANCIENT BRISTLECONE PINE FOREST
KEEFER, Emily, POLETTI, Juliana, HOWARD, Katlin, CHAWLA, Devika, FLEISHMAN,
Suzanne, JEPSON, Ryan, MAZZA, Sarah, RODENBOUGH, Elizabeth, and GLAZNER,
Allen, Geological Sciences, Univ. of North Carolina, Chapel Hill, NC 27599-3315,
[email protected]
The nutrients available in a region’s soil directly affect its ability to sustain various levels of
biodiversity, including crops needed to support human life. In the White Mountains of eastern
California, important plant communities, including stands of bristlecone pine trees (Pinus longaeva), grow in soils developed on rocks such as dolomite and quartzite that provide few nutrients. A previous study (Mazza, this meeting, 2009) found that rhyolitic volcanic ash, a source of
nutrients, forms a significant proportion of the soil developed on Campito Formation quartzite in
two places. We have undertaken a regional study of soils in and around Owens Valley in order to
assess the prevalence of an ash component.
We collected 19 soil samples from ~2 cm below the surface in the region from Mono Lake to
south of Bishop and into the Sierra Nevada and White Mts., and examined grain mounts by SEM.
Fifteen of the samples contained at least 10% rhyolitic ash. Soils from Tuolumne Meadows and
two Sierran streams feeding Mono Lake contained no recognizable ash particles, as did two
samples from the White Mts. Three other samples from the White Mts., however, contained over
20% ash. X-ray fluorescence analyses of 6 soils from bristlecone stands on Reed Dolomite fall on
a crude mixing line between dolomite and rhyolite, consistent with a large ash component in those
soils, some of which are clay-rich. Loess analyses from the literature fall off the trend, indicating that windblown silicate dust is not an important component. We conclude that soils in the
bristlecone pine area likely contain a significant ash component that has been concentrated by
dissolution of dolomite. This component could supply nutrients for bristlecone growth; if so, then
periodicity of eruptions could mediate such growth.
18-20
BTH 20
Daubenmire, Emily
[173051]
STRUCTURAL GEOLOGY OF THE WEST DEREN AND DEREN FAULTS, SOUTH-CENTRAL
MONGOLIA
DAUBENMIRE, Emily1, CHINN, Logan1, KELTY, T.K.1, GENDEN, Ariunbold2, SAUERMANN,
Robert1, and DASH, Batulzii2, (1) Geological Sciences, CSULB, 1250 Bellflower Blvd,
Long Beach, CA 90840, [email protected], (2) School of Geology, Mongolian
University of Science and Technology, PO Box 46/520, Ulaanbaatar, 210646, Mongolia
There are at least three faults located within the Deren Seismic Zone of south-central Mongolia.
These include the Deren Fault, West Deren Fault and Bïrgèd Fault. The purpose of this research
project was to investigate the structural geology and historic seismic activity of the Deren and
West Deren faults. Based on satellite image interpretations and field mapping along the Deren
fault, it appears that the fault strikes N-S and extends approximately 30km. The Deren Fault is
seismically active with a visible scarp at the surface that can be identified for several kilometers
produced by a large-scale earthquake that occurred in the late 1990’s. The West Deren Fault is
located between 46°15’ and 46°25’ latitude and 105° and 106°30’ longitude, south of the city of
Ulaanbaatar, Mongolia. It appears that the West Deren Fault is separate from the Deren Fault due
to the change in strike from N-S to E-W. There is a distinct possibility that the West Deren fault
is a continuation of the Deren Fault. The West Deren Fault was located by measuring attitudes
on either side of the E-W trending valley within the study area specified. Although data indicates
similar strikes ranging from E-W to N70°E on either side of the West Deren Fault, the dip of bedding is dominated by a range of 70° to 87° N on the northern side of the fault and a range of 50°
to 60° N along the southern side of the fault. To the west, the fault truncates the Bïrgèd Fault,
which continues to the SW. West of this truncation the degree of erosion across the terrain rendered the fault undetectable. The fault was easily identified to the east until approximately 106°5’
longitude, east of which the surface is significantly more eroded, resulting in difficulty of directly
locating the fault. Observations to the northeast indicate that the surface expression of the West
Deren Fault is absent.
18-21
BTH 21
Keffer, Sean
[173109]
EARLY TRIASSIC (DIENERIAN-SMITHIAN) PALEOPRODUCTIVITY AND
PALEOENVIRONMENTAL CONDITIONS WITHIN THE NORTHERN WESTERN CANADA
SEDIMENTARY BASIN, BRITISH COLUMBIA, CANADA
KEFFER, Sean1, LIODAS, Nate1, WOODS, Adam D.1, BEATTY, Tyler W.2, and ZONNEVELD,
J.-P.3, (1) Department of Geological Sciences, California State University, Fullerton,
800 North State College Blvd, Fullerton, CA 92834-6850, [email protected],
(2) Consortia for Applied Basin Studies, Dept. of Geoscience, University of Calgary, 2500
University Drive N.W, Calgary, AB T2N 1N4, (3) Department of Earth and Atmospheric
Sciences, University of Alberta, Edmonton, AB T6G 2E3, Canada
The biotic recovery from the Permian-Triassic mass extinction was a complex process whose
timing and scope were strongly affected by environmental conditions. While multiple studies of
macrofaunal trends have been conducted, the recovery of primary producers and their relationship to paleoenvironmental conditions is poorly understood. The Western Canada Sedimentary
Basin (WCSB) is an ideal locality to examine temporal and spatial trends in paleoproductivity
and paleoenvironmental conditions because it contains a complete sequence of Early Triassic
sediments deposited in environments ranging from shoreface to basin. A drill core of the Montney
Formation (A8-7-85-18w6) from the Pedigree-Ring Border-Kahntah River area, located in northwestern Alberta and northeastern British Columbia was examined to determine paleoproducitivity
and paleoenvironmental conditions, specifically paleoxygenation, across the Dienerian-Smithian
boundary. Approximately 75 samples were collected to determine major, minor, and trace element abundances using ICP-AES, while %TOC and %TIC were determined using the Loss on
Ignition method.
Ba and Ni enrichment factors, coupled with TOC levels ranging from 2-4% indicate sustained
primary productivity during deposition of the entire study interval. Paleoxygenation values, determined from V and Mo enrichment factors as well as V/ (V+Ni), vary with grain size, suggesting
that sea level and the stochastic input of coarse-grained sands and oxygen by turbidity currents
controlled the relative degree of benthic oxygenation. Overall, the results from the study interval
suggest the Early Triassic was a time of sustained productivity in the WCSB. Anoxic conditions
persisted in deeper offshore zones, limiting the geographic extent of the recovery from the
Permian-Triassic mass extinction to shallower, wave-affected environments (i.e. the habitable
zone). Future research from cores and outcrops throughout the WCSB will further establish the
timing and shape of the recovery from the Permian-Triassic extinction along the northwestern
margin of Pangea, and its relationship to paleoenvironmental conditions.
18-22
BTH 22
Chinn, Logan
[173115]
STRUCTURAL GEOLOGY OF THE DEREN SEISMIC ZONE AND BÏrgèd FAULT, SOUTHCENTRAL MONGOLIA
CHINN, Logan1, DAUBENMIRE, Emily1, KELTY, T.K.1, GENDEN, Ariunbold2, SAUERMANN,
Robert1, and DASH, Batulzii2, (1) Geological Sciences, CSULB, 1250 Bellflower Blvd,
Long Beach, CA 90840, [email protected], (2) School of Geology, Mongolian University of
Science and Technology, PO Box 46/520, Ulaanbaatar, 210646, Mongolia
The Deren Seismic Zone is located between 46° 10’ and 46° 20’ N, 106° and 108° E. Historic
seismicity of this region shows a 250 km x 50 km zone of earthquakes near and extending
beyond the Deren Fault. There are at least three faults within the Deren Seismic Zone, including
the: Deren Fault, West Deren Fault, and Bïrgèd Fault. Based on this study, it appears that these
three faults have different levels of activity. This study focused on the West Deren Fault and the
Bïrgèd Fault. Satellite images and field mapping along these faults indicate several structural relationships. The Bïrgèd Fault has a strike of ~N36ºE and a surface expression ~30 km in length. It is
truncated to the northeast by the younger, E-W striking West Deren Fault and does not appear to
continue north of this point. The West Deren Fault loses its surface expression at 106º 3’ E, 3 km
west of this intersection. However, the satellite images show the West Deren Fault may continue
~10 km. The lithologic units along the Bïrgèd Fault and West Deren Fault primarily consist of
resistant medium- to coarse-grained metasandstone, as well as recessive moderately metamorphosed siltstone. There is a discordance of bedding across the Bïrgèd Fault, which bifurcates
toward the southwest. These units are broadly folded into gently plunging antiforms and synforms
trending N63ºE and S63ºW. The wavelengths of these folds range from 3-7 kilometers. Data suggests folding occurred before the formation of the Bïrgèd Fault, and before the large Mesozoic(?)
granitic intrusion that is within Baga Gadzrïn Chuluu Park. Joints with similar orientations occur in
both the intrusive and metasedimentary rocks. These joints have a spacing of 1cm–1m and are
oriented N60ºE 70ºSE, N10ºE 30ºNW, and E-W 70ºS. Suggested future work on the Bïrgèd Fault
includes determining its dip and lateral extent.
18-23
BTH 23
Wakefield, Ryan
[173144]
HOW QUICKLY DID PRIMARY PRODUCERS RECOVER FROM THE PERMIAN-TRIASSIC
MASS EXTINCTION? EARLIEST TRIASSIC (GRIESBACHIAN) PRODUCTIVITY ESTIMATES
FROM THE PEDIGREE-RING BORDER-KAHNTAH RIVER AREA (WESTERN CANADA
SEDIMENTARY BASIN) NORTHWESTERN ALBERTA AND NORTHEASTERN BRITISH
COLUMBIA
WAKEFIELD, Ryan, Department of Geological Sciences, CSU, Fullerton, 800 N. State
College, Fullerton, CA 92834-6850, [email protected], WOODS, Adam D.,
Department of Geological Sciences, California State University, Fullerton, 800 North State
College Blvd, Fullerton, CA 92834-6850, BEATTY, Tyler W., Consortia for Applied Basin
Studies, Dept. of Geoscience, University of Calgary, 2500 University Drive N.W, Calgary,
AB T2N 1N4, and ZONNEVELD, J.-P., Department of Earth and Atmospheric Sciences,
University of Alberta, Edmonton, AB T6G 2E3, Canada
The Permian-Triassic extinction was the most devastating biotic crisis in Earth history. The timing
and shape of recovery from this event is still poorly understood, although it appears to have been
strongly controlled by paleoenvironmental factors. Relatively little is known about the recovery of
primary producers, which is crucial, since the base of the food web must recover before any macrofaunal rebound can occur. The Western Canadian Sedimentary Basin (WCSB) contains a variety of sedimentary depositional environments ranging from shoreface to basin and was deposited
across the entire Early Triassic recovery interval, making it ideal for paleoenvironmental and
paleoproductivity reconstructions. Five cores (16-8-86/20W6, 16-33-84/18W6m, B-24-B/9-H-16,
C-74-E/94-H-16, and C-78-I/94-H-9) from the Pedigree-Ring Border-Kahntah River area, located
northwestern Alberta and northeastern British Columbia, were examined to determine palaeoproductivity during the earliest Triassic (Griesbachian). Paleoproductivity was estimated by
measuring %TOC (total organic carbon) and %TIC (total inorganic carbon, or carbonate carbon)
using the loss on ignition method of Dean (1974); while many factors control the accumulation of
organic matter, we assume that organic matter enrichment has to be at least partially due to the
reestablishment of primary productivity.
A total of 241 Samples were analyzed. Results indicate %TOC contents for the cores
range from 3-5% suggesting a rapid and sustained recovery of primary producers during the
Griesbachian. %TIC values typically range from 5-15%, although spikes in %TIC can reach nearly
90% in some cores. Much of the carbonate within the WCSB is thought to be detrital in nature
(Davies, 1997), and therefore %TIC values reflect detrital (i.e., sand) input as opposed to skeletal
input; spikes in %TIC correspond to sandy units, and represent turbidites. The results of this
study imply that primary producers were relatively unaffected by the extinction and subsequent
environmental stress. However, since many factors can affect TOC values, future research will
estimate primary productivity using trace elements (Ba, Cu Zn), as well as paleoxygenation (Mo,
U, V) to determine the robustness of post-extinction recovery and its relationship to environmental
conditions.
SESSION NO. 18
18-24
BTH 24
Prior, Michael G.
[173154]
CONSTRAINING THE EXHUMATION HISTORY ALONG INFERRED FAULTS IN THE WESTERN
CHUGACH MOUNTAINS, ALASKA
PRIOR, Michael G.1, ARKLE, Jeanette C.1, HAEUSSLER, Peter J.2, and ARMSTRONG,
Phillip A.1, (1) Geological Sciences, California State University, Fullerton, 800 N. State
College Blvd, Fullerton, CA 92834, [email protected], (2) U.S. Geological Survey,
4200 University Dr, Anchorage, AK 99508
The southern margin of Alaska is an accretionary complex that is actively being deformed and
exhumed in response to the low angle subduction of the Yakutat microplate. Strain associated with
subduction of the buoyant Yakutat microplate resulted in widespread deformation within the accretionary prism and may be focused in the western Chugach Mountains and Prince William Sound.
Determining whether exhumation is uniform or focused along subsidiary faults in the western
Chugach Mountains and Prince William Sound is important to understanding how strain is accommodated throughout the south-central Alaskan margin. The accretionary prism is bound to the
north by the Border Ranges Fault Zone, which has acted as a backstop to exhumation. Several
subsidiary faults, including the Contact fault, appear to have deformed the heavily glaciated,
and locally high, Chugach Mountains south of the Border Ranges Fault Zone. The locations and
significance of subsidiary faults in the Chugach Mountains are poorly constrained by traditional
methods as they intersect monotonous greywacke packages and become untraceable beneath
glaciers and fiords. Within Prince William Sound, College and Harriman Fiords are parallel to
the NE-SW trend of the Contact fault and dissect the extreme relief of the Chugach Mountains
farther northeast, which suggests their locations are fault controlled. Here we use apatite (U-Th)/
He ages [AHe] to constrain the exhumation history across College and Harriman Fiords. Initial
AHe ages across College Fiord show little variance from 3.8-4.9 Ma to 4.2-4.7 Ma on the south
and north, respectively. Concordant ages indicate that exhumation has been relatively uniform ca.
~4 Ma along College Fiord. Additional samples, however, from Harriman Fiord and the northern
terminus of College Fiord will refine this interpretation. Significant differences in AHe ages are
displayed across the Contact fault ranging from ~5 Ma on the north side to ~ 10 Ma on the south
side. These results indicate that the Contact fault may have acted as a major rock uplift and exhumational boundary for the last 5 Ma, whereas potential faults along Harriman and College Fiords
have accommodated significantly less differential exhumation during this same time.
18-27
18-28
18-25
BTH 25
Morrish, Shawn C.
[173160]
TECTONIC GEOMORPHOLOGY AND EARTHQUAKE HAZARDS OF THE NICOYA PENINSULA
SEISMIC GAP, COSTA RICA, CENTRAL AMERICA
MORRISH, Shawn C., BUTCHER, Amber J., RITZINGER, Brent T., WELLINGTON, Kacie L.,
and MARSHALL, Jeffrey S., Geological Sciences Department, Cal Poly Pomona University,
Pomona, CA 91768, [email protected]
The Nicoya Peninsula, Costa Rica deforms in response to rapid subduction of the Cocos oceanic plate at the Middle America Trench (9 cm/yr). This emergent forearc peninsula lies ~60 km
inboard of the trench axis along a locked segment of the seismogenic zone. The Nicoya segment
is a high-potential seismic gap, with a slip deficit of ~5 m since the last megathrust earthquake
(M7.7, 1950). That event produced widespread damage and >1 m of coseismic coastal uplift.
Since then, the Nicoya coast has undergone gradual interseismic subsidence, reflecting strain
accumulation toward the next earthquake. While elastic seismic-cycle strain produces decadalscale shoreline fluctuations, net tectonic uplift results in long-term coastal emergence. This investigation examines both short-term seismic-cycle deformation and longer-term forearc uplift. The
results provide new insights into the rupture behavior, paleoseismology, and earthquake hazards
of the Nicoya Peninsula seismic gap.
Net coastal uplift is recorded by Quaternary marine terraces and incised valley fill alluvium.
Terrace mapping, surveying, and isotopic dating reveal uplift variations that coincide with three
contrasting domains of subducting seafloor offshore (EPR, CNS-1, CNS-2). Uplift rates vary
between 0.1-0.2 mm/yr inboard of older EPR crust north of Punta Guiones, 0.2-0.3 mm/yr inboard
of younger CNS-1 crust south of Punta Guiones, and >1.0 mm/yr inboard of CNS-2 seamounts
at Cabo Blanco. Variable upper-plate uplift reflects along-strike differences in subducting-plate
roughness, thermal structure, fluid flow, and seismogenic-zone locking. Local uplift anomalies
reveal upper-plate faults that may accommodate significant forearc deformation (shortening and/
or lateral sliver transport). In addition to ongoing terrace studies, new field research includes
wetland sediment coring to extract paleoseismic records, and pre/post earthquake coastal surveying to constrain seismic-cycle deformation. The estimated recurrence interval for large Nicoya
earthquakes is ~50 years. While these events produce meter-scale coseismic uplift, a large fraction is recovered during interseismic subsidence. The net result is gradual long-term emergence
of the Nicoya coastline.
18-26
BTH 26
Woodley, Steven R.
[173190]
INTERPRETING PLEISTOCENE MARINE TERRACE DEPOSITS OVERLYING THE 82 KA
WAVE-CUT PLATFORM, POINT REYES PENINSULA, MARIN COUNTY, CALIFORNIA
WOODLEY, Steven R., San Francisco, CA 94127, [email protected] and GROVE, Karen,
Department of Geosciences, San Francisco State Univ, 1600 Holloway Ave, San Francisco,
CA 94132
The southwestern coast of the Point Reyes Peninsula is characterized by marine terraces consisting of uplifted wave-cut platforms with overlying sedimentary sequences (Qt). The youngest
uplifted wave-cut platform was formed ~82 ka, during the sea-level high stand associated with
oxygen isotope stage (OIS) 5a. It consists of beach and other coastal deposits overlain by a thick
wedge of alluvial sediments. The entire peninsula has been deformed into a large-scale syncline,
and the Qt terrace deposits are deformed as part of the syncline, showing that deformation has
continued for the last 82 k.y. The age of the Qt deposits is bracketed between ~12 ka and ~82 ka.
The ~12 ka minimum age was derived from a previous study of younger inset alluvial deposits,
and the ~82 ka maximum age was determined by applying luminescence techniques to beach
sand at the base of the Qt sequence. The Qt unit, which is a regressive sequence, contains two
distinct deposit types that record variations in depositional environment as controlled by sea-level,
climate, and tectonics. The lower section of Qt is beach and coastal dune sand, whereas the
upper section is alluvial gravel. Field observations were used to create a cross section and stratigraphic columns to illustrate vertical and lateral variations along the coast. Based on previous
studies, including paleoclimate reconstructions and sedimentary responses to climate changes,
we correlated the beach sand to OIS 5a, the dune sand to a time of decreasing sea level leading
to OIS 4, and the alluvial unit to aggradational events associated with climate changes during OIS
4-3. Differential uplift rates along the coast affected depositional energy, as well as the thickness
and distribution of the alluvium, causing an increase in alluvial thickness from southeast to northwest, between Bolinas and Limantour Estero.
64 2010 GSA Abstracts with Programs BTH 27
Boyd, Kimberly Ann
[173267]
HEAVY METAL STEW: AN ANALYSIS OF THE WATER QUALITY OF BARBARA’S LAKE,
ORANGE COUNTY, CA
BOYD, Kimberly Ann1, DILLON, David Byron1, KENYON, Scott B.1, CASEM, Jacelyn2,
NYE, Jonathan1, STEVENS, Lora R.1, and WECHSLER, Suzanne3, (1) Geologic Science,
California State University, Long Beach, 1250 Bellflower Blvd, Long Beach, CA 90840,
[email protected], (2) Millikan High School, Long Beach, CA 90808, (3) Geography,
California State University, Long Beach, Long Beach, CA 90840
Barbara’s Lake is the largest of three naturally occurring lakes in Orange County, California. This
lake is part of the Laguna Coast Wilderness Park, located off SR-133 in Laguna Canyon. Water
levels are maintained by runoff from a nearby housing development and surrounding hillsides.
There is no surface outlet. Lake levels vary according to the seasons. After heavy winter rains,
the maximum depth is approximately 4 m. During summer, evaporation decreases lake levels by
2 to 3 meters. The lake’s water quality is significantly impacted. Nutrients, such as phosphate and
nitrate, are depleted, and blue-green algae are abundant, indicating eutrophication. Fish kills have
been observed. The bottom waters are reducing, as evidenced by the lack of dissolved oxygen
below 50 cm and release of hydrogen sulfide gas during sampling. An assessment during summer 2008 revealed high concentrations of specific metals, principally copper. Continued monitoring over the last 2 years indicates that metal concentrations are strongly linked to lake level.
Copper concentrations are as high as 35mg/L during low stands and plummet to as low as 1 mg/L
after substantial rainfall. The summer (low stand) levels of copper, cadmium and zinc exceed
the EPA Criterion Continuous Concentration (CCC) and/or the Criteria Maximum Concentration
(CMC). However, these data drop below the CCC during lake high stands. There is no clear spatial pattern to heavy metal concentrations, except for generally higher concentrations near a pole
in the west basin. A second metal pole occupies the east basin, and a metal fence runs down the
center of the lake between them. This fence emerges during lake low stands. The high concentration of several metals and persistent reducing conditions suggest that the metal poles and fence
are a likely source of the contaminants. To reduce concentrations we recommend removing the
fence line and aerating the lake.
BTH 28
Cates, Samantha
[173276]
SALINITY VARIATIONS IN MONO LAKE, EASTERN CALIFORNIA, AND FORMATION OF TUFA
TOWERS IN MIXING ZONES BETWEEN LAKE WATER AND GROUNDWATER
CATES, Samantha, FARTHING, Heather, BURNETT, Preston, PIANOWSKI, Laura, and
GLAZNER, Allen, Geological Sciences, Univ. of North Carolina, Chapel Hill, NC 27599-3315,
[email protected]
California’s Mono Lake is known especially for the myriad tufa towers that dot its shoreline.
Russell (1889) observed fresh water entering the lake through tufa tubes and proposed that the
towers form where freshwater springs enter the lake and supply Ca ions that react with highly
saline lake water to form CaCO3 precipitates. Rosen and Coshell (2004) stated that groundwater
inputs are necessary to supply Ca for tufa growth and nutrients for algae that mediate tufa growth.
We have tested this hypothesis by measuring the Na concentrations of surface water samples in
and around Mono Lake.
Thirty-seven 10 mL samples were collected in plastic bottles from various settings: creeks
feeding the lake, shoreline locations without tufa towers at varying distances from stream inlets,
and among tufa towers at the South Tufa and Old Marina sites. Samples were diluted 1:1000 and
analyzed for Na via DCP spectrometry. Creek samples have negligible Na concentrations, and
samples taken hundreds of meters from creeks or tufa towers typically have concentrations near
average lake water. Samples from among the tufa towers, however, range widely in salinity, from
highly dilute to highly saline. Freshwater creek inputs aside, there is a distinct negative correlation
between salinity and tufa tower development, consistent with input of low-Na groundwater. We
conclude that there is significant ongoing groundwater input into the tufa tower sites.
18-29
BTH 29
Schlom, Tyanna M.
[173281]
EARTHQUAKE MAGNITUDE AND RECURRENCE FROM SCARP MORPHOLOGY,
EUREKA VALLEY FAULT ZONE, EASTERN CALIFORNIA
SCHLOM, Tyanna M., Geological Sciences, California State University, Fullerton,
McCarthy Hall 254, P.O. Box 6850, Fullerton, CA 92834-6850, [email protected] and
KNOTT, Jeffrey R., Department of Geological Sciences, California State Univ, Fullerton,
Box 6850, Fullerton, CA 92834
The Eureka Valley fault zone (EVFZ) is a normal-oblique fault zone located in northern Death
Valley National Park, eastern California. Geodetic models infer the northeast-striking EVFZ is a
significant structure in a complex area of the western Basin and Range Province, transferring
regional slip from the Owens Valley fault zone to the Fish Lake Valley fault zone with a slip rate
of 3-3.5 mm/year. The EVFZ is the source of a 1993 Mw 6.1 earthquake with an epicenter in the
western valley near the base of the Inyo Range; however, limited or insignificant ground rupture
was reported. Maps and imagery display discontinuous faults offsetting Quaternary deposits in
the eastern part of the valley along the west side of the Last Chance Range. In the southeastern
portion of Eureka Valley, fault scarps offset landslide and alluvial-fan deposits composed mainly
of Paleozoic limestones. The offset alluvial fans have well developed desert pavements and pitted
limestone clasts consistent with ~70 ka alluvial fans in Death Valley, The lateral levee of the landslide is the oldest unit (profile EV-3) and is offset 18.7 m vertically. Two profiles across the ~70 ka
alluvial fan showed two events. Profile EV-1 has offsets of 5.5 m and 4.0 m (9.5 m total). Profile
EV-4 has offsets of 6.4 m and 5.3 m (11.7 m total). A third profile (EV-3) shows only one 10.4 m
event. All three profiles were completed in close proximity and it is unclear whether two events
were discernible at EV-3. Younger deposits morphologically correlative with ~30 ka fan surfaces
of Death Valley are not faulted. The cross-cutting relations show that faulting occurred between
~70 ka and ~30 ka with no faulting in the last 30 ka. The measured offsets yield a 70 ka-30 ka slip
rate of 0.2-0.3 mm/yr. Regression analysis yields event magnitudes of 7.14-7.63 for normal faults.
The cross cutting relations also indicate that this portion of the EVFZ is inactive. Considering
orientation of the observed surface rupture and aftershock pattern from the 1993 event, it appears
that the southern EVFZ is being cut off by a developing cross valley fault in this extensional basin.
Scarp
Event A
Mw Event A
Event B
Mw Event B
EV-1
5.5
7.24
4.0
7.14
EV-2
18.7
7.63
EV-3
10.4
7.44
EV-4
6.4
7.29
5.3
7.23
SESSION NO. 19
18-30
BTH 30
Gonzalez-Becuar, Elizard
[173295]
THE PUERTA DEL SOL PLUTONIC SUITE, A RECORD OF EOCENE TO MIOCENE
PLUTONISM IN CENTRAL SONORA
GONZALEZ-BECUAR, Elizard, PEREZ-SEGURA, Efrén, and OLGUIN-VILLA, Angel E.,
Departamento de Geología, Universidad de Sonora, Blvd. Luis Encinas y Rosales,
Hermosillo, 83000, Mexico, [email protected]
The Puerta del Sol plutonic suite (PSPS) consists of mid-Eocene subduction-related granodioritic
to granitic intrusions of the Sonoran Laramide Batholitic belt (SBB), and early Miocene gabbroic
to granitic intrusions which are believed to be related to Basin and Range Metamorphic core
complex (MCC) extension. Mid-Eocene intrusions consist of the calcalkaline, amphibole-bearing
Puerta del Sol granodiorite (49 Ma; U-Pb) and the peraluminous, two mica-bearing Oquimonis
granite (42 Ma; U-Pb). These plutons are typical and widespread in the SBB. The early Miocene
intrusions consist of the gabbroic El Garambullo pluton (22 Ma; U-Pb) and the Las Mayitas
granite, both of which are thought to be the source of a great number of dyke swarms that cut
the SBB. Several relevant structural features in the PSPS which are related to Basin and Range
extension include the MCC detachment fault in the western part of the area where PSPS is
the footwall plate of this detachment. Also, along the contact of the two mid-Eocene intrusions,
a mylonitic shear zone with an E-W trend was developed. The relation of this mylonitic gneiss
with the detachment fault is still uncertain but it is believed to be also associated with the MCC.
Studies in further structural, geochemical, and geochronologic features are still taking place to
provide a better understanding of this area.
avoided. The year the original photographs were taken ranged from 1901 to 1974. For each
replicate photograph, the location was recorded by GPS along with the view azimuth, time of day
and other relevant data. Photographs were taken with a digital camera and landscape changes
were estimated by side-by-side comparison of photographs. The landscape changes documented
by the photographs ranged from no discernible change to minor erosion. For example, Natural
Bridge, located 20 km south of Furnace Creek, is Pleistocene Mormon Point conglomerate undercut by an active stream channel that was photographed by Stose in 1940. Natural Bridge shows
no evidence of erosion with individual boulders and rills from 1940 still present. At Breakfast
Canyon, 2 km south of Furnace Creek, a vertical spire of Furnace Creek Formation shows no
evidence of erosion with individual rocks and rills from the 1938 photograph by Thayer still visible.
In contrast, Mushroom Rock, 7.6 km south of Furnace Creek, is a precarious basalt boulder with
a narrow pedestal and broad head formed by salt-wedge weathering. Compared to the original
1901 photograph by Campbell, Mushroom Rock has lost ~50% of the head material due to rock
fall. Along Furnace Creek, ~11 km SSE of Furnace Creek, Thayer photographed a vertical stream
cut with a tributary stream in the foreground in 1938. Extending an unconformity visible in the
1938 photograph shows that the top of the stream cut has eroded ~1 m during the intervening
72 years and the tributary stream has incised ~50 cm and transgressed into Furnace Creek. The
unequal erosion shown by the replicate photography is illustrative of arid-land erosion where erosion rates are low and frequently dependent on catastrophic events.
18-31
BTH 31
Carpenter, David M.
[173302]
GRAVITY CONSTRAINTS ON BASIN GEOMETRY AND FAULT LOCATIONS IN SOUTHERN
CADIZ VALLEY, EASTERN CALIFORNIA SHEAR ZONE
CARPENTER, David M., Geological Sciences, California State University Fullerton, 800 N.
State College Blvd, Fullerton, CA 92834, [email protected] and ARMSTRONG,
Phillip A., Geological Sciences, California State University, Fullerton, 800 N. State College
Blvd, Fullerton, CA 92834
The southern Mojave Desert is a tectonically complex area that is largely affected by deformation
associated with the Eastern California Shear Zone. Cadiz Valley is a NW-SE – oriented valley
located east of the Sheephole Mountains that is bound by the Iron Mountains on the east and
Calumet Mountains on the west. Basement rocks include the Cretaceous Iron Mountain and
Coxcomb Mountain Intrusive Suites, which are mostly comprised of granodiorite and granite.
Although southern Cadiz Valley is located east of the main Eastern California Shear Zone fault
exposures, a poorly constrained NW-SE - striking fault is mapped in the valley below Holocene
alluvial deposits; the presence and location of this fault is presumably based on projection of
basement exposures. In order to analyze basin geometry and evaluate possible fault locations,
a gravity survey was performed across southern Cadiz Valley. From the west side of the valley, adjacent to the Calumet Mountains, Bouguer anomalies (non-terrain corrected) decrease
approximately 10 mGals to the center of the valley. Eastward, Bouguer anomalies increase
rapidly 14 mGal across a distance of 3.4 km (~4 mGal/km). At ~2 km from the Iron Mountains
range front, a prominent inflection point in anomaly values occurs and Bouguer gravity anomalies
decrease 0.4 mGal across a distance of 0.5 km. Farther east, Bouguer gravity again increases at
approximately the same rate as that west of the anomaly inflection. Preliminary evaluation of this
Bouguer anomaly inflection suggests that the Cadiz Valley fault is located on the eastern side of
the southernmost Cadiz Valley near the Iron Mountains range front. Additional gravity data collected farther north across Cadiz Valley, in combination with density measurements of surrounding bedrock and detailed gravity modeling, will be used to further constrain basin geometry and
fault location(s).
18-32
BTH 32
Gevedon, Michelle L.
[173616]
A PALEOENVIRONMENTAL STUDY OF FAUNAL RESPONSE WITHIN THE LATE
CRETACEOUS HOLZ SHALE, SANTA ANA MOUNTAINS, CALIFORNIA
GEVEDON, Michelle L., BONUSO, Nicole, PRIOR, Michael G., KATHE, Kelly K.,
MONARREZ, Pedro M., CONE, Allison J., and BUCHEN, Chris, Geological Sciences,
[email protected]
Faunal changes in response to paleoenvironment perturbation is poorly understood within the
Late Cretaceous Holz Shale . We examine faunal patterns across a deepening marine transect
to document how organisms respond to environmental change. The Holz Shale Member of the
Ladd Formation located in the Santa Ana Mountains of Irvine, CA is exposed along a large
monocline that preserves the ancient active continental margin. Exposed continuous beds yield
well-preserved and abundant benthic marine invertebrates. Previous paleoecological research
conducted by Sundberg (1980) describes a temporal facies relationship that grades from shallow
tidal to a proximal continental slope environment. We partook in a collaborative class project in
which fossil specimens were collected from 3 bulk rock samples, each representing successively
deepening environments of deposition. Specimens were identified to the genus level by comparison using the Sundberg Collection at California State University, Fullerton. The Paleobiology
Database (http://paleodb.org) was used to determine life modes and ecologies for the specific
genera. First, we calculated Simpson’s Diversity Index and Pielou’s Evenness Index to compare
biodiversity and genera distribution between the areas. Second, we calculated Sørenson’s
Coefficient of Community Similarity to test faunal pattern similarity between areas. Finally, we calculated Chi-square to test if abundance patterns of Astarte and Syncyclonema in shallow water
differed from abundances in deep water. Simpson’s Diversity Index indicates that genera diversity
decreases with water depth, while evenness peaks slightly in the environment of intermediate
depth. According to Sørenson’s Coefficient of Community Similarity, approximately 50% of the
total genera are present in each environment producing intermediate similarity. Lastly, the Chisquare test rejects the null hypothesis that the genera occurring in each environment is similar
based on the significant difference in abundance between Astarte and Syncyclonema.
18-33
BTH 33
La Blanc, Kathryn Elaine
[173214]
USING REPEAT PHOTOGRAPHY TO DOCUMENT LANDSCAPE CHANGE IN DEATH VALLEY
OVER THE LAST 100 YEARS
LA BLANC, Kathryn Elaine, 18351 Linden St, Fountain Valley, CA 92708, klablanc18@
hotmail.com and KNOTT, Jeffrey R., Department of Geological Sciences, California State
Univ, Fullerton, Box 6850, Fullerton, CA 92834
Repeat photography is a well-known process used to document landscape changes over the last
150 years. U.S. Geological Survey photographers have been photographing Death Valley landscapes since 1901 with some replicate photographs. In this study, 21 photographs were selected
for replicate photography. The photographs were chosen mainly for the ability to find the location.
Due to the inaccessibility of some of the photographs, only 19 were used for the final analysis.
Photographs with a limited view, low quality, and those with obscure location descriptions were
19-1
BTH 34
Martin, Michael W.
[172970]
A GEOCHRONOLOGIC AND PROVENANCE STUDY OF THE GOLDSTEIN PEAK ROOF
PENDANT, WEST-CENTRAL SIERRA NEVADA BATHOLITH, CALIFORNIA
MARTIN, Michael W., Dept of Geological Sciences, Cal State Fullerton, 800 N. State College
Blvd, Fullerton, CA 92831, [email protected] and CLEMENS-KNOTT, Diane,
California State University, Fullerton, CA 92834
The Goldstein Peak unit of the Lake Kaweah roof pendant is a newly recognized non-marine
deposit composed of clastic metasediments surrounding a lens of metavolcanic rocks (van der
Kolk et al., 2003). This unit contains well-rounded quartz pebble metaconglomerates of fluvial
origin and polymictic pebble metaconglomerates of possible alluvial fan origin and appears to
be one of only two non-marine, pre-mid Cretaceous units in California (Barth et al., 2004). A
granite dike discordant with compositional layering within the Goldstein Peak unit and displaying wet-sediment intrusion structures provides a minimum depositional age estimate of 139 ±
1 Ma (Clemens-Knott and Saleeby, 2005). What is not known is where the rivers that deposited
the Goldstein Peak sandstones and conglomerates originated and to where these rivers flowed.
Paleogeographic considerations support a roughly westward flow direction, with a drainage basin
in the highstanding Sierra Nevada arc and/or North American craton and a mouth in the Great
Valley forearc basin. This study will test the hypothesis that the subangular polymictic pebble
conglomerates were derived locally from the Sierra Nevada arc and that the well-rounded quartz
pebble conglomerates sampled more distant sources. LA-MC-ICPMS analysis of eight detrital
zircon populations from a suite of conglomerate samples collected through a 1-km thick section
will better constrain the depositional age of what might be one of the oldest non-marine sedimentary units in California and provide a basis for assessing a possible sedimentologic connection
between the Goldstein Peak unit and the Great Valley Sequence.
19-2
BTH 35
Ehret, Phillip
[173026]
COMPARISONS OF DETRITAL ZIRCON AGES AND CHARACTERISTICS OF
METASEDIMENTARY PACKAGES IN THE SADDLEBAG LAKE PENDANT, SIERRA NEVADA:
IMPLICATIONS FOR DEPOSITIONAL ENVIRONMENTS AND TECTONIC HISTORIES
EHRET, Phillip1, CULBERT, Kristan1, PATERSON, Scott1, CAO, Wenrong1, MEMETI, Vali2,
and SCHMIDT, Keegan3, (1) Department of Earth Sciences, University of Southern
California, Los Angeles, CA 90089-0740, [email protected], (2) Department of Earth and
Planetary Sciences, Washington University in St. Louis, 1 Brookings Dr, St. Louis, MO
63130-4862, (3) Natural Sciences Division, Lewis-Clark State College, 500 8th Ave,
Lewiston, ID 83501
In the Saddlebag Lake pendant, central Sierra Nevada, California, the implications for depositional environments and tectonic histories are being investigated by studying four distinct
metasedimentary packages in the Virginia Canyon and Saddlebag Lake regions. The westernmost metasedimentary package exposed in Spiller Canyon contains clastic metasedimentary and
metavolcaniclastic rocks, is intruded by a 232 Ma pluton, contains detrital zircons from 380 Ma to
2.8 Ga., and must be late Paleozoic. This package is juxtaposed along a pre-232 Ma thrust fault
with a second, laterally extensive metasedimentary package, consisting of silty muds and siltstones, and less frequently, cross-bedded sandstones, local conglomerates, and limestones. All
five samples from this marine package contain minimum zircon age peaks between 171-190 Ma
and some PC zircons. This package of Jurassic metasediments is bordered on its eastern margin
by a large, dextral strike-slip shear, which is interpreted to be part of the Eastern Sierra Crest
Shear Zone. Late Triassic volcanics lie east of the shear zone, and conglomerate beds lie near
their base. This unit, intruded by the 165 Ma Green Lakes pluton, contains in one nearby sample
~220-250 Ma zircons and rare PC zircon. Farther south near Saddlebag Lake the conglomerates,
previously reported to contain clasts with Permian and Mississippian fossils, are bracketed by
the late Triassic volcanics (Barth, personal comm., 2010). A fourth eastern package of metasediments, containing marine cherts and mudstones (previously mapped as Palmetto), is separated
from the conglomerates by a dip-slip fault. Only 6 zircons from one sample were obtained from
this unit and have ages ranging from 380 Ma-1.8 Ga. Compositions and zircon ages in the first
package match volcanic and marine Golconda strata. Package two is interpreted to be part of a
marine Jurassic overlap sequence now recognized in scattered pendants elsewhere in the Sierra.
The Late Triassic conglomerates have Triassic arc derived(?) zircons and older clasts. The 4th
package may also better match Golconda strata and ages but further zircon ages are needed.
We conclude that all four packages represent distinct assemblages and are displaced by poorly
constrained distances along Paleozoic thrusts and Cretaceous strike-slip faults.
SESSION NO. 19
19-3
BTH 36
Van Guilder, Emily
[173176]
DETRITAL ZIRCON AGES FROM THE CALAVERAS COMPLEX, WESTERN METAMORPHIC
BELT (WMB), CALIFORNIA: IMPLICATIONS FOR MESOZOIC TECTONICS AND
CONTINENTAL GROWTH
VAN GUILDER, Emily1, PATERSON, Scott2, MEMETI, Vali3, EHRET, Phillip4,
GELBACH, Lauren B.5, STANLEY, Ryan5, and CHANG, Jonathan5, (1) Department of Earth
Sciences, University of Southern California, Los Angeles, CA 90007, [email protected],
(2) Department of Earth Sciences, University of Southern California, Los Angeles, CA 900890740, (3) Department of Earth and Planetary Sciences, Washington University in St. Louis,
1 Brookings Dr, St. Louis, MO 63130-4862, (4) Department of Earth Sciences, University
of Southern California, 3651 Trousdale Parkway, Los Angeles, CA 90007, (5) Los Angeles,
CA 90007
Southern portions of the WMB, Sierra Nevada, California are composed of four major complexes
including from east to west: the Shoo Fly Formation, the Calaveras Complex, the Sullivan Creek
Terrane, and the Foothills Terrane. The Calaveras Complex has been previously interpreted
to be a Permo-Triassic accretionary wedge that along its western margin was juxtaposed
across the Sonora Fault with the volcanic rich Sullivan Creek Terrane. Unpublished mapping by
Bhattacharyya and Paterson indicate that from east to west units in this part of the Calaveras
Complex are: (1) a package of quartzites and phyllites, (2) a unit dominated by banded chert,
(3) an argillite/siltone unit with local pebbly mudstones, chert lenses, and Permian to early Triassic
limestone blocks, and (4) a sedimentary package of quartzites, phyllites, marble, pebbly mudstones and local chert sandwiched between large volcanic belts. One marble layer surrounded by
phyllite and siltstone in the western part of #4 preserves Late Triassic fossils. We find no evidence
for the existence of a terrane bounding fault between these rock packages. We collected seven
samples from the different clastic units of the Calaveras Complex. Four of these had too few or
zircons too small to date. However we successfully completed ICP-MS U/Pb dating of detrital
zircons in three samples, two from the easternmost package of quartzite/phyllite and a third from
the western package near one of the volcanic belts. Minimum age peaks of ~159 and ~150 Ma
occurred in the former and ~170 Ma in the latter with Paleozoic zircons and older peaks at
~1100, ~1760, ~2800 Ma in samples as well. These zircon ages indicate that much of what has
been mapped as Calaveras Complex in the southern WMB is Jurassic and thus younger than
the enclosed Permo-Triassic fossiliferous marble blocks, and surprisingly similar in age to the
Mariposa Formation in the Foothills Terrane. It also confirms that clastic units with both Jurassic,
older Paleozoic and Precambrian zircons occur in the Calaveras Complex. No ages are yet available from the banded chert-rich units leaving open the question of whether Jurassic rock packages are getting tectonically mixed in with older chert-rich units.
19-4
BTH 37
Niemi, Nathan A.
[173222]
DILUTION OF DETRITAL ZIRCON POPULATIONS AS A QUANTITATIVE MEASURE OF
FLUVIAL TRANSPORT DISTANCE AND DISCRIMINATOR OF SEDIMENTARY VERSUS
TECTONIC TRANSPORT ACROSS THE DEATH VALLEY EXTENDED TERRANE
NIEMI, Nathan A., Geological Sciences, University of Michigan, 2534 CC Little Bldg,
1100 N. University Ave, Ann Arbor, MI 48109, [email protected]
U/Pb geochronology of detrital zircons has proven useful in identifying potential source terranes
of siliciclastic sediments through the identification of distinct age peaks that can often be linked to
geographically restricted regions. In cases where a sedimentary source region is geographically
distinct enough to be treated as a point source, simple empirical and theoretical relationships
between fluvial catchment area and downstream stream length (Hack’s Law) can be convolved
with detrital zircon age analysis of sediment to quantitatively assess fluvial transport distance
of that sediment from its source. Such analyses are particularly germane to studying the fluvial
transport distances of syn-tectonic sediments for which the present-day distance between sediment and source may be a function of both sedimentary and tectonic transport.
This technique is illustrated by an example from the Death Valley extended terrane in the
central Basin and Range. Middle Miocene clastic sedimentary rocks located east of Death Valley
contain a clast assemblage that includes a distinct Early Jurassic leucomonzogabbro batholith,
the nearest outcrops of which lie 80 km to the WNW. Interpretation of these strata as an alluvial
fan sequence required restoration of the section to a depositional position within 20 km of the
source batholith, and corroborated previous restorations of extension across central Death
Valley based on isopachs in Paleozoic strata and alignment of pre-extensional contractional
structures. Recent re-interpretation of these strata as fluvial in origin permits significantly greater
sedimentary transport distances than did the alluvial fan interpretation, and thus undercuts the
convergence of multiple lines of evidence for large-magnitude extension across central Death
Valley. Detrital zircon U-Pb geochronology reveals that the middle Miocene strata contain >75%
Early Jurassic detrital zircons, and, given the modern areal extent of the Early Jurassic batholith,
that fluvial transport of these sediments could not have exceeded 25 km, and was most likely less
than 10 km. This estimate is independent of any assumptions regarding depositional environment,
and confirms previous interpretations that >200% extension has occurred across central Death
Valley since middle Miocene time.
19-5
BTH 38
Gelbach, Lauren B.
[173273]
ICP-MS DATING OF ZIRCON IN THE IRON MOUNTAIN PENDANT: IMPLICATIONS FOR
SIERRAN TECTONICS
GELBACH, Lauren B.1, PATERSON, Scott1, MEMETI, Vali2, VAN GUILDER, Emily1,
STANLEY, Ryan3, CHANG, Jonathan3, and ZHANG, Tao1, (1) Department of Earth Sciences,
University of Southern California, Los Angeles, CA 90089-0740, [email protected],
(2) Department of Earth and Planetary Sciences, Washington University in St. Louis,
1 Brookings Dr, St. Louis, MO 63130-4862, (3) Los Angeles, CA 90007
The Mesozoic Sierran arc and Phanerozoic host rocks in California have undergone a number
of tectonic events that have been preserved in metamorphic host rock pendants throughout the
region. Members of the USC 2009 undergraduate team research program have studied the Iron
Mountain pendant (SW of the Tuolumne Batholith) to establish ages of the different rock units and
to clarify which tectonic blocks are preserved in the pendant. The Iron Mountain pendant is composed of a mix of metavolcanic, volcaniclastic, metasedimentary, and hypabyssal plutonic rocks.
ICP-MS, U/Pb zircon dating has established that an overlying meta-andesitic to rhyolitic units
are approximately 96-103 m.y., one package of marine metatsedimentary phyllites, schists, and
quartzites have a minimum age peak of about 140 m.y. (thus the units are likely Jurassic), and
an older package of mature quartzites, and phyllites with Precambrian zircon populations with
peaks at 1100, 1400, 1770, and 2700 m.y. that closely resemble miogeoclinal rocks elsewhere.
We interpret these data to indicate that this pendant exposes part of the miogeoclinal Snow Lake
block and a Jurassic marine overlap sequence, both of which are overlain by Cretaceous continental margin arc volcanics. Ductile shear zones occur in the area and may separate the Jurassic
overlap from the miogeoclinal rocks. These observations add support to hypotheses that the
Snow Lake Block extends throughout the central and southern Sierra Nevada and that a Jurassic
marine overlap sequence is also present throughout the central and southern Sierras as well. To
our knowledge the overlying Cretaceous volcanics in this pendant, part of a belt of Cretaceous
66 2010 GSA Abstracts with Programs volcanics locally preserved along the central axis of the Sierra, represent the westernmost
exposure yet recognized to date. The coarse clast size in some volcanic layers, map pattern, and
intrusion by a hypabyssal pluton suggests that these may be near or remnants of a Cretaceous
caldera complex.
19-6
BTH 39
Godinez, Nicholas S.
[173287]
STRATIGRAPHY AND PETROLOGIC EVOLUTION OF THE OLIGOCENE-MIOCENE
COMONDU GROUP NEAR BAHIA CONCEPCION AND LORETO, BAJA CALIFORNIA SUR,
MEXICO
GODINEZ, Nicholas S., KIMBROUGH, David L., and KOHEL, Chris, Department
of Geological Sciences, San Diego State University, San Diego, CA 92182,
[email protected]
The Comondú Group comprises extensive Upper Oligocene to Middle Miocene forearc basin and
volcanic arc deposits in Baja California Sur, Mexico that formed immediately prior to plate boundary reorganization and rifting that opened the Gulf of California. This study contributes XRF whole
rock data and zircon U-Pb ages within a ~20 x 100 km long belt from the Bahia Concepcion
region to Loreto. Prior workers have previously divided the Comondú Group here into three
informal units that reflect westward arc migration from the Sierra Madre Occidental (SMO) and
petrologic evolution. Local aeolian quartz sandstone and arkose at the base of the sequence are
of uncertain stratigraphic affinity but new detrital zircon U-Pb ages provide a maximum depositional age of ~25 Ma for these rocks and tie them into Comondú forearc basin history. Cretaceous
and Proterozoic zircon are the dominant components within these sands. Associated rhyolitic
tuff yield crystallization ages of ~24 Ma and are interpreted as distal forearc deposits derived
from the SMO of mainland Mexico to the east. The lower clastic unit of the Comondú above this
comprise ~300m of nonmarine fluvial sandstone and conglomerate that are dominated by basalt
to basaltic andesite compositions; the mafic composition of these forearc clastics strongly contrast
the more silicic composition of the SMO ignimbrite province. The approximately 750m thick middle
Comondú unit is more andesitic in composition and contains andesite breccia deposited as
proximal debris flows in the transition from forearc basin to volcanic arc, along with interbedded
andesite lava flows. Minor stocks of biotite granodiorite porphyry intruded into forearc strata yield
zircon U-Pb ages of 19.9 ± 0.73 and 16.3 ± 0.49 Ma. One of the stocks contains an abundance
of Cretaceous zircon suggesting remobilization of the underlying Cretaceous batholith. Heat from
the Comondú arc may have been a contributing factor that weakened the lithosphere and guided
the position of rifting within the Gulf of California.
19-7
BTH 40
Worthman, Caleb
[173624]
DETRITAL ZIRCON AGES FROM THE CHUGACH TERRANE: A STUDY OF THE McHugh
COMPLEX MELANGE AT SELDOVIA, ALASKA
WORTHMAN, Caleb and AMATO, Jeffrey M., Department of Geological Sciences,
New Mexico State University, MSC 3AB, PO Box 30001, Las Cruces, NM 88003,
[email protected]
We dated detrital zircons from the Chugach Terrane accretionary complex near Seldovia, Alaska,
to investigate the presence and timing of subduction accretion and erosion events. The McHugh
Complex mesomelange unit consists of incoherent massive beds of argillite and volcanogenic
litharenites (greywacke) interbedded with metavolcanic rocks and chert. We dated 5 samples of
mostly volcanogenic litharenites from Seldovia and Tutka Bay. Seldovia is located on the Kenai
Peninsula and is ~ 200 km south of Anchorage, and Tutka Bay is ~12 km east of Seldovia. The
youngest age population in each sample consists of 10-50 analyses, and the weighted mean of
these ages is the maximum depositional age. Four samples from Seldovia yielded youngest age
groups of 177 ± 2 Ma, 172 ± 2 Ma, 162 ± 2 Ma, and 146 ± 3 Ma. A sample from Tutka Bay has
a youngest age group at 162 ± 2. The samples with 162 Ma and 146 Ma youngest age groups
are similar to those from the McHugh mesomelange at Turnagain Arm near Anchorage. Samples
with youngest age groups of 177 Ma and 172 Ma are lacking the Late Jurassic/Early Cretaceous
populations, suggesting that if the youngest ages approximate accretion age, the Seldovia area
exposes an older part of the McHugh Complex that may have been removed by faulting in other
areas. Four samples of blueschist from the older, inboard part of the accretionary complex at
Seldovia did not yield zircon. The ages of the McHugh Complex zircons are consistent with the
Talkeetna arc being a major source for the sediment.
19-8
BTH 41
Reed, Michelle
[173652]
DETRITAL ZIRCON PROVENANCE OF PRECAMBRIAN–CAMBRIAN MIOGEOCLINAL
SEDIMENTARY ROCKS, NEVADA–UTAH BORDER
REED, Michelle1, PERRY, Kaysea1, JOHNSTON, Scott M.2, and GEHRELS, George E.3,
(1) Physics Department, Cal Poly, San Luis Obispo, San Luis Obispo, CA 93407,
[email protected], (2) Physics Department, California Polytechnic State University,
San Luis Obispo, CA 93407, (3) Department of Geosciences, University of Arizona, Tucson,
AZ 85721
Provenance and sediment dispersal studies of miogeoclinal sedimentary rocks can help provide a
more detailed picture of the evolution of the continental margin of North America. Previous studies
from the northeastern Basin and Range indicate increasing local and decreasing distal sediment
sources during the Precambrian to Cambrian, although few detrital zircon studies have been
completed to supplement this work. To better understand the provenance of the northeastern
Basin and Range during this time, we used LA-MC-ICP-MS at the University of Arizona to analyze detrital zircons from Precambrian–Cambrian quartzites in the Pilot, Deep Creek, and Snake
Ranges along the Nevada–Utah border. Detrital spectra in the Precambrian McCoy Creek Group
from all three ranges display peaks at 1.0–1.2 Ga and ~1.4 Ga, with fewer Archean grains and
1.6–1.8 Ga grains that increase in abundance through time. Zircons from the Cambrian Prospect
Mountain Quartzite are dominated by 1.8 Ga ages in the Snake and Pilot Ranges, and 1.44 Ga
and 1.72 point sources in the Deep Creek Range. These results are consistent with previous studies and indicate that Late Neoproterozoic sediments were derived from distal sources including
Grenvillian and Granite-Rhyolite terranes from the eastern margin of North America, while subsequent Cambrian sediments came from more local sources including the Mojave, Mazatal, and
Yavapai terranes. Possible explanations for the switch in sediment sources at the Precambrian–
Cambrian boundary include the emergence of the proto-Tooele–Uinta Arch, which would have
provided abundant 1.8 Ga detritus to the miogeocline, and shallow marine transgressions into
mid-continental regions that would have precluded transport of grains across the continent.
SESSION NO. 20
19-9
BTH 42
Lovelock, Elizabeth C.
[174037]
EOCENE ZIRCONS AND FOSSIL FLORAS FROM THE NORTHERN SIERRA NEVADA,
CALIFORNIA
LOVELOCK, Elizabeth C., Earth Science, University of California Santa Barbara, Webb Hall,
BLDG 526, Santa Barbara, CA 93106-9630, [email protected]
The Moonlight and Susanville floras are preserved in paleochannel deposits in the Northern
Sierra Nevada. Though the localities have long been regarded as Eocene based on their floras,
there was no radiometric age control. New detrital zircon data from these areas now confirms the
Eocene age of the floras.
Zircons were dated using the new LA ICP MS multi-collector at UC Santa Barbara. Samples
included a tuff near Moonlight, the fossiliferous sandstone that preserves the Moonlight flora, and
a reworked tuff above the Susanville fossil flora locality.
The tuff near Moonlight yielded only late Eocene grains. The fossil bearing sandstone at
Moonlight contained Eocene grains as well as Cretaceous, Paleozoic and Proterozoic age peaks.
The Susanville sample had a broader spread of Eocene and Mesozoic ages but did not include
any of Paleozoic or Proterozoic age.
Though the two localities are less than ten miles apart, these dates indicate that they may
represent different drainages with distinct source areas. Possible source areas for these channels
include northern California, northwestern Nevada and central Nevada. The Susanville locality may
have had its source to the north while Moonlight was perhaps more influenced from sources to
the east.
All sample sizes were between 40 and 70 grains. Further analysis may reveal additional age
peaks. Based on the youngest zircon ages, the Moonlight flora is 34.8Ma +/- 0.6. The Susanville
flora is 34Ma or older.
Friday, 28 May 2010
T1. Sierra Nevada Microplate-Basement and Basins I
20-1
8:45 AM
Kjos, A.R.
[173061]
THE BAHIA TORTUGAS FAULT OPHIOLITIC MELANGE, BAJA CALIFORNIA SUR, MEXICO: A
CORRELATIVE TO CALIFORNIA-OREGON OPHIOLITE-ARC-FOREARC ASSEMBLAGES?
KJOS, A.R., Department of Geological Sciences, San Diego State University, 5500
Campanile Drive, San Diego, CA 92182, [email protected], KIMBROUGH, David L.,
Department of Geological Sciences, San Diego State University, San Diego, CA 92182, and
MAHONEY, J. Brian, Department of Geology, University of Wisconsin Eau Claire, Eau Claire,
WI 54702
South of the California Coast Ranges, the Vizcaino Peninsula, Baja California Sur provides the
best view of Mesozoic forearc basement along the outboard edge of the southwest Cordillera.
Relatively intact ophiolite complexes of Late Triassic and Middle Jurassic age are well-known from
the Vizcaino region. A, lesser known, serpentinite matrix ophiolitic mélange is well-exposed within
an ~10 km-long belt in the northern Vizcaino Peninsula where it is bounded by the northwesttrending Late Miocene-Early Pliocene Bahia Tortugas Fault. The mélange is interpreted as a
serpentinite protrusion related to transpression along the fault. It could represent local basement
to the adjacent Late Jurassic-Early Cretaceous Eugenia Formation, part of the Mesozoic forearc
sequence. The talc-serpentinite matrix of the mélange has a weak subvertical foliation that wraps
around the mélange blocks. Mélange blocks range in size up to approximately 100 x 250 m, average 5-15 m2 and occur in poorly defined zones where specific block types can dominate. Mélange
block types include serpentinized harzburgite-dunite, gabbro, comb-textured hornblendite/diorite,
pyroxenite, amphibolite, plagiogranite, metabasalt and meta-limestone. Although, there is no
internal stratigraphy, the basic elements of a classic ophiolite are present and local semi-coherent
zones exist. The semi-coherent zones occur dominantly in the southeast third of the mélange,
where plagiogranite is associated with comb-textured hornblendite/diorite. Zircon analysis from
plagiogranite blocks, at two localities, yields U-Pb crystallization ages of approximately 188.7±1.5
and 195.0±5.3 Ma. The ages are tentatively interpreted as the crustal formation age of the ophiolite suite. The zircon ages provide the first evidence for early Jurassic ophiolite basement in the
region. Whole rock major and trace element geochemistry of metabasalts reveal fractionated
compositions (Mg# 54-38). The immobile trace element patterns are consistent with a transitional
MORB to island arc tholeiitic affinity. Possible correlatives to the Bahia Tortugas Fault ophiolitic
mélange occur in the western Sierran foothills and Klamath Mountains of California-Oregon.
20-2
9:05 AM
Saleeby, Jason
20-3
9:25 AM
Chapman, Alan D.
[172969]
REGIONAL DISPLACEMENT ANALYSIS AND PALINSPASTIC RESTORATION OF DISPERSED
CRUSTAL FRAGMENTS IN THE SOUTHERN SIERRA NEVADA, CALIFORNIA
CHAPMAN, Alan D.1, SALEEBY, Jason B.1, and WOOD, David J.2, (1) Geological and
Planetary Sciences, California Institute of Technology, 1200 E. California Blvd, MC 100-23,
Pasadena, CA 91125, [email protected], (2) 3423 Broadmead Dr, Houston, TX 77025
The Sierra Nevada batholith (SNB) is a predominantly NNW-trending feature with distinct transverse zonation in structural, petrologic, geochronologic, and isotopic patterns. This zonation is
expressed in terms of bulk composition as a west to east variation from mainly mafic to felsic
plutonic assemblages. South of 35.5 °N latitude, the depth of exposure increases markedly and
aforementioned trends are disrupted in the following ways: 1) the primary zonation of the SNB
takes on an east-west trend; 2) western zone rocks are truncated by eastern zone rocks along
the proto-Kern Canyon fault; and 3) fragments of shallow-level eastern SNB affinity rocks overlie
deep-level western zone rocks and subjacent subduction accretion assemblages (the Rand and
Sierra de Salinas schists) along a major Late Cretaceous detachment system. The magnitude of
displacement along this detachment system is constrained here by palinspastic reconstruction of
vertical piercing points provided by primary batholithic and metamorphic pendant structure and
stratigraphy. We present new field, petrologic, thermobarometric, and U-Pb zircon geochronologic
data from plutonic and metamorphic framework assemblages in the southern SNB that reveal four
potential correlations between dispersed crustal fragments and the SNB autochthon. These correlations include: 1) the Long Valley and Bean Canyon/Tylerhorse Canyon pendants; 2) the Monolith
and Quinn Ranch pendants; 3) the Erskine Canyon sequence and metavolcanics preserved in the
Tehachapi Valley area; and 4) the Pastoria plate, eastern SNB affinity granitoids and metamorphic
pendant rocks preserved in the San Emigdio Mountains, and similar assemblages in the southern
Tehachapi Mountains across the restored Garlock fault. Each correlation suggests at least ~50 km
of SW-directed transport and excision of at least ~5 km of crust along the Late Cretaceous
detachment structure. The timing and pattern of regional dispersion of crustal fragments in the
southern SNB is most consistent with Cretaceous extensional collapse above the underplated
schists. This interpretation is at odds with models linking disruption of the southern SNB to postCretaceous dextral transpression, Miocene transtension, and Cretaceous west-directed thrusting.
20-4
9:45 AM
Lechler, Alex R.
[172952]
SEDIMENTOLOGIC AND ISOTOPIC CONSTRAINTS ON PALEOCENE PALEOELEVATIONS OF
THE CENTRAL AND SOUTHERN SIERRA NEVADA
LECHLER, Alex R. and NIEMI, Nathan A., Geological Sciences, University of Michigan,
2534 CC Little Bldg, 1100 N. University Ave, Ann Arbor, MI 48109, [email protected]
Recent work indicates the topographic evolution of the Sierra Nevada may be quite distinct for
the southern, central, and northern sections of the range. Stable isotope and organic molecular
proxies from the northern Sierra Nevada suggest Eocene range elevations comparable to modern
Sierran topography in this part of the range, thus precluding major late Cenozoic surface uplift.
Constraints from the southernmost portion of the range, however, are lacking. We use U-Pb dating of detrital zircons and δ18O values from Paleocene sediments deposited east of and on top of
the Sierra Nevada batholith to constrain the Paleocene paleoelevation of the central and southern
Sierra Nevada.
The Paleocene Goler Fm. outcrops in the El Paso Mountains to the east of the southern Sierra
Nevada. Detrital zircon age spectra from the upper Goler Fm. are dominated by Middle and Late
Jurassic ages, with a smaller peak of Late Triassic ages, and a few 1.7 Ga zircons. The WhiteInyo Mountains in the eastern Sierra Nevada, where Jurassic plutonic and volcanic rocks, Late
Triassic plutonic rocks, and Neoproterozoic sedimentary rocks all outcrop, are the most likely
source. Paleontologic evidence suggests the Goler Fm. was deposited at or near sea level, however depleted δ18O values (-12.4‰ PDB) from micritic limestone within the Goler Fm. strongly
suggest rainout over an orographic barrier ≥ 1 km in elevation. Taken together, these data imply
at least modest elevations for the Paleocene Sierra Nevada at a modern latitude of ~37°N. Zircon
age spectra from the Paleocene Witnet Fm., which lies atop the southern Sierra Nevada, are
dominated by Early and Middle Triassic ages derived from the western Mojave Desert, indicating
that the Witnet Fm. and the lower Goler Fm. share a common source. This requires the Witnet
Fm. to have been deposited at paleoelevations less than that of the Goler Fm., constraining the
Paleocene southern Sierra at ~35°N to be near sea level. This southward elevation gradient in
the southern Sierra Nevada likely developed in response to Late Cretaceous lithospheric collapse
beneath the Mojave Desert, and these results place new limits on the potential amount of mid to
late Cenozoic elevation gain in this region resulting from the loss of a dense, eclogitic root.
[172746]
MID-CRETACEOUS REGI0NAL EXHUMATION OF THE SIERRA NEVADA-GREAT VALLEY
BATHOLITH AND A POSSIBLE TECTONIC DRIVING MECHANISM
SALEEBY, Jason1, SALEEBY, Zorka2, LIU, Lijun1, and MAHEO, Gweltaz1, (1) Tectonics
Observatory, California Institute Technology, Mail Stop 100-23, Pasadena, CA 91125-0001,
[email protected], (2) Tectonics Observatory, California Institute of Technology,
Pasadena, CA 91125
Petrographic and select geochronological data on ~300 basement cores from the Great Valley
(GV) indicate that at least the eastern half of the GV is underlain by Early Cretaceous batholithic
plutons with pendants of Foothills metamorphic belt-type rocks. The buried plutons yield U/Pb
zircon ages with a range of 140-115 Ma, and were emplaced at ~3-4 kb. Forearc basin strata nonconformably above this westernmost batholithic zone only reach back to Coniacian-Campanian
(88-80 Ma). Igneous barometric data for the Sierra Nevada batholith (SNB) typically show 1-2 kb
more exhumation along the western Early versus eastern Late Cretaceous zones, with western
zone exhumation comparable to that of the GV basement. New He zircon data from the SNB
show rapid exhumation of Early Cretaceous plutons at 92 to 88 Ma, followed by slow exhumation
(~0.06 mm/yr) continuing to a similar rate through much of Cenozoic time as recorded by He apatite. The GV batholith and western to axial SNB shared a common mid-Cretaceous exhumation
event. The southern ~100 km of the SNB has a steep longitudinal exhumation gradient whereby
~11 kb level plutons are exposed in the extreme south. Exhumation occurred very rapidly at 95-80
Ma (Ar hornblende through He zircon), involving first rapid erosion followed by large magnitude
extensional faulting. Much of the southernmost SNB upper crust is dispersed as detachment
sheets along the Garlock and San Andreas faults. An updated plate kinematic model for the
Pacific-Farallon ridge and the Hess-Shatsky Rise and conjugate rise system, complimented by
inverse tomography of subducted Farallon plate seismic velocity anomalies of the mid-mantle
beneath the eastern U.S. track the Shatsky conjugate with impact of its main massif along southernmost SNB-Mojave region at 95-90 Ma. Shallow flat subduction of the massif correlates with
the disruption and uplift of this arc segment, followed by large magnitude extension as the back
edge of the massif subducted. Inspection of bathymetric data around the Shatsky Rise reveals
broad shoulders, particularly off its northern flank. We posit that the subduction of the northern
conjugate shoulder induced enough of a slab flattening component to drive the regional GV-SNB
exhumation event.
20-5
10:20 AM
Blythe, Ann E.
[173298]
POST 20 MA EXHUMATION OF THE SOUTHERN SIERRA NEVADA/ TEHACHAPI
MOUNTAINS, FROM FISSION-TRACK AND (U-TH)/HE ANALYSES
BLYTHE, Ann E.1, LONGINOTTI, Nicole1, and KHALSA, Sopurkh2, (1) Dept. of Geology,
Occidental College, Los Angeles, CA 90041, [email protected], (2) Dept. of Earth Sciences,
University of Southern California, Los Angeles, CA 90089
Zircon and apatite fission track (ZFT and AFT) and (U-Th)/He (He) analyses of nine samples from
a NW-SE transect across the southern Sierra Nevada/Tehachapi Mountains reveal two major
stages of exhumation over the past 70 million years. The data document the cooling history of
the transect from ~250 to 40°C in a region affected by three active faults: the White Wolf thrust
fault in the northwest, and the left-lateral Garlock fault, as well as a relatively unimportant (?)
down-to-the-south normal fault, in the southeast. In the northwestern part of the transect, three
samples yielded ages of ~70 to 50 Ma for all three methods. Two samples from the central part of
the transect yielded progressively younger ages of 68 - 19 Ma. The four samples from the southeastern part of the transect yielded ZFT ages of 52 - 46 Ma, AFT ages of 20 - 18 Ma, and He
ages of 16 - 8 Ma. Thermal models were obtained from these data (which included AFT lengths)
using HeFTy (Ketcham et al., 2005). The thermal models are consistent with two major stages
of cooling and exhumation, the first from 70 to 50 m.y.a., during the waning stages of the Sierra
Nevadan orogeny, and the second from 20 m.y.a. to the present, during the initiation of extension
in the Basin and Range. The second event is more strongly evident in data from the southeastern
part of the range, indicating that the range has tilted to the northwest, and that substantially more
exhumation has occurred in the southeast (3-5 km) than in the northwest (~1 km) over the last 20
million years. The initiation of the second event at ~20 Ma is coincident with previous estimates for
the inception of the Garlock fault but the amount of exhumation that has occurred is more con-
SESSION NO. 20
sistent with that expected from the footwall of a major normal fault, leading us to suggest that the
Garlock fault may have initially been a normal fault.
20-6
10:40 AM
Unruh, Jeffrey
[173157]
UPPER CRUSTAL DEFORMATION ABOVE FOUNDERING LOWER LITHOSPHERE,
SOUTHERN SIERRA NEVADA MICROPLATE, CALIFORNIA
UNRUH, Jeffrey, Fugro WLA, 1777 Botelho Drive, Suite 262, Walnut Creek, CA 94596,
[email protected] and HAUKSSON, Egill, California Institute of Technology, Pasadena,
CA 91125
Quaternary faulting and background seismicity in the southern Sierra Nevada are concentrated
east and southeast of the Isabella anomaly, a high velocity body in the upper mantle interpreted to
be lower Sierran lithosphere that is foundering or convectively descending into the asthenosphere.
We analyzed seismicity in this region to evaluate patterns of upper crustal deformation above
and adjacent to the Isabella anomaly. Earthquakes in the southern Sierra and San Joaquin Valley
were relocated using joint hypocentral inversion and double-difference techniques, and groups
of focal mechanisms were inverted for the components of a reduced deformation rate tensor.
From east to west, the regional seismogenic deformation field derived from this analysis exhibits
the following characteristics: (1) horizontal plane strain in the southern Walker Lane belt and
southwestern Sierra Nevada consistent with distributed NNW-directed dextral shear; (2) heterogeneous extension and crustal thinning in the high Sierra and western foothills east of the Isabella
anomaly; (3) pronounced CCW rotation of the principal strains from regional trends in the SW
Sierra Nevada; (4) horizontal plane strain in the southwestern San Joaquin Valley; and (5) a 20to 40-km-wide zone of transpression directly east of the San Andreas fault. The heterogeneous
extension in the southern Sierra occurs above a zone of anomalous low upper mantle P-wave
velocities, which suggests that the crust is extending above delaminated lithosphere (and possibly upwelling asthenosphere). The CCW rotation of strain trajectories in the SW Sierra occurs
directly southeast of the Isabella anomaly. Speculatively, thickened lithosphere above and possibly connected to the anomaly may form a strong backstop that resists through-going NW-directed
shear propagating westward into the Sierran microplate from the southern Walker Lane belt, and
consequently shearing is deflected to the WNW around the southwestern margin of the anomaly.
Alternatively, the Isabella anomaly may generate gravitational buoyancy forces that modify the
local stress regime and perturb the deformation field, thus rotating the strain trajectories.
20-7
11:00 AM
Amos, Colin B.
[173005]
ACTIVE INTERNAL DEFORMATION OF THE SIERRA NEVADA MICROPLATE ON THE KERN
CANYON FAULT AT SODA SPRING, TULARE COUNTY, CALIFORNIA
AMOS, Colin B., Department of Earth and Planetary Science, University of California,
Berkeley, 377 McCone Hall, Berkeley, CA 94720, [email protected], KELSON,
Keith I., Fugro William Lettis & Associates, Inc, 1777 Botelho Dr, Suite 262, Walnut Creek,
CA 94596, ROOD, Dylan H., Center for Accelerator Mass Spectrometry, Lawrence Livermore
National Laboratory, MS L-397, 7000 East Avenue, Livermore, CA 94550-9234, SIMPSON,
David T., URS Corporation, 1333 Broadway, Suite 800, Oakland, CA 94612, and ROSE,
Ronn S., Dam Safety Assurance Program, U. S. Army Corps of Engineers, 1325 J Street,
Sacramento, CA 95814
The Kern Canyon fault (KCF) represents a major tectonic and physiographic boundary in the
southern Sierra Nevada of east-central California. Previous investigations of the KCF underscore
its importance as a late Cretaceous and Neogene shear zone in the tectonic development of the
southern Sierra Nevada. Study of the late Quaternary history of activity, however, has been confounded by the remote nature of the KCF and deep along-strike exhumation within the northern
Kern River drainage, driven by focused fluvial and glacial erosion. Recent acquisition of airborne
LiDAR (light detection and ranging) topography along the ~140 km length of the KCF provides a
comprehensive view of the active surface trace. High-resolution, LiDAR-derived digital elevation
models (DEMs) for the northern KCF enable identification of previously unrecognized offsets of
late Quaternary moraines near Soda Spring (36.345, -118.408). Predominately north-striking
fault scarps developed on the Soda Spring moraines display west-side-up displacement and
lack a significant sense of strike-slip separation, consistent with detailed mapping and trenching
along the entire KCF. Scarp-normal topographic profiling derived from the LiDAR DEMs suggests
normal displacement of at least 2.8 +0.6/-0.5 m of the Tioga terminal moraine crest. Cosmogenic
10
Be exposure dating of Tioga moraine boulders yields a tight age cluster centered around 18.1 ±
0.5 ka (n=6), indicating a minimum normal-sense fault slip-rate of ~0.1-0.2 mm/yr over this period.
Taken together, these results provide clear documentation of late Quaternary activity on the KCF
and highlight its role in accommodating extension and internal deformation of the southern Sierra
Nevada microplate.
20-8
11:20 AM
Saleeby, Zorka
[172745]
EROSIONAL STRIPPING OF THE SOUTHEASTERN SAN JOAQUIN BASIN (SJB) MARGIN
OFF OF THE SOUTHERN SIERRA NEVADA BASEMENT UPLIFT
SALEEBY, Zorka, Tectonics Observatory, California Institute of Technology, Pasadena, CA
91125, [email protected] and SALEEBY, Jason, Tectonics Observatory, California
Institute Technology, Mail Stop 100-23, Pasadena, CA 91125-0001
Facies patterns of Neogene strata lying along the intensely faulted southern Sierra Nevada range
front indicate that Neogene marine conditions extended for a non-trivial distance across the
currently exposed southern Sierra basement. Emergence of the basement is controlled by active
W-side-up normal faulting along the Kern Canyon-Breckenridge system, and active NE-side-up
normal faulting along the Kern range front-Pond-Poso system. Together these systems produce
the regional wedge shaped Breckenridge-Greenhorn horst. The lower slopes of the horst constitute the Kern Arch, a pervasively faulted homocline across which the remnants of the SE SJB
Neogene section are undergoing erosion. Neogene basin slope, shelfal, shoreline and paralic
facies strata occur continuously along the range front, both faulted against basement and as
nonconformable tongues preserved along relay ramps in the fault system. Geologic relations in
conjunction with He apatite thermochronometry suggest Neogene growth faulting and transfer
motion along the Breckenridge fault, which bounded a system of NW-striking normal faults to the
east. Together these faults produced the volcanic (Walker) graben in which the western flank of
the 21-16 Ma Cache Peak volcanic center ponded. The southwest corner of the Walker graben
was breached by normal faults of the Edison graben that formed a structural trough into the SJB.
Currently it is unclear if marine conditions extended all the way into the Walker graben, either
through an Edison graben channel, or by overtopping the growing Breckenridge fault. Regional
U/Pb zircon basement geochronology and detrital zircon ages from upper Neogene strata, in
conjunction with other provenance and stratigraphic data indicate that the Bena Gravel and “Kern
River” Formation represent a prograding delta-fluvial plain system that flooded into the SJB,
primarily through the Edison graben, as the southern Sierra began regional ascent in the Late
Miocene. Continued regional uplift has resulted in the redistribution of most of the Walker graben
fill into the SE SJB. In late Pliocene-Quaternary time the Breckenridge-Greenhorn horst began
68 2010 GSA Abstracts with Programs forming with the progressive exhumation of overlying SJB margin strata, and the incision of the
lower Kern gorge as a superimposed drainage.
Friday, 28 May 2010
T2. Tectonic Evolution of the Southern Big-Bend
Region, San Andreas Fault (Cordilleran Section GSA;
Pacific Section, AAPG; Pacific Section SEPM)
21-1
8:05 AM
Brune, James N.
[173121]
ASSUMED BACKGROUND SEISMICITY AS A PARTIAL EXPLANATION FOR DISCREPANCIES
BETWEEN PRECARIOUSLY BALANCED ROCKS AND 2008 CALIFORNIA HAZARD MAPS
BRUNE, James N., Seismological Laboratory, University of Nevada, Reno, Reno, NV 89557,
[email protected], BIASI, Glenn, Nevada Seismological Laboratory MS174, University of
Nevada Reno, Reno, NV 89558, GRANT LUDWIG, Lisa, Program in Public Health, University
of California, 101 Theory, Suite 250, Irvine, CA 92697-3957, and ROOD, Dylan H., Institute
for Crustal Studies, University of California Santa Barbara, Santa Barbara, CA 83106
Precariously balanced rocks (PBRs) which have been in place thousands of years provide upper
bounds on seismic hazard at a site. At a number of sites in California, tested measured and
estimated toppling ground motions are inconsistent with 2008 2% in 50 yr hazard maps. The
number and distribution of sites make it unlikely that the discrepancies are due to a statistical
accident. Other possible explanations for the discrepancy include unrecognized site, path, and
attenuation contributions to the hazard, or over-estimation of rates either of known faults or of
random background seismicity. In this presentation we discuss the possibility of incorrect assignment of random background seismicity. In the recent UCERF 2 model of seismicity in California
relatively large earthquakes, M=6.5-7, are randomly assigned to locations within 20 km, in many
cases 5 km, of PBR sites. For the 2% in 50 yr (2475 yr recurrence time) maps there are several
such events, at some sites accounting for half or more of the hazard and apparently making
the hazard maps inconsistent with the PBRs. Random background earthquakes are supposed
to represent the possibility of such large events occurring at sites where there are no mapped
candidate faults, but where blind or buried structures could be active. However many PBR sites
the large background events are assigned where exposures are good and there are no mapped
faults nearby capable of such large earthquakes. Furthermore, most, if not all the “background”
earthquakes cited in UCERF2 as evidence for the rate of occurrence of background earthquakes
actually occurred in known active faulting areas. In our presentation we consider individual site
discrepancies and possible explanations for each case, possible geologic criteria for realistically
designating areas for potential for large background earthquakes, and statistical implications for
earthquake hazard.
21-2
8:25 AM
Martin, Zachary
[173271]
EXHUMATIONAL HISTORY OF THE SAN JACINTO MOUNTAINS, FROM NEW APATITE
FISSION TRACK ANALYSES
MARTIN, Zachary and BLYTHE, Ann E., Dept. of Geology, Occidental College, Los Angeles,
New apatite fission track (AFT) analyses from the San Jacinto Mountains are used to constrain
the exhumational history of the fault-bounded block. AFT ages are commonly interpreted as
recording the time of cooling through a ~110°C closure temperature. In a previous study, George
and Dokka (1994) obtained AFT ages of 79-74 Ma from the San Jacinto Mountains, with no
correlation between age and elevation seen. The six new AFT ages obtained in this study were
substantially younger, ranging from 56 to 29 Ma, and did show a correlation between age and
elevation. Three samples from an elevational transect on the eastern side yielded ages of 54,
40.8, and 29.1 Ma with respect to elevations ranging from 2622 to 227 m. A sample collected
from an elevation of 1240 m from the northern front of the San Jacinto Mountains yielded an AFT
age of 56.6 Ma but is not interpreted as it appears to be in a large landslide block (F. Jordan, pers.
comm., 2009). Two samples from fault blocks on the western side of the San Jacinto Mountains
yielded AFT ages of 56.8 and 44.0 Ma. The age patterns obtained in this study were different
from those obtained by George and Dokka (1994) and corresponded closely to the apatite (U-Th)/
He analyses of Wolf et al. (1997), which represent cooling through a lower closure temperature of
~70°C. We interpret these new AFT data and the existing (U-Th)/He analyses to represent a later,
less rapid phase of cooling and exhumation (~40°C of cooling or 1.3 km of exhumation over ~3-5
Myr at ~55 Ma), than had been interpreted by George and Dokka. The younger AFT ages at lower
elevations may be partially reset; we will use AFT track length analyses to better interpret these
younger ages.
21-3
8:45 AM
Ricketts, J.W.
[173283]
MIDDLE–LATE MIOCENE GROWTH OF A DEPRESSION IN THE CHOCOLATE MOUNTAINS
ANTICLINORIUM, AS RECORDED BY THE BEAR CANYON CONGLOMERATE, SE
CALIFORNIA
RICKETTS, J.W., VOYLES, E.M., SAINSBURY, J.S., SUTTON, L.A., and GIRTY, Gary H.,
Geological Sciences, San Diego State University, 5500 Campanile Drive, San Diego, CA
Between Indian Pass and Picacho State Recreation Area (PSRA), the EW trending Chocolate
Mountains anticlinorium forms a structural depression bounded by two culminations. The depression in the axis of the anticlinorium occurs between PSRA and Carrizo Wash. To the east and
west of the depression the 28-24 Ma Sortan fault, a package of ~23 Ma volcanics, and the Bear
Canyon conglomerate are folded about the anticlinorium, which plunges westward and eastward
into the depression.
Detailed clast analysis within the depression indicates derivation from the underlying volcanic sequence, as a result of the progressive unroofing of the anticlinorium. Moreover, the Bear
Canyon conglomerate can be subdivided into three unconformably bound members. The lower
member is composed of clasts of locally derived volcanics, and generally dips to the east along
the western margin of the depression. The middle member contains clasts of the underlying
volcanics and basement rocks, and occurs as NS oriented panels along both the E and W sides,
dipping inward toward the axis of the depression. Within the structural depression, the middle
member forms an extensive unit which records the growth of the anticlinorium as well as the
SESSION NO. 21
progressive deepening of the depression. The upper member contains clasts of local volcanics,
basement, and pre-existing polymictic conglomerate. Slightly tilted gravels of the upper member
record the final phases of fold growth. To the west of the structural depression, interstratified
within the Bear Canyon conglomerate are the 13.4-9.6 Ma basalts of Black Mountain, which dip
~26°S along the southern limb of the anticlinorium at Indian Pass. Additionally, along the southern
margin of the depression, the upper member Bear Canyon conglomerate is truncated by the
informally recognized EW trending Copper Basin reverse fault.
These data, in conjunction with previously published results, imply that in the region between
Indian Pass and PSRA, ~NS shortening resulted in episodic growth and denudation of the
Chocolate Mountains anticlinorium and the deposition of gravels into a deepening depression during the Early to Middle Miocene. Hence, the formation of these structures may be directly related
to the early formation of the San Andreas fault system.
21-4
9:05 AM
McGill, Sally
[173615]
LATEST PLEISTOCENE SLIP RATES ALONG THE SAN BERNARDINO STRAND OF THE
SAN ANDREAS FAULT
MCGILL, Sally, Geological Sciences, California State University, San Bernardino, 5500
University Parkway, San Bernardino, CA 92407, [email protected], WELDON, Ray J. II,
Department of Geological Sciences, University of Oregon, Eugene, OR 97403, and OWEN,
Lewis A., Geology, University of Cincinnati, Cincinnati, OH 45221-0013
Preliminary results from three sites along the San Bernardino strand of the San Andreas fault
suggest that the latest Pleistocene slip rate decreases southeastward from a previously published
rate of ~ 25 mm/yr in Cajon Pass to a rate in the mid-teens (mm/yr) at two sites along the central
portion of the San Bernardino strand.
At Plunge Creek, the slip rate is measured from the correlation of a southeast-facing truncated
channel edge southwest of the fault with a southeast-facing terrace riser northeast of the fault.
The two landforms are separated 270 m from each other along the fault. Three radiocarbon
dates on detrital charcoal from the base of the colluvial wedge on the incised terrace constrain
the age of initial incision of the riser to ~ 32 ka. (A fourth date is slightly older). The upstream
channel may have initially incised farther southeast than its present location followed by widening of the channel over time. The maximum possible offset since initial incision is 540 m. Using a
trapezoidal-shaped probability density function for the offset, with a plateau from 270-500 m and
limiting offsets of 120 m and 540 m yields a slip rate of 11 mm/yr (95% confidence interval [CI] of
4-18 mm/yr).
At Badger Canyon, an alluvial fan offset 110-210 m with an age of ~13.3 ka (OSL) or ~ 14.8 ka
(C-14) yields a slip rate of 13 mm/yr (95% CI: 7-20 mm/yr). An older fan offset 300-400 m at the
same site yields a slip rate of 14 mm/yr (95% CI:11-18 mm/yr) using the 27.5 ka C-14 age or
18 mm/yr (95% CI: 14-23 mm/yr) using the OSL age of ~ 20 ka. A riser incised into this fan is
offset 280 m and yields a slip rate of 13 mm/yr (95% CI: 11.1-17 mm/yr) based on two ~23 ka
C-14 dates on detrital charcoal that bracket the age of incision.
These data suggest that slip transfers from the Mojave section of the San Andreas fault to the
northern San Jacinto fault zone in the vicinity of Cajon Pass, where the two fault zones parallel
each other and are only 2.5 km apart for a distance of ~ 16 km along strike. Within this proposed
transfer zone, an offset landslide at Pitman Canyon with a Be-10 age of 33.7 ka on exposed
boulders yields a San Andreas fault slip rate of 19 mm/yr (range 13-28 mm/yr). This rate is intermediate between the ~ 25 mm/yr rate a few km to the northwest at Cajon Creek and the rates in
the mid-teens (mm/yr) to the southeast at Badger Canyon and Plunge Creek.
21-5
9:25 AM
Sainsbury, J.S.
[173630]
THE CHOCOLATE MOUNTAINS ANTICLINORIUM: MIOCENE GROWTH AND RE-ACTIVATION
RECORDED IN VOLCANICS AND ALLUVIAL GRAVELS, INDIAN PASS TO CARRIZO WASH,
SE CALIFORNIA
SAINSBURY, J.S., RICKETTS, J.W., MUELA, K.K., and GIRTY, Gary H., Geological
Sciences, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182,
[email protected]
Between Indian Pass and Carrizo Wash, Mesozoic to early Tertiary crystalline basement is
overlain by early Miocene volcanics (~23-24 Ma) and the Bear Canyon conglomerate (BCC). The
basement complex, comprising the core of the Chocolate Mountains anticlinorium, includes in
ascending structural order, the late Cretaceous to early Tertiary Orocopia Schist, a mafic orthogneiss unit, and the Jurassic Winterhaven Formation. The Chocolate Mountains fault separates
the Orocopia Schist from the orthogneiss, while the Gatuna fault separates the orthogneiss from
the structurally overlying Winterhaven Formation. Lying stratigraphically above the Winterhaven
Formation is a thick section of Miocene volcanic rocks which are in turn overlain by alluvial sediments of the Bear Canyon conglomerate. Near Indian Pass, the basalts of Black Mountain (~9.6 13.4 Ma) are included within the upper part of the Bear Canyon conglomerate. We may have a
new Ar-Ar date to report during our talk. Between Indian Pass and Carrizo Wash, the Chocolate
Mountains and Gatuna faults, the section of Miocene volcanics, and the BCC are all folded about
the CMA. In addition, the entire section is cut by NW trending dextral faults some of which die out
into the core of the anticlinorium. We interpret this relationship to indicate that the anticlinorium
may have been tightened during this period of dextral shear. Between Indian Pass and Carrizo
Wash the trace of the axis of the anticlinorium forms a culmination and then between Carrizo
Wash and Bear Canyon a depression. Cropping out along the east side of the structural depression is a thick section of presumably Miocene volcanic rocks. Our preliminary work suggests that
these rocks may represent a dome complex along with vitrophyre and a pumaceous cap. The
dome complex is in turn overlain by a thick section of welded and non-welded pyroclastic rocks
that are interstratified with lahars. Our preliminary geochemical work suggests that the pyroclastic
rocks are unlike the more well known pyroclastic rocks cropping out a few kilometers to the east
at PSRA. In short, our continuing work suggests that the CMA was likely growing after ~9-13 Ma,
and that it and the dextral strike-slip faults that we have mapped are likely the record of the propagation of the Eastern California Shear Zone southward to the latitude of Indian Pass.
21-6
10:00 AM
Medina Luna, Lorena
[173660]
ANOMALOUS OSL APPARENT AGES OF THE BISKRA PALMS ALLUVIAL FAN
MEDINA LUNA, Lorena1, YULE, Doug1, and RITTENOUR, Tammy2, (1) Department
of Geological Sciences, California State University Northridge, 18111 Nordhoff Street,
Northridge, CA 91330, [email protected], (2) Department of Geology and
Luminescence laboratory, Utah State University, Logan, UT 84322
Recent efforts to constrain the geologic slip rate of the Coachella Valley segment of the San
Andreas fault have employed several age-dating methods to determine the age of an offset
alluvial fan near Indio, CA. Cosmogenic 10Be, soil development, and U-series on pedogenic carbonate methods all yield data consistent with a fan age of 45-54 ka (Behr et al., GSA Bulletin, in
press; Fletcher et al., GSA Bulletin, in press). In contrast, this study reports Optically Stimulated
Luminescence (OSL) analyses of quartz grains that yield anomalously young and out-of-sequence
apparent ages for sand layers 1.4 to 30 m beneath the fan surface. The discrepancy between the
OSL and other age-dating methods is probably due to a number of factors that are inherent to
the Biskra Palms site. Chemical analyses reveal that the amount of Thorium present in some of
the sampled sediment is higher than expected and can thus mean there is disequilibrium in the
samples. This disequilibrium may result in a high dose-rate and consequently an underestimate in
OSL age. Additionally, it is likely that a wetter late Pleistocene climate resulted in a higher water
content of the sediment at this location. A 30 to 50% increase in water content can increase the
age calculation by up to 25%. Lab analyses also indicate that the quartz luminescence signals are
very weak and are dominated by a slow-medium component. This may result from the coarse and
proximal setting of the sampled sediment and/or the sediment possibly being eroded directly from
bedrock. The sediment may not have undergone enough transport and deposition cycles to sensitize the sediment and become fully bleached in this proximal setting. Anomalous lab results usually signal a white flag to researchers with regard to the validity of an age-dating method. Using
more than one age-dating method where possible can help corroborate the data. In the case of
Biskra Palms, cosmogenic and U-series methods seem to corroborate with one another, but there
are problems with the OSL analysis. These results suggest that using the OSL method in proximal
alluvial fan settings may yield results that do not represent the depositional age of the sediment.
21-7
10:20 AM
Yule, Doug
[173662]
TESTING THE “SHAKEOUT” SCENARIO EARTHQUAKE IN SAN GORGONIO PASS: FACT
OR FICTION?
YULE, Doug, Department of Geological Sciences, California State University Northridge,
18111 Nordhoff Street, Northridge, CA 91330, [email protected]
Models for the maximum possible earthquake on the southernmost San Andreas fault hinge upon
interpreting the structural complexity and diffuse seismicity of the San Gorgonio Pass (SGP)
region. The “ShakeOut” Scenario Earthquake envisions a fault system that can propagate through
the Pass in complex but understandable ways and generate an ~M 7.8 earthquake that ruptures
from the Salton Sea to the Mojave Desert. Another model argues that the complexity in SGP
arrests through going ruptures and limits their size to less than a M 7.5 earthquake on either the
Coachella Valley or the San Bernardino and Mojave segments, respectively. One test of these
contrasting models is to examine the paleoseismology and geomorphology of the SGP fault zone,
an east-west trending set of thrust and tear faults that carry slip through the compressive stepover
between the strike-slip Coachella Valley and San Bernardino segments of the San Andreas fault
system. Perhaps the most convincing evidence that supports through going rupture is the fact that
stepovers between active fault traces in SGP never exceed 3 km, the threshold limit set by historic
earthquakes for arresting rupture (Wesnousky, 2008). However, a review of published data from
SGP appears to support both models. For example, a study of one segment of the SGP fault zone
shows evidence for at least two ruptures since ~AD 1300, consistent with paleoseismic records
on the San Andreas fault outside the Pass region. In contrast, data from another SGP fault segment support only one rupture in the last 3000 yrs, far less frequent than one would expect for a
through going ShakeOut Scenario Earthquake. The slip rate of the SGP fault zone is estimated to
be ~50% slower than for the strike-slip San Andreas fault segments that feed into SGP and would
seem to argue in favor of the Pass acting as a barrier to through going rupture. Yet SGP fault slip
rates must be considered to be minimum estimates because they are determined from single fault
traces and do not take into account the off-fault deformation that occurs in the region via folding,
secondary faulting, and seismicity, etc. Clearly a more detailed study of the SGP fault zone, both
at the surface and in the subsurface, is necessary to give a definitive ruling in favor or against the
ShakeOut Scenario Earthquake.
21-8
10:40 AM
Nicholson, Craig
[172882]
REVISED 3D FAULT MODELS FOR THE SOUTHERN SAN ANDREAS FAULT SYSTEM
EXTENDING FROM SAN GORGONIO PASS TO THE SALTON SEA
NICHOLSON, Craig, Marine Science Institute, University of California, Santa Barbara, CA
93106-6150, [email protected], HAUKSSON, Egill, California Institute of Technology,
Pasadena, CA 91125, and PLESCH, Andreas, Earth & Planetary Sciences, Harvard
University, Cambridge, MA 02138
Understanding the 3D geometry and sense of slip of the San Andreas fault (SAF) is critical to
accurately evaluating dynamic rupture and ground motion prediction models. We use alignments of hypocenter and focal mechanism nodal planes within a relocated earthquake catalog to
develop improved 3D fault models of principal slip surfaces for the southern SAF system. Through
San Gorgonio Pass, earthquakes define multiple fault strands, and beneath ~10 km depth, intersecting sets of strike-slip, oblique slip and thrust faults representing a volume deformation of the
lower crust. In the northern Coachella Valley, seismicity indicates that the Garnet Hill and Banning
fault strands are most likely sub-parallel (with dips of ~70°NE) to depths of 8–10 km, where they
intersect and merge with a stack of moderately dipping to low-angle thrust faults. Gravity and
water well data confirm that these faults are sub-parallel and near vertical in the upper 2–3 km,
suggesting that these faults tend to decrease dip with depth. The active Mission Creek fault (MCF)
appears to steepen along strike SE from ~60°NE to ~80°NE in the Indio Hills. Gravity and velocity
modeling also suggest a moderately NE-dipping MCF, although this modeled velocity/density contrast may reflect an older ancestral(?) basin-bounding fault, which tends to act as the lower bound
to adjacent seismicity located farther east. SE to North Shore and at Bombay Beach, earthquakes
do locate directly beneath the SAF surface trace, suggesting that a vertical SAF is permissible
here and consistent with observed fault geomorphology. Through the Mecca Hills, much of the
seismicity east of the surface trace is clearly related to slip on adjacent secondary faults. Although
clusters of hypocenters and nodal planes near North Shore and Salt Creek project to the SAF
surface trace with dips ~65°NE, these events appear to be more closely related to slip on the
NE-dipping Hidden Springs fault and other intervening secondary fault splays, and not to slip
on the SAF itself. Along the southern SAF system, hypocenter and nodal plane alignments thus
exhibit a persistent pattern of active multiple fault strands that are often sub-parallel throughout
much of the seismogenic zone, and that change dip and dip direction along strike and with depth.
21-9
11:00 AM
Cooke, Michele L.
[173122]
3D NUMERICAL INVESTIGATIONS INTO THE EVOLUTION OF THE SOUTHERN BEND BEND
OF THE SAN ANDREAS FAULT
COOKE, Michele L., Geosciences, University of Massachusetts, 611 North Pleasant Street,
Amherst, MA 01003-9297, [email protected] and DAIR, Laura, Geosciences, Univ of
Massachusetts, Amherst, MA 01003-9297
During the last 1Ma the southern San Andreas fault within the San Gorgonio Pass region has
been interpreted to have successively abandoned two strands before taking up activity along its
present-day configuration. This evolution is simulated within three-dimensional models to test the
hypothesis that fault systems evolve to increase mechanical efficiency. The three-dimensional
Boundary Element Method models are validated by comparison of modeled fault slip rates and
uplift rates with geologic data. The partitioning of slip among active faults changes between the
three phases of southern San Andreas fault evolution and reveals both a trade-off in strike-slip
rates between the San Jacinto and San Andreas faults as well as a trade-off between strike slip
SESSION NO. 21
on the San Andreas and reverse slip along faults associated with uplifting the San Bernardino
Mountains. Mechanical efficiency of the entire model increases from the Mission Creek to Mill
Creek fault configuration and decreases from the Mill Creek configuration to the present day
configuration strain energy density patterns highlight regions of fault growth over the past 1 Ma
and may be used to predict future fault configuration. The decrease in mechanical efficiency
with the transition to the present-day fault geometry may reflect inaccuracies in the models. For
example downwelling of the mantle beneath the San Bernardino Mountains may foster the activity
of otherwise inefficient thrust faults. Alternatively, the present-day geometry may be a short-lived
transition phase to a more efficient geometry.
Friday, 28 May 2010
T21. Carbon Sequestration and Oil Fields (Pacific
Section AAPG/ Society of Petroleum Engineers (SPE))
22-1
8:00 AM
Van Hollebeke, Philip
[173039]
ADVANCES IN HIGH RESOLUTION SEISMIC METHODS FOR CO2 ENHANCED OIL
RECOVERY (EOR) AND SEQUESTRATION
VAN HOLLEBEKE, Philip and SANDIN, Nils, Bay Geophysical, Inc, 868 Robinwood Court,
Traverse City, MI 49686, [email protected]
New technologies are being developed to produce CO2 from industrial sources for EOR methods
and sequestration in oil and natural gas reservoirs across the U.S. The technical challenge is the
containment and accountability of large volumes of injected CO2 within these oil and natural gas
reservoirs. High resolution seismic methods can be used to delineate and assess the reservoirs
for CO2 injection feasibility as well as quantitative reservoir management, monitoring and leakage
detection. Recent advances in seismic acquisition include low impact vibroseis energy sources
and enhanced source control electronics. These advances directly result in a limited cultural
footprint, including densely populated urban environments as well as agricultural regions.
22-2
8:30 AM
Ouenes, Ahmed
[173817]
INTEGRATED CHARACTERIZATION AND SIMULATION OF THE FRACTURED TENSLEEP
RESERVOIR AT TEAPOT DOME FOR CO2 INJECTION DESIGN
OUENES, Ahmed1, ANDERSON, Thomas Carl2, KLEPACKI, Douglas3, ROBINSON, Gary
Charles4, BACHIR, Aissa3, BOUKHELF, Boukhelf3, BLACK, Brian J.5, and STAMP, Stamp6,
(1) Prism Seismic, Los Angeles, CA 90802, [email protected], (2) Rocky Mountain Oilfield
Testing Center, Los Angeles, CA 90802, (3) Prism Seismic, Long Beach, CA 90802,
(4) Degolyer and MacNaughton, Los Angeles, CA 90802, (5) Rocky Mountain Oilfield
Testing Center, 907 N. Poplar St, Casper, WY 82601, (6) Los Angeles, CA 90802
Characterization of naturally fractured reservoirs is a recurring challenge to many oil and gas
companies. This paper describes the application of the Continuous Fracture Modeling (CFM)
technology and the use of a multitude of post stack attributes to improve the characterization and
simulation of the Tensleep reservoir at the Teapot Dome. Description of Paper: The methodology presented in this paper uses the integration of geophysical, geologic, and engineering data
simultaneously to improve the reservoir description. At the root of the reservoir characterization
lays the more and more accurate seismic data collected on most of the reservoirs around the
world. The initial use of this seismic information is made possible through the use of volumetric
curvatures, high‑resolution post‑stack inversion, and spectral decomposition. These geophysical
processes allows a better imaging of the distribution of the faults and geology in the reservoir.
The multitude of seismic attributes are added to seismically constrained geologic models and
geomechanical attributes to create CFM models of fracture density. The derived fracture density
models are used to estimate a meaningful permeability used as input into reservoir simulators.
Results, Observations, and Conclusions: Illustration on the Tensleep reservoir (Teapot Dome,
WY) using the seismically driven reservoir characterization where wells have been hidden to
validate the methodology. The resulting porosity and permeability model that takes into account
the effect of the fractures is used as input into a reservoir simulator to validate dynamically the
reservoir model. Applications: This study demonstrates the successful use of all available G&G
reservoir data in an integrated approach. Technical Contributions: Efficient use of seismic data in
fractured reservoir characterization. Quantitative use of seismic attributes derived from volumetric
curvature, high‑resolution post stack seismic inversions and spectral decomposition in deriving
improved fracture models.
22-3
9:00 AM
Jordan, Preston
[173818]
BASIN WIDE PRESSURE CHANGES DUE TO CO2 STORAGE: CALIFORNIA PRODUCTION
AS A REVERSE ANALOG
JORDAN, Preston, Lawrence Berkeley Laboratory, Los Angeles, CA 90802,
[email protected]
Storage of point source generated CO2 (such as from fossil‑fueled electricity plants) within
geologic strata is proposed as an alternative to emitting this greenhouse gas to the atmosphere.
Large quantities (billions of tonnes) will have to be stored for this technology to provide significant
climate change mitigation. Storage of such quantities raises concern about basin‑wide pressure
increases and the consequences for hydrocarbon and water resources as well as land surface
configuration. The history of hydrocarbon production in California offers a reverse analog for
studying basin‑scale pressure perturbations due to industrial‑scale CO2 storage. Cumulative
oil production in the State, with most from the San Joaquin Basin, was 4.4 billion cubic meters
(27.8 billion barrels) by the end of 2006 (California Division of Oil, Gas and Geothermal
Resources, 2007). This is a volume equivalent to 3.1 billion tonnes of carbon dioxide (assuming a specific density of 0.7 tonnes/m3). This volume is approximately 40 times the average
annual CO2 emissions from electricity generation within California from 2000 to 2006 (California
Environmental Protection Agency Air Resources Board, 2009). “Virgin” oil and gas field pressures
from almost a century of discovery in the San Joaquin Basin were analyzed for time and spatial
trends in the first part of a multi‑year study. With a few possible exceptions, significant pressure
declines were not observed in this data set. This suggests significant interfield compartmentalization of the San Joaquin reservoirs. Such compartmentalization would limit the impact of CO2
storage‑induced pressure increases beyond the target storage volume. This would come at the
cost of less storage capacity, however “refilling” the pore spaces from which oil has been removed
70 2010 GSA Abstracts with Programs would provide California with decades of capacity, although pore collapse has also reduced this
capacity in some areas.
22-4
9:30 AM
Kuo, Chia wei
[173819]
EFFECT OF GRAVITY, FLOW RATE, AND SMALL SCALE HETEROGENEITY ON MULTIPHASE
FLOW OF CO2 AND BRINE
KUO, Chia wei, PERRIN, Jean Christophe, and BENSON, Sally M., Stanford University,
Stanford, CA 94305, [email protected]
A series of steady state multiphase flow experiments at a range of fractional flows and flow rates
have been conducted using Berea Sandstone. Using the multiphase flow simulator TOUGH2
MP, carbon dioxide saturation distributions, average saturations, and pressure gradients across
the core were calculated to determine the influences of sub‑core scale heterogeneity, gravity
and flow rate on brine displacement efficiency. It is found that measured CO2 saturation patterns
can be replicated using simulation models that include spatially varying porosity, permeability
and capillary pressure curves, The interplay of viscous, capillary and gravity forces in core flood
experiments are also investigated at different Gravity and Capillary numbers representative of
those expected for a typical sequestration project (Gravity numbers 1E2~1E6 while Capillary
numbers 1E‑6~1E‑10). These dimensionless numbers span the range of conditions expected in
the near‑well region to leading of the plume which may be up to 5 km or more from the injection
well. Simulations show that the efficiency of brine displacement and saturation distributions during vertical displacement fall into three separate regimes. At high flow rates representative of the
near‑well region, the brine displacement efficiency is nearly independent of flowrate. When the
Capillary number drops below 1E‑7 and the gravity number is 1800, both the heterogeneous and
homogenous cores display flow rate dependent saturation distributions, with brine displacement
efficiency dropping by about 80%. Most of this effect is caused by the influence of gravity, as the
decrease in brine displacement efficiency is only slightly smaller for heterogeneous cores. At very
low capillary numbers, the brine displacement efficiency appears to asymptotically approach a
constant value (flowrate independent). The implications of the interplay between viscous, capillary
and gravity forces observed in these high resolution simulations on large scale reservoir displacement efficiency are discussed.
22-5
10:30 AM
Behzadi, Seyed
[173820]
COMPARISON OF CHEMICAL AND HYSTERESIS CO2 TRAPPING IN THE NUGGET
FORMATION
BEHZADI, Seyed, U of Wyoming, Laramie, WY 82071, [email protected]
The Moxa Arch Anticline is a regional‑scale northwest‑trending uplift in western Wyoming and it
has been chosen for CO2 capture and storage. The Nugget Sandstone is a deep saline aquifer
that has been a candidate for CO2 storage. In this paper we compare the amount of mineral
and solution trapping in comparison with dynamic hysteresis trapping based on compositional
simulation. To the best of our knowledge this is the first paper to computationally assess the
chemical trapping in the Nugget formation and to compare these three trapping mechanisms
against each other. Reaction‑path and kinetic modeling of CO2C_‑brineC_‑mineral reactions in
the Nugget formation was investigated to probe the factors that affect capacity for CO2 chemical
trapping. The solution and precipitation trapping of CO2 are functions of temperature, pressure,
CO2 fugacity and brine composition. The geochemical simulation of this system was explored in
order to assess how mineralogy might change and the relative importance of mineral and solution
trapping phenomena through time. After 30 years, 0.06 g of CO2 per kg of reacted rock is sequestered as mineral phases and solution trapping amounts to 3.1 g/kg rock. In comparison, a recent
computational study of the Rose Run sandstone, Ohio indicates a much higher (30 times higher)
mineral trapping capacity, mainly because of the presence of glauconite as an iron source for siderite formation. The total hysteresis trapping in our study is 4.5g/kg rock based on compositional
simulation for the same period of time. These results reveal that mineral trapping in the Nugget
formation is not significant but that total chemical trapping might be as high as 70% of hysteresis
trapping. Therefore, the contribution and importance of chemical trapping in CO2 sequestration
should be taken into account for assessment of CO2 sequestration.
22-6
11:00 AM
Haroun, Muhammad Raeef
[173821]
OPTIMIZING CO2 EOR REAL TIME MANAGEMENT TO INCREASE “GREEN OIL”
PRODUCTION THE ELK HILL CASE STUDY
HAROUN, Muhammad Raeef1, SARMA, Hemanta Kumar2, and GHOSH, Bisweswar2,
(1) U of Southern California, Los Angeles, CA 90802, [email protected], (2) The Petroleum
Institute, Los Angeles, CA 90802
The ability of CO2 to cause swelling, favorable mobility and relative permeability alteration made
it an attractive EOR choice. It has gained importance over steam injection for deeper heavy oil
reservoirs where steam operation is economically unviable due to depth limitation and/or potential
excessive heat losses. A recent study on CO2‑EOR in the U.S. indicated that a production of 88
billion bbl of oil is technically feasible, while 39‑48 billion bbl are economically recoverable with
current CO2 EOR technologies. However, with several ongoing projects all over the U.S. only 2.3
Billion bbl have been produced so far. Elk hills oilfield has been selected for the optimization study
due to its wide range of net thickness, with 80% of its oil coming from zones between 5,000 ft and
10,000 ft, its mature condition and environmental sensitivity. Its 1,100+ wells and light oil gravity
(38o API on average) plus extensive data are already available in the public domain make it a
favorable candidate. In this paper we propose a new methodology to alter the MMP by optimizing
the CO2 purity with varying mol fractions of hydrocarbon gases to effectively enhance the mobility
ratio. We emphasize on maximizing reservoir contact to minimize the effects of viscous fingering
and gravity override, while effectively increasing well operating pressure. The optimum distribution
and count of vertical injectors, sufficient CO2 volumes and maintaining favorable fluid balance are
key parameters used in the study. The paper elaborates an optimized next generation CO2‑EOR
real‑time management approach for Elk hills oilfield, which would require a zonal allocation program, formal CO2‑EOR tracking system using observation wells allowing the precise targeting of
the main pay zone, the residual oil zone and continuous CO2 injection.
22-7
11:30 AM
Delshad, Mojdeh
[173822]
A CRITICAL ASSESSMENT OF CO2 INJECTION STRATEGIES IN SALINE AQUIFERS
DELSHAD, Mojdeh, KONG, Xianhui, and WHEELER, Mary Fanett, U of Texas at Austin,
Austin, TX 90802, [email protected]
The main concern in geological storage of CO2 is its long term retention. Development decisions such as number of injection wells, injection rates, placement of injection wells, and the
need for water production/reinjection can have a profound impact on the long term storage.
Several prototype reservoir geomodels were studied to determine the impact of injection strategy on CO2 retention, plume extension, and movement to top seal. Application There is an
overwhelming evidence of increased level of green house gases such as CO2 in atmosphere
SESSION NO. 23
with an urgent need to stabilize the atmospheric content by storage in geological formations.
Several injection schemes were studied to assess the impact on formation pressure during injection, the amount sequestered and the extent of vertical migration. Results, Observations, and
Conclusions Simulations were performed taking into account the hysteresis, dissolution in brine,
and mineralization of CO2 to carbonate. Injection strategies included several well completions
and configurations. Injection options included continuous CO2, water alternating CO2, simultaneous CO2 and water, and inject/stop/inject sequence. The total mass of injected CO2 was kept
constant for comparison purposes. The assessment was based on the amount of mineralized,
dissolved, and trapped CO2. The vertical migration of CO2 and the mobile CO2 at the top seal
was also compared for these cases. The effect of each design on formation pressure during the
injection was also evaluated. The results indicated that the injection strategy has great impacts on
the total amount retained, vertical migration, and extent of the plume at the top seal. Significance
of Subject Matter The development decisions of well placement/ completion, and injection rates
need to be made specific to each candidate storage site to maximize dissolved and trapped CO2
for long term containment.
Friday, 28 May 2010
T34. EOR Technologies II (Society of Petroleum
Engineers (SPE))
23-1
8:30 AM
Ahmed, Tarek
[173829]
CHARACTERIZING THE PLUS FRACTION FOR EOS’ APPLICATIONS
AHMED, Tarek, Anadarko Petroleum Corp, Los Angeles, CA 90802, [email protected] and
MEEHAN, D. Nathan, Baker Hughes Inc, Los Angeles, CA 90802
To use any EOS; the Peng‑Robinson EOS as an example, one must be able to provide the critical pressure, the critical temperature, and the acentric factor for each component in the mixture.
Nearly all naturally occurring petroleum fluids contain a quantity of heavy fractions that are not
well defined. These heavy fractions are often lumped together as heptanes‑plus fraction. The
problem of how to adequately characterize the C7+ fractions in terms of their critical properties
and acentric factors has been long recognized in the petroleum industry. Changing the characterization of C7+ fractions present in even small amounts can have a profound effect on the
PVT properties and the phase Equilibria of a hydrocarbon system as predicted by the Peng and
Robinson equation of state. Recognizing that the inadequacy of the predictive capability of the PR
EOS lies with the improper procedure for calculating the parameters a, b, and C_ of the equation
for the C7+ fraction; this paper presents an approach for determining these parameters from the
following two readily measured physical properties of C7+:
‑ molecular weight M7+
‑ specific gravity C_7+
The approach is based on generating 49 density values for the C7+ by applying the Riazi and
Daubert correlation. These values were subsequently subjected to 10 temperatures and 10 pressure values in the range of 60aF‑300aF and 14.7‑7,000 psia, respectively. The Peng‑Robinson
EOS was then applied to match the 4,900 generated density values by optimizing the parameters
a, b, and C_ using a non‑linear regression model. The optimized parameters for the heptanes‑plus
fraction are given by mathematical expressions. The paper presents results of applying the proposed EOS; without tuning, to numerous experimental data to illustrate the capability of the modified EOS and to demonstrate its accuracy.
23-2
9:00 AM
Sheng, James J.
[173830]
EVALUATION OF THE EFFECT OF WETTABILITY ALTERATION ON OIL RECOVERY IN
CARBONATE RESERVOIRS
SHENG, James J., Total E&P, Bakersfield, CA 93306, [email protected]
More than 60% of the worldC_’s oil reserves are held in carbonate reservoirs. Many unfavorable
factors contribute to low oil recovery in these reservoirs. Fractured and oil‑wet are the two main
factors. Apparently, there is an increasing interest in using chemicals to alter wettability. Injection
of chemicals can result in various effects, for example, wettability alteration and reduction in
interfacial tension (IFT). The question is how much contribution is from each mechanism to the
increase in oil recovery. There is lack of such information in the literature. The information is very
important because it will guide us to select which chemicals to be used, as some chemicals can
effectively reduce IFT, while others alter wettability. This paper is to quantify different mechanisms
in oil recovery related to chemical EOR. Particularly, we compared the effects of wettability alteration and IFT reduction. Analytical and numerical simulation models were used. Our results show
that wettability alteration plays important roles when IFT is high, and it is effective in the early
time. IFT plays very important roles with or without wettability alteration and is effective during the
entire process. The implication is that anionic surfactants are preferred to cationic surfactants in
chemical EOR, as the former are generally used to reduce IFT, while the latter are used to alter
wettability. Other observations are that in surfactant‑induced wettability alteration with low IFT,
gravity drive is a very important mechanism. Molecular diffusion of chemicals affects oil recovery
rate in the early time, but not ultimate oil recovery.
23-3
9:30 AM
Alvarado, Vladimir
[173831]
SELECTION OF THREE PHASE RELATIVE PERMEABILITY MODEL FOR MIXED WET
RESERVOIRS
ALVARADO, Vladimir and BEHZADI, Seyed, U of Wyoming, Laramie, WY 82071,
[email protected]
The most widely used three‑phase relative permeability models are Stone1 and Stone2. However,
two more models have been developed for mixed‑wet reservoir (Blunt, 1999; Jerauld, 1997). The
mixed wet condition is the most frequently encountered wetting condition in reservoirs worldwide.
Blunt’s model is complex to employ in simulators in contrast with the relative ease of Jerauld’s
model. An advantage of Jerauld’sr model is that it incorporates effects of IFT between phases.
The ability to model mixed wettability and to incorporate IFT makes this an attractive option to
investigate recovery in mixed wet reservoirs. In this paper Stone1 and Jerauld’s models are compared. We illustrate the differences between these two models in three‑phase kro for the same
two‑phase relative permeability data. Then we show how these two formulations can be cast on
one another to be able to use them in commercial simulators. Recovery prediction differences as
well as the effect of gas miscibility on krow are shown here. Our results show that three‑phase
kro value, based on Jerauld’s model, can be up to 6 times lower than those predicted by using
Stone1and consequently recovery might be overestimated 6.7% at immiscible condition, while
at 70% miscibility, the underestimation becomes 0.6%, if Stone1 model is used. Gas miscibility diminishes krow , resulting in lower recovery. The recovery is overestimated by 4% at 70%
miscibility, if the effect of miscibility is only accounted for oil‑gas relative permeability. Here, we
show how Jerauld three‑phase relative permeability model can be recast as the Stone1 model.
We show the importance of using an adequate three‑phase model in addition to the effect of
hysteresis in mixed wet systems. This is particularly important for mixed wet reservoir when IFT
is subject to change.
23-4
10:30 AM
Nagineni, Venu Gopal Rao
[173832]
EVALUATION OF CO2 INJECTIVITY FROM WATERFLOOD VALUES
NAGINENI, Venu Gopal Rao1, HUGHES, Richard Gary1, and D’SOUZA, David2, (1) Louisiana
State, Baton Rouge, LA 70803, [email protected], (2) Baton Rouge, LA 70803
Description: Injectivity index values from fields which have undergone waterflood operations
are compared to injectivity index values from the same field while undergoing CO2 flood operations. A number of different methods for evaluating the indices are presented. Application: Aiding
in the design of CO2 floods by estimating the CO2 injectivity value from data from secondary
operations. Results, Observations and Conclusions: The correlations developed have been verified ‑ with good accuracy ‑ on injectors which were brought on later in the same field. It was also
observed that the rates calculated from this correlation were in closer agreement to actual injection rates, than those predicted by theoretical formulas. Significance of Subject Matter: Carbon
dioxide flooding is a very common tertiary recovery IOR method employed in fields which have
relatively easy access to CO2. In some cases, estimating the CO2 injection rate is often the most
important design parameter which decides the planning, field implementation and eventual success of a flood. This paper presents a method for evaluating this important parameter from data
that should be readily available for a field.
23-5
11:00 AM
Saini, Dayanand
[173833]
EXPERIMENTAL DETERMINATION OF MINIMUM MISCIBILITY PRESSURE BY GAS OIL IFT
MEASUREMENTS FOR A GAS INJECTION EOR PROJECT
SAINI, Dayanand and RAO, Dandina Nagaraja, Louisiana State, Baton Rouge, LA 70803,
[email protected]
Knowledge of minimum miscibility pressure (MMP) plays a key role in the success of any miscible
gas injection EOR project. Various theoretical methods but few experimental methods are available for confidently determining the MMP at reservoir conditions using actual reservoir fluids. The
present experimental study reports on the determination of minimum miscibility pressure (MMP)
for recombined live oil with CO2 at reservoir temperature using the vanishing interfacial tension
(VIT) technique. It relies on the measurements of gas‑oil interfacial tension at several pressures
and reservoir temperature. MMP is then obtained by extrapolation of the measured data to zero
interfacial tension. In the present study, interfacial tension (IFT) between two recombined live oil
samples and CO2 was measured at reservoir temperature of 289C_B0F and at several pressures
above the bubble point pressure of 2593 psia using the pendant drop method and the capillary
rise technique. The pressure was then increased in steps to approach a near zero gas‑oil IFT
condition. The MMP that corresponds to the pressure of zero IFT was obtained by extrapolating the measured values of gas‑oil IFT to zero on an IFT vs. Pressure plot. Such extrapolation
yielded MMPs of 3533 psia and 3543 psia for the two recombined live oil samples. This study was
conducted to aid in the implementation of a proposed miscible CO2 flood in a newly discovered
oil field in Mississippi by comparing the results of an independently conducted Equation of State
(EOS) modeling study based on vanishing tie‑line method. Measured VIT‑MMP was slightly lower
compared to the EOS‑estimated MMP (3685 psia). This experimental study reinforces the use of
VIT technique as robust experimental method for determining the MMP and to use this to validate
EOS models before using them in compositional simulation studies.
23-6
11:30 AM
Kalaei, M. Hosein
[173834]
NUMERICAL MODELING OF THE WATER IMBIBITION PROCESS IN WATER WET
LABORATORY CORES
KALAEI, M. Hosein1, GREEN, Don W.2, and WILLHITE, Paul1, (1) U of Kansas, Lawrence,
KS 66045, [email protected], (2) U of Kansas, Long Beach, KS 90802
Oil recovery from water‑wet, naturally fractured reservoirs subjected to waterflooding is governed
by spontaneous imbibition of water from the fractures into the matrix rock due to capillary and
gravity forces, which results in the displacement of the non‑wetting oil. Several parameters, such
as wettability, boundary conditions, rock geometry, fluid properties, and IFT between oil and
water affect the oil recovery. A three‑dimensional, two‑phase numerical simulator was developed
to investigate both mechanisms of oil production and the parameters that influence recovery
in water‑wet laboratory cores. The model was validated by a comparison of calculations to the
numerical simulation of Blair (1964) and experimental data presented by Schechter et al. (1991)
and Fischer & Morrow (2005). Agreement between model calculations and data was excellent.
When capillary forces are negligible, gravity force causes displacement of the oil spontaneously
due to density difference between the oil and water in cores mounted vertically. The effect of
reducing the interfacial tension between water and oil on oil recovery by spontaneous imbibition
was numerically investigated for a wide range of IFT’s in cores oriented vertically and compared
against experimental data. Capillary force is lowered when IFT is reduced through capillary
pressure curve. The study showed that reducing the IFT between oil and water may decrease
the rate of imbibition in low permeability cores. However, the ultimate recovery increases when
compared to the same system with higher IFT. Comparison of the imbibition curves obtained for
the same value of oil/water viscosity ratio revealed that oil recovery is lowest when the one‑end,
open‑boundary condition was applied on the core. Ultimate recovery was almost the same in all
other different boundary conditions.
SESSION NO. 24
24-4
Friday, 28 May 2010
T37. Advanced Reservoir Modeling Concepts
24-1
8:30 AM
Chen, Yan
[173810]
PARAMETERIZATION TECHNIQUES TO IMPROVE MASS CONSERVATION AND DATA
ASSIMILATION FOR ENSEMBLE KALMAN FILTER
CHEN, Yan, Chevron, Bakersfield, CA 90802, [email protected] and OLIVER, Dean,
U of Oklahoma, Norman, OK 90802
The ensemble Kalman filter (EnKF) has shown great potential for becoming a useful tool for
assisted or automatic history matching. In particular, it has been shown to be possible to efficiently integrate many types of data and to history match many types of model variables, including gridblock permeabilities and porosities, facies locations and relative permeability curves. At
each analysis step of EnKF, model and state variables are updated using a linear combination of
the forward models to honor the production history and prior knowledge of the reservoir description. The analysis step, however, could result in updates that are beyond their plausible range,
violation of mass conservation and loss of geological realism. Proper selection of the model and
state variables to be updated in EnKF is critically important to achieve good data match, retain
geological realism of the updated realizations and satisfy nonlinear constraints that may apply.
In this paper, we discuss parameterization techniques for these three purposes. We revisit the
updating formulation of EnKF and investigate the constraint on the weighting coefficients at the
analysis step. We show that by reparameterization of the state vector nonlinear constraints, for
example conservation of mass or volume, can be satisfied without complicating the updating
process. The presence of geological trends or channels induces strong non‑Gaussianity that
violates the Gaussian assumption of the EnKF analysis step, and appropriate parameterization is
necessary to constrain the EnKF solution. Finally, the choice of model variables also depends on
available observations. Including model variables that are highly sensitive to certain types of data
provides improved data match and more realistic updates. A large scale reservoir model is used
to illustrate the parameterization techniques. By using these techniques multiple realistic history
matched models were obtained that provide reliable basis for accessing uncertainty and design of
reservoir management strategy.
24-2
9:00 AM
Tabasinejad, Farshad
[173811]
DENSITY OF HIGH PRESSURE AND TEMPERATURE GAS RESERVOIRS: EFFECT OF NON
HYDROCARBON CONTAMINANTS ON DENSITY OF NATURAL GAS MIXTURES
TABASINEJAD, Farshad1, FRAASSEN, Kees Cornelius Van1, BARZIN, Yalda1, MEHTA,
Sudarshan A.1, MOORE, Robert Gordon1, RUSHING, Jay A.2, and NEWSHAM, Kent E.3,
(1) U of Calgary, Calgary, AB 90802, [email protected], (2) Anadarko Petroleum Corp,
Long Beach, CA 90802, (3) Apache Corp, Los Angeles, CA 90802
New experimental density data are generated in this study for light and heavy dry gas mixtures.
The light mixtures are consisted mostly of methane and small fractions of ethane, propane, and
nitrogen or carbon dioxide. Normal alkanes up to C6, iso‑butane and iso‑pentane together with
nitrogen or carbon dioxide form the heavier gas mixtures. For each mixture, isothermal gas density is measured from 3.45 MPa to 137 MPa at temperatures of 423.15 K and 473.15 K. Effect
of CO2 as a non‑hydrocarbon contaminant on density of gas mixtures is examined in steps of
5 mol%, 10 mol%, and 20 mol%. In addition, water vapor influence on gas phase density of
water‑saturated gas mixtures is also investigated. Different correlations for sweet and sour gas
critical properties are combined with the most widely used equations of state (Hall‑Yarborough,
Dranchuk et al., and Dranchuk‑Abou‑Kassem) to predict 450 measured density data. The most
important results demonstrated from this study are: Among all correlations, the combination of
Dranchuk‑Abou‑Kassem equation (improved by Londono et al.) with the critical properties correlated by Sutton generates the lowest average absolute deviation (AAD) between predicted and
experimental density data. The correction term developed by Wichert and Aziz to modify the critical properties due to the presence of non‑hydrocarbon compounds in the gas mixture, drastically
improves the prediction of density data. At very high pressure and temperature conditions, effect
of water vapor becomes more considerable on gas phase density and it should be considered
in density related correlations. The influence of water vapor on density of saturated gas mixtures
becomes more significant as CO2 concentration increases in the mixture.
24-3
9:30 AM
Rubin, Bary
[173812]
ACCURATE SIMULATION OF NON DARCY FLOW IN STIMULATED FRACTURED SHALE
RESERVOIRS
RUBIN, Bary, Modelling Group Inc, Calgary, AB 90802 Canada, [email protected]
Unconventional shale gas reservoirs require stimulation via hydraulic fracturing of pre‑existing
fracture networks for practical exploitation, creating a stimulated reservoir volume (SRV). Within
the SRV, complex gas flow from the Nano‑Darcy matrix to the complex stimulated fracture network
has been modeled in reservoir simulators using a variety of techniques which upscale/simplify the
fracture network. The simulation techniques used in the past were not compared with reference
solutions. This work creates finely‑gridded single well reference solutions (approximately 8 million cells) for simulating Darcy and non‑Darcy flow within an explicitly modeled complex fracture
network in a SRV, in 2‑D, with and without primary hydraulic fractures, as well as a scenario which
models later restimulation of a horizontal well. The fractures which make up these networks use
cells which are only 0.001 ft. wide. The reference solutions are compared with standard dual permeability and MINC (multiple interacting continua) dual continua models as well as novel models
which simulates flow inside of the SRV using coarse, logarithmically spaced, locally refined, dual
permeability grids, and simulates flow outside of the SRV using unrefined dual permeability grids.
These coarse models can be run in minutes on standard hardware where as the reference models
can take days to run on the same hardware. We will show that excellent matches to the reference
solutions are possible using a modest number of refinements to simulate the flow within the SRV
when the fracture permeability and the fracture Forchheimer number (for non Darcy flow) are
scaled as described in the paper. These techniques allow the use of 2.0 ft. wide fracture conduits
to mimic non‑Darcy flow in 0.001 ft. wide fractures. Good agreement between the reference and
coarse models are observed even during the early flow period of the reservoir.
72 2010 GSA Abstracts with Programs 10:30 AM
Ghods, Ghods
[173813]
ASSISTED HISTORY MATCHING OF A WATERFLOODED RESERVOIR USING EXTENDED
AND UNSCENTED KALMAN FILTERS
GHODS, Ghods1, JAHANGIRI, Hamid Reza1, and ZHANG, Dongxiao2, (1) U of Southern
California, Los Angeles, CA 90802, [email protected], (2) Department of Civil and
Environmental Eng, University of Southern California, 3620 S. Vermont Avenue, Los Angeles,
CA 90089
Petroleum industry has been widely using reservoir simulation to predict the fluid flow in subsurface reservoirs. The challenge to using these simulators is to obtain the input parameters for the
reservoir models e.g. porosity and permeability. Once the spatial variability of these parameters is
known, a system of nonlinear equations could be solved to predict the flow in the porous media.
The challenge in doing so is that these parameters are not known in the whole domain of the
reservoir. What is usually known is the production data such as the well bottom‑hole pressures,
production and injection rates. Inferring the parameters from the observations would require
solving an inverse problem. In this study, a five Spot waterflooding pattern in a two dimensional
reservoir has been investigated by applying the two Kalman filtering techniques to estimate the
essential parameters needed for the reservoir simulation. Kalman Filters are stochastic minimum
mean square error estimation tools that have been widely used in the control theory. The objective
of this paper is to prove the applicability, the shortcomings and the advantages of two of the most
famous Kalman filters for assisted history matching. Extended Kalman filter relies heavily on the
linearization of the complex system of partial differential equations. Unscented Kalman filter generates a set of probable reservoir models and uses the available observations and the covariance
matrices to improve their performance and predictability. The results obtained from these methods
have been compared to one other in the paper. It was observed that Unscented Kalman filter
outperforms extended Kalman Filter owing to the fact that the fluid flow calculations in reservoir is
highly non linear and linearization of such a problem can lead to erroneous results. Both methods
could become computationally expensive as the size of the model size gets larger.
24-5
11:00 AM
Khazaeni, Yasaman
[173815]
INTELLIGENT TIME SUCCESSIVE PRODUCTION MODELING
KHAZAENI, Yasaman and MOHAGHEGH, Shahab D., West Virginia U, Morgantown,
WV 90802, [email protected]
Production data analysis have been used extensively to predict performance of wells and field
recovery but mostly on a single well basis. This paper presents a new approach to production
data analysis using Artificial Intelligence (AI) techniques where production data history is used
to build a field‑wide performance prediction model. In this work AI techniques and data driven
modeling are utilized to predict future production of both synthetic and real field cases. Production
history is paired with geological information from the field to build datasets containing the
spatio‑temporal dependencies amongst different wells. These dependencies are addressed by
information from Closest Offset Wells (COWs) including the geological characteristics (Spatial)
and the dynamic production data (Temporal) of all COWs. Using the created dataset, a series
of single layer neural networks is trained by back propagation algorithm. These networks are
then fused together to form the ‘’Intelligent Time‑Successive Production Modeling ‘’ (ITSPM).
This technique only uses the well log information and the production history of existing wells to
predict performance for new wells and initial hydrocarbon in place by a ‘’volumetric‑geostatistical’’
method. A synthetic oil reservoir is modeled using a commercial simulator. Production and
well‑log data are extracted into an all‑inclusive dataset. Next, several neural networks are trained
and verified to predict different stages of the production. ITSPM method is utilized to estimate
the production profile for nine newest wells in the reservoir and is also applied to the data from a
real giant oil field in the Middle East including more than 200 wells with forty years of production
history. ITSPM’s production predictions of the four newest wells in this reservoir are compared to
reality. When a reservoir simulation model is not a feasible option, ITSPM is an ideal alternative
for real‑time predictive purposes.
24-6
11:30 AM
Gupta, Akhil
[173814]
A HIERARCHICAL ASSISTED HISTORY MATCHING APPROACH WITH GLOBAL AND LOCAL
PARAMETER UPDATES
GUPTA, Akhil, YIN, Jichao Yin, and PARK, Han Young, Texas A&M U, College Station,
TX 90802, [email protected]
Traditional manual history matching commonly follows a structured approach with a sequence of
adjustments from global to regional parameters followed by local changes in model properties.
In contrast, much of the automatic history matching methods utilize parameter sensitivities or
gradients to directly update the fine‑scale reservoir properties. We present a hierarchical assisted
history matching approach that combines elements of both manual and automatic history matching in a structured framework. First, a probabilistic approach is used to estimate uncertainty the
large‑scale static and dynamic parameters. This is followed by a sensitivity‑based deterministic
model calibration for local property changes. In the probabilistic global calibration, design of
experiments and response surface methodologies with evolutionary algorithms are used to calibrate global parameters, for example regional pore volumes, vertical communications, fault transmissibilities and aquifer strength. Key global parameters are first identified via sensitivity analysis
and followed by proxy model construction using experimental design and response surface
analysis. An improved genetic algorithm with heat‑bath sampling strategy is used to generate
updated ensemble of models conditioned to static pressures (MDT/RFT) and total liquid rates at
the wells. Next, each ensemble member is updated using water‑cut, GOR and flowing BHP via
sensitivity‑based local calibration. We utilize streamline‑derived analytic sensitivities to determine
the spatial distribution and magnitude of the local changes. The proposed approach was tested
by a 3D synthetic case and a field application. The synthetic example is the benchmark PUNQ‑S3
reservoir model consisting of 6 producing wells and a strong aquifer support. The field example is
an offshore turbidite reservoir with highly detailed production and pressure information. The static
model contains complex sand depositional distribution combined with fault structures, four pairs of
injector, deviated producing wells and more than 8 years of production history.
SESSION NO. 26
SESSION NO. 25
Friday, 28 May 2010
T37. Advanced Reservoir Modeling Concepts
(Alternate) (Society of Petroleum Engineers (SPE))
25-1
Dahaghi, Amirmasoud Kalantari
[173816]
NEW INSIGHT INTO INTEGRATED RESERVOIR MANAGEMENT USING TOP DOWN,
INTELLIGENT RESERVOIR MODELING TECHNIQUE: APPLICATION TO A GIANT AND
COMPLEX OIL FIELD IN THE MIDDLE EAST
DAHAGHI, Amirmasoud Kalantari and MOHAGHEGH, Shahab D., West Virginia U,
Morgantown, WV 90802, [email protected]
This paper demonstrates the validity of a recently developed reservoir modeling technique called
“Top‑Down, Intelligent Reservoir Modeling”. This new modeling technology integrates reservoir engineering analytical techniques with Artificial Intelligence & Data Mining to arrive at an
empirical, and spatiotemporally calibrated full field model. The model is used to predict reservoir
performance to recommend field development strategies. One of the distinctive features of this
technology is its data requirement for analysis. Although this method can incorporate almost any
type and amount of data that is available in the modeling process, it only requires monthly production rate and some well‑log data (porosity, water saturation and thickness) to start the analysis
and provide a full field model. Presence and incorporation of other types of data such as core
analysis, pressure data, reservoir characteristics, and seismic data can increase the accuracy
and validity of the developed model. In this work we apply Top‑Down Modeling to a large and
complex Oilfield in the Middle East. Production rates and well log data from 210 wells have been
analyzed and used to develop a new empirical reservoir model and make predictions on new well
performance and potential infill locations. Results from Top‑Down Modeling analyses are compared with results concluded from a comprehensive reservoir management study (that included
use of large amount and various types of data and commercial reservoir simulator) performed by
an IOC. Analytical reservoir engineering techniques used in the Top‑Down Modeling presented
in this study include production decline analysis, volumetric reserve and recovery factor estimations and are integrated with Voronoi graph theory, geostatistics, two‑dimensional Fuzzy Pattern
Recognition and discrete, data driven predictive modeling. The resulting full field Top‑Down
Modeling is used to identify the distribution of the remaining reserves, sweet spots for infill locations and under‑performer wells.
Friday, 28 May 2010
T38. California Monterey Reservoirs
26-1
8:30 AM
Kovscek, Anthony Robert
[173823]
TEMPERATURE INDUCED FRACTURE RECONSOLIDATION OF DIATOMACEOUS ROCK
DURING FORCED WATER IMBIBITION
KOVSCEK, Anthony Robert and PENG, Jing, Stanford University, Stanford, CA 94305,
[email protected]
Diatomite reservoirs in California hold about 12 billion barrels oil in place. This resource is high
porosity, low permeability, and oil quality is variable. Steam injection is technically feasible to
unlock such oil. Our previous laboratory work demonstrated the tendency of fractures to reconsolidate or heal during thermal operations. We conducted a series of forced water imbibition
experiments to study the role of pH, temperature, and salinity on silica dissolution of outcrop
diatomite core. Then, several fractured cores were prepared to study the mechanism of fracture
reconsolidation. Fractures were oriented lateral to and normal to flow. Fractured cores were
subject to different brine formulations, temperatures, and confining pressures. Results suggest
that temperature and pH impact silica dissolution of diatomite, in agreement with the literature.
At elevated temperature, significant silica dissolution occurs under basic or acidic in‑situ conditions. Wormholes form during many pore volumes of injection of hot alkaline fluid if basic pH is
maintained within rock. As a result, permeability is enhanced and porosity increases. The presence of steam hinders silica dissolution because less aqueous phase is available to carry ions.
Fracture healing and rock reconsolidation were observed when fluid was injected at elevated
temperature. Tests suggest that both silica dissolution and confining stress are necessary for
fracture reconsolidation. Fractures that are not closed by the confining stress do not tend to heal.
The proposed mechanism for this process has three steps: (i) aqueous silicate production by
silica dissolution, (ii) silicate gelation within the pore space and fracture, and (iii) stress closure of
fractures to ensure that deposited silica cements the fracture closed. Given sufficient heating and
liquid injection, fracture reconsolidation happens. Under laboratory conditions, fracture healing is
possible. The resulting rock is relatively dense and strong. Results suggest conditions that might
be applicable to the field.
26-2
9:00 AM
Frankiewicz, Theodore C.
[173824]
RECONFIGURING A CALIFORNIA PLATFORM FOR OFFSHORE CRUDE DEHYDRATION
AND WATER DISPOSAL VIA INJECTION
FRANKIEWICZ, Theodore C., Spec Services Inc, Los Angeles, CA 82071, ershaghi@
usc.edu, VANNOSTRAND, Robert, Venoco Inc, Los Angeles, CA 82071, and MANNING,
Robert, Contract Engineer, Los Angeles, CA 90802
Venoco Inc. operates Platform Holly off the California coast near Goleta. Produced fluids from
Holly were historically transported to the Ellwood Onshore Facility for separation and processing.
To reduce operating costs and GHG emissions, Venoco undertook a program to reconfigure the
platform so that oil could be dehydrated offshore and produced water injected into wells directly
from the platform. The Holly platform is compact in design, so the challenge was to economically reconfigure the process and identify equipment for removal so an electrostatic treater
could be installed. In this paper, the reconfiguration of the platform is described, starting with
the production header. The service of several vessels was changed. The production separators
were upgraded to provide initial 3‑phase separation and allow wet oil to be dehydrated in the
new treater. Three test separators were removed, an acid surge drum was converted first to a
water skimmer and then converted to a test separator, and a surge vessel was converted to a
water skimmer. State‑of‑the‑art internals were utilized in all vessels to improve both performance
and capacity. Three PD water injection pumps were installed and three wells were converted
to water injection service. A laser‑scan was performed in order to generate a 3‑D model of the
existing platform and develop the design for the new piping. The 3‑D model provided guidance
for the actual installation of the new treater and identified spatial conflicts. The model facilitated
both demolition of old piping and the efficient installation of new piping with a minimum amount of
rework and shut‑down time.
26-3
9:30 AM
Boles, James
[173825]
PERMEABILITY ESTIMATES FOR THE SOUTH ELLWOOD FAULT
BOLES, James, Dept. of Geological Sciences, Univ of California, Santa Barbara, CA 93106,
[email protected], HORNER, Steve, Venoco Inc, Reservoir Engineering, Carpentaria,
93013, and GARVEN, Grant, Department of Geology, Tufts University, 2 North Hill Rd,
Medford, MA 02155
Fault‑zone permeability kf has been estimated by independent methods from two offshore wells
in close proximity to the South Ellwood fault at Platform Holly, Santa Barbara channel, California.
This fault runs parallel to the axis of the structure of the South Ellwood field, a Monterey
Formation with a mean permeability of about kf ~10 md (10‑14 m2) about1 km beneath the sea
bed. The pressure has been 70% of hydrostatic since 1984. Tidal frequency pressure variation
from well #13 indicates that sea water is moving down the fault and entering the reservoir near
well #13. From the pressure build‑up data and an estimate of the fault zone dimensions adjacent
to the well, we calculate kf = 19 md with respect to water for the fault. Our other permeability
estimate comes from well #7, completed about 5.2 km southeast of well #13. Overlying well #7 on
the sea bed are steel tents that monitor gas seeping from the damage zone of the South Ellwood
fault. When well #7 is shut down, seepage production increases at a constant rate of 45.3 m3
day/day to 31.2 m3 day/day (over shut down periods ranging from 21 days in 2003 to 45 days in
2005, respectively. Using these changes in flow rate and the pressure differences between the
seep tents and the perforation intervals in the well, we have calculated kf = 30 md with respect to
gas for the approximate one‑kilometer long fracture/fault flow path with an average cross section
of 1860 m2 from the Darcy equation. Our two independent fault‑zone permeability estimates are
similar and indicate that, at least locally, the damage zones of faults can have surprisingly high kf
values over kilometer length scales.
26-4
10:30 AM
[173826]
THE EFFECT OF TEMPERATURE AND OIL VISCOSITY REDUCTION ON WATER IMBIBITION
OF DIATOMITE
KOVSCEK, Anthony Robert1, VEGA, Bolivia1, and URDANETA, Alfredo H.2, (1) Stanford
University, Stanford, CA 94305, [email protected], (2) AERA, Bakersfield, CA 90802
Previous studies of diatomite reservoir core have revealed a systematic increase in spontaneous water imbibition with temperature leading to increased oil recovery. Forced water imbibition
resulted in a trend of possibly decreasing residual oil saturation with temperature. These tests,
however, were not conducted in a fashion that allows a simple quantification of the fraction of
recovery associated with wettability change and that associated with oil and water phase viscosity
reduction. This work delineates the relative impacts on core‑scale oil recovery due to oil viscosity
reduction as compared to wettability evolution during thermal recovery of light‑oil from diatomite.
Water imbibition tests were conducted with core samples from the exact same depth within a
diatomaceous reservoir. The experiments included spontaneous counter‑current water imbibition
followed by forced co‑current water imbibition to residual saturation. All tests were isothermal and
carried out at temperatures ranging from 45 to 230 oC. Non‑wetting phases were a light diatomite
crude oil and mineral oils viscosity‑matched to the crude oil for each test temperature. The wetting
phase was a synthetic formation brine. Core samples were subject to different pre‑test cleaning
procedures aimed to preserve or alter the initial wettability of the sample. Mixed wettability cores
were used with crude oil as the non‑wetting phase. The other core was water‑wet and used with
the corresponding matched viscosity mineral oil. Increasing temperature resulted in a trend of
increased oil recovery and lower residual oil saturation for both samples; whereas wettability shifts
with temperature were only found in mixed wettability systems, due to the expected effects of
temperature on wettability and fines detachment. Water‑wet systems displayed minimum changes
in wettability at all test temperatures; as verified by experimental measurements of the Amott
index in every test carried out.
26-5
11:00 AM
Urbancic, Theodore I.
[173827]
MONITORING OF MICROSEISMICITY IN DIATOMITES
URBANCIC, Theodore I.1, BLEAKLY, Douglas C.2, MURER, Anthony S.3, MCNEISH,
Greg R.3, and PRINCE, Marc1, (1) ESG, Los Angeles, CA 82071, [email protected],
(2) Engineering Seismology Group Canada Inc, Calgary, AB 82071, Canada, (3) AERA,
Bakersfield, CA 94305
Due to their high porosity (up to 60%) and other formation characteristics, the diatomites in
Southern California offer a great opportunity to investigate possible limitations to microseismic
monitoring. To investigate the potential for utilizing microseismic monitoring, a series of models
were constructed to determine both microseismic event detectability and locatability. That modeling indicated that event signals would most likely be heavily attenuated and therefore event
detectability would be limited to detecting only larger microseismic events, and that poor signal‑to‑noise ratios would constrain the ability to locate events using a single array (single phase
events). Subsequently it has been demonstrated in the field that the dynamic range of a monitoring system can be increased and the potential for locating events improved by installing multiple
arrays having overlapping radii of observation. Results show that both multi‑ and single‑phase
events have been not only detected and located by these multiple arrays, but the observed detection limits and size distribution has far exceeded those originally predicted by the earlier formation modeling. Innovative system design, deployment techniques and operational procedures,
plus advanced multi‑well processing strategies have all contributed to creating a growing data
set that is providing unique insights into treatment and production operations and expanding on
the causal relationship between shear wave dominated microseimic events, fracture growth and
process zone fracturing complexity observed by Vinegar et. al. (1992).
SESSION NO. 26
26-6
11:30 AM
Urbancic, Theodore I.
[173828]
CHARACTERIZING FRACTURE DEVELOPMENT IN DIATOMITES WITH SEISMIC MOMENT
TENSOR INVERSION ANALYSIS
URBANCIC, Theodore I.1, BAIG, Adam2, MURER, Anthony S.3, and MCNEISH, Greg R.3,
(1) ESG, Los Angeles, CA 82071, [email protected], (2) AERA, Bakersfield, CA 93306,
(3) AERA, Bakersfield, CA 94305
Multi‑array microseismic monitoring of a hydraulic stimulation in the diatomites by Vinegar et. al.
(1992) identified near vertical upward and downward hydraulic fracture growth, approximately
N26o E, and a wide process zone related to extensive multi‑fracturing (Mahrer, 1991) surrounding the main fracture. Similar, to the work of Vinegar et. al., data recently recorded on optimally
placed mutli‑level multi‑well downhole triaxial geophone arrays offered an opportunity to examine
the failure mechanisms, both spatially and temporally, associated with a steaming program in the
diatomites. To potentially characterize fracture growth and failure complexity, Seismic Moment
Tensor Inversion (SMTI) analysis and source mechanism k‑T type plots were carried out for
events with good focal sphere coverage. The k‑T type plots provided a measure of the relative
fracture complexity, versus simple fault‑slip type failures, and the components of failure, i.e., crack
opening or closure (with directionality), and shearing (double couple). Additionally, the temporal
and spatial positioning of fracture complexity relative to the start and position of the injection, is
used to examine initiation/reactivation of fractures, breakout into formation, progression of fracture
from the treatment well, and fracture infill behind the fracture front. Based on these studies, further consideration is given to developing a model of fracture development in the diatomites.
Friday, 28 May 2010
27-1
BTH 1
Sanquini, Anne
[172444]
A PETROGRAPHIC LINK BETWEEN THE LATE CRETACEOUS PIGEON POINT
CONGLOMERATE AND FELSITIC VOLCANIC ROCKS NEAR PESCADERO, CALIFORNIA
SANQUINI, Anne1, METZGER, Ellen P.1, and MCLAUGHLIN, Robert J.2, (1) San Jose
State University, Department of Geology, San Jose, CA 95192-0102, [email protected],
(2) U. S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025
The Late Cretaceous (Campanian) Pigeon Point Formation is located west of the San Gregorio
fault and crops out for about 16 km along the California coast between San Francisco and Santa
Cruz. The formation locally overlies 86-90 Ma felsitic volcanic rocks (Ernst and others, 2009).
An on-going provenance study of igneous clasts in the Pigeon Point Formation reveals that ~5
percent of them appear to be a match with the underlying Pescadero felsite. These conglomerate clasts exhibit similar texture and composition, and significantly they contain prehnite and
pumpellyite, as does the Pescadero felsite, indicative of low temperature burial metamorphism.
This metamorphic assemblage is otherwise absent in clasts of the Pigeon Point Formation and
associated sedimentary section, suggesting the Pescadero felsite is the source of the felsitic
conglomerate clasts and significant uplift and erosion of the felsite prior to, or during deposition of
the Pigeon Point Formation. Discovery of Pescadero felsite clasts in the Pigeon Point Formation
corroborates the depositional relation between the Pigeon Point Formation and the felsite inferred
by Ernst and others and partly clarifies the context of the Pigeon Point Formation in the tectonic
history of western California.
27-2
BTH 2
Keogh, Molly
[172737]
STRATIGRAPHIC ANALYSIS OF LATE MIOCENE TO EARLY PLIOCENE (?) SEDIMENTARY
ROCKS, SW ISLA TIBURóN, SONORA, MEXICO
KEOGH, Molly, Department of Geological Sciences, University of Oregon, Eugene, OR
97405, [email protected] and DORSEY, Rebecca, Department of Geological Sciences,
University of Oregon, 1272 University of Oregon, Eugene, OR 97403
Late Miocene to early Pliocene (?) sedimentary rocks exposed on southwest Isla Tiburón, Mexico,
provide a record of basin evolution during initiation of focused plate-boundary strain in the northern
Gulf of California. These rocks include the earliest marine deposits that accumulated during incursion of seawater into the northern Gulf. Structures active at this time, including the La Cruz fault,
were likely involved in opening of the northern Gulf, so analysis of the sedimentology and basin
architecture provides insight into structural controls on deposition of these earliest marine rocks.
The stratigraphy of SW Isla Tiburón can be divided into two unconformity-bounded sequences
that record two stages of basin formation and deformation. The lower sequence includes landslide
breccia that overlies a tuff dated at 6.7 +/- 0.8 Ma (Oskin, 2002), a subaqueous (likely submarine)
olistostrome, debris flow deposits, and fossiliferous sandstone and conglomerate. It is cut by a
series of basin-bounding oblique normal faults and capped by a distinctive tuff named the “upper
tuff” (as-yet undated). The upper sequence consists of marine Gilbert-delta bottomset turbidites,
foreset conglomerate and sandstone that dip 15-30°, and non-marine topset deposits. The upper
sequence records the growth of a broad monocline during progradation of the Gilbert-delta system
to the northwest along the La Cruz fault. The mean transport direction based on orientation of
imbricated conglomerate clasts is toward 342.6 +/- 5.4°, ~17° clockwise from the transport direction determined from average down-dip direction of untilted foreset deposits. This discrepancy may
be due to clockwise rotation of deposits close to the La Cruz fault in response to dextral slip on
the fault. Stratigraphic analysis shows that the marine section on SW Isla Tiburón is ~285 m thick,
much thinner than previously thought. Combined with existing age data, this study confirms that
marine incursion into the northern Gulf of California slightly post-dates 6.7 +/- 0.8 Ma. The association of fault-controlled basin formation with earliest marine deposition shortly after 6.7 Ma supports
a hypothesis that latest Miocene marine incursion into the northern Gulf of California resulted from
localization of regional transtension along the La Cruz and similar strike-slip faults.
27-3
BTH 3
Rivera, Alexei A.
[173013]
ESTIMATION OF TRUE TAXONOMIC LONGEVITIES FROM OBSERVED FOSSIL RANGES: A
COMPARISON OF TWO METHODS
RIVERA, Alexei A., Department of Paleobiology, Smithsonian Institution, Washington, DC
Many problems in evolutionary paleobiology require adequate knowledge of the times of origination and extinction of taxa. Because of the incomplete and biased nature of the fossil record,
however, observed temporal ranges may underestimate true taxonomic durations or longevities.
74 2010 GSA Abstracts with Programs Several methods estimate the extent of truncation of lower and upper range boundaries, and
thus provide a measure of the completeness of the fossil record. The classical approach uses the
number of fossil horizons and the length of the observed range to establish confidence intervals
on the range endpoints. Its central assumptions are 1) a random distribution of fossil horizons
and 2) continuous and uniform sampling of the stratigraphic range, which may preclude analysis
of discretely sampled deep-sea drilling cores (e.g., a wide variety of micropaleontological data).
A new method incorporates estimates of extinction and preservation rate in a branching model
of cladogenesis. This approach has the advantage of requiring only first and last appearance
data (making it applicable to commonly used compendia of fossil ranges), and the frequency of
singleton taxa. Unlike classical confidence intervals, it also requires an explicit estimate of the
number of subtaxa existing during a taxon’s first appearance datum, as well as a formal model of
taxonomic diversification. Sufficient sample size is critical; available data may allow the method to
estimate the time of origin of Aves but not Archaeopteryx, for example. This method is thus perhaps best suited for estimating the true longevities of higher taxa. Both methods are vulnerable to
variable sedimentological regimes; if the disappearance of a taxon merely reflects the closing of a
taphonomic window, neither technique can properly estimate its true time of extinction. I compare
these two methods using case studies from the fossil records of trilobites, scleractinian corals,
inoceramid bivalve mollusks, and titanotheres.
27-4
BTH 4
Rivera, Alexei A.
[173014]
COPE’S RULE AND PHYLOGENETIC TRENDS IN THE NAUTILOIDEA
RIVERA, Alexei A., Department of Paleobiology, Smithsonian Institution, Washington, DC
One of the most commonly reported patterns in the history of life is the tendency of body size
to increase over geologic time. Known as Cope’s Rule, this pattern is traditionally depicted as
anagenetic change within a single lineage towards large body size – the classic ladder-like progression from Hyracotherium to Equus among horses in the Cenozoic Era, for example. More
recent arguments propose that many examples of Cope’s Rule may be better viewed as evolution
from ancestral small body size, the lower limit of which is bounded by constraints in morphospace.
These so-called ‘passive’ trends have found support across a wide variety of clades ranging from
planktonic foraminifera to rodents. The present work explores long-term phylogenetic trends in the
evolution of body size in coiled nautiloids of the order Nautilida, a long-lived stock of shelled mollusks which originated in the Devonian Period and represent almost all Mesozoic and Cenozoic
nautiloids. Analysis of the fossil record indicates that the Nautilida evolved relatively large body
sizes (measured here as shell diameter and simple geometric and allometric estimates of shell
volume) early in their history and away from boundary conditions at the lower size limit. An expansion of total size range or variance occurred during the great Carboniferous radiation of superfamilies Tainocerataceae, Trigonocerataceae, Aipocerataceae, and Clydonautilaceae. Nautiloids were
nearly extinguished by the terminal Triassic mass extinction; the lack of a vigorous post-extinction
radiation of survivors coincided with a substantial contraction in variance during the Jurassic
Period. Both minimum and maximum body size increased during the subsequent Cretaceous
and Tertiary/Quaternary periods, which might suggest the presence of an ‘active’ trend – indeed,
Cope’s Rule in the strict sense. Although more intensive sampling is required to confirm these
patterns, it appears that no single overarching trend dominated the history of the Nautilida.
27-5
BTH 5
McGuire, Terry
[173132]
THE PLIO-PLEISTOCENE MERCED FORMATION IN NORTHERN CALIFORNIA: A WORLDCLASS EXAMPLE OF INTEGRATED SEA LEVEL AND TECTONIC CONTROLS
MCGUIRE, Terry, Consulting Services, Schlumberger, Houston, USA, 1325 S. Dairy Ashford
Rd, Houston, TX 77077, [email protected] and GROVE, Karen, Department of
Geosciences, San Francisco State Univ, 1600 Holloway Ave, San Francisco, CA 94132
The Plio-Pleistocene Merced Formation was deposited in a tectonically dynamic basin and
is presently uplifted and exposed in the coastal bluffs between San Francisco and Daly City,
California. The unit comprises over 1700 m of marginal marine sediments packaged into over 40
unconformity-bounded, generally progradational sequences. In marginal marine basins, accommodation space is controlled by eustatic sea-level change, vertical motion of the basin floor and
sedimentation rate. To investigate the control of eustasy, sedimentation rate and localized tectonic
subsidence on sequence formation, we examined the coastal stratigraphy and compared it with
available age data for the formation and attempted to match sequence boundaries to the ages
of Quaternary sea level high stands indicated by the most recent oxygen isotope curve (OIS)
curve. Using a 400 ka and 500 ka age for an ash marker bed in the formation, we created two
time-deposition models in which we attempted to fit transgressional sequences to Quaternary
sea-level highstands. In the upper part of the Merced, where mineralogical data indicate an
increased sedimentation rate, the transgressional sequence boundaries match well with sea level
high stands in both models. However, in the lower parts of the section, there are more sequence
boundaries than high stands in both models indicating that sequence formation may have been
tectonically driven. During deposition of the lower part of the formation, the Merced basin was
likely more sensitive to minor sea-level fluctuations because of tectonically driven subsidence,
whereas transgressional sequence boundaries in the upper section, during the time of increased
sedimentation appear to have been driven by eustatic changes. Throughout this time period,
subsidence within the basin was also beginning to slow and, during deposition of the uppermost
sequences, contraction was beginning to change the basin into the uplifted block that is currently
exposed to erosion along the sea cliffs.
27-6
BTH 6
Jackson, C.M.
[173193]
ORIGIN AND AGE OF PLEISTOCENE SHELLY MARINE DEPOSITS, TRINIDAD HEADLANDS,
HUMBOLDT COUNTY, NORTHWESTERN CALIFORNIA, USA
JACKSON, C.M., LADINSKY, T.C., GRAEHL, N.A., CALDWELL, D.J., MIELKE, J.L., YORK,
J.V., and JACKSON, A.M., Department of Geology, Humboldt State University, 1 Harpst St,
Arcata, CA 95521, [email protected]
The Trinidad Headlands reveal exposures of the late Mesozoic Franciscan Complex, overlain by
15-20 m of lower-to-middle Pleistocene shelly marine sand and gravel, in turn, capped by a 1-2 m
thick unit of upper Pleistocene terrace sand. Fossils from the Pleistocene units were previously
described by G. L. Kennedy in 1978 and B. Roth in 1979. A reexamination of the stratigraphic
sequences exposed at Moonstone Beach and Megwil Point, and compilation of new fossil assemblage data allow for a new interpretation of the origins and ages for the fossiliferous assemblages.
Historically, the marine deposits have been interpreted as nearshore, but our observations suggest they accumulated farther offshore, below fair-weather wave base, in channels or bars that
were active during storms. These channels and bars are associated with sea stacks and bedrock
topographic irregularities. The fossils consist of mixed assemblages of bivalves, gastropods, barnacles, sand dollars, and bryozoans from epilithic, sandy-bottom, and coelobitic sources. The high
proportion of epilithic invertebrates combined with the overall large body size of the fossils and the
geometry of the shelly beds supports our farther offshore, higher energy interpretation of depositional environment. G. L. Kennedy and K. R. Lajoie, in 1982, reported amino acid racemization
SESSION NO. 28
age estimates for the Megwil Point and Moonstone Beach units that suggested possible correlation with oxygen isotope Stages 11 and 21, respectively. New age estimates using fossil ranges
and new U-series analyses of Balanophyllia elegans for both areas indicate slightly elevated initial
U-isotope ratios, but otherwise closed-system histories. Probable ages are ~ 560 ka, suggesting
that deposits at both localities may correlate with isotope Stages 13 or 15. Further investigations
into the ages of these deposits are being pursued.
27-7
BTH 7
Abeid, John A.
[173274]
LATE CRETACEOUS-EOCENE LANDSCAPE EVOLUTION AND DRAINAGE
REORGANIZATION ALONG THE SOUTHWEST EDGE OF THE CORDILLERA; INSIGHT FROM
VOLCANIC CLASTS IN CONGLOMERATES OF THE CABRILLO FORMATION AND POWAYLA JOLLA GROUPS, SAN DIEGO COUNTY, CALIFORNIA
ABEID, John A., KIMBROUGH, David L., and ABBOTT, Patrick L., Department of Geological
Sciences, San Diego State University, San Diego, CA 92182, [email protected]
The Late Cretaceous Cabrillo Formation records a major pulse of forearc sedimentation derived
from rapid unroofing of the adjacent Peninsular Ranges batholith (PRB) and contains an abundance of silicic volcanic clasts. Unconformably overlying fluvial-deltaic strata of late Paleocene
to latest-middle Eocene age also contain abundant conglomerate with silicic volcanic clasts,
but include the distinctive “Poway-type” clasts that have been recognized by southern California
geologists for over a century and have been matched to Jurassic bedrock sequences in Sonora,
Mexico. Despite distinctions based on hand specimens, the Cretaceous and Eocene volcanic
clasts (n = 53) are all similar in terms of whole rock major and trace element geochemistry determined by XRF. All but 5 of the analyzed rocks are high SiO2 (69-76%), low Sr (~160 ppm), high
Ba (~1100 ppm), high-K calc-alkaline (HKCA) rhyolites ; there is no clear basis for distinguishing
the two groups of rocks on the basis of available whole rock geochemistry. However, zircon U-Pb
ages for the Cretaceous vs. Eocene clast suites are clearly distinct. Ten Cabrillo Formation rhyolites, which include several welded tuffs, yield zircon ages that cluster tightly from ~97 to 104 Ma.
Of the 14 dated Eocene clasts, 12 samples range narrowly from ~166 to 175 Ma overlapping
Sonoran bedrock rhyolite ages of 168.8 ± 1.1 & 168.0 ± 2.6 Ma; the remaining two Eocene clasts
yielded ages of ~142 and 150 Ma. The Cabrillo rhyolites may represent supracrustal volcanic
cover of the eastern PRB (90-100 Ma) which have been completed eroded away, although HKCA
chemical affinities and low Sr characteristic of the clasts is not a good match for the eastern PRB.
The Eocene clasts are clearly extraregional and can be matched Sonoran bedrock as proposed
by previous workers.
27-8
BTH 8
Carmichael, Chelsea N.
[173623]
LACUSTRINE MICROBIALITES FROM AN ACTIVE COLD WATER SPRING MOUND: BRISCO,
BRITISH COLUMBIA, CANADA
CARMICHAEL, Chelsea N. and LEGGITT, V. Leroy, Earth and Biological Sciences,
Loma Linda University, Loma Linda, CA 92350, [email protected]
Two small lakes (fed by subaqueous spring vents) are perched on a large cold water spring
mound located near the town of Brisco, British Columbia. The core of the spring mound is primarily composed of relic bryophyte tufa that is 7 m thick near the spring vents and gradually thins as
it extends southeast about 600 m. Both lakes are slightly alkaline (pH 7.3 and 7.6), have similar
summer temperatures (11.5 and 12.5°C), similar conductivities (summer: 897 and 893 µS/cm)
and similar major ion concentrations. The water in both lakes is supersaturated with respect
to calcite. These similarities suggest a common source for the water that discharges into the
two lakes.
Although the water chemistry of the two lakes is similar, only one of the lakes contains large
lacustrine microbialites (bioherms up to 4 m in diameter and 0.4 m thick). The microbialites are
found as isolated bioherms on the floor of the lake or as thick encrustations of submerged logs
and branches. The microbialites can be characterized as having a calcified, laminated, lobate
crust (about 1 cm thick) that overlies large (1-10 cm diameter), irregularly shaped, internal
cavities. At the base of the mounds, the lamination is obliterated by bioturbation (by bryophyte
rhizoids and other organisms) and by diagenetic processes. Charophytes, bryophytes, diatoms,
cyanobacteria, ostracods, mollusks, testate amoeba and caddisfly larvae are found in and around
the microbialites.
One major difference between the two lakes is that the upper lake is steep-sided and deep
(9.8 m) and the lower lake (containing the microbialite bioherms) has a large, flat-bottomed,
shallow (1.5 m deep) littoral zone. Since many factors that might favor carbonate precipitation are
similar in the two lakes (such as water chemistry and outgassing), microbialite formation in the
lower lake seems to be differentially favored by calcite precipitation mechanisms associated with
improved photosynthesis in the shallow lake.
27-9
BTH 9
Kohel, Chris
[173666]
FOREARC BASIN EVOLUTION OF THE LATE JURASSIC-EARLY CRETACEOUS EUGENIA
FORMATION; NEW MAPPING IN THE VIZCAINO PENINSULA, BAJA CALIFORNIA SUR
KOHEL, Chris and KIMBROUGH, David L., Department of Geological Sciences, San Diego
State University, San Diego, CA 92182, [email protected]
The Tithonian-Valanginian Eugenia Formation represents an enigmatic part of Vizcaino forearc
stratigraphy. Previous workers have interpreted the Eugenia Formation as proximal deposits of
the Sierra San Andres volcanic arc complex on the Vizcaino Peninsula. This interpretation fails
to explain the presence of alkaline pillow lava interbedded in the Eugenia Formation indicating syndepositional rifting of the basin. Further, previously undocumented continentally derived
quartzite clasts in conglomerate beds, which in the Eugenia range up to boulder size, have no
obvious source on the Vizcaino Peninsula. U/Pb data from conglomerate igneous clasts show
contamination of continentally derived zircons. The presence of these continentally derived materials conflicts with models that interpret the Vizcaino as part of an island arc terrane accreted to
the North American margin in the Early Cretaceous. New mapping within the Eugenia block has
refined basic structural and stratigraphic details. The basic structure is a highly faulted anticlinorium cored by Eugenia strata, flanked unconformably by the overlying Aptian-Albian Peforada
Fm, and is cut by dense arrays of normal faults that extend into upper Valle Group strata. Coarsegrained Eugenia facies contain outsized volcanic blocks ranging up to 10m; new U-Pb dating and
field relations suggest an ~200 x 150m volcanic block, mapped by earlier workers as an intrusive
stock, is actually a volcanic olistolith block. Igneous clasts exhibit similar chemical trends with
no sample segregation with respect to time progression of deposition. Additionally, U/Pb data of
igneous clasts from the Eugenia and Valle formations have mean ages of 149.4 and 131.5Ma
respectively. This suggests that the igneous clasts feeding this basin, from Eugenia through Valle
time, were of a common source and were fed by this source for a period no less than 20Ma.
Conglomerate clast counts show a progressive shift in the dominate conglomerate clast type from
volcanic during Eugenia deposition to volcanic/plutonic during Valle deposition, perhaps reflecting
erosional unroofing of the source arc. Finally, U-Pb ages of 156.4 ± 2.6 and 153.2 ± 3.8 Ma for
Eugenia tuff horizons extend the age of the formation into the Kimmeridgian, and provide a maximum age constraint for conglomerate deposition.
27-10
BTH 10
Lackey, Hilary Sanders
[173713]
DEPOSITION, DIAGENESIS, AND CEMENTATION HISTORY OF PLEISTOCENE
VOLCANICLASTIC SEDIMENTS IN LONG VALLEY CALDERA, CA
BEELER, Katherine R., Geology Department, Pomona College, 185 E. Sixth Street,
Claremont, CA 91711, [email protected], LACKEY, Hilary Sanders, Geological
Sciences, California State University, San Bernardino, BI - 113A, 5500 University Parkway,
San Bernardino, CA 92407-2393, [email protected], and LACKEY, Jade Star,
Geology Department, Pomona College, 185 E. 6th St, Claremont, CA 91711
Understanding how volcaniclastic sediments are deposited, cemented, and altered in an active
caldera is critical for interpreting the evolution of hydrothermal systems. An extensive package of
such sediments was first described from Long Valley Caldera by Bailey et al. (1976), who documented a >350 m thick package of lacustrine diatomite, shale, sandstone and conglomerate that
filled Long Valley Lake following the ca. 0.76 Ma eruption of the Bishop tuff, through later periods
of resurgent dome uplift, until the lake drained completely by 100 Ka. Two major pulses of hotsprings discharge, at approximately 300 Ka and 40 Ka, took place along the caldera’s resurgent
dome (Sorey et al., 1991). In this study, we examine the petrography and sedimentology of the
lacustrine deposits, with particular focus on the role of hydrothermal activity in genesis and alteration of the abundant, opaline silica cements.
Preliminary oxygen isotopic analyses of siliceous cements in the sandstones suggest cementation at temperatures of <100°C, assuming equilibrium with water that was isotopically similar to
modern geothermal waters. Petrographic analyses confirm that the primary sediment source is
the resurgent dome, from which clasts of volcanic glass and pumice were derived. Plutonically
derived microcline K-feldspar is absent proximally, and increases in abundance distally. Sediment
sorting increases away from the dome, toward the east moat of the caldera. Porosity, ranging from
<1% to 25%, is highly variable among and within localities, even at cm scale.
Despite the heterogeneous porosity, sandstones consistently show isopachous cement, 10-20
µm thick, rimming the grains. Meniscus and void-filling cements occur along with the isopachous
cements and, in some samples, there is evidence of complete porosity occlusion after the initial
cementation event. X-ray diffraction reveals the presence of opal-A, opal-A/CT, and chalcedony,
suggesting variable digenetic maturation of opaline cements. These observations support a scenario of initial, pervasive cementation followed by pulses of localized cementation infilling relict
porosity as the epithermal fluid flow system in Long Valley Caldera evolved.
Friday, 28 May 2010
T3. Terrestrial and Marine Records of Late Quaternary
Climate from Western North America/Eastern Pacific:
Developments, Comparisons, and Directions (Posters)
28-1
BTH 11
King, Baird L.
[173632]
THE POST-LAST GLACIAL MAXIMUM GLACIER RECORD OF THE TAMARACK BENCH
OF THE EASTERN ROCK CREEK DRAINAGE, EASTERN SIERRA NEVADA MOUNTAINS,
CALIFORNIA
KING, Baird L., Department of Earth Science, University of California, Riverside, Geology
Building, 900 University Ave, Riverside, CA 92521, [email protected], KENNEDY, Martin,
Department of Earth Sciences, University of California, Riverside, Riverside, CA 92521, and
KIRBY, Matthew E., Geological Sciences, California State University, Fullerton, 800 N. State
College Blvd, Fullerton, CA 92834
The eastern Sierra Nevada Mountains present one of the longest and best preserved paleoglacial
records available; however due to the discontinuity of the moraine record and the shortage of
reliable absolute dating techniques for paleoglacial research, the late-Pleistocene and Holocene
glacial history remains poorly constrained. The Tamarack Bench of the eastern Rock Creek
drainage is characterized by a series of moraines and post-glacial lakes that lie between the well
developed Tioga (14-32ka) and Matthes (600-100ya) moraines. Four separate Tamarack Bench
advances were mapped. Based on stratigraphic and cross-cutting relationships combined with
relative dating criteria, the three older moraines are determined to correlate with deposits in the
main Rock Creek canyon. The fourth and youngest moraine postdates the series preserved in
Rock Creek. Lake sediment cores were extracted from four moraine dammed, post-glacial lakes
to obtain radiometric carbon age dates. Well the cores were primarily organic rich mud, three
isolated white sandy layers are interpreted to represent glacial advances in the upper water shed,
postdating the lake forming moraine. Bounding radiocarbon ages on discrete organic detritus
were obtained for the sand layers suggesting neoglacial advances occurred between 1750-1510
cal yr BP, 960-840 cal yr BP, and 770-580 cal yr BP. This evidence provides further insight into the
relationship between the regional Sierra Nevada climate record and global climate trends.
28-2
BTH 12
Player, Gary F.
[170596]
INDICATORS OF EARLY PLEISTOCENE GLACIATION IN SOUTHWESTERN UTAH AND
ADJACENT STATES
PLAYER, Gary F., 1671 W 546 S, Cedar City, UT 84720, [email protected] and
MCDONALD, Blair, Civil Engineering, University of Texas Pan American, 1201 W University
Drive, Edinburg, TX 78539-2999
Landforms and sedimentary textures of surficial deposits on and adjacent to the Markagunt
Plateau near Cedar City, Utah, indicate that the landscape was primarily formed by early
Pleistocene glaciation. Widespread glacial landforms include U shaped valleys; lateral, terminal,
and medial moraines; terraced and dissected ground moraines; polished and striated bedrock outcrops; cirques, hanging valleys, kettle lakes, outwash plains, and reversed dendritic topography.
Unconsolidated sediments include poorly sorted boulder tills, gap graded muddy gravels, erratic
boulders, and lake bed clays. Thick tills in lateral and terminal moraines were intruded and overlapped by basalts about 1.2 Ma BP, and some U shaped valleys were partially filled by younger
basalts about 0.5 to 0.8 Ma BP.
Similar features have now been mapped in Arizona, Nevada, and California, suggesting that
early Pleistocene glaciation occurred at elevations as low as 3,300 feet (1,000 meters) in much of
the southwestern United States.
SESSION NO. 28
28-3
BTH 13
Davies, Nigel
[173215]
LATE HOLOCENE FLUCTUATIONS OF THE MAMMOTH GLACIER, WIND RIVER RANGE,
WYOMING
DAVIES, Nigel and CLARK, Douglas H., Geology, Western Washington Univ, 516 High
Street, Bellingham, WA 98225, [email protected]
Multiple sediment cores from Pleistocene moraine dammed lakes (Upper and Lower Green River
Lakes) in the Wind River Range, Wyoming, preserve a detailed record of late Holocene glaciation. The primary source of glacier outwash to the lakes is from Mammoth Glacier, the largest
(~1.9 km2) glacier on the western slope of the Wind River Range. As a result, these lakes trap the
majority of the rock flour produced by the glacier, preserving a proxy record of fluctuations in size
and activity of the glacier. Our cores include a long core (3.5 m) from Upper Green River Lake
and numerous shorter, higher resolution cores from both lakes. The age model for the cores in the
upper lake is based on 6 AMS radiocarbon analyses. The youngest part of this age model will be
refined by 210Pb analyses that are in process.
Rock flour preserved in the deep cores from the upper lake (recorded in the visual stratigraphy
– VS, organic content – OC, and magnetic susceptibility – MS) began to increase shortly after
~1000 cal yr B.P., increasing rapidly after ~500 cal yr B.P. This increase is capped by a dramatic
surge in clastic sediment recorded in VS, OC, and MS and defines the maximum rock flour flux
to the lake. The age model indicates that this event occurred at ~280 cal yr B.P., shortly before
the maximum for the Little Ice Age (LIA) in the region (~165 cal yr BP: Schuster, 2000). Similar
sedimentation in the lower lake is muted but consistent with this sequence. Sediments predating
the last millennium in the upper lake maintain relatively high MS values and low OC values, with a
modest peak in MS centered at ~3900 cal yr BP.
The increase in rock flour after 1000 cal yr B.P. likely records the growth of the Mammoth
Glacier at the onset of the LIA in the range. The large surge in clastic sedimentation at 280 cal
yr B.P. appears to record an outburst flood from a small lake (Scott Lake) immediately below the
glacier. The coincidence of the outburst with the maximum rock flour flux suggests a causal link
between the flood and the LIA maximum of Mammoth Glacier. The relatively constant high MS
and low OC values in sediments deposited between ~4500-1000 cal yr B.P. suggests that the
Mammoth Glacier was active then but significantly smaller than the LIA maximum.
28-4
BTH 14
Magary, Katharine L.
[173228]
CONSTRAINTS ON ORIGINAL ELEVATIONS OF HIGH-LEVEL LAKE MANLY SHORELINES
DURING RECENT PLUVIAL CYCLES, DEATH VALLEY, CA
MAGARY, Katharine L. and CASKEY, S. John, Department of Geosciences, San Francisco
State University, 1600 Holloway Ave, San Francisco, CA 94132, [email protected]
We initiated a survey of Lake Manly shorelines in the Death Valley basin to better understand
lake-level histories of the most recent Lake Manly pluvial cycles. Our focus has been on high-level
shorelines in areas away from the Black Mountains fault zone (BMFZ) in central Death Valley
(CDV) where Oxygen Isotope Stage-6 (OIS-6) shoreline tufa (~186 ka) occurs at up to 90 m in the
uplifted footwall block. Field observations at a number of sites and limited radiocarbon ages indicate the two most recent Lake Manly cycles, presumably OIS-6 and OIS-2, produced high-stand
elevations of about 60 m and 46 m, respectively. For example: (1) At the Beatty Bar complex in
northern Death Valley (NDV), the highest beach ridge lies at 46 m. Algal tufa from this site yielded
14C ages of 30-27 ka. No higher shorelines have been identified in this area. (2) At Park Village
Ridge (NDV), shoreline gravels are found up to 60 m and are also well exposed at 35-37 m.
(3) West of Furnace Creek (NDV) at the base of the basalt hill north of Blackwater Fan (BF),
BF-derived beach pebbles can be traced up to 56 m. The most prominent shoreline is expressed
by thick, laminated tufa deposits at 47 m. The uppermost BF surfaces in this area are clearly
modified by Lake Manly, but these fan deposits do not appear to be high enough to provide the
source for the 56-m gravels. Hence, the 56-m gravels were likely reworked from older, now eroded
BF fan deposits during an earlier lake phase. (4) On the west side of CDV a prominent strandline
occurs at 60 m on Johnson Fan. At 36-46 m, tufa-cemented beach gravels are inset into a deep
channel that is in turn, incised into the fan surface exhibiting the 60 m strandline. Tufa from the
inset deposits yielded a 14C age of 27.7 ka. (5) On Warm Springs Fan (CDV), shorelines extend
as high as 60 m. (6) In southern Death Valley (SDV) shoreline gravels and young, fine-grained
lake sediments are extensively found at ≤46 m. In contrast, the only shoreline found at >46 m is
a single exposure of backset shoreline gravels at 60 m in the northern Noble Hills. The observation that the highest Lake Manly shorelines in NDV, CDV, and SDV all lie at ~60 m suggest that
shoreline elevations on the west side of CDV are little-affected by the BMFZ. Further, if 60 m
approximates the original OIS-6 high-stand elevation, then ≥30 m of absolute, post ~186 ka uplift
has occurred in the footwall of the BMFZ.
28-5
BTH 15
Garcia, Anna L.
[173611]
GEOCHRONOLOGY AND PALEOENVIRONMENT OF PLUVIAL HARPER LAKE, MOJAVE
DESERT, CALIFORNIA
GARCIA, Anna L., Geological Sciences, CSU Fullerton, Fullerton, CA 92834-6850, agarcia@
mojavewater.org, KNOTT, Jeffrey R., Department of Geological Sciences, California State
Univ, Fullerton, Box 6850, Fullerton, CA 92834, BRIGHT, Jordon, Department of Geology,
Northern Arizona University, Flagstaff, AZ 86011, and MAHAN, Shannon A., U.S. Geological
Survey, Box 25046 Federal Center, Denver, CO 80225
The Mojave River is a well-known recorder of Southern California paleoclimate with past terminations in the pluvial (upstream to downstream) Harper (Harper basin), Manix (Afton, Coyote and
Troy basins), Cronese (East and West basins) and Mojave (Soda and Silver basins) lakes over the
last 40 ka. Previous studies at Harper Lake yielded uncalibrated radiocarbon ages ranging from
>30-24 ka for the lake highstand. The present hypothesis is that the Mojave River: 1) flowed simultaneously into Harper and Manix lakes at ~30 ka; 2) the river then flowed exclusively into Lake
Manix from 28-25 ka; 3) then, resumed simultaneous flow into Harper and Manix lakes, forming
the Harper Lake highstand at ~25 ka; 4) after which the river bypassed Harper basin and the lake
receded. Being upstream and consisting of a single basin without internal sills, the paleohydrology
of Harper Lake is comparatively uncomplicated. Here we present geologic mapping, radiocarbon
and OSL ages from Harper basin. We describe a 2.1 m continuous stratigraphic section from near
the highstand elevation. The section rests non-conformably on quartz monzonite, and is comprised of interbedded lacustrine sands and silts capped by 0.6 m of carbonate mud. Anodonta
californiensis and ostracodes (Limnocythere, Candona, Cypridopsis, and Heterocypris) occur
primarily in the upper and lower portions of the section. Cross-bedded sand and rare, reworked
ostracodes characterize the middle portion of section. IRSL ages date depositional phases of the
Harper Lake highstand to between 45.6 ± 3.1 ka and 27.9 ± 1.7 ka, with calibrated radiocarbon
ages verifying this chronology from 40.2 ± 0.9 ka to 33.6 ± 0.3 ka. Dunes on Harper playa have
OSL ages of 0.8 ± 0.7 ka and 1.3 ± 0.7 ka, which indicate Harper playa has not experienced
significant flooding during historic times. The ages, facies sequence, sedimentary structures,
and ostracodes, combined with a lack of pedogenesis suggest a single transgressive-regressive
sequence at Harper Lake between ~45 ka and ~28 ka with no second highstand at 25 ka, as
previously hypothesized. The IRSL and radiocarbon data suggest that the Mojave River flowed
simultaneously into Harper and Manix lakes between ~45 ka and ~28 ka, similar to the Truckee
76 2010 GSA Abstracts with Programs River (Pyramid and Winnemuca Lakes) in the past and the present-day Mojave River (Soda and
Cronese basins).
28-6
BTH 16
Padilla, Manuel
[173120]
INITIAL RESULTS FROM ZACA DRY LAKE REVEAL EVIDENCE FOR HOLOCENE CLIMATE
CHANGE, SANTA BARBRA COUNTY, CALIFORNIA
PADILLA, Manuel1, KIRBY, Matthew E.2, HINER, Christine2, and KING, Baird3, (1) Geological
Sciences, California State University, Fullerton, 800 N State College Blvd, Fullerton, CA
92834, [email protected], (2) Geological Sciences, California State University,
Fullerton, 800 N. State College Blvd, Fullerton, CA 92834, (3) Earth Sciences, Global
Climate and Environmental Change, University of California, Riverside, 900 University Ave,
Riverside, CA 92521
A 4.64 meter sediment piston core was extracted from Zaca Dry Lake, a natural spill-over basin
down-drainage from perennial Zaca Lake, in July 2009. Zaca Dry Lake is a probable landslide
formed depression; it is located in the Monterey Shale unit in the San Rafael Mountains of Santa
Barbara County, California. Zaca Dry Lake is ideally located for paleoclimatic research for two
reasons: 1) it fills in a geographic gap in coastal California where very little is known about past
climate; and, 2) it is proximal to the Pacific Ocean therefore making it an excellent location for
comparing land-sea paleoclimate records and responses. In addition to physical description,
five basic analyses were used to interpret the lake’s history: mass magnetic susceptibility, total
organic matter, total carbonate, micro-fossil counts, and thin section petrography. Our initial
results indicate that Zaca Dry Lake is at least 7,500 calendar years old. Sedimentologically, there
is no evidence that Zaca Dry Lake was ever a deep perennial lake – for example, like its neighbor
Zaca Lake - but instead fluctuated between a wetland or a shallow lake over the past 7,500 years.
The occurrence of a strange carbonate layer 0.5 meters thick consisting of concentrically layered,
sub-mm scale carbonate nodules may be the evidence of a mid-Holocene “highstand”/perennial
shallow lake. An increase in the abundance of oogonia and gastropods above the carbonate
layer is inferred to represent a possible long-term drying or transition to a wetland before 2,500
calendar years. Sediments younger than 2,500 years are missing due to human activity in the
drainage basin.
28-7
BTH 17
Knott, Jeffrey R.
[173187]
PALEOMAGNETIC AND RADIOCARBON RECORD OF THE SEARLES LAKE FORMATION AT
POISON CANYON, SAN BERNARDINO, CA
KNOTT, Jeffrey R., Department of Geological Sciences, California State Univ, Fullerton,
Box 6850, Fullerton, CA 92834, [email protected], LIDDICOAT, Joseph, Department of
Environmental Science, Barnard College, 3009 Broadway, New York, NY 10027, and COE,
Robert S., Earth Science Dept, University of California, 1156 High St, Santa Cruz, CA
95064-1077
The Pleistocene-Holocene Searles Lake Formation records the last 150,000 years of pluvial
Searles Lake in Searles Valley, California. The type locality for the Searles Lake Formation is a
vertical section of 20 lithologic units in Poison Canyon. In spite of the extraordinary efforts by G.I.
Smith, only the minimum age (>29 ka; conventional radiocarbon) of the older subunits (A, ab1
and ab2) is reliable. In this study, we collected fossils for radiocarbon accelerator mass spectrometer (AMS) analysis and rock samples for paleomagnetic analysis to ascertain the age of the
older subunits. The AMS technique has a greater age range than conventional 14C and the older
subunits should span two paleomagnetic excursions: Mono Lake Excursion (28-32 ka; MLE) and
Laschamp Excursion (40.7 ka; LE) that should also allow correlation to similar deposits three kilometers west at the Tire Farm (informal name). At Poison Canyon, we obtained AMS radiocarbon
ages of 42,900±100 14C yrs B.P. (all ages uncalibrated radiocarbon years) for ab1, 31,830±170,
35,540±420 and 36,850±500 for ab3, 28,280±110 and 35,530±190 for ab5 and 31,410±160 for
b. The Tire Farm fossils yielded ages of 40,210±400 (top of A) and 28,180±180 and 29,150±200
(base of A). The overlying subunit ab3 yielded ages of 30,840±190 and 47,150±190. The radiocarbon ages are not consistently in stratigraphic order; however, these differences may be attributable to interferences from hard water and the effect of changing paleomagnetic field intensity on
radiocarbon production rate. Sediments thermally demagnetized to 600 C recorded reverse paleomagnetic polarity at both locations. The combined mean paleomagnetic directions are I=-37.5,
D=180.2, alpha-95=19.5 (n=12) with a mean Virtual Geomagnetic Pole of 73.6 S, 231.8 E, alpha95=20.6 (n=12). At Poison Canyon, the reverse polarity is in subunit ab2 whereas at the Tire Farm
the reverse polarity is in subunit A. The reverse polarity and underlying radiocarbon ages, ~42 ka
and 40 ka at Poison Canyon and Tire Farm, respectively, are consistent with the LE. The alternating mud and sand deposition of the A and ab subunits record fluctuating lake levels. Assuming the
correlation to the LE is correct, then the Poison Canyon and Tire Farm areas straddled the paleoshoreline between ~28 and ~40 ka.
28-8
BTH 18
Pyke, Brittany N.
[173223]
SEISMIC REFLECTION DATA FROM LAKE ELSINORE, SOUTHERN CA, DETAILS A NEW
CLIMATE DRIVEN RECORD FOR HOLOCENE LAKE LEVEL VARIATIONS
PYKE, Brittany N.1, KIRBY, Matthew E.1, SCHOLZ, Christopher2, and CATTANEO, Peter2,
(1) Geological Sciences, California State University, Fullerton, 800 N. State College Blvd,
Fullerton, CA 92834, [email protected], (2) Department of Earth Science, Syracuse
University, Syracuse, NY 13244-1070
Lake Elsinore, located 120 kilometers southeast of Los Angeles, California, is Southern
California’s largest natural lake. In December 2008, we collected over 75km of high-resolution
seismic reflection data using a CHIRP single-channel seismic-reflection Edgetech Geostar and
the Geopulse™ Boomer systems. Interpretations reveal several interesting seismic sequences
over the past 10,000 calendar years before present (cy BP: age control is based on dated sediment cores tied to the seismic lines). Three distinct sediment packages were identified from their
erosional boundaries. The lowest sequence (I) is subdivided into three subsequences (a,b,c)
and is composed of reflectors that are wavy, show little horizontally continuity and low frequency.
Overall, sequence I is interpreted to represent short-lived lake level regressions and transgressions. Only subsequence Ic, however, shows evidence for a sustained lake level regression in the
form of prominent truncated stratal terminations at the upper boundary. This interval is interpreted
as a lake level lowstand bracketed between ~ 3,000 and 1,800 cy BP. Sediment core data in the
form of mudcracks, decreased average grain size, and high delta-18O(calcite) data from a range
of depositional environments (i.e., littoral and profundal) within Lake Elsinore provide additional
support for Sequence Ic as a sustained lowstand. Regionally, there is evidence for a similar
interval of dry climate at Tulare Lake, the Mojave lakes, the Salton Sea, and possibly Dry Lake.
The middle sequence (II) has extremely continuous, parallel, low frequency reflectors and is
interpreted as a rise in base level and subsequent high lake level. The upper seismic sequence
(III) shows weak, horizontal reflectors, which onlap onto the upper boundary of sequence II and is
interpreted as a lake lowstand known in the historic record as the 1950’s lowstand.
SESSION NO. 28
28-9
BTH 19
Peterson, Carlye D.
[173073]
ORBITAL- TO SUB-ORBITAL-SCALE CYCLICITY IN SEISMIC REFLECTIONS AND SEDIMENT
CHARACTER IN EARLY TO MIDDLE PLEISTOCENE MUDSTONE, SANTA BARBARA, CA
PETERSON, Carlye D.1, BEHL, Richard J.1, NICHOLSON, Craig2, LISIECKI, Lorraine3, and
SORLIEN, Christopher C.4, (1) Geological Sciences, California State University, Long Beach,
CA 90840, [email protected], (2) Marine Science Institute, University of California,
Santa Barbara, CA 93106-6150, (3) Department of Earth Science, University of California
Santa Barbara, Santa Barbara, CA 93106, (4) Institute for Crustal Studies, University of
California Santa Barbara, Santa Barbara, CA 93106
High-resolution seismic reflection records and well logs from the Santa Barbara Channel suggest
that much of the Pleistocene hemipelagic sedimentary sequence records climate variability on
orbital to sub-orbital scales, like strata of the last glacial cycle studied at ODP Site 893. We have
developed and tested a new method to extract lithologic cyclicity from high-resolution marine
seismic profiles. Seismic reflection data (towed chirp) collected on the R/V Melville 2008 Cruise
(MV08) penetrate 10’s of meters below seafloor into a ~1 km-long sequence of south-dipping
seismic reflections. Spectral analysis of seismic reflection data and gamma ray logs from stratigraphically similar Pleistocene sections identify similar cyclic character through the section. This
correlation suggests that acoustic impedance and physical properties of sediment are linked by
climatically-driven oscillations in lithologic composition and fabric during deposition. Furthermore,
shifts in spectral character permit identification of basin-wide changes in sedimentation rate or
climatic forcing.
Where it crops out along the northern shelf of the central Santa Barbara Channel, the early
to middle Pleistocene succession (~1.6-0.7 Ma, middle to upper Pico Formation) is a bathyal
hemipelagic mudstone with remarkably rhythmic planar bedding, finely laminated fabric, and
well-preserved foraminifera. Unlike the coarser, turbiditic successions in the central Ventura and
Los Angeles basins, this sequence has the potential to record Quaternary global climate change
at high resolution. We suggest the following procedure for analysis of this dipping sub-sea succession: 1. Measure reflection amplitude values from several, parallel horizontal transects (constant
2-way-time) of a displayed profile, using absolute values of the SEG-Y data to test the usefulness
of the data. Correlate, stack, and spectrally analyze the data series. 2. Sample several horizontal
series of the digital SEG-Y data, correlate and stack the series, and analyze for cyclicity. Convert
measured distance to true stratigraphic thickness. This method may be used to evaluate the
sedimentation rates, age range, and paleoceanographic potential of sedimentary strata before a
coring vessel is deployed.
28-10
BTH 20
Rhodes, Nisa
[173027]
AN INVESTIGATION OF SHAY’S DELTA (BALDWIN LAKE, CA) AND ITS HOLOCENE
DEPOSITIONAL HISTORY
RHODES, Nisa, Geological Sciences, California State University, Fullerton, 800 N. State
College Blvd, Fullerton, CA 92831, [email protected], KIRBY, Matthew E., Geological
Sciences, California State University, Fullerton, 800 N. State College Blvd, Fullerton, CA
92834, BONUSO, Nicole, Department of Geological Sciences, California State Univeristy,
Fullerton, 800 N State College Blvd, Fullerton, CA 92834-6850, TULACZYK, Slawek,
Department of Earth and Planetary Sciences, University of California, Santa Cruz, 1156,
High Street, Santa Cruz, CA 95064, and BLAZEVIC, Michael, Geological Sciences,
California State Univeristy, Fullerton, 800 N State College Blvd, Department of Geological
Sciences, Fullerton, CA 92834-6850
Along the southern shore of Baldwin Lake at the mouth of Shay’s Creek is a fan-shaped featured
interpreted as a stranded delta (hereafter Shay’s Delta). The depositional history of Shay’s Delta
was investigated using a combination of geophysical, sedimentological, geomorpological, and
chronological data. Ground penetrating radar (GPR) data reveal two stratigraphic sequences: 1) a
lower sequence (I) of weak, thin reflectors that are horizontally continuous, indicating high attenuation material, such as clay. Sequence (I) is interpreted as the prodelta of the oldest, imaged
phase (late-Glacial to early Holocene) of deltaic deposition; and, 2) an upper sequence (II) of
stronger, hummocky and wavy, sub-parallel reflectors, which are fairly discontinuous. Sequences
(II) is interpreted as alternating parasequences of the delta plain /delta front/prodelta; it represents the most recent, but not modern, phase (mid-to-late Holocene) of active deltaic deposition.
A trench and several cores capture the entirety of sequence II and the upper portion of sequence
I. Six sedimentological analyses from the trench and core sediments were measured (i.e. magnetic susceptibility, total organic matter, total carbonate, percent sand, percent silt, percent clay).
A statistically robust facies model based on these sediment analyses was developed using
multivariate statistics. A depositional cross section along our trench/core transect was developed
using this facies model. The cross section reveals six episodes of transgression-regression of the
delta, including the dominant depositional change between Sequence I and II. Geomorphological
data (total station and DEM data) reveal a step-decrease in the delta surface elevation, which
is interpreted to represent two primary phases of deltaic deposition similar to the GPR data (i.e.
Sequence I and II). This step-decrease in surface elevation is coeval to the boundary between
Sequence I and II and matches the sedimentological facies interpretation (see below). In all,
these data suggest a major drop in base level from (i.e. lake level) ca. 5,400 cy BP, which resulted
in the down cutting of Shay Creek into Sequence I and the progradation of the more recent
Sequence II deposits.
28-11
BTH 21
Torres, Mark
[173029]
NEWLY DISCOVERED PALEOSOLS FROM THE PALEOCENE GOLER FORMATION OF
SOUTHERN CALIFORNIA
TORRES, Mark and GAINES, Robert, Geology Department, Pomona College, 185 E. Sixth
Street, Claremont, CA 91711, [email protected]
The Goler Formation of California is the western-most non-marine Paleocene Formation in the
U.S. that has been well constrained temporally (Albright et al, 2010), allowing for regional comparison of paleoclimatic data. Although sub-tropical to tropical forests extended into high latitudes
during the Paleogene (Frakes, 1979), terrestrial sections in the U.S. show evidence of seasonality with respect to rainfall (Koch et al, 2003;Retallack, 2005). Newly identified paleosols from
the Goler Formation were described and sampled in the field and analyzed for clay mineralogy
(XRD), whole-rock geochemistry (ICPMS), and microfabrics associated with calcite nodules in
order to interpret the paleoclimate under which they formed.
Two paleosol types, which developed on overbank deposits within the fluvial succession of the
Goler Formation, were identified and suggest that pedogenesis occurred under seasonal precipitation. Within well-developed gleyed vertisols, ineffective leaching is shown by the enrichment of
Mg and retention of Ca within the profile relative to the parent material. Fluctuations of the Fe and
Mn concentrations within single horizons suggests changing redox conditions as a result of alternating dry and waterlogged conditions. Pedogenic smectite-illite mixed layer clays and abundant
slickensides within profiles are consistent with seasonal precipitation (Retallack, 2001).
Within incipient paleosols, abundant calcite nodules are present and occur scattered throughout the profile, which is indicative of formation under a monsoonal climate (Retallack, 1991).
Petrographic analysis of the nodules reveals dissolution textures between nodule cores and the
surrounding matrix, complex patterns of cracking, and multiple generations of cement, which are
all likely related to alternating dry and waterlogged conditions.
Strong evidence for seasonality with respect to rainfall in the Goler Formation suggests similarities with other Paleogene formations in the western U.S. Previous research has attributed
the seasonality of precipitation evident in the Paleogene formations of Wyoming and Utah to
Laramide uplift (Norris et al, 2003;Retallack, 2005). Similarly, regional paleotopography surrounding the Goler Formation was likely an important control on precipitation.
28-12
BTH 22
Burns, Scott F.
[173668]
ANCIENT CATACLYSMIC FLOODS: ANCESTORS OF THE MISSOULA FLOODS IN THE
PACIFIC NORTHWEST, USA
BURNS, Scott F., Department of Geology, Portland State University, P.O. Box 751, Portland,
OR 97207-0751, [email protected]
The Missoula Floods were catastrophic Ice Age floods that greatly shaped and fashioned the
landscape of the Pacific Northwest through erosion and deposition of sediments from 15,000 –
18,000 calendar years ago. The idea of these floods was developed by J Harlen Bretz in the
1920’s and has been developing every since. Over 89 flood events have been recognized with 40
passing through Portland, Oregon on their way to the Pacific Ocean. The water originated from an
ice dam breaking in the Pend Oreille Trench and liberating over 500 cubic miles of water held in
Glacial Lake Missoula. The largest floods were the first ones, and they got succeedingly smaller
as the ice sheet thinned at the ice dam.
Evidence has been found for older similar cataclysmic floods in the Pacific Northwest. In
order to differentiate these from the earlier Missoula Floods, I would like to call them “Ancient
Cataclysmic Floods”. These flood deposits are characterized by old soils within the sediments
that many times have calcareous paleosols (Bk and K horizons). Sometimes the sediments have
been laid down in quiet water environments and show reversed paleomagnetic orientation (giving
them an age > 700,000 years BP). At least five paleosols have been found south of the Dalles,
Oregon on Highway 97 by Cordero and Burns. A classic section has been described by Baker
and Nummendal (1978) at Marengo, Washington, but they also mentioned similar ones at Revere,
Macall, and Old Maid Coulee, Washington. Bruce Bjornstadt and others (1991) discovered old
soils in flood deposits in the southwest Pasco Basin, Washington at Kiona Quarry, South Bombing
Range Road, Leslie Road, and Oak Street. They also described reversed magnetic polarity sediments at Poplar Heights, Vernita Grade and Yakima Bluffs in the Pasco Basin, Washington. Gene
Kiver and others (1991) also found similar flood deposits with old soils developed in them at Latah
Creek, Malden Gravel Pit and Willow Creek, all near Spokane, Washington.
28-13
BTH 23
Springer, Kathleen
[173675]
COOL WATER TUFAS AND BLACK MATS: INDICATORS OF PALEOENVIRONMENTAL
CHANGE IN LATE PLEISTOCENE SPRING DISCHARGE DEPOSITS OF THE UPPER
LAS VEGAS WASH, NEVADA
SPRINGER, Kathleen, Division of Geological Sciences, San Bernardino County Museum,
2024 Orange Tree Lane, Redlands, CA 92374, [email protected] and MANKER,
Craig, San Bernardino County Museum, 2024 Orange Tree Lane, Redlands, CA 92374
Renewed interest in the Rancholabrean age fossiliferous paleo-spring deposits of the upper
Las Vegas Wash has resulted in a wealth of new information from detailed geologic mapping,
establishing stratigraphic control and elucidating paleoenvironmental change through time.
These fine-grained sediments, indicators of past ground water discharge, closely track hydrologic
change through at least the last two glacial maxima and entomb one of the most significant late
Pleistocene vertebrate assemblages from the American southwest. The regional stratigraphic
framework of these deposits, first described in the Tule Springs area of the upper Las Vegas
Wash, comprises stratigraphically ascending units, A through G. Unit D, the last full glacial
deposit, is marked by extensive wetlands associated with previously reported radiocarbon dates
of >26,300–17,770 14C ka. Unit E (14,780 – 7,400 14C ka) is the latest glacial spring discharge
event. There is a widely recognized paucity of dates in this interval. Newly recognized tufa deposits allow a firm chronology of the transition from the last glacial maximum climatic regime to the
latest glacial spring discharge to be documented, as well as the establishment of the base of Unit
E. The tufas exhibit a distinctive morphology that follows a braided fluvial system. In all observations, they are associated with stream channels cut into the dissected marsh deposits of Unit
D, following the collapse of the full-glacial climate, then filled with sands, silts and tufa of Unit E.
Multiple black mats and other organic material, intercalated with the tufa, yielded radiocarbon
dates of 16,820– 16,300 14C ka at the base of earliest Unit E to allow precise chronologic constraint of the hiatus. Precipitation of tufa favors humid, warm, temperate climatic episodes, and
so constitutes an important paleoenvironmental signal; for the first time, the temporal relationship
with the underlying full glacial deposits has been revealed.
28-14
BTH 24
McCabe-Glynn, Staryl
[173608]
ASSESSING THE PALEOCLIMATE POTENTIAL OF SPELEOTHEMS FROM THE SIERRA
NEVADA MOUNTAINS: A PRELIMINARY STUDY
MCCABE-GLYNN, Staryl, Earth System Science, University of California, Irvine, 3206
Croul Hall, Irvine, CA 92697, [email protected], JOHNSON, Kathleen R., Dept. of Earth
System Science, University of California, Irvine, 3206 Croul Hall, Irvine, CA 92697-3100,
BERKELHAMMER, Max, Department of Earth Sciences, University of Southern California,
699 Exposition Blvd, Los Angeles, CA 90033, and SINHA, Ashish, Dept. of Earth System
Science, California State University, Dominguez Hills, 1000 E Victoria St, Carson, CA 90747
The Southwestern United States (SW) has been experiencing a persistent drought since 1998
and climate models project drying to continue. Tree ring-based proxy data indicate past droughts
in the SW US were of greater magnitude and longer duration than the 20th century droughts.
However, these records only span the past 1 or 2 millennia. To ascertain the full range of climate
variability in the SW US over longer time scales, we are using speleothems from Crystal Cave in
Sequoia National Park, California, to develop a well-dated, high resolution oxygen isotopic record.
To interpret this record in terms of past climate change, we are conducting a detailed calibration
study to assess the modern environmental controls on speleothem geochemistry. Here we present our monitoring results since 6/2007 which show the average δ18O of drip water in Crystal Cave
is similar to the amount weighted δ18O value of precipitation (δ18Op) above the cave, modern calcite is precipitated under isotopic equilibrium conditions, and therefore, Crystal Cave stalagmites
can be used to reconstruct past variations in δ18Op at this site. Analysis of rainfall samples indicate
δ18Op is strongly influenced by moisture source and rainout history of storms and not by temperature or precipitation amount. Back tracking trajectory analysis of storms between 2001 and 2005
indicate δ18Op variations are strongly influenced by the storm track origination, with North Pacific
storm tracks associated with the most depleted δ18O values (-14 to -21‰) and tropical Pacific
storms with the most positive (0 to -10‰). Sequoia National Park speleothem δ18O records may
therefore contain detailed records of storm track variations over the past several thousand years,
which may reflect past variability in coupled climate modes such as ENSO and PDO. To test this
potential, we collected a 140 mm long actively growing stalagmite from Crystal Cave. Preliminary
SESSION NO. 28
U-Th dating indicates that the sample is 1437±12 years old and grew at an average rate of 0.09
mm/yr. We present a high resolution analysis of the top 8 mm that span the last century. We will
compare our results with instrumental records of temperature and precipitation from a nearby site
and discuss the validity of using speleothem δ18O from this region to determine the storm track
trajectories in the SW over longer time periods.
28-15
BTH 25
Johnson, Kathleen R.
[172893]
TESTING MODERN CONTROLS ON SEASONAL 14C VARIATIONS IN SEAWATER DIC AND
MYTILUS CALIFORNIANUS SHELLS: THE POTENTIAL FOR A NEW UPWELLING PROXY
JOHNSON, Kathleen R.1, FERGUSON, Julie1, MEYER, Laura2, ACAYLAR, Karla1,
DOS SANTOS, Guaciara3, and TRIPATI, Aradhna4, (1) Dept. of Earth System Science,
University of California, Irvine, 3206 Croul Hall, Irvine, CA 92697-3100, kathleen.johnson@
uci.edu, (2) MIT, Cambridge, MA 02139, (3) Dept. of Earth System Science - Keck AMS
Lab, UC Irvine, Irvine, CA 92697, (4) Dept. of Atmospheric and Ocean Sciences, UCLA,
Los Angeles, CA 90095
Marine radiocarbon (14C) is a widely used tracer of past ocean circulation, but very few highresolution records have been obtained. Seasonally resolved 14C variations have been utilized to
reconstruct ENSO related upwelling variability from tropical Pacific corals (Druffel et al., 2007),
yet no similar records exist in higher latitudes. Seasonal records from the NE pacific could significantly improve our understanding of the complex interactions between the California Current
strength, coastal upwelling, and coupled climate modes, such as ENSO, which is currently
limited by the short duration of instrumental records and a lack of seasonal-resolution archives.
Seasonal 14C variations in marine mollusk shells collected from Holocene shell middens in coastal
North American sites hold great potential to fill this gap. We have conducted a detailed modern
calibration study to investigate the link between upwelling intensity and the Δ14C of dissolved
inorganic carbon in surface seawater, and how faithfully this seawater signal is recorded in the
calcite growth increments of living California mussel (Mytilus californianus) shells. We present
new data from surface seawater samples collected bi-weekly from Newport Beach Pier for 14C,
salinity, ΣCO2, and stable isotope (δ13C ,δ18O, and δD) analysis from March 2008 to March 2009.
Comparison of this new data, and published data on samples collected since Nov. 2004 (Hinger
et al., in press), reveals a link between upwelling intensity and the Δ14C of marine DIC. Living mussels were collected from Newport Beach, California. Sequential samples were micromilled from
the outer calcite layer of shell cross-sections and analyzed for stable isotopes, trace elements and
14
C. By comparing the geochemical profiles produced from the shells with instrumental records
and the ocean geochemical measurements, it is possible to identify empirical relationships
between shell geochemistry, upwelling and other oceanic variables. We also present results from
Mytilus californianus shells collected from Mexico to Oregon following the strong El Niño event of
1997-1998. This event caused a collapse of upwelling and provides an ideal test of the fidelity of
these empirical relationships along the west coast of North America at a time of dramatic change
within the California Current system.
Friday, 28 May 2010
T6. New Insights into Tectonics of the Central
California Coast Ranges—The Link between
Los Angeles and San Francisco (Posters)
(Cordilleran Section GSA; Pacific Section, AAPG;
29-1
BTH 26
Jachens, Robert C.
[173226]
A THREE-DIMENSIONAL GEOLOGIC MAP OF THE CENTRAL CALIFORNIA COAST RANGES
JACHENS, Robert C., U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA
94025, [email protected], WENTWORTH, Carl M., Emeritus, U.S. Geological Survey,
345 Middlefield Road, Menlo Park, CA 94025, LANGENHEIM, Victoria, U. S. Geological
Survey, 345 Middlefield Road, Menlo Park, CA 94025, GRAYMER, Russel W., U. S.
Geological Survey, 345 Middlefield Rd, Menlo Park, CA 94025, SIMPSON, Robert W., U.S.
Geol Survey, 345 Middlefield Rd, Menlo Park, CA 94025, STANLEY, Richard, U.S. Geological
Survey, 345 Middlefield Road, MS 969, Menlo Park, CA 94025, and COLGAN, Joseph P.,
U.S. Geological Survey, 345 Middlefield Rd. MS 975, Menlo Park, CA 94025
We have constructed a 3D geologic map of west-central California for the region from Monterey
Bay to the Santa Barbara Channel and from the San Andreas Fault westward to the continental
shelf, including the whole crust and uppermost mantle. The map volume is divided by 18 faults
into 19 blocks, each having a distinct lithostratigraphic makeup. Each block-bounding fault satisfies some of the following: 1) recognized as important in San Andreas system; 2) >100 km long
(including aligned faults with consistent structural style); 3) accommodates large total offset
(>1 km vertical, >5 km horizontal); 4) is Quaternary active; 5) represents a profound physical
property boundary. Ambiguity in the shapes and hierarchy of the Rinconada and Oceanic Faults
resulted in 4 different 3D maps. The main purpose for constructing the 3D map was to support a
new probabilistic seismic hazard assessment of the central California Coast Ranges via better
understanding of the subsurface geometry of the faults, but the map is designed for other applications as well. For example: The present map can support computer-based predictive groundshaking estimates from scenario earthquakes once physical properties are assigned based on
geology, and calibrated with the recent San Simeon and Parkfield earthquakes. Simulations of
ground shaking based on a similar 3D map have been successful for the 1906 San Francisco
earthquake and for a suite of scenario earthquakes on the Hayward Fault. The central California
Coast Ranges have a complex tectonic history since inception of the San Andreas Fault system
involving 100s of km of lateral slip on bounding faults, 10s of km of lateral slip on internal faults,
kms of shortening across thrust/reverse faults, rotation of the western Transverse Ranges, and
development of large deep sedimentary basins. The 3D geologic map and its associated geologic
and geophysical data can test models of tectonic evolution of the Coast Ranges by providing 3D
geometric, volumetric, and offset constraints. Quantitative ground-water flow modeling is routinely
used for evaluating and managing ground-water resources and requires detailed 3D geologic
aquifer models. The present 3D geologic map lacks the detail needed to directly support flow
modeling, but provides the foundation upon which to add detailed geologic aquifer models.
BTH 27
Stanley, Richard
[173074]
NEW ISOTOPIC AGE FROM BASALT NEAR CARMEL, CALIFORNIA, AND ITS TECTONIC
SIGNIFICANCE
STANLEY, Richard, U.S. Geological Survey, 345 Middlefield Road, MS 969, Menlo Park,
CA 94025, [email protected], FLECK, Robert J., U. S. Geological Survey, 345 Middlefield
Road, MS 937, Menlo Park, CA 94025, WILSON, Douglas S., Department of Earth Science,
University of California, 1006 Webb Hall, Santa Barbara, CA 93106, and MCCRORY,
Patricia A., U.S. Geological Survey, 345 Middlefield Road, MS 977, Menlo Park, CA 94025
An age of 24.0 to 23.6 Ma on basalt near Carmel, California, provides support for a tectonic
model that relates Neogene volcanism in coastal California to the development of slab windows during collision of the East Pacific Rise with western North America. On the north side
of Arrowhead Point (latitude 36.5626, longitude -121.9391), the basalt rests unconformably on
marine strata of the lower Eocene Carmelo Formation and is overlain by unnamed Miocene
marine sandstone. Three of six samples of basalt collected from sea cliff exposures were not
dated because petrographic examination revealed evidence of substantial alteration. Plagioclase
separates from the remaining three samples were analyzed using the 40Ar/39Ar incremental-heating method. Two of the three samples yielded anomalously old ages of 60 to 30 Ma and U-shaped
age spectra characteristic of excess argon. The age spectrum from the final sample showed
evidence of modest argon recoil but no excess argon. This sample yielded an isochron age of
24.0 ± 0.2 Ma and a total-gas age of 23.6 ± 0.1 Ma, but no age plateau. An eruption age of 24.0
to 23.6 Ma is inferred for this basalt.
The newly-determined age from the Carmel basalt is younger than previously reported wholerock K-Ar ages of 27.1 ± 0.8 Ma and 27.0 ± 0.8 Ma from basalt samples collected in the same
area. K-Ar ages provide no insight into the Ar distribution in these samples, but the presence of
excess argon is inferred based on our 40Ar/39Ar results.
The new age determination supports the hypothesis of Wilson and others (2005) that the
Carmel basalt erupted from one of several volcanic centers that originated about 24-22 Ma
above a slab window that resulted from subduction of the spreading ridge segment between
the Mendocino and Pioneer fracture zones along the California coast. This eruptive episode
is recorded by volcanic rocks that presently occur over a large area from near Point Arena
(Iversen Basalt, about 300 km northwest of Carmel) to the western Transverse Ranges (Neenach
Volcanics, about 360 km southeast of Carmel) and were dispersed from their original relative
positions by Neogene tectonism that included substantial right-lateral displacements along the
San Andreas, San Gregorio, and other strike-slip faults.
29-3
BTH 28
Watt, Janet T.
[172977]
USING POTENTIAL FIELDS TO REFINE BASIN AND FAULT GEOMETRY IN SALINAS VALLEY,
CALIFORNIA
WATT, Janet T., MORIN, Robert L., and LANGENHEIM, Victoria, U. S. Geological Survey,
345 Middlefield Road, Menlo Park, CA 94025, [email protected]
Salinas Valley is an important agricultural basin that is approximately 115-km long and extends
from Elkhorn Slough in the NW to just SE of the town of San Ardo. The Salinas Valley basin is
bounded by the Gabilan Range on the NE and the Santa Lucia Range and Reliz-Rinconada fault
zone on the SW. We combine new gravity data, aeromagnetic data, and well information to refine
basin and fault geometry in the Salinas Valley as part of a broader effort to investigate the tectonics and water resources of the Central California Coast Ranges.
Gravity data collected during 2009 in the basin and surrounding mountains show that the
Salinas Valley is characterized by an elongate gravity low that widens to the north, east of
Monterey Bay. Based on a preliminary inversion of gravity data, basin depths average 2-3 km with
a maximum of 6 km in southern Salinas Valley. South of where Arroyo Seco Canyon intersects the
Salinas basin, the thickness of the Monterey Formation within the basin increases dramatically
and corresponds to an apparent deepening of the basin. However, diatomaceous rocks within the
Monterey Formation are often less dense than other basin fill, and would lead to an over-estimation of basement depth in areas with no well control.
Gravity and magnetic gradients help characterize the geometry of basin-bounding structures,
such as the Reliz-Rinconada fault zone, which marks the western boundary of the Salinas Valley.
For example, the Reliz segment of the fault is located at the base of a 50-km-long gravity gradient, suggesting a SW dip. Fault exposures at the mouth of Arroyo Seco canyon and geophysical
modeling confirm a SW dip. At Arroyo Seco canyon, where the Reliz and Rinconada segments
meet in a right-step, the fault no longer follows the gravity gradient and instead cuts through
lower-density Cenozoic rocks. While rocks of the Sierra de Salinas are essentially non-magnetic,
there appear to be magnetic sedimentary deposits within northern Salinas Valley that delineate a
possible northern extension of the Reliz fault into Monterey Bay. In contrast to the western margin,
the linear gravity gradient along the eastern boundary of Salinas Valley is continuous along the
entire length of the valley. While no Quaternary structures are mapped along this boundary, the
gravity gradient could be controlled by an older, buried structure.
29-4
BTH 29
Menotti, Tess
[173617]
INVESTIGATIONS INTO BURIAL HISTORY AND PETROLEUM SYSTEM DEVELOPMENT IN
THE SALINAS BASIN, CALIFORNIA THROUGH 1-D MODELING
MENOTTI, Tess, Geological and Environmental Sciences, Stanford University, 450 Serra
Mall, Braun Hall, Building 320, Stanford, CA 94305-2115, [email protected]
The Salinas basin is a Cenozoic strike-slip basin in western central California, bounded to the
east by the San Andreas Fault. A one-dimensional (1-D) burial history model was created in
the Hames Valley syncline, the thickest depocenter of the basin, located 9 km southwest of the
San Ardo oil field. The half-billion barrel San Ardo oil field is anomalously large in contrast to the
six other oil fields in the Salinas basin, which collectively amount to 2% the size of San Ardo.
The Salinas basin is no longer at maximum burial depth: the shallowest thermally mature (0.6%
Ro) source rock, which occurs within the Hames Member of the Miocene Monterey Formation,
is currently at a burial depth of 2400 m (8000 ft); however, the present-day threshold for thermal
maturation of the Monterey Formation in the neighboring San Joaquin basin occurs at 4000 m
(13,000 ft) burial depth. Thermal maturity data from pyrolysis analysis serves as calibration for
a 1-D model to determine the time and depth of hydrocarbon generation. A pseudo-well for the
model was created between two 3,000+ m (10,000+ ft) wells, Texaco Shell NCT-1 1 and Shell
Labarere 27X-21, located on opposite flanks of the Hames Valley syncline, and controlled by
reflection seismic data. The pseudo-well penetrates the Hames and Sandholdt members of the
Monterey Formation, and penetrates basement at 4,000 m (13,000 ft). Based on previously collected geochemical data, the 1-D model incorporates source rock properties of a type II kerogen
with 3 wt% TOC and 700 mgHC/gTOC hydrogen index. Multiple models were developed to
identify the burial history scenario required to produce the thermal maturation signature in the
source rock. However, these early models reveal unexpectedly high thermal maturity values.
Uncertainties in heat flow and overburden thickness are being explored to explain and resolve this
inconsistency.
SESSION NO. 29
29-5
BTH 30
Sweetkind, Donald S.
[173604]
CONFIGURATION AND LITHOLOGY OF MESOZOIC BASEMENT BENEATH THE SANTA
MARIA BASIN, CA FROM ANALYSIS OF BOREHOLE DATA
SWEETKIND, Donald S., U.S Geological Survey, Mail Stop 973, Box 25046, Denver,
CO 80225, [email protected], LANGENHEIM, Victoria E., U.S. Geological Survey,
345 Middlefield Road, Menlo Park, CA 94025, and SHUMAKER, Lauren E., Santa Cruz,
CA 95064
Stratigraphic information from oil and gas wells from the onshore Santa Maria basin suggests that
the basin is floored by Mesozoic rocks of the Franciscan Complex, with lesser amounts of Coast
Range ophiolite and overlying marine sandstones generally equivalent to Great Valley Sequence
rocks. Understanding the spatial distribution of basement lithology helps unravel the basin
structural evolution and bears on basement density assumptions and resultant gravity-based
depth-to-basement models that delineate basin depth and shape. Previous investigations of these
rocks interpreted various basement lithologic types and basement structure contour maps differed
markedly. Two previous sandstone petrofacies studies separated Franciscan rocks from Great
Valley-like rocks, but differed in the interpreted depositional setting of the Cretaceous sandstones.
We present a revised borehole stratigraphic compilation that attempts to reconcile these
disparate lithologic interpretations. The compilation emphasizes the domainal nature of basement types; Franciscan rocks dominate, but Cretaceous rocks with Great Valley affinities are
intercepted by boreholes in the northwest and southwest parts of the basin. The continuity and
consistency of elevation of these strata suggest that they are more likely forearc Great Valley-type
strata, rather than localized trench-slope deposits. Electric logs may be of use in distinguishing relatively undeformed Great-Valley like strata from sandstones surrounded by Franciscan
mélange. Differing sandstone petrofacies and abrupt transitions from marine sandstone to
Franciscan Complex rocks suggest the presence of faults within the basin, but provide no piercing
points. In contrast to Paleogene marine sandstones found to the south of the basin, no Paleogene
strata occur north of the Lompoc-Solvang fault. Cretaceous sandstones are locally present as
far north as the Lions Head fault and may suggest that this fault juxtaposes Cretaceous rocks of
differing age and lithology. Serpentinites exist as linear bodies that are aligned along fault traces
and probably represent mobilized forearc rocks within transpressional faults. The serpentinites,
both exposed and penetrated locally by drillholes, coincide with magnetic highs that may help
map these rocks in the subsurface.
29-6
BTH 31
Sweetkind, Donald S.
[173239]
TERRAIN ANALYSIS AND GEOLOGIC FIELD INVESTIGATIONS USED TO CONSTRAIN
DRAINAGE EVOLUTION AND BASIN-FILLING HISTORY WITHIN AND NEAR THE NORTHERN
SALINAS VALLEY GROUNDWATER BASIN, CENTRAL CALIFORNIA COAST RANGE
TAYLOR, Emily M., U.S Geological Survey, Mail Stop 980, Box 25046, Denver, CO 80225,
[email protected], SWEETKIND, Donald S., U.S Geological Survey, Mail Stop 973,
Box 25046, Denver, CO 80225, [email protected], GARCIA, Antonio F., Physics
Department, California Polytechnic State University, San Luis Obispo, CA 93407, and
SHUMAKER, Lauren E., Santa Cruz, CA 95064
Groundwater models of sedimentary basins can be improved by high-resolution stratigraphy and
estimates of hydraulic properties of basin-filling materials. However, such information is difficult to
extract from well drillers’ records. Preserved stream terrace deposits within and near sedimentary
basins are a record of erosional history that provides a context for down-stream basin aggradation, basin-margin fault-related uplift, and paleoclimate events. We combine terrain analysis of
a digital elevation model with traditional geologic field methods to develop a record of the longterm erosional history of the Arroyo Seco drainage, near the Salinas Valley in the Central Coast
Ranges of California. Based on data from oil and gas exploration drillholes and water wells, the
Salinas Valley is filled with about 10,000-15,000 ft of Tertiary and Quaternary marine and terrestrial sediments.
Arroyo Seco is a perennial stream, one of the largest tributary drainages of the 100-mile-long
Salinas River. Arroyo Seco has cut a narrow canyon that opens into a 10-mile-long valley that
transects the Santa Lucia Range. Arroyo Seco progrades from an elevation of 945 ft at the
canyon mouth to 500 ft where it flows into the Salinas Valley. In the Arroyo Seco valley there is a
spectacular sequence of at least six, and perhaps as many as fifteen, strath terraces and strathterrace deposits. Strath-terrace deposits are as much as about 1,100 ft above the modern drainage; however, younger deposits are 150 to < 3 ft above the modern drainage. The highest (oldest)
deposits and their terrace treads record stream erosion and deposition prior to valley incision. A
gently sloping, low-relief geomorphic surface northwest of Arroyo Seco records a pre-Arroyo Seco
relict landscape above the modern drainage. Remnants of terrace deposits in Arroyo Seco overlie
Miocene marine Monterey Formation, and are composed of coarse alluvial gravel less than 10 ft
thick. Alluvium transported by Arroyo Seco was deposited across and was cut by the Rinconda
and Reliz range-bounding Faults. Valley-side down, reverse movement along the faults resulted in
the deposition of an asymmetric, westward-thickening alluvial wedge that provides a long, relatively continuous record of basin aggradation in the Salinas Valley.
29-7
BTH 32
Wiegers, Mark O.
[173236]
GEOLOGIC MAP OF THE MORRO BAY SOUTH 7.5’ QUADRANGLE
WIEGERS, Mark O., California Geological Survey, 135 Ridgway Avenue, Santa Rosa,
The California Geological Survey (CGS) has released a preliminary geologic map (1:24,000scale) of the Morro Bay South 7.5’ Quadrangle. This map is the first to be completed in a multiyear project to prepare a seamless onshore/offshore geologic map of the of the San Luis Obispo
30 x 60-minute quadrangle in cooperation with the USGS and others. CGS will use this map and
subsequent maps to prepare state-mandated Seismic Hazard Maps showing zones of required
investigation for liquefaction and earthquake-induced landslides. These maps will also be used to
improve estimates of earthquake ground shaking to be integrated into California’s building codes.
The Morro Bay South Quadrangle includes two structural blocks juxtaposed by the northwesttrending Los Osos Fault. On the southwest side of the fault, the San Luis Range is uplifting as a
rigid block with a flight of up to twelve emergent marine terraces along the coast. Dating of these
terraces by others indicates an uplift rate of 0.23 m/kyr. On the northeast side of the fault, the
Cambria block is tilting southwest, with a deep basin south of Morro Bay and uplifted Quaternary
fluvial deposits along Chorro Creek to the north. The geomorphic expression of the Los Osos
Fault in the map area is weak, consisting of discontinuous tonal and topographic lineaments. The
fault is poorly expressed in recent aeromagnetic and gravity maps prepared by the USGS. This
suggests that the west end Los Osos Fault has a low rate of late Quaternary activity.
The San Luis Range is underlain by the Miocene Monterey and Pismo Formations. These rocks
were folded in the late Miocene and Pliocene to form the Pismo syncline. The Pismo syncline
extends through the southern part of the map area and continues offshore, where it is prominently
expressed in high resolution bathymetric images acquired by CSU Monterey Bay. The Edna Fault
is on the northeast limb of the Pismo syncline and has a complex history of displacement. It may
have originated as an extensional fault during opening of the Pismo basin and later became a
reverse fault during contraction of the Pismo syncline. Basement rocks of the Franciscan Complex
are exposed in the Cambria block north of the Los Osos Fault. The Franciscan rocks are intruded
by Oligocene dacite which forms distinctive peaks locally known as “The Morros” between Morro
Bay and San Luis Obispo.
29-8
BTH 33
Rytuba, James
[173111]
GEOTHERMAL SYSTEMS IN THE PASO ROBLES GROUNDWATER BASIN, CENTRAL COAST
RANGES, CALIFORNIA
RYTUBA, James, Geology Discipline, U.S. Geological Survey, 345 Middlefield Rd, MS 901,
Menlo Park, CA 94025, [email protected]
Sources of water in the Paso Robles area of the central California Coast Ranges are a major
concern because of increased demand associated with population growth. Aquifers within the
Paso Robles groundwater basin are the primary water source and occur within the middle to
lower Pleistocene Paso Robles Formation, and Quaternary younger and older alluvial deposits.
The basin is bounded on the west by the Rinconada Fault and on the east by the Red Hills and
San Juan faults. On the west side of the Paso Robles Basin a shallow, low temperature (18-48
degrees C) geothermal system along the Rinconada Fault extends eastward into the basin. The
geothermal waters are characterized by elevated concentrations of B, Cl, and bicarbonate. After
the December 2003 San Simeon M 6.5 earthquake, numerous hot springs developed along
the Rinconada fault including a hot spring within the central commercial district of Paso Robles.
Because of the chemistry of the hot spring effluent (high B, Cl, sulfide and bicarbonate), the
water is diverted into the Salinas River. The ratio of B/Cl in the geothermal fluid is a constant
and increases in B and Cl concentration correlate with increasing temperature of the geothermal
fluid. The geothermal fluids are mixtures of meteoric and connate fluid, and B and Cl concentrations can be used to determine the relative proportion of each fluid source. On the east side of
the basin, similar composition connate waters with high B, Cl and carbonate are present. The
connate fluids are localized along the Red Hills Faults and extend westward into the basin. Silicacarbonate type mercury deposits are localized along the Rinconada and adjacent faults and
formed along the margin of the basin in the past. The present day geothermal system has similar
fluid chemistry and alteration to that associated with the mercury deposits and has the potential
to develop similar mineralization. Geothermal waters have been an important in the evolution of
the Paso Robles groundwater basin. Both past hydrothermal alteration and mineralization and
present day geothermal systems potentially contribute to degradation of the quality of the groundwater resource.
29-9
BTH 34
Colgan, Joseph P.
[172975]
CRUSTAL STRUCTURE ADJACENT TO THE SAN ANDREAS FAULT FROM CHOLAME VALLEY
TO THE NORTHERN CARRIZO PLAIN, CENTRAL CALIFORNIA
COLGAN, Joseph P., U.S. Geological Survey, 345 Middlefield Rd. MS 975, Menlo Park, CA
94025, [email protected] and MCPHEE, Darcy K., U.S. Geol Survey, 345 Middlefield Road,
Menlo Park, CA 94025
A synthesis of geologic and geophysical data places constraints on crustal structure adjacent to
the San Andreas Fault (SAF) from Cholame Valley to the northern Carrizo Plain. Southwest of
the SAF, Quaternary to Oligocene(?) sedimentary rocks up to 3 km thick overlie variably magnetic granitic basement of the Salinian block. The most prominent Neogene structure is the Red
Hills Fault, a thrust ~10 km SW of the SAF that dips 30º NE and places granitic basement over
Pliocene sedimentary rocks. It offsets the subhorizontal basement surface ~2.5 km vertically
(NE-side up), equivalent to ~4 km of SAF-perpendicular shortening. No Quaternary deformation
is mapped where it projects to the surface, and it appears to intersect the near-vertical SAF at
a depth of only 4-6 km. It cannot move as a thrust without cutting the SAF, so we interpret it as
an inactive fault within a crustal block that has been transported north along a strike-slip fault
to its present location. Northeast of the SAF, post-Miocene deformation within 7-10 km of the
SAF is accommodated by tight folds and steeply dipping faults that may merge with the SAF at
depth. From Orchard Peak to the Pyramid Hills, several east-dipping thrusts verge SW and place
Cretaceous Great Valley sequence over late Miocene to Pliocene sedimentary rocks. These faults
may have been localized because Cretaceous strata here were already east-dipping prior to
Pliocene shortening. On the west edge of the San Joaquin Valley, Pleistocene and older strata are
deformed by the fault-cored Kettleman Hills anticline. There are two major magnetic anomalies
(highs) NE of the SAF. The Palo Prieto high is adjacent to the SAF and extends for 30-40 km
parallel to the SAF. No magnetic rocks crop out above this anomaly, but we model the top of
it at a depth of ~2 km; the bottom is not resolved. The Great Valley anomaly extends for over
500 km along strike and we model the west edge of it beneath the Kettleman Hills. Our models
indicate that the Palo Prieto and Great Valley anomaly sources are not connected at a depth
shallower than ~15 km. We interpret them as different lithologies: the Palo Prieto source as partly
serpentinized ultramafic rock, and the Great Valley source as basement of Sierran affinity. The
non-magnetic basement between these bodies is most likely Franciscan thrust under the Great
Valley Sequence.
29-10
BTH 35
Prothero, Donald R.
[172887]
MAGNETIC STRATIGRAPHY OF THE MIOCENE-PLIOCENE ETCHEGOIN GROUP,
WESTERN SAN JOAQUIN BASIN, CALIFORNIA
PROTHERO, Donald R., Geology, Occidental College, 1600 Campus Rd, Los Angeles,
One of the best Pliocene sequences on the Pacific Coast is the Etchegoin Group of the westcentral San Joaquin Basin. The formations of the Etchegoin Group (from bottom to top: Jacalitos,
Etchegoin, San Joaquin) were the original basis for the Pliocene Pacific Coast marine chronology
of the Weaver Committee in 1944, and their mollusks and stratigraphy have been intensively studied for over 100 years. Yet the age control on these crucial strata has long been poor. We sampled
34 sites spanning 8000 m of section at nearly every exposure in the Big Tar Canyon-Baby King
Canyon area of Reef Ridge. Most samples showed a single component of remanence held mainly
in magnetite, with some overprinting on reversed samples. The samples passed a reversal test,
showing that the remanence is primary and not an overprint. The entire Jacalitos Formation is
reversed in polarity, and based on dates of 5.0 and 5.3-5.5 Ma on the upper and lower parts,
probably correlates with Chron C3r (5.3-6.0 Ma, latest Miocene to earliest Pliocene). Most of the
San Joaquin Formation is normal in polarity, and based on a date of 2.5 Ma at the top, probably
correlates with Chron C2An (2.5-3.6 Ma). The upper Etchegoin Formation is reversed in polarity
and appears to correlate with Chron C2Ar (3.6-4.2 Ma). The lower Etchegoin Formation appears
to correlate with part of Chron C3n, but a large unconformity at the base has apparently removed
the earlier parts of Chron C3n.
SESSION NO. 29
29-11
BTH 36
Marshall, Courtney J.
[173261]
SEDIMENTATION IN AN ACTIVE FOLD AND THRUST BELT, SANTA BARBARA BASIN, CA:
SPATIAL AND TEMPORAL EVOLUTION OF SEDIMENTATION FROM 1.0 MA TO PRESENT
MARSHALL, Courtney J., Geology, California State University, Long Beach, Long Beach,
CA 90840, [email protected], SORLIEN, Christopher C., Institute for Crustal Studies,
University of California Santa Barbara, Santa Barbara, CA 93106, NICHOLSON, Craig,
Marine Science Institute, University of California, Santa Barbara, CA 93106-6150, BEHL,
Richard J., Geological Sciences, California State University Long Beach, 1250 Bellflower
Blvd, Department of Geological Sciences; PH1-104, Long Beach, CA 90840, and KENNETT,
James, Earth Sciences, University of California Santa Barbara, Webb Hall, University of
California Santa Barbara, Santa Barbara, CA 93106
The offshore Santa Barbara Basin (SBB) fold and thrust belt provides an excellent opportunity
to study the relation between tectonics, accommodation space, and sediment supply on basin
stratigraphy in a dynamic continental margin setting. It also provides constraint on the timing and
impact of key tectonic events on the Quaternary southern Californian margin. Seismic stratigraphy
and isochore maps reveal shifts in location, shape, and accumulation rate of sedimentary depocenters in SBB during the last 1 Myr and a major reduction of sediment supply at ~500 ka that
likely marks major diversion of the Santa Clara River to the Santa Monica Basin and inception of
the Hueneme submarine fan. Distinctive sequence boundaries and other stratigraphic horizons
identified on deep-penetration industry marine multichannel seismic (MCS) reflection data, and
high-resolution MCS and USGS towed chirp data acquired during 2005 and 2008 research
cruises provide the basis for stratigraphic and isochore analysis. Horizon ages are assigned by
correlation and interpolation between ODP Site 893, a previously recognized 1-Ma horizon, dated
tephra layers, biostratigraphic markers, and MIS climate transitions identified from oxygen isotopic
analysis of recovered cores that sample strata back to ~700 ka. Isochore maps were created from
gridded horizons, first in two-way travel time, then converted to depth and volume. Sedimentation
rates were highest between 1 Ma and ~500 ka, but then decreased sharply with a marked change
in stratal architecture. Since ~710 ka, sedimentation was localized within a WNW-ESE-trending
offshore trough located between the North Channel and Oak Ridge fault systems and westward
into the central basin. Continued uplift across these two bounding fault systems and development
of the structurally complex northern shelf and south-bounding Mid-Channel anticline is reflected
in the 3 dimensional geometry and spatial pattern of basin sedimentation and constriction of the
main central trough. Evolution of these depocenters thus reflects the growth history of faults and
folds, and related subsidence and development of seafloor morphology, while changes in sedimentation rates reflect either an unlikely decrease in the sediment load of the Santa Clara River
or its tectonic divergence and initiation of the Hueneme Fan.
29-12
BTH 37
Scheirer, Daniel
[173312]
CAN GRAVITY ANOMALIES BE USED TO MAP PRE-PLIOCENE SEDIMENTARY BASINS IN
THE CENTRAL COAST RANGES, CALIFORNIA?
SCHEIRER, Daniel, U.S. Geological Survey, 345 Middlefield Road, MS 989, Menlo Park,
CA 94025, [email protected], SWEETKIND, Donald, USGS, U.S Geological Survey,
Mail Stop 973, Box 25046, Denver Federal Center, Denver, Denver, CO 80225,
LANGENHEIM, Victoria, U. S. Geological Survey, 345 Middlefield Road, Menlo Park, CA
94025, and STANLEY, Richard, U.S. Geological Survey, 345 Middlefield Road, MS 969,
Menlo Park, CA 94025
In relatively simple tectonic settings such as the Basin and Range, gravity anomalies correlate
with Neogene basin-filling deposits, and the gravity anomaly can be modeled as a Cenozoic
basin-fill component superimposed on a regionally varying pre-Cenozoic basement component.
However, many sedimentary basins in the California Coast Ranges have had multi-stage basinfilling histories such that Pliocene and younger sediment accumulations are often poorly correlated with older Cenozoic sedimentary thickness, resulting in a complex gravity anomaly pattern.
In these basins, Neogene tectonic deformation associated with the San Andreas Fault system has
disrupted marine and non-marine depositional basins formed in an earlier tectonic environment.
We are modeling gravity anomalies in the multi-stage Cuyama and Carrizo Plain basins by
separating the gravity effects of Pliocene and younger deposits from those of Miocene through
upper Cretaceous deposits, with the goal of estimating how pre-Pliocene sediment accumulations
have been disrupted since deposition. We utilize down-hole logs from oil and gas wells to constrain basin thickness estimates derived from depth-inversion of gravity anomalies. Our analysis
shows that in the Carrizo basin, Pliocene and younger sediments are as thick as 1.5 km near the
center of Carrizo Plain, and pre-Pliocene deposits have a smaller gravity signature than overlying
deposits. In the Cuyama basin, the Pliocene and younger sediments are slightly less than 2 km in
maximum thickness, and older sediments are 3-5 km thick. In western Cuyama basin, a narrow
region of thick, interpreted-pre-Pliocene sediments extends to the northwest of the present-day
valley. Restoration of ~30 km of right-lateral offset on the buried Russell Fault places this narrow
region of sediments adjacent to similarly thick pre-Pliocene accumulations observed east of the
Russell Fault in central and eastern Cuyama Valley. By analyzing the disruption of Miocene and
older basins west of the San Andreas Fault in conjunction with evidence for piercing relations
from bedrock outcrop and magnetic anomalies, we hope to define better the pattern and timing of
deformation along the faults that segment this portion of the California Coast Ranges.
29-13
BTH 38
Feigelson, Leah M.
[173229]
SLIP RATE ON THE SAN ANDREAS FAULT, SAN FRANCISCO PENINSULA, CALIFORNIA
FEIGELSON, Leah M.1, PRENTICE, Carol S.2, GROVE, Karen3, CASKEY, John3, DAVIS,
Jerry4, and RITZ, Jeff5, (1) Department of Geosciences, San Francisco State University,
1600 Holloway Ave, San Francisco, CA 94132, [email protected], (2) US Geological Survey,
345 Middlefield Rd MS 977, Menlo Park, CA 94025, (3) Department of Geosciences, San
Francisco State Univ, 1600 Holloway Ave, San Francisco, CA 94132, (4) Department of
Geography and Environmental Studies, San Francisco State University, 1600 Holloway Ave,
San Francisco, CA 94132, (5) Laboratoire Géosciences Montpellier, Université Montpellier 2,
Place E. Bataillon, 34095 Montpellier cedex 5, Montpellier, France
The most recent large earthquake on the San Francisco Peninsula segment of the San Andreas
Fault (SAF) was the great Mw 7.8 San Francisco earthquake of April 18, 1906. This event ruptured the North Coast, Peninsula, and Santa Cruz Mountains segments of the SAF. An accurate
slip rate for the peninsula segment is important for refining seismic hazards in this highly urbanized region. Two previous slip rate studies on the San Francisco Peninsula yielded differing sliprate estimates. One study by Hall (1984), at the San Andreas Dam site, estimated an average slip
rate of ~12 mm/yr and the other study by Hall et al. (1999) at the Filoli site, estimated an average
slip rate of 17±4 mm/yr. We excavated a trench north of these two sites where an abandoned
stream channel crosses the SAF between the San Andreas and Lower Crystal Spring reservoirs.
Channel abandonment occurred when a new channel cut across the fault. The new, and currently
active channel has since been offset in a right-lateral sense. Our trench investigation revealed
channel-fill alluvium that was later incised and filled with probable debris flow sediments, and
a 2-m wide fault zone in Franciscan Complex bedrock west of the channel-fill deposits. One of
the prominent fault strands in the trench breaks nearly all the way to the surface and is probably
80 2010 GSA Abstracts with Programs the strand that ruptured in 1906. The debris-flow deposits contained grass seeds that yielded
radiocarbon ages of 910-730 cal. yr BP, 1310-1190 cal. yr BP, and 2340-2150 cal. yr BP. These
dates are consistent with their stratigraphic order and indicate the occurrence of multiple debrisflow events. We assume that the age of the youngest debris flow sediments approximate both
the abandonment age of the older channel and the initiation of the active channel. A total-station
survey of channel morphology together with LiDAR data, allow us to estimate the amount of offset
of the active channel. Right-lateral offset of this active channel is between 6–18 m with a preferred
estimate of ~13 m. If initiation of this offset is synchronous with abandonment of the older channel, then the SAF at this site shows a late Holocene slip rate between 7–25 mm/yr with a preferred rate of 14–18 mm/yr. This preferred rate is similar to rates determined by earlier studies.
Friday, 28 May 2010
T1. Sierra Nevada Microplate-Basement and Basins II
30-1
1:45 PM
Busby, Cathy J.
[173042]
BIRTH OF A PLATE BOUNDARY
BUSBY, Cathy J.1, HAGAN, Jeanette C.2, KOERNER, Alice A.2, PUTIRKA, Keith3, PLUHAR,
Christopher J.4, and MELOSH, Benjamin L.5, (1) Department of Earth Science, University of
California, Santa Barbara, Webb Hall, BLDG 526, Santa Barbara, CA 93106-9630, cathy@
crustal.ucsb.edu, (2) Department of Earth Science, University of California, Santa Barbara,
Santa Barbara, CA 93106, (3) Department of Earth and Environmental Sciences, California
State University - Fresno, 2345 E. San Ramon Ave, MS/MH24, Fresno, CA 93720,
(4) Department of Earth & Environmental Sciences, California State University, Fresno,
2576 E. San Ramon Ave., Mail Stop ST-24, Fresno, CA 93740, (5) Earth Sciences, University
of California at Santa Barbara, Webb Hall, BLDG 526, Santa Barbara, CA 93106-9630
The transtensional eastern boundary of the Sierra Nevada microplate is a “classic” discrete plate
boundary that provides an ideal natural laboratory for studying the rupture of continental lithosphere. Regional-scale plate-tectonic reconstructions show a change from more westerly motion
to more northerly motion of both the Pacific plate and the Sierra Nevada microplate, relative to the
Colorado Plateau, at 10-12 Ma. We use new geologic map data from the central Sierra Nevada to
identify features that signal the birth of the Sierra Nevada microplate at ~10.5 Ma.
Releasing transtensional stepovers (or pull-aparts) along the plate boundary began to control
the siting of large volcanic centers by ~ 10.5 Ma, and continue to do so today (e.g. Long Valley
Caldera and Lassen Volcanic Center). Onset of transtension within the axis of the Ancestral
Cascades arc at ~ 10.5 Ma resulted in “flood andesite” eruptions over a >40 km long segment
of the new plate boundary, in the Sonora Pass to Bridgeport region (the largely trachyandesitic
“Table Mountain Latite/Formation”). These “flood andesites” were erupted from 6–8 km long fissures within volcanotectonic depressions that currently lie along the Sierra Nevada range crest
and range front. Individual lavas flowed distances up to 130 km, with volumes up to 20 km3, and
the >200km3 lava flow field was erupted in only 28-230 kyr. The Little Walker Caldera formed
at the site of maximum extension in this volcanotectonic lava depression complex, and erupted
~9.5 – 9.4 Ma large-volume trachydacite ignimbrites.
The birth of the plate boundary was also signaled by derangement of ancient drainage systems. For much of Cenozoic time, the present-day Sierra Nevada formed the western shoulder
of the “Nevadaplano” and was crossed by E-W paleocanyons/paleochannels carved into the
Nevadaplano, with a drainage divide >230 km to the east. Our mapping demonstrates progressive
derangement of this ancient E-W drainage system by N-S plate boundary structures, including:
(1) diversion of lavas and pyroclastic flows into N-S grabens at ~11-9 Ma, (2) stream capture at
the western edge of the volcanotectonic graben complex, on the modern range crest, at ~9 – 6
Ma, and (3) stream capture at the eastern edge of the volcanotectonic graben, at the base of the
range front, by the modern Little Walker River after 6 Ma.
30-2
2:00 PM
Rosenberg, Jessica E.
[172983]
IS PLIOCENE MAGMATISM IN THE NORTHERN SIERRA NEVADA RANGE LINKED TO
LITHOSPHERIC DELAMINATION OR TO THE ANCESTRAL CASCADE RANGE?
ROSENBERG, Jessica E. and GLAZNER, Allen F., Geological Sciences, Univ. of North
Carolina, Chapel Hill, NC 27599-3315, [email protected]
Delamination has been invoked to explain high-potassium magmatism in the central and southern
Sierra Nevada Range around 3.5 Ma (Pliocene), but magmatism of this age also occurs around
and north of the Lake Tahoe area of the northern Sierra Nevada. Plate reconstructions indicate
that the Mendocino Triple Junction was located well north of the southern and central Sierra during Pliocene volcanism there, but south of the Tahoe-Reno area. Therefore, Pliocene volcanism in
the southern and central Sierra cannot be part of the ancestral Cascade arc, but Pliocene volcanism near and north of Lake Tahoe may be. We have undertaken a geochemical and geochronological study of volcanic rocks between Lake Tahoe and Mt. Lassen in order to determine whether
they exhibit characteristics of the ancestral Cascade arc or of delamination. This study extends a
similar study by Cousens (2008) in the Tahoe-Truckee area. Ar-Ar analyses are in progress.
Samples from the Portola and Tahoe-Truckee areas are largely basalts and andesites. Although
they are not nearly as potassic as Pliocene rocks farther south, they exhibit chemical variations
that are distinct from those of the Mt. Lassen volcanic field of the Cascade Range, which lies
immediately to the north. Principal major-element differences are: (1) higher K2O and lower MgO
and CaO at a given value of SiO2, and (2) a restricted range of SiO2, with most samples <62 wt%.
In contrast, the Lassen field ranges up to ~75 wt%. Passing north from Tahoe toward Mt. Lassen,
the chemical differences between these rocks and the Lassen field lessen (K2O decreases
whereas MgO and CaO increase), although restricted silica variability remains.
Our analysis indicates that late Cenozoic volcanism near and north of Lake Tahoe is chemically
distinct from Lassen volcanism, but the trends converge passing northward. Chemical differences
may reflect changes in lithospheric composition (reflecting the general northward transition from
N. American to accreted lithosphere), and the greater silica variability at Mt. Lassen may occur
owing to the large central volcanic center there. Volcanism near and north of Lake Tahoe seems
to have occurred in a discrete Pliocene pulse, similar to delamination magmatism to the south, but
exhibits geochemical characteristics that are similar to Cascade volcanism.
SESSION NO. 31
30-3
2:15 PM
Cassel, Elizabeth J.
[173100]
DEPOSITIONAL AGES, PROVENANCE, AND PALEO-DRAINAGE PATTERNS FROM
DETRITAL ZIRCON GEOCHRONOLOGY OF EOCENE-OLIGOCENE FLUVIAL SEDIMENTS
(“AURIFEROUS GRAVELS”) IN THE NORTHERN SIERRA NEVADA, CALIFORNIA
CASSEL, Elizabeth J., GRAHAM, Stephan A., and MAATTA, Sara C., Geological and
Environmental Sciences, Stanford University, 450 Serra Mall, Bldg. 320, Stanford, CA
To gain a better understanding of the Cenozoic tectonic and landscape evolution of the northern Sierra Nevada, we collected samples of Eocene to Oligocene fluvial sediments (‘auriferous
gravels’) throughout the Yuba and Feather River drainages for detrital zircon geochronology.
Sediments reflect braided stream deposition in basement-incised paleovalleys within a structurally
controlled intermontane basin, and age population differences between locations have allowed
us to reconstruct source terranes and drainage patterns within the Eocene system. U-Pb ages
of zircons in 14 samples were determined using LA-ICPMS. The majority of samples have large
populations from one of two distinct Mesozoic sources, as well as 5-30% Proterozoic grains,
reflecting provenance from basement terranes of both the Sierra Nevada and central Nevada (i.e.,
Shoo Fly Complex, Roberts Mountain Allochthon, western Nevada Triassic strata). Samples in
the southwestern Yuba River drainage were sourced predominantly from Campanian to Aptian
batholithic rocks, whereas eastern Yuba and Feather River drainage samples reflect provenance
from Jurassic basement terranes with no Cretaceous grains present. This distinction indicates diachronous sediment deposition across the basin and may reflect differential erosion of batholithic
rocks. Eastern samples also contain limited Eocene-early Oligocene populations, ranging from
42.7 to 28.6 Ma, which are interpreted to be youngest single-grain maximum depositional ages
(Dickinson and Gehrels, 2009). These results show long-term aggradation of the auriferous gravels as the locus of deposition migrated across the basin, and suggest that age determinations of
paleoflora from within the section may require revision. Youngest single-grain detrital zircon ages
are similar to the range of ages of Eocene volcanic rocks in central Nevada, and the presence of
these grains, along with Proterozoic populations found only in the Roberts Mountain allochthon
or western Nevada Triassic strata, suggests that Eocene paleovalleys extended as far east as
the Caetano Caldera in central Nevada, as has been suggested by previous studies (i.e., Henry,
2008). This provides support for the existence of a high elevation plateau at the latitude of Nevada
(‘Nevadaplano’) from Eocene through Oligocene time.
30-4
2:30 PM
Cecil, M. Robinson
[173631]
PALEOTOPOGRAPHY OF THE CENTRAL - NORTHERN SIERRA NEVADA AND
IMPLICATIONS FOR UPLIFT AND TILTING OF THE SIERRAN BLOCK
CECIL, M. Robinson1, DUCEA, Mihai N.1, REINERS, Peter W.1, GEHRELS, George E.1,
MULCH, Andreas2, ALLEN, Charlotte M.3, and CAMPBELL, Ian H.3, (1) Department of
Geosciences, University of Arizona, Tucson, AZ 85721, [email protected], (2) Institute
of Geology, Universität Hannover, Callinstr. 30, Hannover, 30167, Germany, (3) Research
School of Earth Sciences, Australian National Univ, Canberra, 0200, Australia
Because of its high elevations and rugged relief, the Sierra Nevada has commonly been considered an example of youthful topography, yet available paleoaltimetric and thermochronologic data
suggest topographic antiquity of the range. We address this issue by using the geo- and thermochronology of Eocene fluvial deposits, preserved along the western flank of the central and
northern Sierra Nevada, to trace the sourcing of detritus in paleoriver systems and to constrain
the development of the Sierra Nevada range front. U-Pb ages of detrital zircons from the ancestral
Yuba, American, Mokelumne, and Stanislaus Rivers, are measured with the aim of constraining
the paleotopography of source regions, and the development of regional drainage systems. U-Pb
ages are bimodal, with a dominant age peak between ~110 – 90 Ma, and lesser, but significant,
peaks in the Jurassic (between ~ 170 and 150 Ma), a distribution that matches that of pluton ages
in the central and northern Sierra. Pre-Mesozoic aged grains represent a small fraction (up to
6%) of the total population from a given sample locality, and are a good match to local metasedimentary belts. A subset of zircons (n = 11) from one locality were double-dated using U-Pb and
(U-Th)/He methods. Zircon crystallization ages range from ~ 2500 Ma to 90 Ma and have corresponding (U-Th)/He ages which do not correlate with U-Pb age, and which range from 114 Ma to
74 Ma, consistent with cooling ages reported for the northern Sierra Nevada. Our results suggest
that Eocene rivers were sourced locally within the Sierra and were likely shorter, steeper, and
draining smaller catchments than was commonly thought. Furthermore, our data suggest that the
Sierra Nevada was a major topographic barrier that had an established drainage divide through
the early – mid Cenozoic. Given geologic and paleoelevation data, which indicate moderate
to high mid Cenozoic elevations for the adjacent Great Basin, the Sierran crest was likely high
(>2 km) in the Eocene, with a western flank characterized by a gradient similar to the modern one.
Our results, therefore, are consistent with a model of Sierran topographic antiquity, and preclude
major post-Eocene crestal uplift and /or westward block tilting.
30-5
3:00 PM
Figueroa, Andrea M.
[173710]
TECTONIC GEOMORPHOLOGY OF THE SOUTHERN SIERRA NEVADA MOUNTAINS
(CALIFORNIA): EVIDENCE FOR UPLIFT AND BASIN FORMATION
FIGUEROA, Andrea M. and KNOTT, Jeffrey R., Department of Geological Sciences,
California State Univ, Fullerton, Box 6850, Fullerton, CA 92834, [email protected]
There are a number of hypotheses regarding Late Cenozoic uplift of the Sierra Nevada Mountains
(Sierra), California, U.S.A.:,a single, slowly tilting, homogenous block driven by normal faulting on
the eastern margin; rapid Pliocene uplift generated by lower crust delamination; erosion driven
in part by late Pleistocene glaciation; uplift related to the Mendocino triple-junction’s northward
migration. Tectonic geomorphic studies have focused on the eastern margin and the historically
active Owens Valley frontal fault; however, crustal delamination is along the western margin and
adjoining valley. To test the various late Cenozoic uplift hypotheses, we examined geomorphic
indices of the western Sierra such as longitudinal profiles of the larger westerly flowing rivers,
mountain front sinuosity, valley floor width to height ratio, range-crest profile and basin relief
ratio. We chose these morphometrics and the western rivers to avoid the influence of glaciation
and to better investigate the western margin of the range. In some areas, application of certain
morphometrics is limited due to the presence of dams along the rivers. In the southernmost area,
the mountain front is more linear and valley narrower and the Kern River has a convex-up profile.
The morphometrics indicate slightly greater tectonic activity near the Kings River as well, but not
a strongly as the south. Our results show that relative tectonic activity is greatest in the southern
Sierra near the Kern River Gorge fault and the highest range elevations. In addition, the region
centered near the Kings River, where crustal delamination is suspected shows greater tectonic
activity, but at a lower rate, compared to other areas. We interpret these data to indicate that the
southern Sierra is presently experiencing relative base level changes (basin formation and range
uplift) related to proximity to the San Andreas and related fault zones and that the Kings River
geomorphology records a rapid uplift in the past, probably related to Pliocene delamination.
30-6
3:15 PM
Kleck, Wallace D.
[172941]
A PRELIMINARY STUDY OF THE CENOZOIC HISTORY OF THE KERN RIVER, SIERRA
NEVADA MOUNTAINS, CALIFORNIA
KLECK, Wallace D., 23940 Basin Harbor Court, Tehachapi, CA 93561,
[email protected]
This study of the Kern River (southern Sierra block--SSB), shows that the course changes of the
river can be related to tectonic events affecting the SSB of the Sierra Nevada. The nature of the
course changes reveals some of the dates and nature of the tectonic activity affecting the SSB.
Deposits from the Kern River during ~70-40 Ma occur in the El Paso Mountains of the southwestern Basin and Range province; distal deposits less than ~20 Ma occur in the well documented
San Joaquin Basin. These deposits provide the primary source of data for the courses of the
Kern River.
Between ~70 and ~20 Ma, the combined blocks of the Sierra Nevada were reduced to a lowlying, low-relief terrain. Until ~40 Ma, the Kern River delivered sediment to a basin east of the
Sierras; this sediment indicates that the river dates from ~70 Ma. At ~20 Ma and approximately
contemporaneous with the beginning of the current San Andreas Fault and the San Joaquin
Basin, tectonic events separated the SSB from the rest of the Sierra mountains. This included the
development of the Garlock and San Andreas Faults (south side), Kern Front Fault system (west
side), and the Sierra Nevada Fault system (east side). A fault, bounding the north side of the SSB,
occurred at about 36o N latitude and is marked by an offset of the drainage, a remnant of an earlier drainage, later basaltic volcanism, and a distinct change in topography. At this time, the drainage of the upper Kern River shifted and that of the lower Kern River changed from east to west.
The block moved vertically upward along the Kern Front Fault system by at least 10’s of meters,
and the SSB became a fault-bounded block distinct and separate from the central-northern block.
At ~12 Ma, movement on a reactivated part of the Kern Canyon fault system tilted a small block
of the central part of the SSB 1-2 degrees northwest, and redirected the river into its present
channel. This faulting also created two ancient lake basins which were emptied by the end of the
Pleistocene Ice Ages. Starting at ~5 Ma, additional uplifts plus late discharge changes related to
the Pleistocene Ice Ages created several nick points and valley-shape changes in the Kern River
Gorge. Sometime between 9 and 3 Ma, the central-northern Sierra Block tilted (east side up),
rejoining the two Sierra blocks as well as the northern most drainage of the Kern River.
Friday, 28 May 2010
T6. New Insights into Tectonics of the Central
California Coast Ranges—The Link between
Los Angeles and San Francisco (Cordilleran Section
GSA; Pacific Section, AAPG; Pacific Section SEPM)
31-1
1:35 PM
Langenheim, V.E.
[172689]
IMPLICATIONS OF CUMULATIVE OFFSETS ALONG THE SAN GREGORIO-HOSGRI FAULT,
CALIFORNIA: WHY THE SANTA MARIA BASIN MATTERS
LANGENHEIM, V.E., JACHENS, R.C., GRAYMER, R.W., WENTWORTH, C.M.,
COLGAN, J.P., and STANLEY, R.G., U.S. Geological Survey, 345 Middlefield Road,
Menlo Park, CA 94025, [email protected]
Cumulative offsets on the San Gregorio-Hosgri fault derived from analysis of modern aeromagnetic surveys may help resolve the wide range in published offset estimates, but also indicate
that the Santa Maria Basin may hold the key to understanding how transrotation of the Western
Transverse Ranges is kinematically linked to right-lateral slip on strike-slip faults in the central
Coast Ranges. Linear ophiolitic belts that have been cut by the San Gregorio-Hosgri fault produce
offset magnetic anomalies that suggest southward-decreasing apparent right-lateral displacements, consistent with the pattern of published southward-decreasing Quaternary slip rates. The
southward decrease in apparent offset along the San Gregorio-Hosgri fault requires balancing
offsets onto other faults or structures. The 23 km difference in offset between Cape San Martin
(148 km) and Pt. Buchon (122 km) could be balanced by 23 km right-lateral slip on the OceanicWest Huasna fault, which offsets gravity and magnetic anomalies associated with the southeast
end of the Pismo syncline (and its underlying ophiolitic basement) by as much as 33 km. The
10-km discrepancy could be taken up in part by minor faulting along the Southwest Boundary
fault zone, south of Point Buchon, where marine and helicopter magnetic data suggest 1-2 km of
apparent right-lateral offset in places. However, magnetic data do not readily support continuation of the Hosgri fault south of Pt. Arguello and the edges of an elongate gravity low that curves
around Pt. Arguello from the Santa Barbara channel into the offshore Santa Maria basin also do
not appear to be offset by a southward continuation of the Hosgri fault. Thus, the largest change
in offset along the San Gregorio-Hosgri fault is located along the southern part of the fault, given
magnetic and geologic evidence for about 90 km of displacement of the Pt. Sal ophiolite (north to
San Simeon) and evidence for little or no displacement south of Pt. Arguello. Crustal shortening
across the southwestern Santa Maria basin as the sole mechanism to accommodate 90 km of
apparent right-lateral offset is unlikely (see Graymer et al., this session). A possible solution is to
transfer significant right-lateral displacement onto a proto-Hosgri fault just south of Pt. Sal prior to
5-6 Ma, yet this remains to be tested.
31-2
1:50 PM
Ernst, W.G.
[173087]
U-PB AGE OF THE PESCADERO FELSITE: LATE CRETACEOUS ARC VOLCANISM IN THE
WEST-CENTRAL CALIFORNIA COAST RANGES?
ERNST, W.G.1, MCLAUGHLIN, R.J.2, and CLARK, Joseph C.2, (1) Geological and
Environmental Sciences, Stanford University, Building 320, Room 118, Stanford, CA
94305-2115, [email protected], (2) U.S. Geol Survey, 345 Middlefield Road, Menlo Park,
CA 94025
Felsite structurally underlying unmetamorphosed Campanian-Maastrichtian Pigeon Point strata
near Pescadero, California contains disaggregated sandstone inclusions, minor neoblastic
pumpellyite ± prehnite, and later carbonate + laumontite veining. We analyzed 43 oscillatoryzoned zircon crystals from three felsite samples, 17 by SHRIMP-RG, 26 by LA-ICPMS. Thirtythree zircons gave late Mesozoic U-Pb ages, with single-grain values ranging from 81-167 Ma; ten
have pre-Mesozoic, chiefly Proterozoic ages. Four youngest Pescadero zircons yield a maximum
igneous age of ~86-90 Ma. Relative-probability curves for these Mesozoic and pre-Mesozoic
zircons compare reasonably well with U-Pb age data for detrital zircons from Diablo Range +
SESSION NO. 31
San Francisco Bay area Franciscan trench deposits, San Joaquin Great Valley forearc turbidites,
and Upper Cretaceous Nacimiento block Franciscan + Great Valley clastics of the Transverse
Ranges. The source region for the felsite is problematic reflecting poorly constrained pre-San
Gregorio-Hosgri fault system displacements by breaks within and bounding the Nacimiento block,
but restoration of ~150 km San Gregorio-Hosgri dextral offset would place the Pescadero felsite
adjacent to the Nacimiento block, which restores to southern California in pre-San Andreas fault
system time. Direct correlation with Diablo Range, San Francisco region, and San Joaquin strata
seems unlikely, whereas correlation with Nacimiento block Franciscan seems likely. The felsite
erupted in Late Cretaceous time, was metamorphosed at depth, then was uplifted, altered and
weathered before Pigeon Point deposition. Pescadero volcanism reflects a previously unrecognized ~86-90 Ma felsic igneous event in the accretionary margin resulting from anatexis of clastic
strata sourced from a calcalkaline volcanic-plutonic arc. Evidently this arc source, superposed on
ophiolitic + Franciscan rocks, resided south of the Sierra Nevada and Salinia, requiring pre-San
Andreas juxtaposition with the Salinian block. East of the San Gregorio-Hosgri fault system, arc
volcanics of similar Late Cretaceous age, metamorphism and paleogeographic setting are known
only south of the Peninsula Ranges, although their absence to the north might be the result of
crustal shortening, uplift and/or erosion.
31-3
2:05 PM
Titus, Sarah
[173046]
PALEOMAGNETIC DATA FROM THE RINCONADA FAULT IN CENTRAL CALIFORNIA:
EVIDENCE FOR OFF-FAULT DEFORMATION AND LONG-TERM CREEP ALONG THE
SAN ANDREAS FAULT
TITUS, Sarah1, CRUMP, Sarah1, MCGUIRE, Zack1, HORSMAN, Eric2, and HOUSEN,
Bernard3, (1) Dept. of Geology, Carleton College, Northfield, MN 55057, [email protected],
(2) Dept. of Geological Sciences, East Carolina University, Greenville, NC 27858, (3) Geology
Department, Western Washington University, Bellingham, WA 98225
In central California, the plate boundary system is composed of three major sub-parallel faults,
including the creeping segment of the San Andreas fault, which separate internally deforming
fault-bound regions. Documenting the style and magnitude of deformation in these fault borderlands is difficult but important for understanding the partitioning of plate boundary deformation.
We sampled ~150 sites from the Miocene Monterey Formation adjacent to the Rinconada fault
in central California to look for evidence of paleomagnetic vertical axis rotations. The sites were
located within 15 km of the fault trace along a segment of the Rinconada fault that stretches from
Greenfield to Paso Robles. Because this unit was deposited while the San Andreas fault system
was active at this latitude, any deformation recorded by these rocks must be related to plate
boundary deformation. Unlike the large (>90˚) rotations observed in the Transverse Ranges to the
south, vertical axis rotations adjacent to the Rinconada fault are smaller and vary with distance
from the fault as well as along strike. In the northwest and central portions of the fault, 15-25˚
clockwise rotations are observed close to the fault; these rotations decrease with distance from
the fault. In the southeast portion of the fault, small (~5˚) to negligible clockwise vertical axis rotations are observed with ~15˚ counterclockwise rotations from several sites.
We suggest that spatial patterns of vertical axis rotations are controlled, in part, by the creeping segment of the San Andreas fault. Creeping behavior alters the modern velocity field, and
counterclockwise rotations are predicted from the velocity field in the area that coincides with
our observed counterclockwise rotations. To match the observed paleomagnetic rotations, we
suggest that aseismic deformation along the creeping segment has been occurring for several
million years.
31-4
2:20 PM
AbramsonWard, Hans
[173638]
PALEOSHORELINES OFFSHORE OF THE SAN LUIS RANGE, SAN LUIS OBISPO COUNTY,
CENTRAL COASTAL CALIFORNIA
ABRAMSONWARD, Hans1, HANSON, Kathryn1, GREENE, H. Gary2, PAGE, William D.3, and
LETTIS, William R.4, (1) AMEC Geomatrix, Inc, 2101 Webster Street, 12th Floor, Oakland,
CA 94612, [email protected], (2) CapRock, Santa Cruz, CA, (3) Pacific Gas
and Electric Company, 245 Market Street, San Francisco, CA 94105, (4) Fugro Willam Lettis
& Associates , Inc, Walnut Creek, CA 94596
Emergent marine terraces mapped in the San Luis Range between Morro Bay and Pismo Beach
record a history of slow tectonic uplift. This flight of terraces consists of wave-cut platforms and
paleo-seacliffs whose intersections (shoreline angles) record the relative sea level during middle
to late Quaternary highstands. Terrace ages have been established based on multiple dating and
correlation techniques (Hanson et al., 1994). These terraces are important datums for evaluating
rates of Quaternary uplift and locations of active crustal structures in this area.
Similar to the emergent terraces, submerged wave-cut platforms and paleo-seacliffs offshore
record paleosea-level lowstands, stillstands and highstands. These paleoshorelines are recorded
in detailed multibeam bathymetry and shallow seismic reflection lines collected in 2008 and 2009.
We have identified several gently-sloping platforms backed by steeper scarps (paleo-seacliffs),
both as well expressed geomorphic features evident in the bathymetry of the rocky parts of the
shelf and also buried beneath mobile sand sheets and thicker marine sediments evident in seismic reflection profiles. We estimate ages of submerged paleoshorelines based on correlation to
global Quaternary sea-level curves. We recognize that wave erosion during the Holocene sealevel rise may have partly eroded the paleoshorelines; however, the (local) clarity of their geomorphic signature suggests that erosion during the short time (~hundreds of years) that the rise in
sea level crossed any paleoshoreline was not sufficient to change its basic geomorphic character.
We find that lateral correlation of individual features is complicated by the lack of continuity of
many of the paleoshorelines due to fluvial erosion during sea-level lowstands, marine planation
during younger sea-level high stands, burial of the features by younger sediment, and possible
tectonic deformation. Precise dating of these shorelines will be difficult because the Holocene
sea-level rise likely removed most of the older sediment and fossils that could be used to date the
platforms and shorelines. Nonetheless we are using the offshore terrace sequence to help locate
deformation known onshore as it projects offshore and to help estimate vertical slip rates.
31-5
2:35 PM
Nishenko, S.P.
[173105]
SHORELINE FAULT ZONE, SOUTH-CENTRAL COASTAL CALIFORNIA
NISHENKO, S.P.1, MCLAREN, M.K.1, PAGE, W.D.1, LANGENHEIM, V.E.2, WATT, J.T.2,
GREENE, H.G.3, RIETMAN, J.D.4, LETTIS, W.R.4, ANGELL, M.4, and KVITEK, R.5, (1) Pacific
Gas and Electric Company, 245 Market Street, San Francisco, CA 94105, [email protected],
(2) U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, (3) CapRock,
Santa Cruz, CA, (4) Fugro Willam Lettis & Associates , Inc, Walnut Creek, CA 94596,
(5) Seafloor Mapping Lab, California State University Monterey Bay, Seaside, CA 93955
High-resolution multibeam echo sounding, seismic-reflection, and aeromagnetic data collected
in 2009 have improved the resolution and definition of the Shoreline fault zone (SFZ) in southcentral coastal California. The SFZ was identified by Hardebeck (2009) as a lineation of relocated
seismicity about 0.5 km offshore of the Irish Hills between Point Buchon and Point San Luis, east
of the Hosgri fault zone. Subsequent investigations indicate that the seismicity lineament is coin-
82 2010 GSA Abstracts with Programs cident, in part, with a series of prominent bathymetric and magnetic lineaments that cut across
Cretaceous and Miocene rocks. The surface expression of the SFZ consists of three distinct
segments: 1] a 6 to 9 km Northern segment that is defined by a distinct N40°W trending discontinuous scarp that truncates bedding and structures of the Obispo and Monterey formations; 2] an
8 km Central segment expressed as a distinct bathymetric and magnetic lineament that juxtaposes different bedrock lithologies, truncates bedding and structures, and has scarps, gas-related
pock marks and mud extrusions; and 3] a 6 km Southern segment expressed as a poor to moderate bathymetric lineament with local scarps and juxtaposed bedding. The Central and Southern
segments form a right-stepping en echelon pattern with a strike of N60° to 70°W, consistent with
the right-lateral strike-slip focal mechanisms and the vertical plane of the microseismicity lineament that extends to a depth of ~10 km. The northern part of the seismicity lineament is more diffuse, extends to a depth of 12 km and diverges west from the surface expression of the Northern
segment. High-resolution seismic-reflection profiles across the northern portion of the seismicity
lineament indicate the lineament is not associated with near-surface faulting. It may be that this
portion of the seismicity lineament is associated with a fault that does not reach the surface or is
associated with the western trace of the Hosgri fault zone that dips east toward the SFZ.
31-6
2:50 PM
Coppersmith, Ryan Thomas
[173206]
STRUCTURAL ANALYSIS OF THE SAN SIMEON FAULT ZONE, CALIFORNIA: IMPLICATIONS
FOR TRANSFORM TECTONICS
COPPERSMITH, Ryan Thomas, AMEC Geomatrix, 2101 Webster Street 12th Floor,
Oakland, CA 94612, [email protected]
This study provides a detailed structural analysis of the abundant bedrock faulting along the
sea-cliff exposure neighboring the San Simeon fault zone (SSFZ). The San Gregorio-Hosgri fault
zone (SGH), located in the Southern Coast Ranges of California, is a 420 km long right-lateral
strand of the San Andreas fault system. The SSFZ is a segment of the SGH that crosscuts the
Nacimiento block, which is primarily composed of Franciscan Complex accretionary prism. The
Nacimiento fault juxtaposes the Nacimiento block with the Salinian block, a portion of the Sierra
Nevada batholith. Both blocks have been displaced from the south in a right-lateral sense due to
movement within the San Andreas fault system. The SSFZ juxtaposes mid-Jurassic Coast Range
ophiolite with Cretaceous Franciscan accretionary prism material. These units are locally overlain
by the Oligocene Lospe Formation and the Miocene Monterey Formation.
To better understand the movement history near the SSFZ, 28 km of outcrop were examined
along the sea cliff between Ragged Point and Pico Creek. The bedrock exposure included 7 km
of ophiolitic material, 16 km of Franciscan Complex, 2 km of Lospe Formation, and 3 km of
Monterey Formation. In all, 718 faults were mapped, and 22 of these juxtapose formations or
different units within the ophiolite. Slickenlines were identified on 517 faults, of which 237 record
sense of slip. Of the faults measured, 199 are strike-slip, 179 are dip-slip, and 139 are obliqueslip. Kinematic indicators record a wide range of movements: 49 right-lateral, 47 left-lateral, 40
normal, 38 reverse, 18 reverse left-lateral, 17 normal left-lateral, 15 normal right-lateral, and 13
reverse right-lateral faults.
The study transect was divided into structural domains based on fault kinematic patterns. Fault
kinematics that differ from the regional N35W strike of the SSFZ are explained by local variations
in movement patterns that include local bends and splays off of the fault zone The fault splays that
juxtapose mélange with ophiolite have multi-kilometer offset. This study finds that the kilometerscale offset occurred during transform movement rather than during earlier subduction-related
movement. Further, the study redefines the SSFZ as a 1 km wide zone indicated by a cluster of
faults near the San Simeon Pier that define the eastern boundary.
31-7
3:05 PM
Graymer, R.W.
[173114]
NEW INSIGHTS INTO THE TECTONICS OF THE CENTRAL CALIFORNIA COAST RANGES
FROM CROSS-SECTIONS BASED ON DIGITAL GEOLOGIC MAPPING AND POTENTIALFIELD GEOPHYSICS
GRAYMER, R.W.1, LANGENHEIM, V.E.2, ROSENBERG, L.I.3, COLGAN, J.P.2, and
ROBERTS, M.A.4, (1) U.S. Geological Survey, 345 Middlefield Road, MS 973, Menlo
Park, CA 94025, [email protected], (2) U.S. Geological Survey, 345 Middlefield Road,
Menlo Park, CA 94025, (3) Tierra Geoscience, P.O. Box 1693, Tijeras, NM 87059, (4) U. S.
Geological Survey, 345 Middlefield Rd, Menlo Park, CA 94025
We have compiled a new digital geologic map of the central California Coast Ranges, covering
the area from Monterey Bay southward to the Santa Ynez Mountains, and from the coast eastward to the San Andreas fault. This map synthesizes digital geologic maps of Monterey and San
Luis Obispo Counties, the Santa Maria and Cuyama 30’X60’ quadrangles, and other published
geologic maps with a new, unified stratigraphic interpretation. We combined this map with oil-well,
gravity, and aeromagnetic data to produce a series of crustal-scale cross-sections that offer new
insights into the 3D structure of the Coast Ranges, including as follows:
1. In the subsurface beneath the San Antonio River valley, we model a northeast-dipping, blind,
reverse (oblique?) fault as a southeast-trending continuation of the Jolon fault. Deformation and
uplift of Pleistocene gravels in the hanging wall block suggests Quaternary slip along the Jolon
fault, but further work is necessary to determine whether there has been Holocene activity and to
establish a Quaternary slip rate.
2. Preliminary restoration of Miocene and younger Hosgri fault-parallel compression across the
Santa Ynez River and Lion’s Head faults yields about 4 km shortening (27% strain) along a line
from Point Conception through Santa Rita Valley. This computation suggests that an apparent
southward decrease in right-lateral offset on the Hosgri Fault, from about 90 km at Point Sal to
zero at Point Arguello (see Langenheim et al., this session) was not accommodated by fault-parallel Coast Range shortening between the Santa Ynez River and Lions Head faults, and instead
was accommodated by slip along yet-to-be-identified faults.
3. Gravity and aeromagnetic data along a line from Point San Luis through the Irish Hills demonstrate that the southwest-dipping Los Osos fault is a young reverse fault with modest (<1 km
total) dip separation that has been superimposed on a older, larger, northeast-dipping basement
normal fault.
We continue to develop widely spaced regional cross-sections spanning the central Coast
Ranges together with closely spaced, detailed cross-sections in certain areas that exhibit key tectonic relationships. We are using these cross-sections to refine a preliminary 3D seismotectonic
model of the central Coast Ranges (see Jachens et al., this session).
SESSION NO. 32
Friday, 28 May 2010
T7. Late Neogene Tectonics and Deformation along
Active Faults East of and Including the San Andreas—
San Jacinto Fault Zones (Cordilleran Section GSA;
Pacific Section, AAPG; Pacific Section SEPM)
ping, determined ages and remanent magnetizations of Miocene strata, acquired detailed
aeromagnetic data, and evaluated LiDAR topographic data to examine these puzzles. Major
findings to date include: (1) Apparently complex geometry of the west side of the sinistral fault
domain is greatly simplified by the recognition of a new NNW-striking active dextral fault (Paradise
fault). (2) The southern three sinistral faults (Cave Mountain, Manix, and Cady faults) are active,
whereas the northern faults last ruptured during the late Pleistocene. (3) However, total offsets on
the three southern sinistral faults range from 4-6 km to less than 1 km, less offset than those to
the north. (4) Also, vertical-axis rotations of these southern blocks are significantly less than the
northerly blocks. (5) Sinistral faults are interwoven in time and space with dextral faults along the
east side of the sinistral domain. (6) Smaller fault blocks and off-fault strain manifested by folding
locally accommodate slip at domain boundaries. These observations indicate that boundaries
between dextral and sinistral domains consist of dynamically adjusting small tectonic blocks and
that east-striking faults represent a stable, if enigmatic, mode of failure in the Mojave Desert.
32-4
32-1
1:35 PM
Andrew, Joseph E.
[173099]
LARGE-MAGNITUDE EXTENSION OF THE DEATH VALLEY DETACHMENT SYSTEM AND
EVOLUTION OF THE GARLOCK FAULT
ANDREW, Joseph E., Department of Geology, University of Kansas, Lawrence, KS 66045,
[email protected]
The Death Valley extensional system has been variously interpreted as having extreme to moderate extension. Large-magnitude slip is based mainly on reconstruction of the Miocene Eagle
Mountain Formation in the Nopah Range to a location near the Hunter Mountain batholith in the
Cottonwood Mountains for ~100 km of displacement (Niemi et al., 2001). The applicability of the
Eagle Mountain Formation as a piercing point was questioned by Christie-Blick et al. (2007). An
additional piercing point for the Death Valley detachment system is needed to support, refine, or
refute the reconstruction using the Eagle Mountain Formation.
Another possible feature for reconstructing the displacement on the Death Valley detachment
system is a set of Miocene rapakivi granites. The Little Chief stock (LCS) of the Panamint Range
is in the hanging wall of the detachment system, whereas the granite of Kingston Peak (GKP) in
the Kingston Range is in the footwall. These two plutons are distinctive and have similar ages,
intrusive structures, and geochemical signatures (Calzia and Ramo, 2005). A possible difference
between these plutons is their relative depth of emplacement: the GKP is interpreted to have
been emplaced at or less than 4 km depth (Calzia and Ramo, 2005) and the LCS at 1.2 to 2.7 km
(McDowell, 1967). Both plutons intrude similar facies Proterozoic Pahrump Group rocks (Prave,
1997), and in part, the GKP intrudes somewhat structurally deeper rocks. Reconstruction of these
two plutons into a single intrusive body yields a displacement vector of ~105 km to the WNW, very
similar to that from reconstruction of the Eagle Mountain Formation.
This extension model has implications for the evolution of the Garlock fault. The reconstruction of the LCS over the GKP and restoration of the left-lateral slip on the Garlock fault places
the Nipton fault in Ivanpah Valley, as an eastern extension of the Garlock fault. The Nipton fault
has ~15 km of left-lateral slip (Mahan et al., 2009) and may preserve the early slip history of the
Garlock fault. If this interpretation is correct, then the Garlock and Nipton faults were offset by
~90 km of right-slip on the Southern Death Valley fault zone. The timing and details of this scenario may elucidate the evolution of slip on the Garlock and its interactions with the bend of the
San Andreas fault.
32-2
1:55 PM
Schmidt, Kevin M.
[172971]
GEOLOGY AND GEOPHYSICS ILLUMINATE LATE QUATERNARY OFFSET ALONG THE CADY
FAULT WITHIN THE EASTERN CALIFORNIA SHEAR ZONE, SOUTHERN CALIFORNIA
SCHMIDT, Kevin M.1, LANGENHEIM, Victoria2, HANSHAW, Maiana N.1, MILLER, David M.3,
HILLHOUSE, J.W.2, and PHELPS, G.A.4, (1) U. S. Geological Survey, 345 Middlefield
Rd, MS 973, Menlo Park, CA 94025, [email protected], (2) U. S. Geological Survey,
345 Middlefield Road, Menlo Park, CA 94025, (3) U.S. Geological Survey, 345 Middlefield
Road MS 973, Menlo Park, CA 94025, (4) Geologic Division, U.S. Geological Survey,
345 Middlefield Road, MS 989, Menlo Park, CA 94025
We interpreted geologic mapping, magnetic anomalies, and paleomagnetic vertical axis rotations to constrain offsets along the east-striking sinistral Cady fault within the Mojave block of
the eastern California shear zone. Field mapping of Quaternary deposits and aeromagnetic data
indicate that the Cady fault forms a significant structural boundary separating NW-striking faults
to the south, such as the dextral Rodman, Pisgah, and Lavic Lake faults, from ENE-striking faults
to the north, such as the Manix fault. Both methods indicate that Cady fault strands truncate
NW-striking dextral faults and hence sinistral offset in this region is likely younger in age and more
dominant kinematically. Oblique sinistral offset rates, estimated from field mapping of displaced
Quaternary alluvial fan deposits and regional age constraints obtained through luminescence
dating techniques, decrease with older deposit age such that late Pleistocene/Holocene deposits yield 0.8 mm/yr rates; whereas, minimum rates for middle to early Pleistocene deposits are
as low as 0.002 mm/yr, assuming the time-averaged fault offset ensued immediately following
deposit formation. We estimate a total sinistral offset of ~5-6 km along the Cady fault based upon
reconstruction of displaced magnetic anomalies and assuming extensional strain in the region
began ~10 Ma, and a long-term offset rate of ~0.6 mm/yr. The mapped surface trace of the Cady
fault is ~23-km long and is concealed at its western end by Holocene eolian and fluvial deposits
south of the Mojave River. Aeromagnetic data support the interpretation that the fault bends to
a more WNW-strike extending westward for a total length of ~32 km, where it possibly connects
with the Manix fault. Kinematic reconstructions incorporating both slip along the Cady and Manix
faults and differential vertical axis rotation of blocks across the Cady fault are consistent with the
present topographic low of the Newberry Springs basin, which also coincides with a prominent
gravity low.
32-3
2:15 PM
Miller, D.M.
[173158]
INTERACTIONS OF ACTIVE SINISTRAL AND DEXTRAL FAULTS IN THE CENTRAL MOJAVE
DESERT, CALIFORNIA
MILLER, D.M.1, SCHMIDT, K.M.1, LANGENHEIM, V.E.2, HILLHOUSE, J.W.2, REHEIS, M.C.3,
and LESLIE, S.R.1, (1) U.S. Geological Survey, 345 Middlefield Road, MS 973, Menlo Park,
CA 94025, [email protected], (2) U.S. Geological Survey, 345 Middlefield Road, Menlo Park,
CA 94025, (3) U.S. Geol. Survey, MS 980, Federal Center, Denver, CO 80225
East-striking sinistral faults in the northern Mojave Desert form a domain that extends from the
eastern segment of the Garlock fault south to near Ludlow, CA and is surrounded by northweststriking dextral faults. The sinistral faults have very little resolved sinistral shear stress because
maximum stress is nearly perpendicular to the faults, yet several are active (cut Holocene
deposits), as are adjacent dextral faults. Puzzles associated with the faults include the behavior
of domain boundaries, the magnitude and timing of fault slip and vertical-axis block rotations,
and whether new faults initiate as old faults are abandoned. We have conducted detailed map-
2:35 PM
Hillhouse, J.W.
[173085]
NEW CONSTRAINTS ON TECTONIC ROTATIONS IN THE MOJAVE DESERT, CALIFORNIA:
PALEOMAGNETISM AND 40AR/39AR DATING OF THE MIOCENE PEACH SPRINGS TUFF
HILLHOUSE, J.W., U. S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025,
[email protected], TURRIN, Brent, Geological Sciences, Rutgers University, 610 Taylor
Road, Piscataway, NJ 08854-8066, and MILLER, David M., U.S. Geological Survey,
345 Middlefield Road MS 973, Menlo Park, CA 94025
We report new paleomagnetic results and 40Ar/39Ar ages from a key marker bed in the region
between Barstow, California and Peach Springs, Arizona. The single-crystal 40Ar/39Ar ages were
determined from ash-flow specimens used in previous paleomagnetic studies at sites correlated
to the Miocene Peach Springs Tuff (PST). Eight site-mean ages, which range from 18.43 Ma to
18.78 Ma, were obtained from areas near Fort Rock, AZ; McCullough Mts, NV; Cima, Parker
Dam, Danby, Ludlow, Kane Wash, and Stoddard Wash, CA. The regional mean age determination is 18.71 ± 0.13 Ma (1 sd of the mean), after the data from all sites were selected for sanidine
crystals that yielded greater than 90% radiogenic argon (N = 40). This age is compatible with
previous 40Ar/39Ar dating of the PST (18.5 ± 0.2, 18.42 ± 0.07 Ma), taking various neutron-flux
monitor calibrations into account. We report paleomagnetic results from 8 new sites that bear on
reconstructions of the Miocene basins associated with the Hector Formation, Barstow Formation,
and similar fine-grained sedimentary deposits in the region. The results extend and confirm
correlation of tuffs near Barstow (Daggett Ridge and Harvard Hill) with the PST. Other key findings pertain to age control of the Hector Formation and clockwise rotation of the Northeast
Mojave Domain. Our paleomagnetic study of a rhyolitic ash flow at Baxter Wash, northern Cady
Mountains, confirms the correlation of the PST in the Hector Formation and prompts reinterpretation of the previously determined magnetostratigraphy. Our model correlates the PST
to a normal-polarity zone just below the C6-C5E boundary (18.75 Ma) of the astronomically
tuned Geomagnetic Polarity Time Scale. After emplacement of the Peach Springs Tuff at Alvord
Mountain and the Cady Mountains, the southern part of the Northeast Mojave Domain (between
Cady and Coyote Lake faults) rotated clockwise 30°-55°. Clockwise rotations increase with distance northward from the Cady fault and may reflect Late Miocene and younger accommodation
of right-lateral motion across the Eastern California Shear Zone.
32-5
3:15 PM
Onderdonk, Nate
[172978]
PRELIMINARY RESULTS FROM MYSTIC LAKE: A NEW PALEOSEISMIC SITE ALONG THE
NORTHERN SAN JACINTO FAULT ZONE
ONDERDONK, Nate, Department of Geological Sciences, Cal State Long Beach, 1250
Bellflower Blvd, Long Beach, CA 90840, [email protected], MARLIYANI, Gayatri, Dept.
of Geological Sciences, San Diego State University, 5500 Campanile Dr, San Diego, CA
92182, ROCKWELL, Thomas K., Geological Sciences, San Diego State University, 5500
Campanile Dr, San Diego, CA 92182, and MCGILL, Sally, Geological Sciences, California
State University, San Bernardino, 5500 University Parkway, San Bernardino, CA 92407
We present preliminary results from a new paleoseismic site along the Claremont strand of the
San Jacinto Fault Zone in southern California. The site is located along the northeast edge of the
ephemeral Mystic Lake at the north end of the San Jacinto Valley step-over. A small-scale releasing step-over along the Claremont fault has created a sag depression that can be seen in early
aerial photography. We excavated a 1.5-2 m deep, 400 m-long trench across the full width of this
sag, exposing multiple faults and a structural depression filled with excellent shallow lake stratigraphy. Evidence for at least six surface ruptures is recorded in the stratigraphy, and preliminary
radiocarbon dating indicates that all six events occurred in the past 1600 years.
Most of the rupture events recorded in the stratigraphy are recognized along the fault that
bounds the southwest edge of the sag. This fault is expressed in the trench as a zone of progressively folded and displaced strata. The stratigraphic relationships suggest a model in which each
surface rupture results in subsidence of the sag, followed by clay deposition as the sag is filled in,
culminating in a weak surface soil. Upward terminations, fissures, folding, and growth stratigraphy
provide evidence for the six events. Preliminary 14C dating of 19 samples (out of over 200 that
were collected) indicates that the most recent rupture occurred after AD 1706-1719, and two
events have occurred since ca. AD 1200. There is evidence of a cluster of three events between
about AD 1020 and 1220, with a 6th event between AD 260-560. A similar event cluster between
AD 1050 and 1400 was observed at the Hog Lake paleoseismic site located 50 km to the south
along the Clark fault (Rockwell, 2008). This observation suggests that either some large San
Jacinto events may jump across the San Jacinto Valley releasing step-over that separates the
northern and central fault segments, or that stress triggering along one segment causes the other
to fail in close succession. Additional work will test these models, as well as whether ruptures
along the San Andreas fault identified at Wrightwood may have ruptured down the San Jacinto,
which would help explain the significant reduction in slip-rate southward along the San Andreas
fault in the San Bernardino area (McGill et al., 2008).
32-6
3:35 PM
Mahan, Shannon A.
[173642]
A COMPILATION OF OSL GEOCHRONOLOGY COLLECTED BY THE U.S. GEOLOGICAL
SURVEY FROM SOUTHERN CALIFORNIA: WHAT THE AGES TELL US AND HOW THEY
WILL BE USED
MAHAN, Shannon A., U.S. Geological Survey, Box 25046 Federal Center, Denver,
CO 80225, [email protected], MATTI, Jonathan, Environ & Nat Resources Bldg, US
Geological Survey, Tucson, AZ 85719-5035, MENGES, Christopher M., Geologic Division,
U.S. Geological Survey, 520 N. Park Avenue, Tucson, AZ 85719, and POWELL, Robert E.,
U.S. Geological Survey, Geology and Geophysics Science Center, 520 N Park Ave, Tucson,
AZ 85719
Over the last several years, the U.S. Geological Survey has investigated the geochronology
of surficial deposits associated with the San Andreas Fault (SAF) and the Eastern California
Shear Zone (ECSZ) in southern California using optically stimulated luminescence (OSL) dating.
These OSL ages elucidate ongoing landscape evolution and active tectonics, especially near
SESSION NO. 32
intersections between the fault systems, and span multiple physiographic provinces, including the
Peninsular Ranges, the Transverse Ranges, the Mojave Desert, and the Salton Trough. More than
sixty five OSL ages were generated from this study.
Within the Transverse Ranges, study areas included the Cottonwood Mountains, the
Cottonwood Pass-Cottonwood Springs area, and strands of the Chiriaco Fault where it crosses
the north piedmont of the Orocopia Mountains west of Chiriaco Summit. Within the Mojave Desert
Province we focused on the Twentynine Palms area, at the intersection between the ECSZ and
the Pinto Mountain Fault.
At the boundary between the Transverse Ranges and Peninsular Ranges Provinces, we
focused on complexities within the SAF zone associated with San Gorgonio Pass. Sample targets included terraces in the canyons of San Gorgonio River and Little San Gorgonio River, the
Banning Bench, the alluviated Beaumont Plain at the west end of the San Gorgonio Pass Fault
zone, the intersection of the Yucaipa horst-and-graben complex and the San Bernardino strand
of the SAF (Wilson Creek area), and a nested alluvial-fan complex astride strands of the SAF
at the mouth of Mission Creek at the northwestern head of Coachella Valley. Coachella Valley
and basins within the sinistral fault complex of the Eastern Transverse Ranges were also dated.
Samples were selected to help constrain the age of last movement on the Chiriaco fault, a major
sinistral fault zone in the eastern Transverse Ranges province, and to begin to document the ages
of major alluvial events in that province.
While most of the OSL ages are destined for maps or investigative reports, individual local sites
where intensive systematic sampling was possible can provide new and useful age control for the
latest Pleistocene to Holocene deposits and future investigations will be able to use the database
that has accumulated from this study.
Friday, 28 May 2010
T33. Reservoir Characterization II (Pacific Section,
AAPG; Society of Petroleum Engineers (SPE))
1:30 PM
Doris, N.
[172681]
INTEGRATING VINTAGE DATA WITH MODERN DATA TO OPTIMIZE FIELD EVALUATION,
WILMINGTON FIELD, CA
DORIS, N.1, HENDERSON, J.M.1, and SKARTVEDT-FORTE, Peggie2, (1) Warren E&P,
Inc, Long Beach, CA 90802, [email protected], (2) Schlumberger, Data and
Consulting Services, Bakersfield, CA 93309
The Wilmington Townlot Unit (WTU) is located in the northeast end of the Wilmington Field anticline and has been in various stages of development since 1937. Warren E&P, Inc. has drilled 76
highly deviated “S” shaped wells into the Upper Terminal Formation. The modern logging data
acquired from these wells has been very beneficial in the development of a 3D model in the central portion of WTU. However, a full WTU evaluation required the integration of up to an additional
1400 vintage wells covering the central portion as well as the remainder of WTU.
The overwhelmingly large amount of vintage data was filtered down to a select set of wells that
were dispersed over all of WTU. The vintage well logs were then normalized and modernized.
These updated logs were geologically interpreted and incorporated into the previously interpreted
modern data set. The existing structure model of the central portion was extended out to the
known OWC, increasing the modeled area by 66%. Petrophysical properties determined by the
modern data set were then distributed throughout the model honoring correlations with the vintage geological interpretations.
Integrating vintage data with modern data was beneficial in creating a comprehensive 3D full
field model. This model will be useful for identifying the remaining oil saturated sands throughout
the lease and designing highly targeted well trajectories with optimum placement throughout WTU.
33-2
2:00 PM
Little, Jeffrey D.
[173184]
A PRACTICAL APPROACH TO PETROPHYSICAL MODEL CONSTRUCTION IN ARKOSIC
AND SUB-ARKOSIC SEDIMENTS OF THE SESPE FORMATION USING LOG BASED
GEOCHEMICAL SPECTROSCOPY DATA
LITTLE, Jeffrey D.1, HORNER, Steve2, HORKOWITZ, Jack3, and SKARTVEDT-FORTE,
Peggie1, (1) Schlumberger, Data and Consulting Services, Bakersfield, CA 93309, little2@
slb.com, (2) Venoco Inc, Reservoir Engineering, Carpentaria, 93013, (3) Schlumberger,
Sugar Land, TX 77077
The Oligocene Sespe formation has produced more than 400 MMBO in Ventura County,
California. The arkosic reservoir sands contain highly variable mineralogy with significant quantities of feldspars, lithic fragments and clay minerals. The petrophysical response of the Sespe has
been very difficult to interpret since there is often little resistivity contrast between reservoir and
non-reservoir rocks. The practical goal is to infer the relative quantities of oil and brine in the pore
space of the rocks from knowledge of the complex mineralogy and the porosity of the rocks. This
task is greatly facilitated by knowledge of the elemental composition of the rock matrix and its
relationship to detailed mineralogy of the composite reservoir material. A geochemical instrument
capable of measuring the elemental abundance of the major rock forming minerals provides a
means to quantify the complex mineralogy of the Sespe formation and provide an accurate petrophysical interpretation.
A variety of models have been proposed by various authors for brine saturated rocks and other
synthetic composite materials. While it is unrealistic to assume the existence of a universal mixing
law appropriate for all rocks (irrespective to their depositional source), it seems reasonable that
specific families of rocks, each characterized by a suite of common minerals, could be described
by a specific geochemical model. Thus for example an arenitic sandstone might be described by a
different geochemical model than that which is appropriate to describe an arkosic sandstone.
In this paper we propose an analytical methodology to construct a mineralogy model to
describe the arkosic and subarkosic rocks of the Sespe formation. This geochemical based model
is shown to be in good agreement with laboratory mineralogy and chemistry measurements of
formation samples collected over a limited range of sedimentary rocks contained within the Sespe
formation. The core based model can then be applied to the much larger Sespe formation using
downhole geochemical logs. This scenario has been successfully applied in the West Montalvo
field, with good agreement between log based petrophysical interpretation and production results.
84 2010 GSA Abstracts with Programs 2:30 PM
Nichols, Jerry M.
[173637]
RESERVOIR CHARACTERIZATION PROVIDES OPTIMIZED COMPLETION STRATEGY IN THE
MONTEREY SHALE OF SOUTH BELRIDGE FIELD
NICHOLS, Jerry M., Orchard Petroleum Inc, 3585 Maple Street, Suite 284, Ventura, CA
93003, [email protected], GRAYSON, Stephen T., Schlumberger, 1710 Callens Rd,
Ventura, CA 93003, and LITTLE, Jeffrey D., Schlumberger, Data and Consulting Services,
Bakersfield, CA 93309
Reservoir characterization in the Miocene Monterey Shale formation is difficult due to a high
degree of heterogeneity. Lithology, texture, and silica phase can vary widely, rendering standard
saturation analysis of limited use. In addition, natural fractures can help or hinder completion strategies. A robust approach has been adopted to overcome the limitations of standard characterization techniques. This approach uses spectral gamma ray and elemental capture spectroscopy
to improve lithologic definition including additional minerals. It uses dielectric measurements to
understand changes to the near wellbore region due to invasion, and also to provide an independently derived saturation analysis. It also uses resistivity imaging to characterize the rock texture
and to identify faults and fracture systems. Finally, it uses Stoneley wave acoustic response to
identify permeable features observed in the images. Combining these methods can provide a
more complete characterization that helps define an optimum completion strategy, combining
natural and stimulated completions. Selective hydraulic stimulations using coiled tubing methods
have shown to be effective in certain zones but quickly add cost to the well, requiring increased
production to maintain profitability. Identification of zones capable of producing without hydraulic
stimulation greatly increases the profitability of the well.
33-4
33-1
33-3
3:00 PM
Harris, John H.
[173691]
FAULT DELINEATION IN OIL BASED MUD AT WEST MONTALVO FIELD USING A 3-D
RESISTIVITY TOOL
HARRIS, John H., Numeric Solutions, 2506 Bayshore Ave, Ventura, CA 93001, harris@
numericsolutions.com, GRAYSON, Stephen T., Schlumberger, 1710 Callens Rd, Ventura,
CA 93003, and ZAHNER, Bob, Venoco Inc, 6267 Carpinteria Ave., Suite 100, Carpinteria,
CA 93013
The exploitation of West Montalvo field has been recently invigorated when the field was purchased by Venoco in 2007. Long term success in this effort is dependent on gaining an accurate
picture of the faults that segment the field. Data available from the previous drilling programs is
from the 1950s & 60s and has some structural ambiguities. The recent drilling program helped
to gain a better understanding of the reservoir characterization and also the structural geology.
The delineation of important faults is made more complex because of the required oil based mud
system and the large amount of sedimentary effects on the observed bedding dips. However, a
new 3-D resistivity tool was run on wireline to provide dip corrected resistivities and formation
structural dip. This induction tool contains a series of 3-axis, co-located, transmitter and receiver
coils which provide sensitivity to resistivity anisotropy in the formation. Dipping beds or angled
boreholes can be accurately measured with this tool. So in the oil based mud environment where
standard resitivity imaging and dip analysis is more difficult, this tool provided both resistivity and
formation dip information that allowed the identification of a major fault in West Montalvo field.
These data has been integrated into the 3-D geologic model as an important control on the fault
characterization. Currently these data are used to further constrain the 3-D geologic model that
will aid in the future development of the West Montalvo field.
33-5
3:30 PM
Grayson, Stephen T.
[173706]
CHARACTERIZATION OF A THIN BEDDED RESERVOIR IN CALIFORNIA USING 3-D
RESISTIVITY MEASUREMENTS
GRAYSON, Stephen T.1, PRESTRIDGE, Andrew L.2, CAVETTE, Greg2, NELSON,
Michael P.2, SWAGER, Lee3, and KOVAC, Katherine3, (1) Schlumberger, 1710 Callens
Rd, Ventura, CA 93003, [email protected], (2) DCOR, LLC, Ventura, CA 93003,
(3) Schlumberger, Data and Consulting Services, Bakersfield, CA 93309
The Puente formation of offshore California contains thin-bedded turbidite sands. Geologic and
petrophysical evaluation of these zones has historically underestimated their net pay and hydrocarbon saturation parameters. The use of advanced logging technology has allowed an enhanced
understanding and quantification of this reservoir. Wireline resistivity imaging techniques were
used to identify the nature of the bedding and to quantify the bed thickness distribution. It was
recognized that bed thickness less than 2” were common in some subzones and that the resulting
net pay and saturation calculations were pessimistic. The under-estimation comes in part from
the averaging of the low-resistivity shale beds with the higher-resistivity pay sands, measured in
a vector parallel to the logging tool. A new 3-D resistivity tool was utilized which employs an array
of 3-axis, co-located coils, which provide horizontal (Rh) and vertical (Rv) resistivity measurements, corrected for bedding dip and hole angle. The thin bedded zones in the study field demonstrated resistivity anisotropy showing substantial differences between the vertical and horizontal
measurements, which are typical in thin bedded pay zones. The use of this 3-D resistivity data
resulted in the calculation of lower water saturations and increased net pay attributed to the thin
bedded zones.
33-6
4:00 PM
Perez, Enrique
[172868]
LABORATORY MEASUREMENTS OF PERMEABILITY REDUCTION IN NATURALLY
OCCURRING SHEAR BANDS FORMED IN UNLITHIFIED SANDS
PEREZ, Enrique, Geosciences, Penn State University, 320 Deike Bldg, University Park,
PA 16802, [email protected], KAPROTH, Bryan M., Dept. of Geological Sciences, Penn
State University, State College, 16802, HAINES, Samuel H., Geosciences, Pennsylvania
State University, 510 Deike Building, University Park, PA 16802, and SAFFER, Demian,
Geosciences, Penn State University, 310 Deike Bldg, University Park, PA 16802
Strain localization in porous sands leads to the formation of shear bands, which typically accommodate a few mm to tens of cm of slip, through grain fracturing, grain rotation and grain boundary
sliding. Reduced bulk permeability due to grain size reduction, porosity loss, and cementation in
shear bands can lead to decreased reservoir quality and compartmentalization. Previous studies have mainly focused on characterization of band geometry, grain size, structure, and origin.
Permeability measurements for shear bands are rare, and have generally been limited to shear
bands created in a laboratory or to field measurements under atmospheric pressure conditions.
The purpose of this study is to quantify permeability reduction in shear bands, and investigate
links between permeability and other shear band properties. We present a comprehensive suite of
data obtained for naturally occurring shear bands from an outcrop of unlithified sand in the footwall of the McKinleyville thrust fault in northern California. These data include laboratory permeability, porosity, and grain size measurements, as well as SEM analyses. We measured shear
band and host sand permeability under isostatic stress conditions, for confining pressures ranging
from 0.1 - 5 MPa. At each confining pressure, we applied a constant flow rate across the sample,
SESSION NO. 34
measured the resulting pressure gradient using a differential pressure transducer, and determined
permeability by Darcy’s Law.
We find that the mean grain size for host sand is 208 µm, whereas the mean grain size for
shear bands ranges from 31 – 185 µm, with the mean grain size decreasing with increased shear
band thickness. Host sand porosity ranges from 42 - 45%, and shear band porosity ranges from
32 - 39%. SEM images indicate that shear bands are weakly cemented; there is no evidence
of cementation in the host sand. Host sand permeability decreases from 1x10-14 m2 (10 mD) to
2x10-15 m2 (2 mD) as confining pressure is increased from 0.1 to 5 MPa. Results for six shear
bands illustrate a decrease from 1x10-14 m2 to 1x10-17 m2 over the same stress range. Preliminary
results suggest a clear and systematic relationship between larger shear band thickness and
decreased grain size, decreased porosity, and decreased permeability.
33-7
4:30 PM
Garven, Grant
eral years. This linear flow will be followed by BDF at later times. Therefore, the method proposed
in this study is practical for forecasting production data for these wells, as it considers these
two important flow regimes. The model is validated by comparing its results against test cases
which are built using numerical simulation to generate a 50‑year synthetic production profile. For
each case, the first year of the synthetic production data was used. It is found that there is an
excellent agreement between the forecast rates obtained using this method and the numerically
simulated rates. Currently, analysis techniques using material balance time (MBT) are being used
in industry to analyze shale/tight gas reservoirs. As MBT is superposition time during BDF, these
analyses may indicate BDF data, while the reservoir is still in transient. Here are the advantages
of the forecasting method proposed in this study: (1) It is not bias towards any flow regimes as
no superposition time functions are used; (2) An excellent forecast can be obtained without using
pseudo‑time. This is an advantage as using pseudo‑time introduces complexities and an iterative
procedure; and (3) The only parameter that it needs is drainage area.
[173259]
A GEOHYDRODYNAMIC STUDY OF THE ROLE OF FAULTS ON PETROLEUM MIGRATION IN
THE CALIFORNIA BORDERLAND BASINS
GARVEN, Grant1, JUNG, Byeongju1, and BOLES, James R.2, (1) Department of Geology,
Tufts University, 2 North Hill Rd, Medford, MA 02155, [email protected], (2)
Department of Earth Science, University of California, Webb Hall, BLDG 526, Santa Barbara,
CA 93106
We are applying newly-developed computational models to study the effects of Cenozoic extension, basin subsidence, transpression, and faulting on the migration of deep subsurface fluids (formation waters and petroleum) within the siliciclastic and petroleum-rich reservoirs of the California
Borderlands, including the Santa Barbara and the Los Angeles basins. Subsurface geology, reservoir data, and structural-seismic sections provide a clear picture of the degree of apparent compartmentalization for these well-known, petroleum-rich fault networks in an active tectonic setting.
These data also provide constraints for geohydrodynamic flow models that are being developed
to forward model pore pressures, flow rates, reactive-flow patterns, effects of fault-based fluid
mixing and mineralization, geothermics, and large-scale deformation. For example, we have
constructed numerical simulations to characterize the fluid flow history of the Los Angeles basin
for both single and two-phase fluid migration. The single-phase flow models are similar to those
of Hayba and Bethke (1995), and simulate the basin-scale compaction-driven flow associated
with deep-basin subsidence and later uplift of the San Gabriel Mountains. The two-phase flow
models provide a more detailed resolution, showing the effects of the stratigraphy and structure,
and do a robust job simulating patterns of petroleum migration associated with the southwestern
basin margin where deep faults produced thick stacking of petroleum accumulation over multiple
formations. Our model results suggest a long periods of episodic flows (100~200 kyr) from the
deep depocenter towards the western flank of the LA basin and the Palos Verdes Peninsula.
Computational experiments clearly strong effects of fault, the fluid physics being controlled by
Peclet and Capillary Numbers. The models also predict a strong preference for focused flow and
petroleum trapping along the Newport-Inglewood Fault Zone, but also substantial leakage across
the NIFZ and other faults, to elevate petroleum saturations in the the siliciclastic reservoirs of the
giant Wilmington field.
34-2
34-3
33-8
5:00 PM
Kovac, K.M.
[173895]
GEOLOGIC MODELING OF LAMINATED TURBIDITE SANDS OF AN OFFSHORE OILFIELD
KOVAC, K.M.1, KHAN, Shahnawaz1, NELSON, Michael P.2, SWAGER, Lee1, GRAYSON,
Stephen T.1, and BLUME, Cheryl1, (1) Schlumberger, [email protected], (2) DCOR, LLC,
Ventura, CA 93003
Economically productive sands in offshore turbidite reservoirs can be less than one foot thick.
Identification of those sands can determine a well’s economic viability. The federal government
estimates that 10 billion barrels of oil exist in the rocks of offshore California. This paper describes
detailed geologic characterization and modeling of a portion of an offshore California oil field. This
technique is based on a detailed workflow requiring resistivity-contrast generated borehole image
logs as input. The result is a fine resolution model incorporating both geologic and petrophysical
data to pinpoint potential thin bed net pay zones that could be overlooked using standard resolution wireline logs.
33-9
5:30 PM
O’Brien, Charles
[171975]
RESERVOIR MODELING OF THE BELRIDGE DIATOMITE
O’BRIEN, Charles, 10000 Ming Avenue, Bakersfield, CA 93311, [email protected]
The Belridge giant oil field is an elongated, faulted anticline on the west side of the San Joaquin
Valley, California. Since discovery in 1911, it has produced more than 1.2 billion BO. The Miocene
diatomite reservoir has approximately 6,000 well penetrations with a large associated core and
well log data base. Because the role played by silica diagenesis is poorly understood, estimation
of hydrocarbon volume has always been a challenge.
A workflow for an improved volumetric hydrocarbon estimation is presented. This is an integrated workflow which includes the use of mineralogy (XRF), oil-base core data, mercury-air
capillary, open-hole logs, production tests, and 3D geological modeling software.
Friday, 28 May 2010
T39. Tight Plays and Unconventional Reservoirs
34-1
1:30 PM
Nobakht, Morteza
[173835]
SIMPLIFIED AND RIGOROUS FORECASTING OF TIGHT/SHALE GAS PRODUCTION
NOBAKHT, Morteza and MATTAR, Louis, Fekete Associates Inc, Los Angeles, CA 90802,
[email protected]
In this paper, a simplified, yet rigorous, method of production forecasting for tight/shale gas reservoirs, which exhibit extended periods of linear flow, without the use of complex tools is proposed.
The method is simple as it relies principally on a plot of 1/rate versus square root time, and it
is rigorous in that it is based on the theory of linear flow and combines the linear flow transient
period with the hyperbolic decline during boundary‑dominated flow (BDF). The dominant flow
regime observed in most fractured tight/shale gas wells is linear flow, which may continue for sev-
Jessen, Kristian
[173836]
2:30 PM
Ghods, Ghods
[173837]
ENSEMBLE BASED CHARACTERIZATION AND HISTORY MATCHING OF NATURALLY
FRACTURED TIGHT/SHALE GAS RESERVOIRS
GHODS, Ghods, U of Southern California, Los Angeles, CA 90802, [email protected] and
ZHANG, Dongxiao, Department of Civil and Environmental Eng, University of Southern
California, 3620 S. Vermont Avenue, Los Angeles, CA 90089
Tight sand and shale gas reservoirs are becoming bigger players in natural gas supply system
as easily developed gas resources become scarcer, natural gas prices go higher, and more
efficient technologies become available to develop these hard to access reservoirs. Although
these reservoirs are really hard to develop but better hydraulic fracturing techniques are making
them more productive. Production and development of these types of reservoirs depend heavily on the hydraulic fracturing and the existence of natural fractures in the formations, since the
permeability of the matrix is so low that no commercially feasible gas production can be achieved
without fracturing. Therefore, characterizing and understanding the fractures have become of
great importance. We have proposed using different methodologies for fracture characterization and simulation in tight gas reservoirs. Dual Porosity, Dual Permeability modeling has been
used for simulation purposes. For a commercial simulator to be able to simulate the fluid flow
in a reservoir, properties such as permeability and porosity should be known which are usually
unknown because enough observations are unavailable. The only known values are measurements such as bottom‑hole pressures and production rates. Such a system requires solving an
inverse problem. Ensemble Kalman Filter has been used for our estimation purposes. EnKF is a
Monte Carlo based, MMSE estimation tool that generates multiple realizations based on our prior
knowledge of the reservoir and improves their performance using data assimilation. Our proposed
methodology has been tested on a synthetic 2D reservoir model containing a couple of fractures,
some intersecting the wells. The results have proven the applicability and the advantages of this
methodology. We have shown that EnKF can be used efficiently to characterize a fractured reservoir when the approximate orientations of fractures are known which may be obtained from the
stress‑strain field data in the reservoir.
34-4
2:00 PM
IMPACT OF RESERVOIR CHARACTERISTICS ON WATER PRODUCTION IN ENHANCED
COALBED METHANE OPERATIONS
JESSEN, Kristian and JAMSHIDI, Marjan, U of Southern California, Los Angeles, CA 90089,
[email protected]
Coalbed methane formations deliver a considerable amount of the US natural gas production
and have the potential of storing significant amounts of carbon dioxide through enhanced gas
recovery operations. Enhanced coalbed methane (ECBM) recovery by injection of carbon dioxide
or a mixture of carbon dioxide and nitrogen has been proven to recover additional natural gas
resources. However, since coalbeds are normally saturated with water and can be in communication with an aquifer, a large amount of water is often co‑produced during the natural gas extraction. The conventional approach for methane production relies on the reduction of the gas partial
pressure in the coal seam. This can be accomplished by either pumping the formation water to the
surface or injecting a mixture of gases. Disposal of the produced water is an environmental challenge since harmful impurities must be removed. Consequently, reduction of the water production
is desirable. In this paper we present a detailed numerical investigation of the potential reduction
in water production during ECBM operations while increasing the methane production. We use a
two‑ and a three‑dimensional coalbed models with an aquifer located on the bottom to investigate
the amounts of gas and water produced in ECBM operations per volume of coal seam as a function of aquifer support, cleat spacing and sorption characteristics of the coal. The amount of gas/
water produced varies significantly depending on the aquifer strength. We demonstrate that injection of carbon dioxide in some settings reduces the water handling problem. CBM is becoming an
important worldwide energy source with a large number of formations being excellent candidates
for ECBM recovery processes. Our analysis of the interplay between coal characteristics, aquifer
support and the resultant behavior in terms of gas/water production and carbon dioxide storage
capacity provides valuable new guidelines for future operations.
3:30 PM
Palmer, Ian D.
[173838]
THE PERMEABILITY FACTOR IN COALBED METHANE WELL COMPLETIONS AND
PRODUCTION
PALMER, Ian D., HiggsPalmer Tech, Los Angeles, CA 90802, [email protected]
Description: After 30 years of CBM production in the USA, general principles and decision trees
have emerged to guide an operator in choosing a well completion based on permeability. This
paper discusses the role of permeability in choosing CBM well completions, as well as examples
of those completions. We also re‑examine the striking observations of permeability increases with
depletion (10‑100 times) in the San Juan basin. Application. If enough permeability measurements are made, well completions can be prioritized, and hybrid well completions evaluated.
The benefits of horizontal and multi‑lateral wells are made clear. Low permeability is a serious
challenge for CBM ventures, and success will entail finding regions of enhanced permeability,
utilizing horizontal wells, and “creating” permeability by new‑paradigm methods. Industry results
have led to two benchmarks for evaluating, ahead of full‑field development, (1) commercial success from reservoir parameters, and (2) effectiveness of well completions by comparing early
production with reservoir parameters. The latest attempts to model and match the strong permeability increases with depletion in the San Juan basin are reconciled, although there remain
differences. Results and Conclusions. (1) guidelines for CBM well completions are given, which
include permeability bands, benchmarks, and decision trees, (2) options are evaluated for CBM
completions in low‑permeability “tight” coals, (3) a concensus has been obtained for some reservoir parameters after matching the strong permeability increases with depletion in the San Juan
basin. Significance: The guidelines, including permeability bands and benchmarks, are simple
and practical, and should benefit any CBM completions strategy. The concensus from modeling
SESSION NO. 34
permeability increases in the San Juan basin will assure better predictability of CBM production,
and of greenhouse gas injection into coalbeds.
34-5
4:00 PM
Wang, Jianwei
[173839]
APPLICATION OF ADVANCED RESERVOIR SIMULATION WORK FLOW IN TIGHT GAS
RESERVOIRS
WANG, Jianwei, ROBINSON, John R., THOMPSON, John Webster, and FAN, Li,
Schlumberger, Los Angeles, CA 90802, [email protected]
As demand for natural gas is increasing yearly, full field reservoir studies are becoming more
important to optimize recovery of tight gas fields. However, there are several challenges in tight
gas reservoir simulation studies. Since most wells are hydraulically fractured, appropriate representation of hydraulic fractures in a coarse grid is a key to overcome an impractical number of grid
blocks resulted using explicit gridding. During history matching fast updating hydraulic fracture
parameters is necessary since it may be time consuming when large number of wells and fracture
stages are involved. For tight gas reservoirs, shut‑in and initial well bottomhole pressures are
important for individual well matches and even fieldwide match, so accurately simulating observed
bottom‑hole pressures controls history match quality. In this paper we developed a practical
workflow to address the above challenges. First, hydraulic treatments were analyzed to estimate
fracture geometries (half‑length, height growth). Then hydraulic fractures were represented by
increasing transmissibilities of gridblocks that contain the fractures both in x and y direction. To
match initial well bottomhole pressure, bottomhole pressures were simulated by artificially completing wells earlier with negligible production rates and disabling wellbore cross‑flow. The process was automated using a VBA program, so updating the fracture model can be done in a very
short time. The workflow was applied in a fluvial tight gas field in Canada. History matching was
done by adjusting rock properties and hydraulic fracture parameters. Good history matches were
achieved for most wells, despite the complexity of this fluvial reservoir system. The calibrated
mode was then used to predict future performance for different development scenarios and evaluate infill locations. The chief technical contribution is the presentation of a workflow to model tight
gas reservoirs more efficiently. The workflow described can be applied to any tight gas reservoirs.
34-6
4:30 PM
King, James G.
[173840]
A RUN HISTORY OF NEW TECHNOLOGIES IN THE BAKKEN PLAY: MULTILATERALS AND
INCREASED STAGE OPENHOLE PACKER/SLEEVE SYSTEMS
KING, James G., Baker Oil, Los Angeles, CA 90802, [email protected], DEMARCHOS,
Andronikos S., Hess Corp, Los Angeles, CA 90802, and BUFFINGTON, Neil, Los Angeles,
CA 90802
This paper describes the run history results of a multilateral well with an increased number
of openhole packer and sleeve system (OHP/S) stages in the Bakken play in Williston Basin,
North Dakota. OHP/S systems reduce the completion elapsed time and inherent risks in pumping plugs in deep, long, horizontal hydraulically fractured completions. They are in wide use and
provide improved well productivity in multi‑stage hydraulically fractured completions, such as
the Bakken, resulting in markedly improved well performance, when compared to offset wells.
Multilateral completions greatly enhance the operational efficiency and production capability of
a well by doubling the exposure of formation from one surface location. Application The OHP/S
system works in low‑permeability formations requiring hydraulic fracturing for productivity. It also
is being used in multistage isolation for acidizing. It offers an alternative to traditional “plug & perf’
completions. The multilateral system enhances productivity of a well, decreases time to production of an operator’s asset, and minimizes surface impact of drilling activity. Results, Observations,
Conclusions The Multilateral equipment and increased stage OHP/S were deployed successfully;
the well was fractured, and is now on production. Many more similar completions are scheduled
for deployment in the Bakken shale. Significance This paper will discuss the applicability of using
OHP/S and multilateral systems in tight gas, gas shale, oil shale, and other low‑permeability
formations that require hydraulic fracturing to be commercially viable, and will illustrate the technology through a run history. The new technology design, lessons learned, best practices, well
performance improvement, and run history of these combined systems will be discussed. The
technologies applied here are of significant importance to all operators working in unconventional
reservoirs which require hydraulic fracturing.
Friday, 28 May 2010
T40. Managing Heavy Oil Resources
35-1
1:30 PM
[173841]
SIMULATION OF CYCLIC STEAM INJECTION INCLUDING THE EFFECTS OF TEMPERATURE
INDUCED WETTABILITY ALTERATION
KOVSCEK, Anthony Robert, Stanford University, Stanford, CA 94305, [email protected]
and HASCAKIR, Berna, Stanford University, Stanford, CA 90089
Cyclic steam injection into representative, low‑permeability, hydraulically fractured, diatomaceous,
heavy‑oil formations is investigated using reservoir simulation. Previous laboratory research has
shown that diatomite reservoir rocks exhibit temperature‑dependent wettability. Water‑oil and
liquid‑gas relative permeability are varied here and a reservoir simulator used to evaluate the
effects on oil recovery. Sensitivity studies are carried out for actual field data compiled from literature for diatomaceous reservoirs. The various field parameters included in the analysis are relative
permeability end points and viscosity variations with increasing temperature, rock and fluid properties (such as thermal conductivity and heat capacity), injected steam temperature, pressure,
and quality, bottom hole pressure for injectors and producers. Through this analysis, the optimum
injection, soaking, and production periods for each case are determined. The results indicate
that the liquid‑gas relative permeability affects process performance most sensitively, because
gas displacement determines the shape of the heated zone during cyclic steam injection. For the
recovery of heavy oil from diatomaceous formations, realistic evolution of the liquid‑gas relative
permeability at steam temperatures increases the oil recovery on the order of 100% in comparison to cases with no evolution of wettability with temperature.
2:00 PM
Wu, Yongfu
[173842]
AN EXPERIMENTAL STUDY OF ALKALINE SURFACTANT FLOODING FOR ULTRA SHALLOW
HEAVY OIL RESERVOIRS
WU, Yongfu1, HUNKY, Mohammed2, BAI, Baojun3, and NORMAN, Shari Dunn3, (1) Missouri
State, Springfield, MO 65897, [email protected], (2) h, Springfield, MO 65897, (3) Missouri
U of Science and Tech, Long Beach, 90802
Economic recovery of heavy oil from ultra shallow oil reservoirs (<500 ft) is of interest as many
such reservoirs exist throughout Utah, Missouri, and California. EOR methods, such as thermal
flooding, can be limited in these ultra shallow situations, and other methods of heavy oil recovery are of interest. A study of alkaline‑surfactant flooding in the Pennsylvanian Warner sand of
Western Missouri has been conducted. This work has included testing more than 30 commercially
available surfactants using sands saturated with heavy oil (API 17). It has been found that a few
surfactants can create a stable emulsion with the Warner heavy oil and the formation brine. In
all cases examined, highest recovery is from water wet sands. Applications: This study benefits
the industry by demonstrating the applicability of alkaline surfactant flooding to the Warner
sands of Western Missouri, and detailing experimental methods necessary to extrapolate this
work to other ultra shallow heavy oil reservoirs. Results, Observations, Conclusions: Viscosity
of Missouri heavy oil can be reduced from 28834 cp to 2.5 cp at 25 B0C through emulsion of
certain surfactants. Emulsion of the heavy oil and formation brine is stable for several weeks at
25 B0C. But the heavy oil in the emulsion can be easily separated without addition of de‑emulsion
agent. Alkaline‑surfactant (AS) system can change oily sand wettability from strongly oil‑wet to
water‑wet. Heavy oil recovery by AS flooding test at 25 B0C has been improved significantly.
Significance: The total volume of heavy oil in the United States is 100~180 billion barrels and a
significant amount of these reserves are in ultra shallow reservoirs (<500ft). Results of the current
work demonstrate that alkaline surfactant flooding can be effective in enhancing oil recovery in
the ultra shallow heavy oil reservoirs.
35-3
2:30 PM
Babadagli, Tayfun
[173844]
EFFICIENCY ANALYSIS OF STEAM OVER SOLVENT INJECTION IN FRACTURED
RESERVOIRS (SOS FR) METHOD FOR HEAVY OIL RECOVERY
BABADAGLI, Tayfun and AL BAHLANI, Al Muatasim Mohammad, U of Alberta, Edmonton,
AB T6G 2R3, Canada, [email protected]
Heavy‑oil recovery from fractured carbonates is a real challenge, yet no proven technology exists
as an efficient solution. Reservoir heating is generally inevitable and steam injection is the only
effective way to heat heavy‑matrix oil using the fracture network distributing steam. We propose a
new method minimizing heat needed for efficient heavy‑oil recovery from oil‑wet fractured rocks
by adding solvent component. Efficiency is a critical issue in this process as it involves a costly
application. The new technique called Steam‑Over‑Solvent in Fractured Reservoirs (SOS‑FR),
consists of cyclical injection of steam and solvent in the following manner: Phase‑1: Steam injection to heat up the matrix and recover oil mainly by thermal expansion, Phase‑2: Solvent injection
to produce matrix oil through diffusion‑imbibition‑drainage processes, and Phase‑3: Steam injection to retrieve injected solvent and recover more heavy‑oil. We performed static and dynamic
experiments by immersing samples into hot‑water and different hydrocarbon solvents or injecting
hot water and heptane alternatively to displace heavy‑oil. We showed that, under very unfavorable
conditions (oil‑wet, 4,000cp crude), oil recovery at the end of Phase‑3 was around 85‑90% OOIP
with 80‑85% solvent retrieval. The dynamic experimental results were matched to a single matrix/
single fracture numerical model and parameters needed for field scale simulation (matrix‑fracture
thermal diffusion, solvent diffusion and dispersion coefficients) were obtained. Using the data
obtained through matching, field scale simulations were performed for efficiency analysis and to
identify the optimal injection schemes (soaking time for cyclic and injection rate for continuous
injection) and durations, and surface steam quality. Specific conclusions as to how to apply this
technique efficiently in the field considering the cost of the process were reported.
35-4
3:30 PM
Ayodele, Oluropo Rufus
[173845]
TESTING AND HISTORY MATCHING OF ES SAGD (USING HEXANE)
AYODELE, Oluropo Rufus, Shell Exploration and Production, Los Angeles, CA 90802,
[email protected]
The use of Expanding‑Solvent SAGD (ES‑SAGD) as a recovery technology in bitumen and
heavy oil reservoirs has been shown to lead to accelerated oil recovery while reducing green
house gas (GHG) emissions because it requires less steam (lower SOR) than equivalent pure
SAGD recovery technology. As ES‑SAGD matures, there is need to provide additional understanding of the technology to assist in design, operational parameters selection and actual field
execution of pilot or commercial scale projects. In the original patent of ES‑SAGD, hexane (or a
pseudo‑hexane solvents mixture) was identified as the most suitable co‑injected solvent in term of
accelerated recovery and better energy efficiency. Also, several lab‑scale and field‑scale numerical simulations have been published that provide additional understanding and optimization of the
ES‑SAGD either with single‑component or multi‑component solvents. A recent paper also focused
on the design of injection wells for ES‑SAGD using hexane as the co‑injected solvent. There exist
propriety experimental results or data on ES‑SAGD with hexane as the co‑injected solvent, but to
date there is no publicly available 2D scaled experimental data on the ES‑SAGD with hexane as
the co‑injected solvent, hence the motivation for the work presented in this paper. Experimental
results of ES‑SAGD (with hexane) were also compared with the equivalent SAGD. The 2 experiments, which were conducted at the Alberta Research Council_s Thermal gravity laboratory, are
2‑D high pressure/high temperature experiments and were conducted at 2100 kPag +/‑ 50 kPag.
The comparison of ES‑SAGD and SAGD experiments shows that ES‑SAGD using hexane performed better than equivalent SAGD experiment. The energy consumption per unit oil recovered
for ES‑SAGD is lower than that of the SAGD (11.5% less). The average oil recovery within the
first 500 minutes (i.e. 11.3 years at field‑scale) for the ES‑SAGD process is also much higher
(~10.93% higher). The results presented in the paper provide data that can be scaled to field and
assist in the design, optimization and parameters selections when ES‑SAGD (with hexane or a
pseudo‑hexane solvents mixture) is considered as a recovery technology.
35-5
4:00 PM
Mohammadzadeh, Omidreza
[173846]
FURTHER IMPROVEMENTS IN PORE SCALE STUDIES OF SAGD PROCESS
MOHAMMADZADEH, Omidreza, REZAEI, Nima, and CHATZIS, Ioannis, University of
Waterloo, Waterloo, ON N2L 3G1, Canada, [email protected]
Steam Assisted Gravity Drainage method was developed, pilot tested, and commercialized in
Canada. This process has been proven successful in producing unconventional oil resources at
a high production rate and economical steam‑to‑oil ratios. With a quick review over the published
SAGD literature, lack of a comprehensive pore‑level mechanistic study is observed. A series of
visualization studies of the SAGD process were developed earlier to capture the pore‑level physics of the process using qualitative analysis. The main objective of this paper is to present recent
improvements made in this regard using glass micromodels. Experiments were conducted inside
SESSION NO. 37
an environmental vacuum chamber to reduce the excessive heat loss to the surrounding while
steam was injected under different superheating levels. Local temperatures along the model’s
height and width were recorded on a real time basis. Visualization results were analyzed using
image processing techniques. The results indicated that near a well‑established oil‑steam interface, gravity drainage takes place through a thick layer of pores within the mobilized region. The
interplay between gravity and capillarity forces results in the drainage of mobilized oil. Moreover,
the phenomenon of water‑in‑oil emulsification at the interface were also demonstrated which is
due to the local steam condensation. The extent of emulsification directly depends on the temperature gradient between the steam and bitumen phases. Other pore‑scale aspects of the process
such as drainage displacement mechanisms of the mobilized oil, localized entrapment of steam
bubbles as well as condensate droplets within the mobilized oil continuum due to capillarity phenomenon, sharp temperature gradient along the mobilized region, co‑current and counter‑current
flow regimes at the chamber walls, condensate spontaneous imbibition followed by mobilized oil
drainage, and local heat transfer mechanisms are also illustrated using these pore‑level studies of
the SAGD process.
SESSION NO. 36
Friday, 28 May 2010
T40. Managing Heavy Oil Resources (Alternates)
36-1
Babadagli, Tayfun
[173847]
BIODIESEL AS SURFACTANT ADDITIVE IN STEAM ASSISTED RECOVERY OF HEAVY OIL
AND BITUMEN
BABADAGLI, Tayfun, U of Alberta, Edmonton, AB T6G 2R3, Canada, [email protected]
and OZUM, Baki, Apex Eng, Edmonton, AB T6G 2R3, Canada
Solvents or surfactants are considered as additives to increase the efficiency of steam assisted
heavy oil and bitumen recovery processes. Commercial use of solvents has setbacks due to
their high costs and retrieval difficulties. We propose the use of biodiesel (BD) such as fatty
acids methyl esters as a surfactant additive reducing heavy oil/bitumen‑water interfacial tension.
Chemical stability under reservoir operating pressure and temperature, harmlessness on bitumen
quality and water chemistry and low cost are the advantages of using biodiesel as a surfactant
additive. The BD is produced as a byproduct by several companies and commercially available at
amount of field scale applications. We conducted experiments to clarify the effect of biodiesel as a
surfactant additive on recovery potential and efficiency of bitumen production. The porous media
used was artificial loose sands saturated with a heavy oil of 3,000‑4,000 cp and surface mined oil
sands. Laboratory tests performed exposing the sample to saturated steam under atmospheric
and 1.8 MPa pressures with and without BD addition. In these tests BD was spread on oil sands
samples and packed into the sample basket made of perforated walls. Laboratory data showed
that BD addition at about 1 g‑BD/kg‑bitumen dosages resulted in significant increase in oil recovery. Further tests were performed by injecting BD into high pressure steam line. In these tests, BD
derived from tall oil, i.e. tall oil fatty acids methyl ester was used; vapor pressure of which were
measured to gain confidence that BD saturation concentration in steam is greater than its desired
dosages. Remarkable increase in the recovery by steam injection with biodiesel addition was
promising for further field testing also supported by relatively low cost of biodiesel compared to
other surfactants.
36-2
Li, Weiqiang
[173848]
NUMERICAL SIMULATION OF THERMAL SOLVENT REPLACING STEAM UNDER STEAM
ASSISTED GRAVITY DRAINAGE (SAGD) PROCESS
LI, Weiqiang and MAMORA, Daulat Debataraja, Texas A&M U, College Station, TX 77843,
[email protected]
Steam Assisted Gravity Drainage (SAGD) is one successful thermal recovery technique applied
in Athabasca reservoir to produce the in‑situ high viscosity bitumen. To remove the limited supply and expensive water treatment required in SAGD process, injecting high temperature solvent
instead of steam is investigated in this study. In this study, hexane co‑injection under Athabasca
reservoir condition is simulated to analyze the drainage mechanism in the high temperature solvent chamber. The production performance is compared with the steam injection case. The study
shows that hexane is vaporized and transported to the solvent chamber boundary. The phase
change of hexane, from vapor to liquid, can reduce the bitumen viscosity efficiently and replace all
the original oil out. The production rate under thermal solvent process is about 1.5 times of steam
injection case. This study also shows that almost all the injected hexane can be recycled easily by
re‑vaporization process. From this study, thermal solvent can successfully remove the requirement
of steam injection in SAGD process with higher production rate and higher recovery factor. With
hexane recycling process, the required large solvent injection volume will not limit its application.
Friday, 28 May 2010
T41. Advances In Completion And Production
Operations (Society of Petroleum Engineers (SPE))
37-1
1:30 PM
Haroun, Muhammad Raeef
[173849]
A NOVEL OILFIELD SCALE CONTROL APPROACH IN SITU ION DIVERSION THROUGH
ELECTROKINETICS
HAROUN, Muhammad Raeef1, GHOSH, Bisweswar2, PAMUKCU, Sibel3, WITTLE, J.K.4,
AL BADAWI, Manal Abdel Aziz5, and CHILINGAR, G.V.1, (1) U of Southern California,
Los Angeles, CA 90802, [email protected], (2) The Petroleum Institute, Los Angeles, CA
90802, (3) Lehigh University, Bethlehem, PA 18015, (4) Electro Petroleum Inc, Los Angeles,
90802, (5) The Petroleum Institute, Abu Dhabi, United Arab Emirates
Sulfate scaling in oil well and near wellbore formation is a common phenomenon in a water flood
recovery system where sea water, rich in sulfates mixes with formation water rich in Ba, Sr and
Ca ions. This leads to a chronic flow assurance problem and warrants frequent well intervention
for chemical squeeze and well cleaning operation. Apart from production loss, in offshore operations this could lead to a significant addition to production cost. To find a long term solution for this
commonly occurring problem, we experimented on a novel idea of applying electrokinetic phenomena on controlling incompatibility scale in‑situ. The concept of electro‑kinetic scale remediation is derived from our successful experience with electro‑remediation of heavy metals in highly
contaminated coastal area of Abu Dhabi, where di/tri‑valent cations were separated by applying
DC current through metal electrodes. In the present study we focused on Barium Sulphate scaling
through a series of experiments conducted in sand‑packed glass electrokinetic‑cell with multiple
electrode positioning and fluid injection options. DC power was applied at 2V/cm through a
single electrode configuration. Cation injector (500 ppm Ba+2) is converted to cathode and anion
(SO4‑2) injector as anode. Salinity of fluid varied from 0‑40000 ppm and flown for equal period at
flow rate 1 ml/min for all the flow studies. Results of pressure build up (due to scale deposition)
compared with control, show that under electrokinetic application, scaling rate reduced to 1/10th
or less. ICP‑MS mapping of scale deposits at various points show high localized concentration
near electrodes and 50% (or less) deposition near the production well, indicating arresting/diverting of scaling ions in the vicinity of electrodes. Effect of salinity on flow pressure and current is
analyzed and used for current/cost optimization.
37-2
2:00 PM
Ahmadi, Mohabbat
[173850]
CHEMICAL TREATMENT TO MITIGATE CONDENSATE AND WATER BLOCKING IN
CARBONATE GAS WELLS
AHMADI, Mohabbat1, TORRES, David Enrique1, SHARMA, Mukul2, LINNEMEYER, Harry1,
and POPE, Gary Arnold1, (1) U of Texas at Austin, Austin, TX 78745, [email protected],
(2) University of Texas, Austin, TX 78745
Many gas wells are suffering from near wellbore liquid accumulation. Stimulation in near wellbore
region is used as a remedy, attempting to alter the wettability to non‑liquid wetting using chemicals. Successful treatments increase the fluids mobility and the wells deliverability. This paper
presents, to our knowledge, the first effective treatment for carbonates. We have developed an
appropriate solvent to deliver the chemical to the rock surface. The treatment solution is compatible with both brine and condensate; therefore, it will not precipitate and will not reduce permeability of the rock. We demonstrate measured relative permeability values from high‑pressure,
high‑temperature coreflood experiments before and after treatment. Measurements were taken
under pseudo‑steady‑state method using gas‑condensate mixtures. The chemical treatment
developed in this research can be applied to increase the well deliverability and final recovery of
both gas and condensate in the field, providing that, it is designed properly for different conditions
of reservoir’s temperature, brine salinity, and initial water saturation. We found X‑ray photoelectron
spectroscopy an effective and a quick tool to screen out potentially effective chemicals from a
large pool of compounds. During drop imbibition tests (water and n‑decane) we observed a quick
and complete imbibition before treatment compared to no imbibition after treatment. The gas
relative permeability increased considerably ‑ 80% ‑ after treatment compared to that before treatment. This increase remained substantial‑ higher than 60% ‑ upon injection of more pore volumes
of fluids‑ 1000PV. We found even more increase in gas relative permeability during unsteady
displacement of water. Chemical stimulation of carbonate gas wells is now possible with our new
treatment and a special primer. The primer will enhance the adsorption of chemical. This will
increase the durability of the treatment and will reduce the frequency of retreating a well.
37-3
2:30 PM
Diaz, Brigida Meza
[173851]
SAND ON DEMAND: AN APPROACH TO IMPROVING PRODUCTIVITY IN HORIZONTAL
WELLS UNDER HEAVY OIL PRIMARY PRODUCTION PART II
DIAZ, Brigida Meza1, SAWATZKY, Ronald P.1, and KURU, Ergun2, (1) Alberta Research
Council, Edmonton, AB T6G 2R3, Canada, [email protected], (2) U of Alberta, Edmonton,
AB T6G 2R3, Canada
The cold production recovery process is successful in vertical wells in western Canada. In this
process, large amounts of sand are produced on a continuing basis along with heavy oil. Attempts
at cold production in horizontal wells have not been particularly successful. When sand production
has been generated in horizontal wells, these wells have tended to become plugged with sand.
This paper presents the results of experiments performed to assess the feasibility of applying cold
heavy oil production with horizontal wells using less aggressive (i.e., managed) sand production
strategies. Specifically, the effects of slot size, confining stress, fluid velocity and sand grain sorting on sand production were investigated. The results indicate that slot size selection is critical
for establishing “sand on demand”. From the experiments, a correlation between slot size and
controlled sand production was found for well sorted sands. This correlation should allow for the
specification of appropriate slot sizes for target reservoirs containing well sorted sands. In the
experiments, when flow rates resulted in low but persistent sand production, channels and/or
elliptical dilated zones were created that greatly enhanced the effective permeability near the slot.
This observation suggests that producing at low and steady sand cuts for a long period of time
might bring two benefits: a way to transport the sand out of the well without causing plugging,
and the creation of high permeability channels or zones that can improve production from the
reservoir. To summarize, if the appropriate slot size was combined with the right draw down rates,
controlled sand production could be achieved with attendant significant increases in permeability.
SESSION NO. 37
This suggests that substantially increased oil production rates could be achieved from horizontal
wells if sand production rates could be maintained at low but persistent levels.
37-4
3:30 PM
Shuler, Patrick J.
[173852]
HEAVY OIL PRODUCTION ENHANCEMENT BY VISCOSITY REDUCTION
SHULER, Patrick J., ChemEOR, Los Angeles, CA 90802, [email protected], TANG,
Yongchun, Power, Environmental & Energy Research Center, California Institute of
Technology, Covina, CA CA 91722, and TANG, Hongxin, Long Beach, CA 90802
This paper presents an evaluation of different chemical agents that can reduce dramatically the
apparent viscosity of a heavy crude oil or a thick emulsion. This method can improve the production of heavy oils and very viscous emulsions such as are found in California. This method to
reduce the backpressure from the well to the surface facilities improves well productivity. It is
especially suited for produced fluids at relatively colder temperatures (less than 150 B0F). This
laboratory investigation employed a unique novel viscometer built for this study that measures
accurately the effective dynamic viscosity of multi‑phase liquids (emulsions) up to thousands of
centipoise. Application: This chemical treatment strategy provides one option to increase productivity from wells making viscous emulsions. Because this method is suited for reducing viscosity
even at cooler temperatures, it is attractive especially for treating viscous emulsions at locations
with colder production. Results, Observations, Conclusions: By use of these chemical additives
the viscosity of thick emulsions may be reduced, and in some cases by as much as a thousand
fold. For example, for an oil from the Bakersfield area its viscosity reduced at room temperature
from 50,000 cp to less than 100 cp with a chemical dosage o 400 ppm. The surfactant chemical systems that work for this process are fairly specific for each crude oil. . The new viscometer
method based on the sensitive measurement of torque in a stirred cell can determine the dynamic
viscosity of emulsions at shear rates representative of that found in flowlines. Significance of
Subject Matter: This study demonstrates selected chemical additives can reduce greatly the backpressure associated with production of thick viscous emulsions. The development of a new tool to
measure the viscosity of emulsions of multi‑phase fluids at conditions representative of pipe flow. .
37-5
4:00 PM
Akhimiona, Nosakhare
[173853]
AN ANALYSIS OF THE PERFORMANCE OF GRAVEL PACKS AND SLOTTED LINERS IN
HEAVY OIL OPERATIONS
AKHIMIONA, Nosakhare1, AUFFANT, Ariel1, GORHAM, Timothy Lee1, and HARRELSON,
Jonathan Preston2, (1) Chevron, Los Angeles, CA 90802, [email protected], (2) Colorado
School of Mines, Golden, CO 80401
As hydrocarbon prices continue to fluctuate, it is imperative for engineers to come‑up with optimum and cost effective ways of managing and developing a field. This is especially true in heavy
oil operations, where the margins are very small. So it is pertinent to gain a better and broader
understanding on how things such as completions technique can be optimized to gain the maximum value for the company. This work presents an analysis/evaluation of gravel packs and slotted
liners in a heavy oil field in California. The objective of this work is to compare gravel packs and
slotted liners from a production and sand control standpoint. This work also has a secondary
objective of re‑evaluating the performance of old gravel pack wells that have been sidetracked
using slotted liners. Also the effect of several variables such as flow rate, oil viscosity and API
gravity on sanding in a heavy oil operation will be looked into. The results of this work indicate
that there is not a “one size fit all” solution to the problem of sanding in a heavy oil field. So it is
imperative that all feasible completion techniques be analyzed and their impact on production and
economics be considered. The conclusions and recommendations from this study will provide an
insight through which petroleum engineers in heavy oil operations will make educated decisions
on how to optimally complete a field and also get the most bang for the buck.
37-6
4:30 PM
Mahadevan, Jagannathan
[173854]
GEL DAMAGE REMEDIATION BY EVAPORATIVE MECHANISMS: A LABORATORY
INVESTIGATION
MAHADEVAN, Jagannathan1, LE, Duc Huu1, and MCQUEEN, Kenley H.2, (1) U of Tulsa,
Tulsa, OK 74104, [email protected], (2) The Williams Companies
Polymeric gels are widely used in hydraulic fracturing operations to produce natural gas from
tight sands. The recovery of injected gel is often poor and large quantities are left behind, which
can cause a loss in gas productivity due to a reduction in the fracture conductivity. In this paper,
we present a novel study of remediation of gel damage from proppant packs by dry gas injection. We experimentally investigated removal of polymeric fracturing fluid gels from proppant
packs and their impact on recovery of gas flowrate at constant pressure drawdown conditions.
The gel removal process takes place in two steps, the first being a viscous displacement process
which is followed by the evaporative process. Due to the high viscosity, gel removal by simple
displacement is ineffective and only 20‑25% of the gel is removed at high drawdown pressures
and only 1 % of the undamaged flow rate is recovered. However, when dry gas is injected, the
entire water content in the gel is completely removed. Results from experiments conducted with
sandpacks and fracture packs show that about 30% of the undamaged flow rate is recovered by
dry gas injection. Dry gas injection is effective in removing water content of the gel from sandpack
and fracture pack. Hence the residual gel saturation is lowered, leading to greater gas relative
permeability and gas flowrate. A compositional model is developed to predict the rate of removal
of water from gel and the rate of recovery of gas in damaged laboratory scale fracture and sandpacks. The model results show a good comparison with the experimental data and therefore can
be used to predict field scale performance of dry gas injection operations. Thus field scale gel
blockage due to unbroken polymer may be remediated, by a simple dry gas injection process.
SESSION NO. 38
Friday, 28 May 2010
T41. Advances In Completion And Production
Operations (Alternates) (Society of Petroleum
Engineers (SPE))
38-1
Yuan, Hong
[173855]
A NEW MODEL FOR PREDICTING INFLOW PERFORMANCE OF FRACTURED
HORIZONTAL WELLS
YUAN, Hong and ZHOU, Desheng, IHS, Englewood, CO 80112, [email protected]
Based on the analyses of horizontal well flow characteristics and flow in fractures, the paper
presents a new model to describe the inflow performance of fractured and un‑fractured horizontal
wells with single phase flow. More and more horizontal wells are drilled today and we encounter
more fractured horizontal wells. While predicting the inflow performance of fractured horizontal
wells, we found that there is a need for a new model which couples the flow from rock matrix and
flow from fractures, and is applicable for horizontal wells with and without fractures. This model
serves the purpose. The new model may be used in well planning, production design, production
system analysis and well efficiency improvement. The presented model couples the flow from
rock matrix and the flow from fractures, and can be easily used in horizontal wells with or without
fractures. Results from the new model are compared with those from commonly used models
in petroleum industry for fractured and un‑fractured horizontal IPRs such as Economides et al.
, Joshi, Guo and Schechter, etc. Results from the new model are also compared with field data
obtained from published literature. The comparison with previously models of fractured horizontal
wells shows that the new model is better in matching field data. The new model couples both the
flow from rock matrix and the flow from fractures and can be used for predicting the inflow performance of horizontal wells with and without fractures.
38-2
Pan, Yi
[173856]
RESEARCH PROGRESS OF MODELLING ON COLD HEAVY OIL PRODUCTION WITH SAND
PAN, Yi1, ZHANGXIN, John Chen1, XIAO, Lizhi2, SUN, Jian3, and BAO, Xia1, (1) U of
Calgary, Calgary, AB T6G 2R3, Canada, [email protected], (2) China Univ of Petroleum,
(3) U of Calgary
Heavy oil has been playing a critical energy that accounts for todayB!B/s world oil supply. The
total amount of heavy oil in place is five to ten times greater than the current proven conventional
crude. One of the recovery methods, which oil comes with unconsolidated sands, is known as
Cold Heavy Oil Production with Sand. The advantages of CHOPS lie in its commercial success
as an inexpensive start up application for CHOPS reservoirs as well as its considerable recovery.
The general reservoir characteristic associated with successful applications of CHOPS has been
established, particularly highlighted in the thin reservoirs with non‑active edge and bottom water.
Heavy oil researchers have accumulated local knowledge for the CHOPS fields, particularly
research groups in Alberta have taken integrated approaches to the questions posed by the field
success of cold production. CHOPS gives high early production rates and become very efficient
in reservoirs less than 15 m thick, whereas some thermal methods have been economically
unsuccessful in such cases. Aggressive sand production was encountered in California prior to
the First World War. Two key mechanisms lead to the success of cold production in laboratory
and field studies, foamy oil flow and wormhole network growth. A variety of numerical models
are presented and compared in this paper. Such models can be mainly divided into two broad
categories: preliminary model and comprehensive model. For a large number of variables still in
limited recognition for the complex mechanisms, several models lack capability in fully simulating
CHOPS processes. While progress was achieved in modeling the reservoir heterogeneity with the
integration of seismic attributes at specific fields. A detailed discussion of the strengths and weaknesses of cold production models is proposed. The paper ends with the future work of modeling
proposed on cold production.
Friday, 28 May 2010
T42. Social Responsibility, Health, Air and Water
Quality and GHG Emissions (Society of Petroleum
Engineers (SPE))
39-1
1:30 PM
Baghdikian, Serge
[173857]
ENHANCEMENTS TO GPS BASED SUBSIDENCE MONITORING AT THE WILMINGTON
OIL FIELD
BAGHDIKIAN, Serge1, JEPSON, John J.1, HOLTZ, Kimberley1, BOCK, Lydia2, FAYMAN,
Jeffrey2, and MADER, Gerald2, (1) City of Long Beach, Long Beach, CA 90802,
[email protected], (2) Geodetics Inc
Subsidence was first identified in the Wilmington Oil Field in the 1940s. The City of Long Beach,
Gas and Oil Department (LBGO) has been conducting surface elevation surveying using spirit
leveling and, since 2002, the Global Positioning System (GPS). Recently, software for the LBGO
Deformation Network of 12 real‑time GPS stations was upgraded with new state‑of‑the‑art technologies and solution to provide more reliable and accurate continuous monitoring to support
elevation survey campaigns. Current oil field waterflood management practices as they relate to
surface elevation changes and benefits from the software upgrade for Wilmington Oil Field subsidence monitoring and control are discussed. Waterflood operations in the Wilmington Oil Field are
managed for effective oil recovery and injection/production balancing while maintaining stable
surface elevations for continued regional economic growth. For cost‑effective and timelier surface
elevation monitoring, a real‑time GPS network provides control for all LBGO subsidence monitor-
ing activities. Using mobile GPS survey equipment, quarterly and semi‑annual elevations of over
240 bench marks are calculated from the 12 permanent GPS stations’ elevations. The LBGO GPS
network and software allow for real‑time elevation monitoring of key locations and automated data
processing, with the regional picture updated semiannually. Surface elevation contour maps and
individual survey bench mark elevation trends as a function of time allow for timely adjustments to
the waterflood operations to maintain effective oil recovery. Real‑time GPS monitoring of surface
elevations provides the capability for early detection of surface deformation resulting from production/injection imbalances. The necessary operational adjustments can then be identified and
implemented to mitigate the situation. The advantage of early detection is in minimizing the extent
of irreversible reservoir rock compaction, resulting in more stable future surface elevations, and
preventing elevation changes detrimental to surface infrastructure.
39-2
2:00 PM
Esposito, Ariel
[173861]
REMEDIATION OF POSSIBLE LEAKAGE FROM GEOLOGIC CO2 STORAGE RESERVOIRS
INTO GROUNDWATER AQUIFERS
ESPOSITO, Ariel and BENSON, Sally M., Stanford University, Stanford, CA 94305,
[email protected]
Maintaining the long term storage of CO2 is important for a large scale geologic CO2 storage
project. The possibility remains that the CO2 will leak out of the formation into overlying groundwater aquifers. A site specific remediation plan is important during the site selection process and
necessary before storage begins. Due to the importance of protecting drinking water sources,
we determined the optimal remediation scenario for various leakage conditions. We used the
multiphase flow simulator TOUGH2 to analyze the plume at various leakage rates. At the depth of
most groundwater aquifers a significant portion of the CO2 is in gas phase. Due to the difference
between the density of the brine and the CO2, we found that the leakage rate and the quantity of
CO2 have an important impact on the leakage plume. We then determined the physical processes
that control removal of the CO2 plume. Important processes include capillary trapping as a result
of hysteresis in the relative permeability and capillary pressure curves, dissolution and buoyancy
induced flow. We found that the ease of removal was correlated with the shape of the plume. We
next examined what occurred when we injected water to dissolve all the gaseous CO2 and reduce
the overall concentration. With water injection, the main controlling factors were the residual gas
saturation and the distance from the injection well. Based on the initial simulations, the characteristics to optimize are the extraction well depth, the number of wells, and the placement of the
wells. We used three criteria to determine the optimal remediation scenario: the half life of the
CO2 plume, the time until 95% is removed or dissolved, and the cost of remediation. Determining
the optimal remediation scheme provides a starting point for planning groundwater remediation
scenarios for possible leakage events at geologic storage sites.
39-3
2:30 PM
Jahangiri, Hamid Reza
[173872]
OPTIMIZATION OF CARBON DIOXIDE SEQUESTRATION AND ENHANCED OIL RECOVERY
IN OIL RESERVOIR
JAHANGIRI, Hamid Reza, U of Southern California, Los Angeles, CA 90802, ershaghi@
usc.edu and ZHANG, Dongxiao, Department of Civil and Environmental Eng, University of
Southern California, 3620 S. Vermont Avenue, Los Angeles, CA 90089
Carbon dioxide (CO2) storage into depleted or partially depleted oil reservoirs is an immediate
option to reduce CO2 emissions into the atmosphere. This process, if implemented in depleted oil
reservoirs, combines environmental benefits by reducing CO2 concentration in the atmosphere
and economical benefits by maximizing oil recovery. CO2 oil recovery processes, to date, have
attempted to minimize the amount of CO2 needed to recover each barrel of oil. For a sequestration process, however, the aim is to maximize both the amount of oil produced and the amount of
CO2 stored. As part of this process, significant quantities of CO2 remain to be sequestered in the
reservoir. If CO2 emissions are regulated, EOR process may therefore be able to earn sequestration credits in addition to oil revenues. This paper discusses the effects of several injection strategies and injection timing on optimization of oil recovery/CO2 storage capacity for a synthetic,
three dimensional, heterogeneous reservoir models. A simulation study was completed using a
3‑D compositional simulator “ECLIPSE 300” in order to optimize oil recovery and CO2 storage.
The simulation study proceeded through the following steps: 1) comparison of different injection
schemes; 2) testing the effect of injection timing on the CO2 storage capacity. The results show
that innovative reservoir engineering techniques are required for co‑optimizing CO2 storage and
oil recovery.
Friday, 28 May 2010
T43. Society of Petroleum Engineers (Posters)
40-1
BTH 1
Mondal, Satyajit
[173866]
TIGHT GAS EXPLOITATION: A STOCHASTIC MODELING STUDY OF A LOW SINUOSITY
RIVER SYSTEM
MONDAL, Satyajit, AGARWAL, Siddhartha, MONGRAIN, Joanna, and MISRA, Debasmita,
University of Alaska, Fairbanks, AK 99701, [email protected]
The overall objective of this research was to develop reservoir models using published petrophysical and geological data, representative of the Kenai Group of tight gas sands in Cook Inlet,
Alaska, in order to simulate tight gas exploitation using viable technologies. We initially analyzed
the eighteen parameters influencing the porosity and permeability (P&P) of tight gas sands of the
region to develop suitable correlations, based on published petrographic data. The data from 33
available sandstone samples were first divided into cemented and non‑cemented rock categories.
The non‑cemented samples provided better representation of P&P. Analysis of the data revealed
that there was a moderate correlation (R2=0.455) when depth(ft) and rigid (%) was used to predict porosity. However, macropore %, mean grain size (mm) and quartz % to predict permeability
revealed relatively high correlation (R2= 0.796). It was evident that P&P of the non‑cemented
sandstone was directly controlled by mechanical compaction and a useful regressional relationship was developed for petrophysical modeling. Next we used published geological data (Flores
et al. 1997 and AOGCC 2008) for simplified channel facies modeling. The parameters used to
build the channel facies models were sand volume fractions, channel width, sinuosity, orientation and azimuth. Twenty one different scenarios were developed based a range of sand volume
fractions and channel sinuosity. Each scenario was used to generate ~20 realizations to capture
the antecedent uncertainty. Effective sand body connectivity was analyzed for each model by
streamline simulation technique. This channel facies modeling in conjunction with petrophysical
modeling may assist in predicting the factors controlling sand body connectivity of tight gas reservoirs of Kenai group of sands. Further, this work may help to determine the required well spacing,
well type, orientation and completion technique to enhance recovery efficiency in Cook Inlet tight
gas sands.
40-2
BTH 2
Sheng, James J.
[173867]
NEW CONCEPTS OF THE OPTIMUM MICROEMULSION PHASE TYPE AND THE OPTIMUM
SALINITY PROFILE IN SURFACTANT/POLYMER FLOODING
SHENG, James J., Total E&P, Bakersfield, CA 93306, [email protected]
According to the conventional concepts in surfactant/polymer flooding (SP), a type III microemulsion phase environment would give higher oil recovery than either a type II(‑) or a type II(+)
environment, and a negative salinity gradient is a preferred gradient which provides the highest oil
recovery factor. Many measured data suggest these concepts cannot be universally valid. In this
paper we investigate the effects of microemulsion phase type and salinity profile on oil recovery
quantitatively by using a chemical flood simulator, UTCHEM. Over 200 simulation cases covering a variety of flow conditions have been made. The simulation results clearly demonstrate that
the two conventional concepts cannot be universally valid. In surfactant‑polymer flooding, many
parameters can affect oil recovery, especially multiphase flow parameters. In this paper we propose two new concepts. One is the optimum microemulsion phase type which is not necessarily
type III. Another one is the optimum salinity profile which has the following characteristics: 1. The
optimum salinity is within the optimum phase type which corresponds to the highest oil recovery,
not necessarily within the type III. 2. The optimum salinity must be used in the surfactant slug.
3. Two cushion slugs (polymer or water) with the same optimum salinity are placed immediately
before and after the surfactant slug. But the optimum salinity in the cushion slug before the
surfactant‑polymer slug is preferred but not mandatory. 4. The salinity in the post‑flush must be
below the lower salinity bound of Type III. Our simulation results show that the optimum salinity
profile can always lead to the highest recovery, especially higher than that from the corresponding
negative salinity gradient. Extensive literature information and laboratory data are used to support
these new concepts. These concepts are used to design an optimized field SP program.
40-3
BTH 3
Aguilera, Roberto
[173868]
STORAGE AND OUTPUT FLOW FROM SHALE AND TIGHT GAS RESERVOIRS
AGUILERA, Roberto, RAHMANIAN, Mohammad Reza, and SOLANO, Nisael, U of Calgary,
Calgary, AB T6G 2R3, Canada, [email protected]
Crossplots of porosity vs. permeability from various North American basins show that there is a
continuum between conventional, tight and shale gas reservoirs. This is significant as some of the
key issues, particularly in shale and tight gas reservoirs, are having good estimates of storage
and flow capacity. The crossplots include data from the Fayettville, Barnett, Ohio and Marcellus
shales in the United States; Horn River and soft shales in Canada, tight gas Nikanassin formation in Canada and several conventional North American gas reservoirs. The data used in the
crossplots have been obtained from plugs, crushed samples and drill cuttings. The results permit
integration of the storage and potential gas deliverability for determining flow units and other
important characteristics such as brittleness and/or ductility, hydraulic fracturing alternatives,
effect of water saturation and mud filtrate; and differentiation between viscous and diffusion dominated flow. Examples of simulation at the pore throat level, from which it is possible to estimate
petrophysical, rock‑fluid interaction and rock mechanics properties, are presented The storage
and flow capacity in the case of stacked layers, or lateral variations of conventional, tight and
shale gas formations, are discussed in detail. The data suggest that permeability determinations
from crushed shale samples might be pessimistic as they do not take into account the possible
presence of microfractures and pores in organic matter within shale matrix. It is concluded that
crossplots of porosity vs. permeability are very powerful for distinguishing and evaluating storage
and flow capacities of conventional, tight and shale gas reservoirs. The concept of flow units in
shales should prove powerful in future simulation work.
40-4
BTH 4
Paidin, Wagirin Ruiz
[173869]
THE POTENTIAL OF NCG ENHANCED SAGD APPLICATION IN US HEAVY OIL RESERVOIRS
PAIDIN, Wagirin Ruiz and RAO, Dandina Nagaraja, Louisiana State, Baton Rouge, LA
US heavy oil reserves equal about 105 billion barrels of which 13 billion had already been
produced by 2004. This sizeable target comprises a prime candidate for implementation of a
gravity‑stable thermal recovery method such as SAGD which has been very successfully applied
in Athabasca heavy oil reservoirs. Because 50% of US heavy oil reservoirs are thinner than 100ft
SAGD application might be less effective in terms of sweep efficiency and overburden heat loss.
This simulation study aims to investigate not only the viability of implementing SAGD in thinner reservoirs by using a proposed well configuration involving vertical injectors and horizontal
producers, but also the effect of the addition of non‑condensable gases (NCG) to steam. The
generation of steam requires large amounts of water and fuel and one way have to reduce the
heat required and improve the thermal efficiency is NCG addition. In this study, the SAGD performance utilizing vertical injectors with horizontal producers, and steam with and without NCG
has been evaluated for a prototype reservoir model using a commercial reservoir simulator. The
study demonstrates that the addition of NCG to steam reduced the steam‑oil‑ratio significantly
compared to “steam‑alone” cases, thus making the overall process more economically attractive.
Adding NCG to steam resulted in maintaining a higher average reservoir pressure, and limited the
heat loss to the overburden. It could also go towards reducing greenhouse gas emission. The oil
recoveries in the cases with the proposed gravity‑stable thermal recovery process using vertical
injectors instead of horizontal injectors were found to be comparable to conventional SAGD, so
using a combination of vertical injectors and horizontal producers may be an attractive option for
recovering heavy oil using a gravity‑stable thermal recovery process involving the addition of NCG
to injected steam in thinner reservoirs.
40-5
BTH 5
Odi, Uchenna
[173870]
ENSEMBLE BASED OPTIMIZATION OF EOR PROCESSES
ODI, Uchenna, LANE, Robert H., and BARRUFET, Maria Antonieta, Texas A&M U,
College Station, TX 77843, [email protected]
The advent of smart well technology has allowed control of a hydrocarbon field in all stages of
production. This holds great promise in managing EOR processes, especially in terms of applying optimization techniques. However, some procedures for optimizing EOR processes are not
based on the physics of the process, which lead to erroneous results. Additionally, optimization of
EOR processes can be difficult if there is no access to the simulator code for computation of the
SESSION NO. 40
adjoints used for optimization. This work is a general procedure for designing an initial starting
point for a surfactant flood and water flood optimization. The method does not rely on a simulator’s adjoint computation. Instead of using adjoints for optimization, the Ensemble Kalman Filter
optimization (Enkfopt) was developed and used to optimize the net present value (NPV) of a 5
spot surfactant flood and water flood process. Additionally, constrained optimization was created
and added to the Enkfopt method. The controls for this work were based on surfactant flood and
water flood process dynamics and included production control for four producers, injector injection
rate, and surfactant concentration. Field Permeability, field porosity, and economic inputs were
parameters held constant for the optimization. Once the optimal solution was obtained, multiple
realizations of the permeability and economic inputs were used to generate a cumulative probability distribution of the NPV. Preliminary results show an improvement of the NPV of the water
flood process (up to 60% increase) and surfactant flood process (up to 150% increase). Results
also show that the optimized controls retain the same relationship as the original controls. This
work provides a method to manage risk by performing an optimization and then using the optimal
solution to assimilate possible geological and economic scenarios. Cumulative distribution curves
of NPV provide tools in accessing the probability of project success.
40-6
BTH 6
Jabbari, Hadi
[173871]
A NEW SEMI ANALYTICAL MODELING OF TOE TO HEEL AIR INJECTION IN IN SITU
COMBUSTION PROCESS
JABBARI, Hadi1, KHARRAT, Riyaz, ZENG, Zhengwen2, MOSTAFAVI, Vahidreza1, and
EMAMZADEH, Abolghasem1, (1) University of North Dakota, Grand Forks, ND 58202,
[email protected], (2) Geology and Geological Engineering, University of North Dakota,
81 Cornell St, Stop 8358, Grand Forks, ND 58202
Laboratory combustion tube experiments can be operated far more rapidly and cheaply than to
be operated in the field. Forecasts of reservoir response to the application of thermal methods are
necessary before starting a project. Thermal numerical models are available to provide forecasts.
However, these models are expensive and consume a great deal of computer time. An alternative to numerical modeling is to use a semi‑analytical model. Toe to heel air injection (THAI) is
studied in this research and the temperature distribution as well as the consequential oil production rate have been formulated and compared against the experimental data. The main objective
was to investigate thermal applications of horizontal wells for displacement and gravity drainage
processes using analytical modeling as well as experiment. The main novelties presented in the
paper are: a) Regarding the Bailey‑Larkin’s and Penberthy‑Ramey’s work, the differential equations of heat transfer process around a moving combustion front in a vertical combustion tube is
derived, b) using the Laplace Transform method the solution of these equations are introduced,
c) the temperature distribution ahead and behind the moving combustion front is obtained and
it is resulted that the temperature distribution ahead of the front is a function of dimensionless
time and dimensionless front velocity while the distribution behind the front is only a function of
dimensionless time, d) the average temperature over the oil column from the combustion front
to the underburden is formulated, e) the recorded temperatures ahead and behind the front are
compared against the proposed analytical temperature distribution models, f) new “type curves”
are set up for approximating the front velocity while propagating beyond the injection well to the
lower boundaries, and g) an indirect formulation method for evaluating the combustion front velocity into the reservoir is introduced.
40-7
BTH 7
Mahadevan, Jagannathan
[173873]
PRODUCTIVITY LOSS IN GAS WELLS DUE TO SALT DEPOSITION
MAHADEVAN, Jagannathan and LE, Duc Huu, U of Tulsa, Tulsa, OK 74104,
[email protected]
Production of gas can result in drying of the near wellbore region due to gas expansion which
causes evaporation and hence salt deposition. The deposition of salt usually leads to a reduction
in porosity and permeability of the rock in the near wellbore which then leads to reduction in well
productivity. The main objective of this study is to understand the role of capillary effects on the
salt deposition process and well productivity reduction. We develop and solve the dimensionless conservation equations for solid salt saturation using numerical methods under radial flow
conditions. The results of the calculations show that when the capillary effects are strong, the salt
accumulates near the wellbore which leads to plugging and hence higher skin values. The salt
saturation continues to evolve until a limiting value, in the rock pores, is reached. Higher values
of the limiting saturation leads to a greater reduction in permeability and hence results in a larger
skin value for the gas well. The flow efficiency of a gas well, calculated as a dimensionless ratio of
the flow with and without skin, decreases continually with time eventually approaching a constant
value. In a simulation for dimensional case we find that the largest increase in skin factor and
corresponding decrease in flow efficiency occurs in approximately the first 50 days after which the
changes are slower. Using the model developed in this study the decline of gas well productivity
due salt deposition can be predicted and hence accurate timing of the well operations such as
water wash can be made. Also, the modeling study can be used to select remediation strategies
such as wettability alteration to reduce capillarity or application of inhibitors which can reduce the
limiting salt saturation by preventing growth salt crystals within the reservoir rock.
40-8
BTH 8
Yousef, Ali A.
[173874]
FIELD BRINE COMPOSITION IMPACT ON TERTIARY OIL RECOVERY FROM CARBONATE
RESERVOIRS AN EXPERIMENTAL STUDY
YOUSEF, Ali A., AL SALEH, Salah, and AL KAABI, Abdulaziz Ubaid, Saudi Aramco,
Dhahran, 31311, Saudi Arabia, [email protected]
The impact of brine salinity and ion composition on oil recovery has been an area of research in
the last years. Evidence from laboratory studies supported by some field tests has distinctly shown
that oil recovery depends on the injected water salinity and ion composition. This paper presents the results of laboratory coreflooding study conducted using composite cores from a Saudi
Arabian carbonate reservoir to investigate the impact of salinity and ionic content on oil/brine/
rock interactions and eventually on oil recovery. The experimental parameters and procedures
were well‑designed to reflect the reservoir conditions and current field injection practices, including reservoir pressure, reservoir temperature, salinity and ionic content of initial formation water
and current types of injected water. Two systematic coreflood experiments‑each with a type of
field injection water‑‑ were deliberately conducted using the same rock samples to neutralize the
discrepancies that appear from variation in rock properties, and eventually to assess accurately
the impact of salinity and ion composition on oil recovery. The experimental results revealed that
substantial tertiary oil recovery beyond conventional waterflooding can be achieved by altering the
salinity and ionic content of one type of field injected water. The new emerged trend is distinct from
what have been addressed in previous reported studies on topics of low salinity waterflooding for
sandstones, or seawater injection into high temperature chalk reservoirs; also it is considered by
all measures a significant achievement in terms of large incremental recovery, application to carbonate reservoirs, and unique coreflooding experimental parameters and procedures.
BTH 9
Babadagli, Tayfun
[173875]
MECHANICS AND UP SCALING OF HEAVY OIL BITUMEN RECOVERY BY STEAM OVER
SOLVENT INJECTION IN FRACTURED RESERVOIRS (SOS FR) METHOD
and SINGH, Rajpreet
Recently, steam‑over‑solvent injection in fractured reservoirs (SOS‑FR) method was proposed
to be a potential solution for efficient heavy‑oil/bitumen recovery. The method is based on injection steam initially followed by solvent. In the third cycle, steam is injected again to recover more
oil. Solvent retrieval during the third cycle was observed to be very fast if the temperature is
around the boiling point of solvent. This process is controlled by efficient matrix recovery and the
mechanisms and the physics of the process are needed clarifications to further determine the
efficient application conditions for given matrix and oil characteristics. Single matrix behavior during the process was numerically modeled for static and dynamic conditions and the results were
matched with the experimental observations for different matrix wettability, oil viscosity, solvent
type, and matrix boundary conditions (co‑ or counter‑current transfer). The physics of the recovery
mechanism was analyzed through visual inspection of saturation, temperature, and concentration
profiles during each cycle. Then, an efficiency analysis was performed by determining the optimal
heating time, solvent soaking period, solvent retrieval time for different matrix characteristics,
most importantly matrix size, to maximize the recovery time and minimize matrix residual oil
saturation. Next, an up‑scaling analysis was performed. The initial matrix size was 1.5x3 inch for
verification of the model with the same size experimental core. The critical parameters that control
the matrix‑fracture transfer of heat, solvent, and water were determined at different scales (for
different matrix sizes) and up‑scaling parameters (diffusion and dispersion coefficients for heat,
mass and volume transfer) were determined. This work provides practical information (especially
the amount of injectant needed and time required to recover targeted oil) for field scale application
of heavy‑oil/bitumen recovery from fractured reservoirs, especially oil‑wet carbonates.
40-10
BTH 10
Gil, Baldev Singh
[173876]
AN ANALYTICAL METHODOLOGY TO DETERMINE OIL IN PLACE: AQUIFER INFLUX
AND ULTIMATE SWEEP EFFICIENCY OF A MATURE HEAVY OIL WATERFLOOD IN THE
WILMINGTON BASIN
GIL, Baldev Singh, City of Long Beach - Long Beach Gas and Oil, 211 E. Ocean Blvd,
Suite 500, Long Beach, CA 90802, [email protected]
The significance of and goal of this paper is to outline a methodology to better understand the
impact of water injection on the overall efficiency and recovery factor of heavy oil reservoirs under
mature water flood. The methodology presented in the paper would be a useful toolkit for the
evaluation of the performance and efficiency of current waterfloods. This paper describes both
conventional and unconventional analytical techniques to determine and quantify original oil in
place, size of water influx and ultimate sweep efficiency of a mature Wilmington field. This reservoir has been under both active peripheral water injection and natural water influx since the early
1960s. The analytical techniques indicate that the field is a continuous reservoir with original oil
in place of approximately 250 MMBO. The derived original oil in place value from the study is in
alignment with the reservoir simulation study and with the geological and petrophysical evaluation
previously conducted. The paper constructs a methodology to evaluate the relative strength of
the water influx, allowing a reservoir engineer to identify weak, moderate and strong influx drive
mechanisms and hence plan for appropriate injection support. Finally the effectiveness of the
sweep efficiency was determined by using oil recovery versus hydrocarbon pore volume injected,
type curves obtained from core studies of various crude oil viscosities. It was determined that the
water influx volume was relatively small compared to the volume of water injected and was calculated to be at 8% of the total water injected. The sweep efficiency was determined to be approximately 55% based on the relative distance of the peripheral injection.
40-11
BTH 11
Li, Xin
[173877]
INVESTIGATION OF OIL BY PASSED MECHANISMS FOR IMPROVED OIL RECOVERY IN
DEEPWATER GULF OF MEXICO
LI, Xin, LONGMUIR, Gavin, MCMILLEN, Kenneth James, and DUAN, Shengkai,
Knowlege Reservoir, Houston, TX 77027, [email protected]
Deepwater Gulf of Mexico oil fields (DW GoM) typically get modest Ultimate Recovery Factors in
the 10% ‑ 35% range, because reservoirs tend to be small, deep, and complex. The Remaining
Oil target for Improved Oil Recovery (IOR) is tempting large, with about 40 Billion Bbl estimated
to be left in discovered fields at abandonment. Procedures on by‑passed oil mechanisms analysis
are based on analysis of field data compiled by Minerals Management Service, on data extracted
from focused literature reviews, and on original work to analysis by‑passed oil mechanisms and
describe the remaining oil distribution in turbidite reservoirs of DW GoM. This paper describes a
study on oil trapped mechanism, by‑passed oil categories and their distributions. It is key part of
study directed at recommending a select group of IOR processes for multi‑million dollar Research
& Development funding by Research Partnership to Secure Energy for America (RPSEA). The
DW GoM oil fields have been catalogued and characterized by geological setting and reservoir
engineering. (1) By‑passed oil depends on structure settings and depositional system. The
trapped oil mechanism was reviewed in the context of eight defined geologic classification types
for structural setting and depositional environment. (2) Detailed examination of reservoir performance and simulation studies has been conducted for a number of GoM fields and reservoirs. In
this study, case study with actual field data for Neogene age Tertiary reservoirs is included, and
followed by conclusions. Authors established static and dynamic model referring MMS database
to quantify by‑passed oil. This work defines the significance of bypassing mechanisms so that
appropriate IOR methods can be selected in DW GoM.
40-12
BTH 12
Jung, Jung
[173878]
SIMULATION OF TIME LAPSE MINERAL CARBONATION AND ISOTOPE FRACTIONATION OF
INJECTED CO2 IN AQUIFER: IMPLICATIONS FOR MONITORING CO2 SEQUESTRATION
JUNG, Jung, Texas A&M U, College Station, TX 77027, [email protected] and
YANG, Daegil
A theoretical aquifer model during CO2 sequestration predicts time‑lapse mineral carbonation
and isotope fractionation of injected CO2 in sediment. The kinetics of CO2 hydration and the
dissociation of carbonic acid are used to simulate the model. The conversion rate of CO2 into
hydrogen and carbonate ions in an aqueous solution is controlled by diffusion and reaction kinetics. Geologic sequestration of CO2 has become one of the promising ways to reduce atmospheric
emission of CO2 from human activity. However, the current and future effects of geologic storage
formation after injecting CO2 are not known well. Therefore, monitoring and verification of CO2
sequestration is very important in carbon capture and sequestration projects. In this study, we
injected CO2 for a certain amount of time period and shut in the injection well and generated
CO2 flume and properties distribution in the reservoir. Using data generated from the simulator,
we developed a mathematical model based on a transport‑reaction equation and calculated the
SESSION NO. 40
abundance of carbon and oxygen stable isotope in the reservoir with respect to time which allows
us to predict CO2 saturation in sediment or CO2 flume distribution by sampling reservoir water.
In addition, injected CO2 can be migrated into a ground water aquifer. The migrated CO2 can be
detected by comparing the stable isotopes in sampled groundwater and predicted stable isotopes.
These results indicate significant potential of the theoretical aquifer model for monitoring and
verification of CO2 sequestration into the sediment.
40-13
BTH 13
Babadagli, Tayfun
[173879]
CALCULATING EQUIVALENT FRACTURE NETWORK PERMEABILITY OF MULTI LAYER
COMPLEX NATURALLY FRACTURED RESERVOIRS
and JAFARI, Alireza
Modeling naturally fractured reservoirs (NFRs) requires an accurate representation of fracture
network permeability. Conventionally, logs, cores, seismic, and pressure transient tests are used
as data base for this. Our previous attempts showed that a strong correlation exits between
the fractal parameters of 2‑D fracture networks and their permeability (SPE113618). We had
also showed that 1‑D well (cores‑logs) and 3‑D reservoir data (well test) may not be sufficient
in fracture network permeability (FNP) mapping and 2‑D (outrop) characteristics are needed
(SPE124077). This paper is an extension of these studies where only 2‑D (single layer, uniform
fracture characteristics in z‑direction) representations were used. In this paper, we considered
a more complex and realistic 3‑D network system. 2‑D random fractures with known fractal and
statistical characteristics were distributed. Variation of fracture network characteristics in the
z‑direction was presented by a multi layer system representing ten different facieses with different
fracture properties. Wells were placed in different locations of the model to collect 1‑D fracture
density, multi‑well pressure transient data. In addition, twelve different fractal and statistical properties of the network of each layer were measured. The equivalent FNP was calculated using a
commercial software package as the base case. Using available 1‑D, 2‑D, and 3‑D data, multivariable regression analyses were performed to obtain equivalent FNP correlations for many different
fracture network realizations. The derived equations were validated against synthetic and natural
fracture networks and conditions at which 1‑D and 3‑D are sufficient to map fracture network
permeability were determined. Also performed was an analysis on the determination of minimum
number wells to be logged, cored, and tested using an ANN analysis. Importance of the inclusion
of 2‑D data in the correlations was discussed.
40-14
BTH 14
El Shaari, Nabil Abdalla
[173881]
IMPROVED WELL FRACTURE STIMULATION PERFORMANCE THROUGH THE APPLICATION
OF UNIQUE SOLID CHEMICAL INHIBITORS
EL SHAARI, Nabil Abdalla, FRITZ, Steven Arthur, and BERGSTROM, Jason, BJ Services
Company, Bakersfield, CA 93306, [email protected]
The production performance of hydraulically fractured wells is dependent on many variables.
Many of such variables are related to reservoir characteristics and fracture design. A slower
production decline rate and enhanced production performance of a fractured well can be realized by the addition of inhibitor‑coated substrates to the proppant during the fracturing process.
These proppant pack inhibitors are designed to mitigate the negative effects of scale, paraffin and
asphaltene deposits, in addition to corrosion. The addition of inhibitors and their placement within
the proppant pack is based on the premise that fluid flow regimes post proppant fracturing, from
initial linear to pseudo‑radial flow, will be through the proppant pack. Chemical inhibitors are most
effective when placed within the proppant pack, providing a controlled and extended inhibitor
release. Chemically‑coated substrate inhibitors have been designed to function in varied reservoir
and well conditions, yet are strong enough to maintain fracture conductivity of the proppant pack.
This technology provides significant benefits by minimizing scale, wax, and asphaltene deposition
in the fracture and wellbore, minimizing the effects of corrosion, delaying well workover intervention, and reducing well remediation costs.
40-15
BTH 15
Al Otaibi, Ajab Mohammed
[173882]
TRANSIENT BEHAVIOR AND ANALYSIS OF NON DARCY FLOW IN POROUS AND
FRACTURED RESERVOIRS ACCORDING TO THE BARREE AND CONWAY MODEL
AL OTAIBI, Ajab Mohammed, Colorado School of Mines, Golden, CO 80401,
[email protected] and WU, Yu Shu
This study introduces the usage of the Barree and Conway flow model in well test analysis of a
single‑phase non‑Darcy flow in porous and fractured reservoirs. The non‑Darcy flow behavior is
handled using a numerical model incorporating the non‑Darcy flow effects according to the Barree
and Conway model. The developed numerical model is capable of simulating all near wellbore
effects, such as wellbore storage and skin effects under non‑Darcy flow condition. A steady‑state
non‑Darcy radial flow solution is also derived to verify the numerical simulation results. The
numerical model is used to interpret radial flow pressure‑transient responses for pressure buildup
and drawdown well tests. In simulated pressure drawdown tests with non‑Darcy flow with no skin
and wellbore storage effects, the permeability, obtained using the standard straight‑line analysis,
is an apparent permeability and not the Darcy’s constant permeability. The estimated permeability
ranges from the minimum permeability and to less than the Darcy’s permeability. Thus in pressure
drawdown tests the standard straight‑line analysis techniques underestimate the Darcy’s permeability when non‑Darcy flow exists. A pressure buildup test, following non‑Darcy flow drawdown
tests, may be good for determining Darcy’s permeability values using standard straight‑line analysis without significant non‑Darcy flow. The Barree and Conway non‑Darcy model parameters may
not be directly estimated from pressure‑transient well tests. However, it can be estimated by a
matching process using the generated type curves from the developed numerical model. The type
curves are provided to demonstrate a methodology for modeling single phase non‑Darcy flow
effects in porous and fractured rocks. The developed numerical model is used to interpret several
actual well tests from single‑phase high rate wells in Kuwait.
40-16
BTH 16
Jiang, Haifeng
40-17
BTH 17
Li, Weiqiang
[173884]
SIMULATION INVESTIGATION OF SOLVENT CO INJECTION IN VAPOR AND LIQUID PHASE
TO REDUCE SHALE BARRIER IMPACT ON SAGD PERFORMANCE
LI, Weiqiang and MAMORA, Daulat Debataraja, Texas A&M U, College Station, TX 77843,
[email protected]
Heterogeneous, especially the shale barrier, significantly reduce steam‑assisted gravity drainage
(SAGD) performance at Athabasca field. The objective of this experiment study is to investigate
the drainage mechanism for solvent co‑injection in vapor and liquid phase to reduce the shale
barrier effect in field. An extensive 2D simulation study shows that the throttling effect at the end
of shale barriers and the extra heat required by the residual water inside the unproductive shale
barrier are the main reasons for the shale barrier effect. A long continuous shale barrier located
vertically above or near the wellbore reduces production performance significantly. We investigated potential strategies, including solvent co‑injection, top injector application, or combining
both, to reduce the shale barrier impact. Solvent in vapor phase can pass though the narrow flow
path at the end of shale barrier, meanwhile its phase condensing from vapor to liquid reduces the
throttling effect of shale barrier efficiently. Liquid solvent co‑injection can accelerate the near‑wellbore flow and reduce the residual oil saturation significantly at the wellbore vicinity. Co‑injecting
multi‑component solvent can take advantage of both vaporized and liquid solvents. Top steam
injector applications show only marginally improvement. The conclusions from this study can be
used to design suitable solvent mixture and solvent co‑injection strategy to reduce shale barrier impact on SAGD Performance with higher production rate, higher recovery factor with lower
steam to oil ratio (SOR).
40-18
BTH 18
Cheng, Kun
[173885]
A NOVEL OPTIMIZATION MODEL FOR ANALYZING PRODUCTION DATA
CHENG, Kun, WEI, Yunan, WU, Wenyan, and HOLDITCH, Stephen A., Texas A&M U,
College Station, TX 77843, [email protected]
The production data analysis is very important for petroleum industry since it serves as the fundamental step for reservoir development. In computer science, the self‑adapting bionic optimization model is a state‑of‑the‑art intelligent computation technique which can be used to analyze
production data. In this paper we applied the self‑adapting bionic optimization model to analyze
production data. This method combines the heuristic approach, grey correlation analysis, and
fuzzy clustering method in computer science to optimize the reservoir production plan. To develop
the method, we firstly perform grey correlation analysis to describe the initial correlation between
production data parameters. By applying fuzzy clustering method, the production data are divided
into different categories according to the degrees of their correlations. This heuristic information
is used to construct the production data analysis model. Finally the best‑optimized correlations
among the various production data can be discovered. A simple example with related parameters
is presented to show the algorithmic strategies. This example proved that our method is a flexible and cost‑effective quantitative analysis method for production data analysis. To evaluate this
model, we selected 50 wells in some gas reservoirs from Xinjiang oilfield, China. The 50 wells
have been developed for many years. Therefore, we have enough data on the 50 wells to test this
model. It is demonstrated that this model is useful in production data analysis.
40-19
BTH 19
Zhai, Daoyuan
[173886]
AN INEQUALITY CONSTRAINED EXTENDED KALMAN FILTER FOR CONTINUAL
FORECASTING OF INTERWELL CONNECTIVITIES IN WATERFLOODS
ZHAI, Daoyuan, U of Southern California, Los Angeles, CA 90089, [email protected]
Liu, et al 1 first developed an Extended Kalman Filter (EKF) for a producer‑centric reservoir modeled as a collection of continuous‑time impulse responses that convert injection rates of all contributing injectors into a production rate. This original EKF model estimates, for each producer‑injector pair, two parameters, that can be used to compute an
Injector‑Producer‑Relationship (IPR) value. Zhai, et al 4 then modified the EKF model to directly
estimate the square‑root of the IPR value for each producer‑injector pair, and developed a set
of heuristic strategies for implementing the EKF model on much more complicated and noisy
real field data. In both these works, the IPR values of a whole field are obtained by the EKF
processing of each producer independently; however, an important type of injector‑centric
constraints needs to be imposed across producer‑centric models, namely, the sum of the IPR
values of each injector has to be less than or equal to one. Unfortunately, it is not possible to
impose such constraints using the current EKF structure. Recently, D. Simon, et al 2, 3 and
Yang and Blasch 5 have shown how to incorporate linear equality and inequality constraints
into the structure of a Kalman filter. This paper extends their constrained Kalman Filter for our
producer‑centric EKF model so as to handle nonlinear inequalities. For the first time in our works,
all of the producer‑centric models are coupled together due to the constraint on the sum of the
IPRs ‑ constraint coupling. This paper uses a mini‑simulated field to show how unconstrained EKF
processing can cause the sum of the IPRs to be greater than one; and, demonstrates how the
constrained EKF can be used to couple the whole field thereby obtaining the correct IPR values.
[173883]
THE EFFECT OF SALINITY OF INJECTION BRINE ON WATER ALTERNATING
GAS PERFORMANCE IN TERTIARY MISCIBLE CARBON DIOXIDE FLOODING:
EXPERIMENTAL STUDY
JIANG, Haifeng, NURYANINGSIH, Lily, and ADIDHARMA, Hertanto, U of Wyoming, Laramie,
WY 82071, [email protected]
The effect of salinity of the injection brine on Water Alternating Gas (WAG) performance in tertiary
miscible carbon dioxide (CO2) flooding is investigated. Coreflood experiments are performed in
Berea sandstone core, from which the WAG performance (oil recovery, tertiary recovery factor,
and CO2 utilization factor) are determined. Coreflood experiments are conducted at 60oC and
miscible condition. A model oil, which is a mixture of 50 wt% n‑decane and 50 wt% n‑hexadecane, and a crude oil from Cottonwood Creek are used. For the experiments with model oil,
artificial injection brines are made by dissolving NaCl into distilled water with different salinities
ranging from 1000 to 32000ppm (mg/L); artificial brines containing 4000ppm NaCl and 4000ppm
CaCl2 are also used to investigate the effect of divalent salt in the injection brine. Artificial brines
containing 20000ppm NaCl and 10000ppm CaCl2 are used to mimic connate brines, and artificial
injection brines containing 66.67wt% of NaCl and 33.33wt% of CaCl2 with salinities ranging from
10000 to 32000ppm are used in experiments with Cottonwood Creek oil. Six alternate cycles of
brine and CO2 with a half‑cycle slug size of 0.25 pore volumes (PV) and a CO2/water ratio (volume ratio) of 1:1 are injected in every core flood test. At the same miscible condition, the tertiary
recovery factor of WAG is demonstrated to be higher than that of continuous CO2 flooding. The
tertiary oil recovery and recovery factor of the model oil and the crude oil are found to increase
slightly with the salinity of the injection brine due to the decrease in the CO2 solubility in brines.
The CaCl2 in the injection brine is found to have similar effect as NaCl. Comparisons of WAG and
continuous gas injection are also made on both model oil and crude oil.
40-20
BTH 20
Al Shuwaikhat, Hisham Ibrahim
[173887]
ENERGY CONSERVATION AND OIL PRODUCTION OPPORTUNITIES IN GHAWAR FIELD IN
SAUDI ARAMCO
AL SHUWAIKHAT, Hisham Ibrahim, Saudi Aramco, Dhahran 31311 Saudi Arabia,
[email protected]
Energy conservation is the key aspect to reduce high energy consumption in a Gas Oil
Separation Plant (GOSP) where oil is separated from water and gas and shipped. Saudi Aramco
is putting a lot of efforts to produce large fields, such as Ghawar field, with optimized energy
consumption; especially in summer time which is always a peaking high demand period. Swing
line network has been constructed between major field GOSPs to optimize energy consumption
SESSION NO. 40
while meeting required production targets by reallocating oil production to reduce energy consumption. The swing lines were approved and structured in late 2005. Presently, they are in use
and emerged as a proven tool to lower operating expenditure (OPEX) for GOSPs. This has not
only reduced the cost of power but also minimized the environmental impact to a large extend.
Also, as part of the field production strategy several high water cut wells were shut‑in resulting
in a very remarkable power consumption reduction at their respective plants. This conservation
was reached by shutting some of the disposal pumps and/or deferral of upgrade for the disposal
system. This paper and presentation will focus on energy conservation and oil production efforts
in Southern part of Ghawar field and highlight major achievements.
40-21
BTH 21
Lane, Robert H.
[173888]
DEEP PLACEMENT GEL BANK AS AN IOR PROCESS: MODELING, ECONOMIC ANALYSIS
AND COMPARISON TO POLYMER FLOODING
LANE, Robert H., Texas A&M U, College Station, TX 77843, [email protected] and
SEYIDOV, Murad
Commercial reservoir simulation software was used to model a five spot water flood in a synthetic
vertically‑heterogeneous reservoir with cross flow. At 85% water cut, the pattern was either continued on water flood, converted to a polymer flood, or treated with a deeply‑placed stationary gel
“doughnut” then continued on water flood. Floods were continued to 95% water cut. Production
performance and economics were analyzed for the three processes. The methodology developed in this project enables real‑case comparison of oil recovery and economics to aid selection
of an IOR process as an alternative to continuing the water flood to its economic limit. For the
three‑layer reservoir of this study, simulation results show that both IOR methods lead to higher
ultimate recovery than water flooding alone, with polymer flooding yielding the larger increase.
However, due to slow oil bank formation and production, polymer flooding exhibits a delayed
increase in oil rate which adversely impacts its economics. Deep gel placement yielded the highest NPV. Sensitivity analyses on deep‑placement gel cases show that distance from the injection
well and size of the “doughnut” plug have the greatest effects on treatment performance for a given
reservoir. Impacts of these and other parameters on treatment design are presented. Direct performance comparisons of water flooding, polymer flooding, and deep‑placement gels are provided.
Engineers can used this methodology as a screening tool for choosing deep reservoir diversion or
polymer flooding as a preferred IOR method for a given vertically heterogeneous reservoir.
40-22
BTH 22
Fuentes Cruz, Gorgonio
[173889]
A UNIFIED APPROACH FOR FALLOFF AND BUILDUP TESTS ANALYSIS FOLLOWING A
SHORT INJECTION/PRODUCTION TIME
FUENTES CRUZ, Gorgonio, VELAZQUEZ, Rodolfo Gabriel Camacho, and VASQUEZ
CRUZ, Mario Alberto, Inst Mexicano del Petroleo, San Bartolo Atepehuacan, 07730, Mexico,
[email protected]
This study presents a general methodology for analyzing falloff/buildup tests, particularly with
short injection/production time; this methodology consists of a simultaneous match of the pressure drop, superposition derivative, and the normalized impulse derivative, by using the first and
second drawdown derivative. Furthermore, a new radial composite model with a fractal transition
zone (RCMFT) is also proposed for falloff tests; the RCMFT considers an intermediate region with
fractal behavior between the invaded zone by the injected fluid and the non‑invaded homogeneous zone. New short‑, intermediate‑, and long‑time approximations for the pressure response
are introduced. Application The methodology is general for analyzing falloff/buildup tests, but it is
particularly suitable in those cases where neither the conventional semi‑log nor modern methods
based on first derivative, can be applied. The RCMFT is helpfully for falloff tests in low mobility
reservoirs, since it honors the dynamic of flow occurring when an injected fluid displaces another
one with lower mobility. Results, Observations, and Conclusions It is important to distinguish the
cases in which the superposition derivative matches with the second drawdown derivative and
the normalized impulse derivative, in order to have a good control on the model selection, and on
the parameters determination. In falloff tests, it is necessary to take into account the intermediate
transition zone, since it has a sound influence on the pressure response of the system. Therefore,
if it is ignored, then the skin factor could be overestimated. From the field cases presented, we
have evidence of the fingering phenomenon at greater scales than those ones of laboratory
experiments. Significance of Subject Matter The proposed methodology is promising, since it
facilitates the well test interpretation in many practical situations. Therefore, it is recommendable
to incorporate it into the transient pressure analysis workflow.
40-23
BTH 23
Kalaei, M. Hosein
[173865]
NUMERICAL MODELING OF THE WATER IMBIBITION PROCESS IN WATER WET
LABORATORY CORES - POSTER
KALAEI, M. Hosein1, GREEN, Don W.2, and WILLHITE, Paul2, (1) U of Kansas, Lawrence,
KS 66045, [email protected], (2) U of Kansas, Long Beach, KS 90802
Oil recovery from water‑wet, naturally fractured reservoirs subjected to waterflooding is governed
by spontaneous imbibition of water from the fractures into the matrix rock due to capillary and
gravity forces, which results in the displacement of the non‑wetting oil. Several parameters, such
as wettability, boundary conditions, rock geometry, fluid properties, and IFT between oil and
water affect the oil recovery. A three‑dimensional, two‑phase numerical simulator was developed
to investigate both mechanisms of oil production and the parameters that influence recovery
in water‑wet laboratory cores. The model was validated by a comparison of calculations to the
numerical simulation of Blair (1964) and experimental data presented by Schechter et al. (1991)
and Fischer & Morrow (2005). Agreement between model calculations and data was excellent.
When capillary forces are negligible, gravity force causes displacement of the oil spontaneously
due to density difference between the oil and water in cores mounted vertically. The effect of
reducing the interfacial tension between water and oil on oil recovery by spontaneous imbibition
was numerically investigated for a wide range of IFT’s in cores oriented vertically and compared
against experimental data. Capillary force is lowered when IFT is reduced through capillary
pressure curve. The study showed that reducing the IFT between oil and water may decrease
the rate of imbibition in low permeability cores. However, the ultimate recovery increases when
compared to the same system with higher IFT. Comparison of the imbibition curves obtained for
the same value of oil/water viscosity ratio revealed that oil recovery is lowest when the one‑end,
open‑boundary condition was applied on the core. Ultimate recovery was almost the same in all
other different boundary conditions.
92 2010 GSA Abstracts with Programs SESSION NO. 41, 1:30 PM
Friday, 28 May 2010
T44. American Association of Petroleum Geologists
(Posters) (Pacific Section, AAPG)
41-1
BTH 24
Higley, Richard T.
[172219]
NEW OIL OPPORTUNITIES IN THE EASTERN VENTURA BASIN
HIGLEY, Richard T., 9961 e. Paseo San Bernardo, Tucson, AZ 85747, [email protected]
Re-evaluation of some old prospects and properties in the Eastern Ventura Basin of California, in
light of discoveries adjacent to older fields, indicates the potential for small but profitable new oil
reserves. The discovery in the late 90’s of a new “pool” to the south of the old Temescal Oil Field
along Piru Creek is an example of how newer drilling techniques and completion practices can
yield small but profitable new reserves. The region between Piru Creek and Sespe Creek on the
hanging wall of the San Cayetano Thrust was mostly drilled before 1940. The few “modern wells”
drilled prior to 1985 showed potential, but the exodus of majors from California in the middle 80’s
left the regions’ remaining potential untapped. Today new oil production from shallow wells may be
found within a proven oil province which, paradoxically, does not suffer from the extreme environmental scrutiny characteristic of other California oil plays.
41-2
BTH 25
Olson, Deborah M.
[172976]
FROM PAPER TO BINARY: PROBLEMS AND SOLUTIONS IN CREATING AND VERIFYING
DIGITAL LOG DATABASES
OLSON, Deborah M. and HOWARD, Thomas M., PayZone Inc, P O Box 5146, Bakersfield,
Over the last 30 years major efforts have been made to capture well log data from paper records
as digital representations. In the late 1970’s, field capture of digital logs became common.
However, the archival records stored in most corporate well files and the majority of U.S. public
data repositories are still the paper log plots or their scanned images.
The digital logs in corporate databases often have a long history including migration from previous platforms and data structures, merging of information from multiple sources, and access by
many people who could edit the data. The staff assumes validity of the data to generate reservoir
characterizations. Management bases critical decisions on the analytical results. The entire process relies on the credibility of the digital curves as true representations of the actual well logs,
but all too often they are not.
In verifying and repairing many field-wide digital well log databases for a variety of clients,
we have found that most of them have defects (sometimes extensive) that must be remediated
before any further work can be done. When databases are not verified, much staff time is lost in
attempts to repair data in a piecemeal fashion to move the immediate job forward. This costs time
and money on every project. And there is always the potential for making incorrect interpretations
based on faulty data that was not recognized.
It is not easy, quick, or cheap to verify a log database, and the work should be performed (or at
least closely supervised) by staff with extensive knowledge of logging tool physics, well logging
operations, methodology of petrophysics, and the geology of the logged intervals. However, validity of basic field data is vital to making sound economic decisions. Many development projects in
mature basins still have a long remaining life, and an investment now in an accurate set of reservoir data will provide a significant future payoff.
41-3
BTH 26
He, Meng
[173153]
ONE-DIMENSIONAL BURIAL HISTORY MODEL SHEDS NEW INSIGHTS INTO THE
PETROLEUM SYSTEMS IN THE VALLECITOS AREA AND OIL FIELD, SAN JOAQUIN BASIN,
CALIFORNIA
HE, Meng, Dept of Geological and Environmental Sciences, Stanford University, 450 Serra
Mall, Braun Hall, Bldg320, room 118, Stanford, CA 94305, [email protected]
The Vallecitos syncline is a westerly structural extension of the western San Joaquin basin. By the
end of 1959 the Vallecitos field, comprised of eight separate producing areas (Griswold Canyon,
Franco, Cedar Flat, Ashurst, Silver Creek, Pimental Canyon, Central, and Los Pinos Canyon), had
produced approximately 2.2 MMBO and 1.5 BCF of gas from Cretaceous and Paleogene reservoirs. Cumulative oil and gas production through 2007 in the Vallecitos area reached 5.4 MMBO
and 3.9 BCF, respectively (California Division of Oil, Gas, and Geothermal Resources, 2008).
However, dispersed oil accumulations in the Vallecitos area make the oil and gas exploration
challenging. In order to better understand the petroleum systems in the areas and demonstrate
oil generation locally, 1D burial histories have been generated for the Vallecitos areas. Prominent
features of the Vallecitos syncline documented in published works include complexities of subsurface geology and rock records of tectonic events. These are important for understanding the origin
of the oils captured in the present day traps in this syncline.The 1D model is based on a pseudowell placed at the axis of Vallecitos syncline where the overburden rock above the uppermost
Cretaceous Moreno Formation is thickest. The pseudo-well is compiled from two nearby wells,
Ne-Tex 1and Ortis 48-24. Using a cross-section through the pseudo-well and these two wells,
there appears to be no basis for adding additional eroded stratigraphic section to the model, even
though significant erosion did remove significant overburden rocks on the flank of the syncline.
The thickness of the stratigraphic section and migration of the Mendocino triple junction were
considered in terms of the heat flow for the model. Results suggest that the bottom and the top
of the Cretaceous Moreno Formation reached thermal maturity at 19 Ma and 9Ma, and the synclinal Eocene Kreyenhagen Formation became thermally mature 4 Ma. It is highly likely that the
Kreyenhagen Formation with Maximum transformation ratio (TR) (~18%) in relatively recent time
is a minor source contributor to the oils. Those results differ from those obtained from the early
studies in terms of source origins of the oils in the syncline.The Eocene Kreyenhagen Formation
was believed to be a significant source rock and the deep sources were dismissed.
SESSION NO. 42
42-4
Friday, 28 May 2010
T45. San Andreas and Walker Lane Neotectonics
(Posters)
42-1
BTH 27
Gooding, Margaret L.
[172986]
ANALYSIS OF SEISMIC ACTIVITY AND POTENTIAL SEISMIC HAZARDS OF THE FONTANA
SEISMIC TREND IN SOUTHERN CALIFORNIA
GOODING, Margaret L., 2217 N Cedar Ave, Rialto, CA 92377, [email protected]
Southern California is a seismically active region with a large population. The Study Area is
the Fontana Seismic Trend, an area of intense earthquake activity in western San Bernardino
County. There has not been much significant work done to quantify the potential seismic hazard
posed by it. This presentation will show that there is potential for a moderate seismic event on the
Fontana Seismic Trend that will likely cause quite a bit of damage and disrupt lives. The major
faults nearby have been studied extensively, but this is not the case for the Fontana Seismic
Trend. When plotted on a map, the earthquake epicenters of the Fontana Seismic Trend display a
significant linear pattern both two dimensionally and three dimensionally. In this presentation, the
location and direction of movement of the underlying fault are identified and configured to fit the
earthquake data. Using the plotted fault location, direction of movement and length, the maximum
potential event that might occur on this fault was also quantified. HAZUS-MH (a FEMA software
extension to ArcGIS) was used to perform a seismic hazard analysis to find out what type of damage and casualties can be expected if a moderate event occurs on this fault. This presentation
discusses the methods used to determine the fault parameters and details the results from the
seismic hazard analysis.
42-2
BTH 28
Masana, Eulalia
[173159]
COMBINING NEW AIRBORNE LIDAR DATA AND PROVENANCE OF ALLUVIAL FAN
DEPOSITS TO CONSTRAIN LONG-TERM OFFSETS ALONG THE ELSINORE FAULT IN THE
COYOTE MOUNTAINS, IMPERIAL VALLEY, CALIFORNIA
MASANA, Eulalia1, ROCKWELL, Thomas K.1, and STEPANCIKOVA, Petra2, (1) Geological
Sciences, San Diego State University, 5500 Campanile Dr, San Diego, CA 92182-1020,
[email protected], (2) Institute of Rock Structure and Mechanics, Academy of
Sciences of the Czech Republic, V Holesovickach 41, Prague, 182 09, Czech Republic
The Elsinore-Laguna Salada fault is part of the San Andreas fault (SAF) system in southern
California, extending 250 km from the Los Angeles Basin southeastward into Mexico. The slip
rate on the southern Elsinore fault is believed to be low, based on recent InSAR observations,
although a recent study near Fossil Canyon suggests a rate in the range of 1-2 mm/yr. However,
the fault is well-expressed in the geomorphology in the Coyote Mountains, which argues for a
reassessment of the long-term rate along this branch of the SAF system. For this study, we used
the new, recently acquired airborne LiDAR dataset (EarthScope Southern & Eastern California,
SoCal) to map alluvial offsets in the Coyote Mountains in western Imperial Valley. We reprocessed
the point clouds to produce DEMs with 0.5m and 0.25m grids. We varied the hill shade and insolation angles to illuminate and map the various fault strands and alluvial deposits. This allowed us
to detect not only the major offsets along the primary fault strands, but also the many secondary
minor faults. We identified numerous offset features, such as rills, channel bars, channel walls,
alluvial fans, beheaded channels and small erosional basins that varied in displacement from 1 to
350 m. These are compared to measurements on many of the same features in the field. For the
larger offsets, we recognize that older alluvium that is offset greater amounts is commonly buried
beneath younger pulses of alluvial fan deposition, and are separated by buried soils. To determine
the actual source canyon of various alluvial elements, we quantified the clast assemblage of
each source basin and each alluvial fan on both sides of the fault. To accomplish this, we used a
portable grid and classified more than 300 clasts at each of more than 35 sites along the fault. We
found a very good fit between displaced alluvial fan elements and their inferred source canyons,
but a poor match with the alluvium from neighboring canyons, which allows us to resolve longterm offset. Future dating of the pedogenic carbonate associated with these buried soils will allow
resolution of the long term slip rates over multiple time frames to test the constancy of fault slip
rate during the late Quaternary, as well as to test the lateral variations in rate along the length of
the fault.
42-3
BTH 29
Herbert, Justin
[173189]
INTERSEISMIC DEFORMATION OF THE SAN BERNARDINO REGION FROM GEOLOGICALLY
BASED MODELS
HERBERT, Justin, Geosciences, University of Massachusetts, Morrill Science Center,
611 N Pleasant St, Amherst, MA 01002, [email protected] and COOKE, Michele L.,
Geosciences, University of Massachusetts, 611 North Pleasant Street, Amherst, MA
01003-9297
Investigation of the active faults in the San Bernardino region requires three-dimensional models
that can simulate the complex, non-planar intersecting active fault surfaces. Rather than directly
inverting for slip along highly simplified fault surfaces, we use a two-stage approach. First we
simulate geologic time-scale deformation and then we use these results to produce interseismic
models. Geologic timescale numerical models with 4 km resolution produce good match to geologic slip rates collected in the region. In the interseismic model, slip from the geologic model is
prescribed below the locking depth and faults are bonded above the locking depth. The model
predicted surface velocities are compared with geodetic velocities from ~80 stations in the region.
In some areas the predicted velocities very closely match those of GPS stations in the area.
Residuals between the model and data velocities may reflect heterogeneous basement material,
inaccurate fault surface representation or inaccurate tectonic boundary conditions.
BTH 30
Hebert, Chris
[173207]
CLAYBOX SIMULATIONS OF THE EVOLUTION OF THE SOUTHERN BIG BEND REGION OF
THE SAN ANDREAS
HEBERT, Chris, Department of Geo-Sciences, University of Massachusetts Amherst,
611 North Pleasant Street, 233 Morrill Science Center, Amherst, MA 01003, cbhebert@
student.umass.edu, SCHOTTENFELD, Mariel T., Geology, University of Massachusetts
Amherst, Amherst, MA 01003, COOKE, Michele L., Geosciences, University of
Massachusetts, 611 North Pleasant Street, Amherst, MA 01003-9297, and HERBERT,
Justin, Geosciences, University of Massachusetts, Morrill Science Center, 611 N Pleasant St,
Amherst, MA 01002
We simulate three stages of San Andreas fault evolution within the past 1 My using wet clay. The
early, intermediate and late stages of fault configuration represent times when the Mission Creek,
Mill Creek and Garnet Hill/San Gorgonio strands of the San Andreas fault were active. For each
stage, strands of the San Andreas and San Jacinto faults are cut into wet clay. The cut clay is
deformed according to present-day plate motions within a servo-controlled rig. Laser scans of the
clay surface document deformation at intervals throughout the experiments. Some experiments
include a layer of silicone gel beneath the clay to distribute basal displacement. Simulation of
present-day active fault configuration match well geologic data for slip rates and uplift pattern.
At each evolutionary stage, new splay faults develop off the San Andreas fault. We track the
partitioning of strain as both fault slip and distributed shear. Slip along new splay faults inhibits
slip along the primary fault and decreases distributed shear. The splay faults may play a role in
the abandonment of active fault strands and the evolution of the southern Big Bend of the San
Andreas fault.
42-5
BTH 31
Schottenfeld, Mariel T.
[173057]
INVESTIGATION OF NEW FAULT DEVELOPMENT WITHIN CONTRACTION BENDS IN A
CLAYBOX
SCHOTTENFELD, Mariel T., Geology, University of Massachusetts Amherst, Amherst, MA
01003, [email protected] and COOKE, Michele, Geosciences, Univ of Massachusetts,
Amherst, MA 01003-9297
We investigate the growth of new faults near a contractional bend within a strike-slip faults system
using wet clay analog models. The models simulate conditions similar to that of the southern Big
Bend of the San Andreas where new active fault traces have developed within the past 1 My.
We explore a range of contractional bend fault geometries with a servo-controlled claybox. For
each experiment, a contraction bend comprised of three kinked segments is cut into the clay.
The kink angle and size of the step-over are systematically varied whereas fault dip is vertical
in all models. Various basal plate geometries facilitate slip along the kinked fault geometries.
Silicone putty is also introduced below the clay in some experiments to allow more distributed
application of the basal displacements to the clay. During the experiment, the clay is periodically
scanned with a 3D laser scanner to document slip, off-fault strain, new fault formation, and uplift.
Contractional bends with large kink angle (e.g. 90˚) and large step-over length (e.g. 10 cm) do
not exhibit significant strike slip. Instead, two new thrust faults develop to form a bivergent pop-up
structure that promotes uplift within the contraction bend. Smaller step-over and smaller angle of
fault kink promotes strike slip through the contractional bend via the development of new strikeslip faults that splay from the primary fault. The degree of new splay fault development decreases
with decreasing step over size and kink angle. The mechanical efficiency of these evolving fault
systems can be analyzed from the slip data collected. The results from this parametric study can
be compared to the evolutionary history of the southern Big Bend of the San Andreas to provide
insight into the processes controlling abandonment and initiation of active fault strands within this
complex system.
42-6
BTH 32
Luo, Shangde
[173232]
DATING PALEO-SEISMIC/TECTONIC EVENTS BASED ON U-SERIES DISEQUILIBRIUM IN
EVAPORATES FROM THE FAULT ZONES
LUO, Shangde1, WU, Yi-Chen1, SHEN, Chuan-Chou2, and PALACIOS, Carlos3, (1) Earth
Sciences, National Cheng-Kung University, 1 University Road, Tainan, 701, Taiwan,
[email protected], (2) Geosciences, National Taiwan University, Taipei, 106, Taiwan,
(3) Departamento de Geología, Universidad de Chile, Santiago, Chile
Evaporite minerals (e.g.. gypsum and halite) are formed in active fault zones when deep saline
groundwater is episodically forced up by an seismic/tectonic event. Precise dating of such
deposits bears important information on past changes in regional tectonics. In this study, we
investigated the potential of 238U-234U-230Th radioactive disequilibria in evaporites as a tool for
such dating. Samples were collected from the hyper-arid Atacama Desert, northern Chile and
each sample was separated into several sub-samples via suspension method. Isotopes of U
(238U and 234U) and Th (232Th and 230Th) were analyzed using a multi-collector inductively coupled
plasma mass spectrometer (MC-ICPMS). Results show that significant 238U-234U-230Th disequilibria
occured in the evaporites and may be associated with the authigenic phases in clay minerals.
Uranium and thorium are well preserved in the evaporites due to the cementation or locking-in of
clay minerals by gypsum and/or halite minerals. With precise MC-ICPMS analytical technique, this
study shows that an isochron method can be established based on the observed 238U-234U-230Th
disequilibria in evaporites to date the paleo-seismic/tectonic events.
42-7
BTH 33
Rittase, William M.
[173040]
OFF-FAULT DEFORMATION, UPLIFT AND SEDIMENTATION IN PILOT KNOB VALLEY,
CALIFORNIA -- PIECING TOGETHER COMPLEX STRUCTURAL AND KINEMATIC
PROCESSES BETWEEN THE GARLOCK FAULT AND PANAMINT VALLEY FAULT
RITTASE, William M., Geology, University of Kansas, Lawrence, KS 66046, [email protected],
WALKER, J. Douglas, Geology, University of Kansas, 1475 Jayhawk Blvd, 120 Lindley Hall,
Lawrence, KS 66045, KIRBY, Eric, Department of Geoscience, Penn State Univ, University
Park, PA 16802, MCDONALD, Eric, Division of Earth & Ecosystem Sciences, Desert
Research Institute, 2215 Raggio Parkway, Reno, NV 89512, and GOSSE, John, Earth
Sciences, Dalhousie Univ, Halifax, NS B3J 3J5
The intersection of the dextral (2-3 mm/yr) Panamint Valley fault (PVF) with the sinistral (5-15
mm/yr) Garlock fault (GF) in eastern Pilot Knob Valley (PKV) controls the active off-fault tectonic
deformation in the southern Slate Range (SSR) and northern PKV. We suggest here that rapid
uplift of the Pleistocene Christmas Canyon Formation (CCF) and overlying fanglomerates, from a
base (valley floor) elevation of 670 m, to a peak of 1100 m (adjacent to the SSR), accommodates
decreased slip on the southern PVF near the GF. We present preliminary data that constrain
exhumation and rock uplift in the SSR and northern PKV over Quaternary time: (1) new Be-10
cosmogenic and soil development data from offset geomorphic surfaces, (2) sedimentological
data from the CCF, and (3) pending thermochronometric data for the SSR.
The structural makeup of the study area includes three blocks, from north to south: (1) SSR
cored by Mesozoic metamorphic rocks, (2) uplifted and northerly tilted Pleistocene and Holocene
SESSION NO. 42
sediments between the SSR and GF, and (3) buried (flat-lying?) late Neogene sediments south of
the GF in PKV. Sedimentological evidence for an evolving strain field includes three provenance
facies within the CCF: (1) a basal, distal fanglomerate with Eagle Crags-derived volcanic clasts;
(2) a medial, inter-basinal lacustrine facies; and (3) an upper, SSR-derived sandstone and conglomerate. During CCF deposition, the topographic low within PKV migrated progressively southward from its formal position adjacent to the SSR. Finally, a 50 ± 13 ka Be-10 cosmogenic profile
age for a 15-m-high terrace tread adjacent to the GF suggests a minimum throw rate of ~0.3 ±
0.08 during the late Pleistocene.
A three-stage model is invoked to explain the present structural and sedimentological configuration here: (1) an early Pleistocene period of minimal uplift of the SSR, with the topographic low
of PKV north of the present GF; (2) a middle Pleistocene period of moderate uplift of the SSR and
CCF north of the GF, to explain the influx of SSR-derived sediments above the lacustrine CCF
facies; and (3) rapid uplift of the SSR, and basin inversion of the CCF and capping fanglomerates
during last 200-300 ky. We attribute the change in structural and kinematic style to recent strain
accommodation at the southern terminus of the PVF on the GF in eastern PKV.
42-8
BTH 34
Danskin, Wesley R.
[173238]
MAPPING THE SAN DIEGO FORMATION NEAR CHULA VISTA, CALIFORNIA
DANSKIN, Wesley R., USGS, California Water Science Center, 4165 Spruance Road,
Suite 200, San Diego, CA 92101, [email protected] and SCHUG, David L.,
URS Corporation, 1615 Murray Canyon Road, San Diego, CA 92108
Deep monitoring wells have been helpful with mapping the San Diego Formation in the subsurface near Chula Vista, California. In particular, the contact between the lower marine part of the
San Diego Formation and the underlying Otay Formation is well defined by changes in lithology
and borehole geophysical logs. The contact occurs at the bottom of a coarse-grained basal
sand about 10-feet thick, which is coincident with a cool deflection in a geothermal log for a well
(SDOT) near San Diego Bay. This contact is exposed in outcrops east of the La Nacion Fault
Zone, and occurs at depths of about 500 to 600 feet below land surface west of the fault zone.
The inferred vertical offset across the fault zone is about 900 feet.
preferred model interprets the thrust as the surface trace of the Banning strand where it overrides
the Biskra Palms fan and merges with Mission Creek strand.
42-11
BTH 37
Harvey, Janet C.
[173646]
THE LATE NEOGENE DEFORMATION HISTORY OF THE SOUTH BRISTOL MOUNTAINS
FAULT ZONE
HARVEY, Janet C., Geological and Planetary Sciences, California Institute of Technology,
MC 100-23, Pasadena, CA 91125, [email protected], STOCK, Joann, Div. Geological and
Planetary Sciences, Calif. Inst. Tech, MC 252-21, Pasadena, CA 91125, and MILLER,
David M., US Geol Survey, 345 Middlefield Rd, Menlo Park, CA 94025-3561
The Southern Bristol mountains lie near the eastern border of the Mojave block and eastern
California shear zone. The rock units composing the range are dissected by at least two generations of faults: early Miocene normal faults associated with early Miocene volcanism and sedimentation, and high angle northwest striking faults of the South Bristol Mountains fault (SBMF),
including fault splays that cut Quaternary units. Total offset on the SBMF is estimated to be at
least 6 km based on correlation of plutonic rocks across the fault zone. The range is composed
of remnants of Proterozoic plutons, metamorphosed Paleozoic passive margin rocks, Jurassic
hypabyssal and plutonic rocks, and. Neogene volcanic and sedimentary sequences.The onset of
early Miocene volcanism and sedimentation in the Southern Bristol mountains predates a newly
dated ash with a U-Pb zircon age of 23.8 ± 0.4 Ma (1 sigma) overlying rhythmic fluvial to lacustrine volcaniclastic beds. The early Miocene lake bed sequence and subsequent volcanic and
sedimentary sequences have been dismembered by Neogene and Quaternary faulting. Detailed
mapping of the Neogene sedimentary and volcanic rocks should allow us to produce a more
detailed total slip budget for the Quaternary strike slip faulting.
Saturday, 29 May 2010
42-9
BTH 35
Menges, Christopher M.
[173625]
COMPLEX QUATERNARY DEFORMATION AMONG INTERSECTING SETS OF STRIKE-SLIP
FAULTS NEAR TWENTYNINE PALMS, SOUTHERN CALIFORNIA
MENGES, Christopher M., U.S. Geological Survey, 520 N. Park Avenue, Tucson, AZ 85719,
[email protected], MATTI, Jonathan C., US Geological Survey, 520 N. Park Ave,
Tucson, AZ 85719-5035, LANGENHEIM, Victoria E., U.S. Geological Survey, 345 Middlefield
Road, Menlo Park, CA 94025, MAHAN, Shannon A., U.S. Geological Survey, Box 25046
Federal Center, Denver, CO 80225, and HILLHOUSE, John W., U. S. Geological Survey,
345 Middlefield Road, Menlo Park, CA 94025
We present geomorphic, structural, stratigraphic, and geophysical data indicating complex timevariant strain developed in a region of intersecting right- and left-lateral faults in the Eastern
California Shear Zone (ECSZ) near Twentynine Palms, CA. Here two NW-trending, right-lateral
faults of the ECSZ in the central Mojave Desert, i.e., the Mesquite Lake (MLF) fault on the east
and the “airstrip” fault directly to the W, intersect the EW-trending sinistral Pinto Mountain fault
(PMF) of the Eastern Transverse Range (ETR) fault domain. Major strain patterns include: (a) mismatches between fault traces and gravity-defined subsurface basins that suggest changes in
fault organization and deformational style (from transtension to transpression); (b) transpressive
deformation (linear ridges, pop-ups, and tilted or folded sediments) along the eastern PMF and
SE part of the MLF; (c) contractional deformation and uplift localized at intersections of the dextral
faults with the PMF; (d) significant off-fault deformation (asymmetric uplift and tilting from the
SW to NE block margins, widespread fault-related folding) of the intervening blocks between the
dextral faults north of the PMF; and (e) large arch-like regional uplift (>600 m) rising southward
from the Mojave lowland across the PMF and the entire northern range front of the ETR. New
stratigraphic, structural, geomorphic and geochronologic data suggest that much of this deformation developed after mid-Quaternary time. We propose the following geologic history: (1) deposition of fine-grained muddy and sandy sediment (containing a .layer of Bishop Ash (~760 ka age),
identified by paleomagnetism and tephrochronology) within a regional depositional system as
yet not understood in terms of ECSZ history, but discordant with younger mid-late Quaternary
deposits; (2) deposition of gravelly and sandy sediment that spread eastward from the rising
San Bernardino Mountains (SBM), probably post 760 ka; (3) disruption of the SBM depositional
system by surface deformation and uplift associated with the ECSZ and its intersection with the
sinistral faults of the ETR. This latter event clearly is post 760 ka, and probably younger than 300200 ka. Deformation has spanned late Pleistocene to Holocene time, as indicated by deformed
deposits dated using OSL (80 ka to 1 ka).
42-10
BTH 36
Guzman, Nathan E.
[173641]
GEOLOGY AND GEOMORPHOLOGY OF THE INTERSECTING MISSION CREEK AND
BANNING FAULT STRANDS, SAN ANDREAS FAULT
GUZMAN, Nathan E. and YULE, Doug, Department of Geological Sciences,
California State University Northridge, 18111 Nordhoff Street, Northridge, CA 91330,
[email protected]
The Mission Creek and Banning strands of the San Andreas fault zone merge at Biskra Palms,
near Indio, CA. Here faulting appears to have displaced the northern margin of an ~50 ka alluvial
fan by ~600 to 700 m in a right-lateral sense. However, some geologic maps show a thrust fault
that merges with the downstream edge of the fan and raises the possibility that the fan edge has
been structurally modified since abandonment. We excavated a series of cuts across the fan edge
to test this hypothesis. These cuts reveal features that support the thrust fault model as they show
a 1-m-thick, sub-horizontal shear zone that contains Plio-Pleistocene Palm Spring Formation in its
hanging wall and late Pleistocene alluvium and Holocene(?) colluvium and alluvium in its footwall.
The excavations clearly show that the shear zone overrides paleo-topography of the ~50 ka fan.
In places, colluvium and alluvium filled low-lying areas ahead of the hanging wall block that was
subsequently overridden by motion on the thrust. Therefore, faulting post-dates the youngest
footwall unit. Though no dateable material has been obtained, the unconsolidated nature and
lack of soil development suggest that the colluvium and alluvium found in the footwall is quite
young. Several features support a SE-vergence of the fault including map-scale E-W trending
open folds in the hanging wall, and SE-trending slickenlines and SW-trending boudinage within
the shear zone. In addition, the hanging wall block contains alluvial strath terraces that are cut
into the Palm Spring Formation, ~30-50 m above the footwall. Though their age is unknown, the
soil and desert varnish on terrace boulders resembles the ~50 ka fan surface in the footwall. This
possible correlation yields an uplift rate of 0.5-1.0 mm/yr, and slip rate of 1-2 mm/yr assuming a
30-degree dipping thrust and a San Andreas-parallel slip vector. The margin of the ~50 ka fan
is therefore substantially modified by thrust faulting, and using the fan edge to constrain motion
would underestimate the total amount of right-lateral slip across the San Andreas fault here. Our
94 2010 GSA Abstracts with Programs Structural Geology/Tectonics I
43-2
9:00 AM
Morgan, George J.
[172686]
POST PLIOCENE DETACHMENT ON THE EASTERN SIDE OF THE COYOTE MOUNTAINS,
SALTON TROUGH, SOUTHERN CALIFORNIA
MORGAN, George J. and MORGAN, J.R., 4671 Lee Avenue, La Mesa, CA 91942,
[email protected]
On-going mapping in the Coyote Mountains on the western side of the Salton Trough indicates
that a post-Pliocene Imperial Group aged detachment formed during the continuing opening
and deepening of the Salton Trough. In the area mapped, the first unit above the detachment
surface is a marine mudstone of the Pliocene Imperial Group. Rocks below and cut by the
detachment surface are; a basal conglomerate of the Pliocene Imperial Group, the Miocene
Alverson Volcanics, and, possibly. the metamorphic rocks that make up the core of the Coyote
Mountains. The detachment was then cut and folded by movement along northwest, primarily
right-lateral faults that are associated with the Elsinore Fault. Uplift of the Coyote Mountains along
these right-lateral faults preserves the detachment in graben valleys on the eastern side of the
Coyote Mountains.
43-3
9:20 AM
Haugerud, Ralph A.
[172996]
DIRECT OBSERVATION OF TILT ASSOCIATED WITH GLACIO-ISOSTATIC REBOUND,
WESTERN WHATCOM COUNTY, WASHINGTON
HAUGERUD, Ralph A., U.S. Geological Survey, Dept Earth and Space Sciences, University
of Washington, Box 351310, Seattle, WA 98195, [email protected] and KOVANEN, D.J.,
Bellingham, WA 98225
Estimates of tilt during glacio-isostatic rebound of the southern Salish Lowland have been questioned because they depend on uncertain correlation of landforms and deposits formed during a
period of rapid relative sea level change. Furthermore, the underlying observations are distributed
along a N-S corridor and provide little constraint on possible E-W tilt.
Subtle latest Pleistocene fossil shoreline benches (FSB) are evident in a 6-ft (XY resolution)
DEM derived from a 1 pulse/m2 lidar survey of western Whatcom County. Most FSB are short
(233 m mean length, 2409 m maximum, n = 1693). Observations of tilt based on change of elevation along a single FSB are suspect because of probable error in the lidar survey, error associated
with interpretation of the position of a FSB, and DEM artifacts related to misidentified and missing
ground returns. However, by disaggregating each FSB arc into evenly-spaced points, calculating
the XYZ centroid of each point group, and then translating the group such that its centroid is at
(0,0,0), we discard the where and how high associated with each arc and preserve its shape,
including any tilt. Least-squares fitting of a plane to the resulting point cloud gives the mean tilt.
For the FSB analyzed, mean tilt is 1.2 m/km up to the NE (azimuth 38º). Higher-elevation FSB
appear to be tilted more than lower-elevation FSB. This result is consistent with previous estimates, derived from correlation of discontinuous features 60–200 km farther south, of 0.6–1.15
m/km up to the N tilt (Thorson, 1989, Dethier and others, 1995; Kovanen and Slaymaker, 2004).
Using this mean tilt, we correlate fossil shoreline segments that trim early Sumas-age moraines
of the Blaine upland, the Lake Terrell upland, and the Lummi Peninsula. Least-squares fit of a
plane to this shoreline yields an estimated tilt of 0.9 m/km up to the NE. The low tilt may reflect
low elevation (hence relative youth), or that the shoreline is diachronous, younger in the direction
of ice retreat to the NE. North of Ferndale the fossil shoreline is consistently 2–4 m higher than
the best-fit plane, suggesting Holocene deformation consistent with observed recent uplift of the
late Holocene shoreline at nearby Birch Bay.
43-4
9:40 AM
Arkle, Jeanette C.
[173090]
FOCUSED EXHUMATION IN THE SOUTHERN ALASKA SYNTAXIS
ARKLE, Jeanette C.1, ARMSTRONG, Phillip A.1, and HAEUSSLER, Peter J.2, (1) Geological
92834, [email protected], (2) U.S. Geological Survey, 4200 University Dr, Anchorage,
AK 99508
The western Chugach Mountains lie in a critical position that may link active margin-parallel deformation, where the interface between the North American Plate and Yakutat microplate are locked,
to the southern Alaskan syntaxis. This syntaxis is characterized by arcuate fault systems and the
SESSION NO. 44
highest topography of any accretionary prism in the world, whereupon accretionary wedge mass
flux input may be focused and maintained by erosional mass flux output. We address mass flux
and the exhumation history of the accretionary prism, with apatite fission-track (AFT) and apatite
(U-Th)/He (AHe) ages from a N-S sea level transect in the Prince William Sound and compare
these data with published data from the periphery ranges. New AFT and AHe ages from the
center of Prince William Sound generally decrease northward from ~35 Ma to 11 Ma and from
~10 Ma to 3 Ma, respectively. The youngest ages are at the base of the highest mountains and
largest glaciers of the western Chugach Mountains. Along the Border Ranges Fault Zone, north
of the proposed syntaxial core, AFT ages are ~15-30 Ma and in the Talkeetna Mountains AHe
ages are ~15-20 Ma; these ages may mark the beginning of Yakutat collision and subduction.
AHe ages on the windward side of the Kenai and western Chugach Mountains are ~12-18 Ma,
but on the leeward sides they range from ~20-40 Ma. These relations have been interpreted to
reflect climatic control and faster exhumation on the windward sides of the ranges. Three samples
from the Copper River/Cordova area are ~5-7 Ma and indicate more recent exhumation there.
The northward decrease of AFT ages and the young AHe ages in the Prince William Sound,
represent a nested pattern of reset ages that record higher exhumation rates on the southern side
of the Chugach Mountains. Collectively, AFT and AHe ages from the Prince William Sound and
surrounding regions decrease inward to form a bull’s eye pattern of localized exhumation in the
core of the syntaxis. These patterns suggest that partial plate locking and underplating, extended
to million year time scales, has produced rapid exhumation above or north of the locked section
and within the syntaxis. The arcuate structural boundaries, such as the Border Ranges Fault zone
and Contact fault, may enhance and control localization of exhumed material related to forearc
convergence.
43-5
10:00 AM
Page, Bryan R.
[173296]
ASSESSING THE STATISTICAL SIGNIFICANCE OF MASS AND VOLUME CHANGES IN THE
DEVELOPMENT OF SAPROCK FROM CORESTONE NEAR THE ELSINORE FAULT ZONE,
SAN DIEGO COUNTY, CALIFORNIA: POTENTIAL IMPLICATIONS FOR GROUND SHAKING
EVENTS
PAGE, Bryan R., Geological Sciences, San Diego State University, San Diego, CA 92109,
[email protected] and GIRTY, Gary H., Geological Sciences, San Diego State
University, 5500 Campanile Drive, San Diego, CA 92182
Spheroidal weathering resulting in the development of saprock from corestone has been
observed in gabbro and granodiorite near the Elsinore fault zone, San Diego County, California.
Thin section observations reveal that plagioclase and biotite (gabbro and granodiorite), and
amphibole and pyroxene (gabbro only), are altered in various proportions to various clay minerals
during the development of saprock. Additionally, the transport function τ, indicates an elemental
mass change of -5% ±1 Ca, -2% ±1 Na, -3% ±1 Mg, +11% ±3 Mn, -5% ±2 Zn, -5% ±3 V, -27% ±4
K, and -39% ±18 Ba, during the formation of saprock in the gabbro. In the granodiorite, τ indicates
an elemental mass change of +7% ±4 Al, -41% ±4 Ca, -38% ±4 Na, -12% ±5 K, -24 ±7 Mn,
and +25% ±9 Ti. The development of saprock from corestone is also accompanied by a positive
volumetric strain (ε) of 12% ±2% in the gabbro and 35% ±11% in the granodiorite. The change in
bulk mass (τ) was determined to be -0.2% ±0.8 in the gabbro and -0.6% ±2% in the granodiorite.
Porosity in the gabbro is 12% ±2% and 26% ±4% in the granodiorite. Statistical analysis indicates
that these results are significant at the 95% confidence level. These observations and data are
inconsistent with the commonly observed isovolumetric development of saprock from corestone
in non-seismogenic areas. The proximity of the study areas to the Elsinore fault zone, and the
many ground shaking events from earthquakes since inception of the fault, have likely contributed
to the observed positive volumetric strain. Ground shaking events have weakened and broken
intercrystalline bonds, and opened migration pathways through rotation of grains during dilation.
Such a process provides pathways for fluids and therefore enhances breakdown and weathering
of the corestone.
T4. Advances in Understanding Magma Petrogenesis
and Eruption Dynamics at Basaltic Monogenetic
Volcanoes (Cordilleran Section GSA)
44-1
9:05 AM
Browne, Brandon L.
[173218]
CONSTRAINTS ON THE DEVELOPMENT AND EVOLUTION OF QUATERNARY SCORIA
CONE PLUMBING SYSTEMS IN THE SIERRA NEVADA: INSIGHTS FROM CLINOPYROXENEMELT GEOTHERMOBAROMETRY
BROWNE, Brandon L., VITALE, Michelle, and CAMPBELL, Colin, Department of Geological
Basaltic scoria cones situated in continental monogenetic volcanic fields are generally thought
to erupt single magma batches over short periods of time. However, field mapping efforts combined with petrologic, geochemical, and thermobarometric analysis of erupted products from two
unrelated volcanic fields in California (Red Cones, 5 km SW of Mammoth Mountain; and Golden
Trout, 5 km SW of Mt Whitney) indicate pronounced differences in the eruption volumes and
Pressure-Temperature crystallization histories of erupted basalts despite overall similarities in
magma source. Geothermobarometry results from Red Cones clinopyroxene microphenocryst
cores indicate nucleation and crystallization pressures ranging widely from 1.5 to 16.7 kbars and
temperatures between 1155 and 1233°C, compared to 5.7-13.2 kbars and 1185-1230°C for the
4 cores of clinopyroxene phenocrysts analyzed. Interestingly, 87% of analyzed clinopyroxene
cores from scoria deposits formed through explosive volcanic activity originated from 10-25 km
depth compared to those from lava flows formed through effusive volcanic activity, which exhibit
a broader range in crystallization depths extending from approximately 4 to 60 km depth. Similar
results are observed from the basaltic scoria cones and lava flows in the Golden Trout Wilderness
field, where clinopyroxene crystals in scoria tend to record shallow crystallization conditions compared to those from lava flows. These findings suggest that magma plumbing systems and the
mechanisms for magma supply at scoria cones are actually quite complex, and therefore require
us to modify our perspectives on how they form as well as the types of geophysical signals they
potentially yield before, during, and after eruptions.
44-2
9:20 AM
Self, Stephen
[173308]
INTERPRETATION OF THE C. AD 1075 ERUPTION OF SUNSET CRATER, ARIZONA, USA
SELF, Stephen, US NRC, NMSS, Washington DC, DC 20555, [email protected], ORT,
Michael H., SESES, Northern Arizona University, Flagstaff, AZ 86011, and AMOS, Robert C.,
2539, Diamond Hill Rd, St. Johnsbury, VT 05819
About 900 years BP, the largest recent eruption from a monogenetic basaltic volcano field in
the present-day continental USA took place at Sunset Crater in San Francisco Volcanic Field,
Arizona. The eruption is estimated, on volcanological evidence, to have lasted from a few weeks
to perhaps 2-3 years, and most likely occurred, based on paleomagnetic evidence, between AD
1050 and 1100. Notable eruption features are: the 10-km-long eruptive fissure on which Sunset
scoria cone grew; large eruptive volume (given here as DRE), apportioned between the broad
(~ 2-km-wide base), 300-m-tall Sunset scoria cone (~ 0.2-0.3 km^3, depending on the topography
engulfed), a 0.3-0.4 km^3 scoria fall deposit, and ~0.1 km^3 of lava (current work is re-evaluating
these volumes); the widespread dispersal of some scoria fall units (up to 60 km away); the two
lava flows formed, the longer of which flowed down a pre-existing valley for ~ 11 km, with both
having sections with no scoria-fall on them; and evidence of disruption of a prehistoric, welldeveloped, agrarian society. The Sunset eruption demonstrates that societal effects of scoria cone
eruptions can easily reach tens of kilometers from the vent.
This talk concentrates on interpretation of the fall deposit and eruption mechanisms of the main
phase of activity. Eight scoria fall units were described in previous work by the authors. Basal fall
units 1 and 2 are related to vents along the SE fissure, while the dispersal of units 3 and 4 indicate a vent at Sunset and record activity during intense periods of the main cone-building phase.
They are deposited over the entire area of preserved primary fallout, with a southeasterly and
almost circular (windless) dispersal, respectively. Units 5-8 are more locally dispersed and are
interpreted to record later cone-building phases. The fall deposits appear typical of Strombolian
fallout; lithic fragments are uncommon. Units are distinguished by abrupt grain-size changes and
occasional wispy ash layers; reverse grading is dominant in widespread units 3 and 4. Units 3 and
4 have thinning and fining characteristics that place them in the violent Strombolian to sub-Plinian
range on various classification scheme plots, depending on assumptions made about the units in
the proximal regions, whereas earlier and later portions of the eruption had lower columns.
44-3
9:35 AM
Carlisle, Catherine J.
[173982]
PALEOMAGNETISM OF AN INFLATED LAVA FLOW: KILAUEA, HAWAII
CARLISLE, Catherine J.1, MATTOX, Stephen1, COLGAN, Patrick M.1, and HON, Ken2,
(1) Geology, Grand Valley State University, 133 Padnos, Allendale, MI 49401-9403,
[email protected], (2) Geology, University of Hawaii at Hilo, 200 W. Kawili Street,
Hilo, HI 96720
Pahoehoe lava flows emplaced on flat ground inflate and expand vertically from less than a half
a meter to over five meters in thickness. Inflation results as flow advance slows and the flow’s
outer crust cools, and becomes rigid, while the volume continues to increase. In order to better
understand the inflation process, we studied the paleomagnetism of basalt samples from a 1990
Kupaianaha flow on Kilauea Volcano just west of Kalapana, Hawaii. Several samples were drilled
and oriented from the horizontal top of the flow and the flank, which was dipping about twenty
degrees. If the flow cooled below the Curie Temperature (~570º Celsius for basalt) before inflation,
there should be a difference in magnetic inclination from cores collected from the horizontal top
of the flow and the dipping flank. If the flow cooled below the Curie Temperature after inflation,
samples from all over the flow should preserve the same magnetic inclination. A Molspin spinner
magnetometer was used to measure inclinations and declinations. Randomly selected samples,
demagnetized up to 60 mT using an alternating field demagnetizer, showed no magnetic overprints. Results document differences of at most a few degrees in inclination between horizontal
samples from the top of the flow and the dipping samples from the flank. The magnetic minerals
of some inflated lava flows must not have acquired inclinations until after the flow inflated, thus the
data from these flows is an accurate representation of earth’s magnetic field. For a small number
of flows, inflation rotated the magnetic data a few degrees but these changes are minimal and
do not reduce the utility of paleomagnetic data. Therefore, it is safe to assume that paleomagnetic research of pahoehoe flows does not need to account for the process of inflation except in
rare cases.
44-4
11:00 AM
Hanson, Sarah L.
[173110]
GEOCHEMISTRY AND AGE DETERMINATIONS OF LAVA FLOWS IN THE NORTHEASTERN
SAN FRANCISCO VOLCANIC FIELD, NORTHERN ARIZONA
HANSON, Sarah L., Geology Department, Adrian College, 110 S. Madison St, Adrian,
MI 49221, [email protected]
The San Francisco Volcanic Field, located in northern Arizona, is one of several late Cenozoic
volcanic fields located along the southern margin of the Colorado Plateau. Intermittent volcanic
activity produced over 600 vents beginning in the western portion of the field approximately 6 Ma.
Through time, this activity progressed eastward, culminating with the eruption of Sunset Crater
(~900 a). In the northeastern portion of the field at Wupatki NM, sporadic volcanic activity over the
last million years produced ten distinct lava flows including the Black Point, Citadel, Arrowhead
Sink, Red House Basin, and Gem City, Woodhouse Mesa, Wukoki, and Grand Falls flows as well
as the Doney Crater cinder cones and flows. Geochemical analyses suggest that these flows
were derived from partial melting of an OIB-like parental material. Differences in trace element
signatures show that there were at least seven individual volcanic events, each attributed to
variable amounts of partial melting and subsequent modification by AFC processes. These melts
ascended quickly producing short-lived eruptions.
The ages of five flows were reevaluated using 40Ar/39Ar age dating techniques and yielded ages
that were significantly younger than older K-Ar ages. This likely due to the presence of excess Ar
inherited from incompletely degassed magma from the mantle source region and/or the result of
contamination contained in xenocrysts. In western Wupatki, the Black Point flow yielded an age of
0.873 ± 0.008 Ma, two samples from the Citadel Flow yielded ages of 0.85 ± 0.02 Ma and 0.87 ±
0.04 Ma, and the Red House Basin flow yielded an age of 0.89 ± 0.17 Ma. The similarities in geochemisty and age suggest that these flows may represent a single eruptive event. The Arrowhead
Sink flow, although in close proximity to the above flows, is much younger (0.61 ± 0.03 Ma). In
eastern Wupatki, the Wukoki flow yielded disparate ages, likely the result of significant excess Ar,
a problem exacerbated by the younger age of this flow. Thus, the isochron age (0.15 ± 0.07 Ma) is
interpreted to represent a maximum age. The Woodhouse Mesa flow yielded a significantly older
age, 0.96 ± 0.03 Ma. These age dates, coupled with the field relationships for the younger and
more weathered flows, are consistent with seven episodes of volcanic activity at Wupatki.
SESSION NO. 44
44-5
11:15 AM
Wypych, Alicja
[172958]
MID-MIOCENE SILICIC VOLCANSIM IN THE IDAHO-OREGON-NEVADA REGION AS A
WINDOW INTO CONTINENTAL CRUST FORMATION AND MODIFICATION
WYPYCH, Alicja and HART, William K., Geology, Miami University, 114 Shideler Hall, Oxford,
OH 45056, [email protected]
We report the preliminary results of an investigation designed to address issues of crust formation
and modification during intracontinental volcanism in the northwestern United States; specifically
within the Idaho-Oregon-Nevada (ION) region. This region is characterized by mid-Miocene silicic
volcanism associated with the onset of regional flood basalt volcanism and extension. The silicic
volcanism and its continuation through time to the NE (Snake River Plain-Yellowstone) and NW
(High Lava Plains) is related to mantle upwelling behind an active magmatic arc, basalt magma
intrusion into the crust, melting of heterogeneous lithosphere, and mixing of melts from heterogeneous sources. ION region bimodal volcanism also provides a glimpse into complex magmatic
processes occurring within heterogeneous transitional lithosphere at the western boundary of the
Wyoming craton. In order to identify and quantify the sources and processes responsible for ION
region silicic magmatism we have undertaken an integrated petrologic, geochemical and isotopic
investigation of volcanic glass separates complemented by whole rock analyses from five specific
eruptive centers selected to represent spatial, temporal (16.5 to 13.5 Ma), and compositional
diversity. Pure glass separated from rhyolite flow and ash-flow vitrophyres is utilized in order to
facilitate comparisons with data derived from regional fallout tephra and to best represent the
pre-eruptive magma compositions.
Major and trace element and Sr, Nd, and Pb isotope data for 23 glass separate - whole rock
pairs representing important eruptive units from the ION area silicic centers clearly illustrate the
variable imprint of inherited crystals and the role of open system magmatic processes, allow for
estimates of the relative proportions of mantle-derived and crustal-derived materials involved
in silicic magma evolution, and provide a more detailed picture of the lithospheric architecture
within the transition from Proterozoic-Archean to Mesozoic and younger lithosphere. The latter is
further enhanced by the combined evaluation of Nd-Hf isotope systematics in the glass separates.
Ongoing work is targeting selected eruptive products for mineral chemistry and mineral isotope
analyses and crystal isotope stratigraphy studies.
44-6
11:30 AM
DeWolfe, Y. Michelle
[172988]
PEPERITIC TEXTURES AND FACIES ARCHITECTURE OF A PALEOPROTEROZOIC
BASALTIC ANDESITE INTRUSION, FLIN FLON, MANITOBA, CANADA: EVIDENCE FOR THE
EMPLACEMENT OF A CRYPTOFLOW DURING THE GROWTH OF A DOMINANTLY BASALTIC
VOLCANO
DEWOLFE, Y. Michelle, Earth Sciences, Mount Royal University, 4825 Mount Royal Gate
SW, Calgary, AB T3E 6K6, Canada, [email protected], GIBSON, Harold L., Earth
Sciences, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON P3E 2C6, Canada,
and PIERCEY, Stephen J., Earth Sciences, Memorial University of Newfoundland, St. John’s,
NF A1B 3X5, Canada
The Paleoproterozic 1920 unit occurs at the base of the Hidden formation and stratigraphically
overlies the volcanogenic massive sulphide deposits at Flin Flon, Manitoba, Canada. The 1920
unit is an Fe-Ti-P-rich basaltic andesite (Fe2O3, 12 wt.%, TiO2, 1.1 wt.% and P2O5, 0.30 wt.%)
and, with its overlying volcaniclastic unit, crudely defines a localized fault-bounded subsidence
structure. The presence of blocky and fluidal peperite along its upper contact, and lens-shaped
inclusions of tuff along its basal contact, suggests the basaltic andesite was emplaced as a
cryptoflow into wet, unconsolidated volcaniclastic sediments. Locally the basaltic andesite overran
the wall of the graben into which it was emplaced, breaching surface and forming a pillowed flow.
The abundance of synvolcanic basaltic dikes within the footwall to and cross-cutting the unit also
indicate that magmatism, like that in modern back-arc environments, was controlled by fissure-fed
eruptions during extension. The unique geochemistry of the 1920 unit suggests the presence of
a high-level magma chamber. This heat source, combined with evidence of extension, provides
an environment conducive to the formation volcanogenic massive sulphide deposits. The 1920
unit and its confining graben occur above the Callinan and Triple 7 ore bodies indicating that the
synvolcanic structures that controlled magmatism, subsidence, and hydrothermal fluids during
the emplacement of the 1920 unit were long-lived structures that likely also controlled these
processes within the massive sulphide-hosting footwall succession. Therefore, the synvolcanic
structures within the hanging wall, can be used to target massive sulphide mineralization at depth.
T11. New Insights into the Petrology of Mesozoic
Cordilleran Batholiths I (Cordilleran Section GSA)
45-1
8:40 AM
Morton, Douglas M.
[173003]
ANATOMY OF A 100 MA SUTURE, NORTHERN PENINSULAR RANGES BATHOLITH
MORTON, Douglas M., U.S. Geological Survey, Dept of Earth Sciences, University of
California, Riverside, 92521, [email protected], ALVAREZ, Rachel M., Kleinfelder,
Redlands, CA 92374, ALCOTT, Alison, Rockware, Inc, Golden, CO 80401, MILLER, Fred K.,
U.S. Geological Survey, West 904, Riverside Ave, Spokane, 99201, and COSSETTE,
Pamela, U.S. Geological Survey, Spokane, WA 99201
Within the northern Peninsular Ranges Batholith, major structural dislocation occurred during
suturing of relatively thin Mesozoic oceanic crust to older, thicker continental crust. During suturing, the style of ongoing pluton emplacement radically changed from passive to dynamic, and
prebatholithic rocks underwent pronounced structural and thermal changes. In the Diamond
Valley Reservoir area, a pronounced thermal gradient resulted from the suturing. West of the
suture are greenschist facies rocks of medium-P/T type. The suture-affected rocks are subdivided
into four structural domains that include five mineral isograds. Penetrative structural features
synchronous with suturing extend over a 5 km wide zone. Mineralogic changes are evident in a
3.5 km wide zone. Structures related to the suturing include three progressive structural transpositions and folding. Regional S1 schistocity was transposed to S2, which in turn was transposed to
S3 that was folded and transposed to S4. Thermal effects resulting from structural dislocations is a
low-P/T type metamorphic gradient. Progressive changes in mineral assemblages of andalusite,
cordierite, sillimanite, garnet, and K-feldspar reflect changes from greenschist facies to lower
granulite facies. East of the suture rocks are amphibolite facies medium-P/T type. West of the
suture, plutonic rocks predating suturing intruding greenschist facies rocks indicate pressures of
96 2010 GSA Abstracts with Programs 2-3 kb. Pressures of plutonic rocks contemporaneous with suturing indicate pressures of 5-6.5 kb
while those to the east of the suture average 4.5 kb.
45-2
9:00 AM
Holk, Gregory J.
[173022]
MAJOR AND TRACE ELEMENT METASOMATISM BY SUBDUCTION-RELATED FLUIDS
ALONG THE EASTERN PENINSULAR RANGES MYLONITE ZONE
HOLK, Gregory J., Department of Geological Sciences, California State Univ Long Beach,
1250 Bellflower Blvd, Long Beach, CA 90840, [email protected]
Stable isotope studies (Holk et al., 2006) demonstrated infiltration of subduction-related metamorphic water at depths of at least 15-20 km during early Tertiary thrust faulting of a 15X15 km
tonalite pluton west of Borrego Springs, CA. New geochemical data reveal this pluton experienced
a complex history of metasomatism and alteration as these deep fluids ascended through the
EPRMZ. Protomylonites are enriched in SiO2 and Na2O and depleted in K2O relative to undeformed tonalite. Transition zone tonalites are depleted in K2O, MgO, and total Fe and enriched in
CaO relative to undeformed tonalite. The increase in Na2O and decrease in K2O is likely the result
of albitization of plagioclase as Na-rich subduction fluids leached Ca and K from feldspar, with
the Ca taken up by epidote. Most trace elements are depleted in protomylonite and in the transition zone relative to undeformed tonalite. Th, Nb, and Y are enriched in protomylonite relative to
undeformed tonalite. Sr, Hf, and Zr are enriched in the transition zone. Elements unaffected by
deformation include Ba, Be, Sc, Sr, Ga, Hf, and Zr in the protomylonite, and Ba, Ga, and Ag in
the transition zone. The large ion lithophile and transition metals display the greatest degree of
depletion in the deformed rocks. The transition zone tonalites experienced a greater degree of
trace element depletion than the protomylonites, suggesting this zone as the locus of hydrothermal fluid circulation. Protomylonites are enriched in REE relative to undeformed tonalite, with all
these rocks displaying a negative Eu anomaly. Transition zone tonalites have much lower REE
concentrations than undeformed tonalite and a positive Eu anomaly. One undeformed tonalite and
one protomylonite each contain allanite and display very high Th and L-REE concentrations. A
comparison of δD values between the EPRMZ, Catalina Schist, and the Orocopia Schist indicate
that the fluid source was dehydration of seawater-saturated accretionary wedge sediments. The
transition zone is intruded by 0.5-to-10-m-thick pegmatite dikes and cut by 1-10 cm-thick myloniteto-ultramylonite zones. These features are also present in the protomylonite zone, but pervasive
deformation obscured this evidence. Pegmatites may have served as an effective fluid transport
medium with the shear zones acting as transport avenues.
45-3
9:35 AM
Barnes, Calvin G.
[173155]
LATE MIDDLE JURASSIC ‘RETRO-ARC’ MAGMATISM IN THE KLAMATH MOUNTAIN
PROVINCE
BARNES, Calvin G., Geosciences, Texas Tech, Lubbock, TX 79409-1053, Cal.Barnes@
ttu.edu, COINT, Nolwenn, Department of Geosciences, Texas Tech University, Lubbock, TX
79409, and ALLEN, Charlotte M., Research School of Earth Sciences, Australian National
Univ, Canberra, 0200, Australia
Middle Jurassic magmatism in the Klamath Mountain province (KMp) ceased when regional
thrusting along the Wilson Point fault imbricated the Middle Jurassic arc + arc basement beneath
older terranes of the province. Subsequent Late Middle Jurassic magmatism occurred in three
zones. Transtension in the western KMp resulted in formation of the Josephine ophiolite (JO). To
the west, the Rogue-Chetco arc was built on basement rocks rifted from the main KMp during
JO development. In contrast, plutonism east of the JO evidently occupied a ‘retro-arc’ setting.
This retro-arc magmatism was not confined to a narrow belt of magmatism, but instead spanned
the length of the province in a zone at least 90 km wide. Retro-arc pluton ages are 170-152 Ma
and compositions range from gabbro to two-mica granite, with diorite–tonalite as principal rock
types. Most large plutons are distinctly composite; available U-Pb age data indicate emplacement of individual plutons took as much as 8 m.y. Recent dating of the Wooley Creek batholith
shows that even plutons that lack discernable internal intrusive contacts span age ranges of ~4
m.y. Retro-arc magmas were emplaced into crust that had been thickened by thrusting (> 40 km
thick). Plutonism was approximately coeval with regional metamorphism that reached granulite
facies conditions. With the exception of the oldest, southernmost plutons, the suite is characterized by εNd lower than, and 87Sr/86Sr and δ18O values higher than those expected from depleted
mantle sources. Moreover, U-Pb (zircon) data indicate sources or contaminants of these magmas
contained 180-186 Ma zircons and in some cases ~168 Ma zircons. The data suggest that late
Middle Jurassic retro-arc magmatism involved emplacement, differentiation, and contamination
of mantle-derived magmas into thickened crust, that mafic magmas provided the heat for high-T,
moderate-P metamorphism, and that crustal melting provided at least one component of contamination and mixing. Inherited 180–186 Ma zircons cannot be correlated with known magmatic
events in exposed KMp terranes, which suggests that Klamath plutons may be used as temporal
and spatial probes of otherwise cryptic terranes within the province.
45-4
9:55 AM
Coint, Nolwenn
[173033]
MULTIPLE MAGMA BATCHES IN THE TILTED WOOLEY CREEK BATHOLITH, KLAMATH
MOUNTAINS, CALIFORNIA
COINT, Nolwenn, Department of Geosciences, Texas Tech University, Lubbock, TX 79409,
[email protected] and BARNES, Calvin G., Geosciences, Texas Tech, Box 41053,
Lubbock, TX 79409-1053
The Wooley Creek batholith (WCb), situated in the Klamath Mountains, is a tilted intrusion that
was emplaced between 160 and 155 Ma. Roof dikes of similar chemical composition to the
intrusive rocks represent snapshots of magma that escaped the system (Barnes et al, 1990). The
WCb was originally thought to consist of a pyroxene-bearing lower unit of gabbro to tonalite and a
hornblende-bearing upper unit of tonalite to granite, without no visible contact between them. The
two parts differ in terms of chemical and isotopic compositions but original U-Pb ages indicated
emplacement at ~161 Ma (Barnes et al, 1987). Pyroxene and hornblende-bearing roof dikes
were thought to sample the lower part and the upper part of the intrusion, respectively. New laser
ablation ICP-MS trace element data on amphibole and pyroxene as well as new U-Pb SHRIMP
data on zircon have shown that the evolution of the magmatic system is more complex. U-Pb
SHRIMP ages on zircon for the lower part of the system range from 160.1 ± 1.6 Ma to 158.0 ±
1.3 Ma for the northern diorite and northern tonalite respectively whereas in the upper part ages
range from 156.6 ± 1.3 Ma on granodiorite to 154.2 ±2.1 Ma on late-stage granite. Trace elements
in zircon support the division of the intrusion in two main parts, with zircon from the lower part
having larger negative Eu anomalies and lower Yb/Gd ratios compared to zircon from the upper
part of the system. Pyroxene from roof dikes show evidence of oscillatory zoning and high Ti and
low Cr concentrations compared to pyroxene from the lower part of the WCb which are normally
zoned, implying a different origin for the roof dike pyroxenes. Euhedral hornblende crystals from
both roof dikes and the upper part of the system have similar compositions, suggesting that some
of the roof dikes came from the upper part of the system; however, late poikilitic reversely zoned
amphiboles, have been found in the upper tonalite unit, indicating a more complex history, locally
involving recharge and mixing. New data show that despite the lack of sharp internal intrusive
SESSION NO. 47
contacts, the gradational change from lower to upper parts of the system conceals a 4 m.y.-long
record of magma emplacement.
tions should be conducted. If a well is found to be completed through two zones such as those
found in the pilot borehole of the subject well, sealing, packing, or otherwise isolating the deeper
zone could increase injection/production rates in the short term and/or increase the efficiency or
longevity of the well in the long term.
T18. Managing Groundwater in the Cordillera I
(Cordilleran Section, GSA and Pacific Section, AAPG)
46-1
8:40 AM
Hibbs, Barry J.
[173678]
HYDROGEOLOGIC FACTORS IN SELENIUM LOADING TO SOUTHERN CALIFORNIA
WATERSHEDS
HIBBS, Barry J., Geological Sciences, California State University, Los Angeles, 5151 State
University Drive, Los Angeles, CA 90032, [email protected]
We have identified three urban watersheds with elevated selenium in the Los Angeles Basin.
These include San Diego Creek Watershed of Orange County, Malibu Creek Watershed of
Los Angeles County, and tributaries to the Los Angeles River. Dry weather surface flows in these
watersheds contain 20 to 35 ug/L dissolved selenium. Shallow groundwater in these watersheds
contains 30 to 300 ug/L dissolved selenium. Concentrations exceed the USEPA chronic criterion
for selenium of 5 ug/L for protection of aquatic life. Miocene marine shales in the MonterreyModelo-Puente formation appear to be the original sources of selenium in these watersheds.
Selenium is leached into groundwater from these low-permeability strata, along with standard
inorganic constituents (primarily sulfate) and phosphorous. Elevated selenium concentrations
develop in shallow groundwater, and baseflows carry selenium into urban surface streams.
Groundwater baseflows account for most of the selenium loading to streams. Positive correlations are observed between nitrate and selenium in both groundwater and surface water in the
watersheds we investigated. Previous theoretical calculations showed favorable Gibbs free energies for oxidation of selenium by dissolved nitrate. Empirical batch studies support theoretical
calculations for mobilization of selenium by nitrate in marine shales. Positive correlation between
nitrate and selenium in our studies appears to be related to nitrate sourced from atmospheric
fallout, agriculture, and treated wastewater application. Laboratory leaching experiments carried
out on weathered and unweathered Monterrey rocks from the Malibu Creek Watershed showed
high selenium concentrations only when nitrate was leached from the rocks in high concentrations. Selenium concentrations were non-detectable or very dilute when nitrate was not leached
from rocks. Weathered rock generally had high concentrations of nitrate in leachate, possibly from
accumulation from atmospheric fallout. Leachate from non-weathered Miocene rock generally
had low nitrate concentrations and low selenium. Miocene shales are exposed in vast areas of
Southern California. We are undertaking regional studies to determine if other Southern California
Watersheds are affected by elevated nitrate and selenium concentrations.
46-2
9:00 AM
Barker, Shelby R.
[173000]
AN INVESTIGATION OF POTENTIAL SURFICIAL RECHARGE IN THE LUCERNE VALLEY
GROUNDWATER BASIN, MOJAVE DESERT, CA
BARKER, Shelby R., LATON, Richard, and FOSTER, John, Department of Geological
To better understand the characteristics of recharge within the Lucerne Valley groundwater
basin, a series of infiltrations tests, soil analyses and computer simulations were conducted
throughout the watershed. Previous studies have suggested that because desert valleys receive
less than eight inches of precipitation per year and have deep, unsaturated zone, natural recharge
cannot occur. However, gaps in the most recent water budget as well as water groundwater
levels and geochemical evidence indicate that additional recharge must be occurring at some
point within the valley. Studies elsewhere in the Mojave Desert have suggested that recharge can
occur as infiltration from stream flow in ephemeral channels. Field investigations (infiltration tests
and soil sample collection) and laboratory tests (sieve analyses, chloride tests, falling-head permeameter, moisture content and numerical modeling) suggest that a similar source of recharge
exists in the Lucerne Creek within the northwestern section of the basin as well. This research
is intended to better understand the natural surficial recharge in the Lucerne Valley groundwater
basin. Furthermore, this research may also provide a cost-effective method to determine potential
recharge in other basins and better understand surficial recharge in desert environments.
46-3
9:20 AM
Kear, Jordan
[172287]
ROLES OF AQUIFER HYDRAULICS IN OPTIMIZING ASR WELL PERFORMANCE
KEAR, Jordan, Water Resources Division, Daniel B. Stephens & Associates, Inc,
5951 Encina Road, Suite 208, Santa Barbara, CA 93117, [email protected]
During pilot hole drilling and aquifer isolation zone testing for an intended aquifer storage and
recovery (ASR) well in southern California, the existence of a significant, 150-foot-thick perching
layer separating two aquifers was discovered. The upper aquifer is unconfined with a static water
level depth of 400 feet, and the deeper aquifer is semi-confined with a static water level depth
of 700 feet. Based on the data from the borehole, the team generated conceptual designs that
would have maximized production from a completed well using either a dual-casing or a discretely
sealed and packer-equipped single casing. Either option would have prevented downward flow
from the upper to the lower zone. However, due to the high differential in water levels, lower than
expected production rates (only 600 gpm), and marginal water quality in some zones, as well as
the additional expense over what the local water district had budgeted, the pilot borehole was
abandoned.
During the analysis it was determined that, to extract groundwater from the targeted aquifers
using a single, unsealed casing completion, pumping water levels would need to be deeper than
the lowest static water level in the aquifers. In cases such as this where a large difference in water
levels exists, such deep pumping water levels would be detrimental to the long term integrity of
the well. In addition to the hydraulic challenges, slightly differing geochemistry may have limited
the compatibility of using the well for groundwater recharge.
Unless properly sealed or packed, wells with perforations across multiple aquifer zones under
significantly differing pressures may be yielding less water than potentially capable due to the
deep aquifers ‘thieving’ water from upper zones. To determine if such a condition exists, and ultimately design and implement a plan to modify wells to optimize recharge or production, a detailed
well evaluation including a down-hole ‘spinner’ or ‘flow-meter’ test under static or pumping condi-
T29. The California Geological Survey I: Providing
Scientific Products and Professional Services to
Californians for 150 Years
47-1
8:45 AM
Parrish, John G.
[173182]
CALIFORNIA GEOLOGICAL SURVEY -- STAYING RELEVANT AFTER 150 YEARS
PARRISH, John G., State Geologist, California Geological Survey, 801 K Street St,
MS 12-30, Sacramento, CA 95814, [email protected]
It has been attributed to the historian Will Durant that, “Civilization exists by geologic consent –
Subject to change without notice.” Unlikely that California’s early State Legislature had this in
mind in 1851, during the heady Gold Rush Days, when it appointed Dr. John B. Trask (a physician) as the first State Geologist.
Dr. Trask impressed the State’s officials with the need for a geological survey, and the
Legislature established in 1860 the Geological Survey of California. It appointed Dr. Josiah D.
Whitney as the second State Geologist. Dr. Whitney’s first work was on the State’s paleontology –
not its mineralogy. This was especially frustrating to the Legislature, since it wanted information
on the State’s gold resources. Whitney’s rather sharp rebukes to the Legislature and the Governor
ultimately resulted in Whitney’s departure in 1874.
It is from this example that a renamed survey, the State Mining Bureau, came into existence in
1880, well instructed with the need to be “relevant” in its products.
Since 1860, California has had six different names attached to its Survey. Each name was created to more accurately reflect the relevancy of the work being performed. Perhaps appropriately,
the Survey has had 12 different logos over the last 150 years to reflect its work and government
agency affiliation.
With few initial lapses, the California Geological Survey (CGS) has evolved to provide relevant
products and services to its constituents. Whereas the early Survey was focused on geologic
mapping and mineral resources, later surveys have successively expanded into broader areas.
The name “Geology” was reincorporated into the Survey’s name in 1962, showing that the
Survey was more than just Mining. Two State agencies, the Division of Oil, Gas and Geothermal
Resources and the Office of Mine Reclamation, were born from CGS.Today, CGS produces a
variety of modern, detailed geologic maps, reports and data about the State’s geologic and seismic hazards, mineral resources and other geologically related topics. CGS’s products are used by
a variety of Federal, State and local government agencies, businesses, consultants, universities
and schools. CGS is internationally recognized as a leading influence on public policy related to
geologic and seismic hazards.
47-2
9:00 AM
Testa, Stephen M.
[173205]
HISTORY OF THE CALIFORNIA STATE MINING AND GEOLOGY BOARD - 125 YEARS OF
DEVELOPMENT AND IMPLEMENTATION OF EARTH SCIENCE POLICY
TESTA, Stephen M., California State Mining and Geology Board, 801 K street, Suite 2015,
Sacramento, CA 95814, [email protected] and ARCAND, Will J., California
State Mining and Geology Board, 801 K Street, Suite 2015, Sacramento, CA 95814
The State Mining and Geology Board (SMGB) was established in 1885 as the Board of Trustees
(Board). Its purpose was to oversee the activities of the State Mineralogist and the Bureau of
Mines, now the California Geological Survey (CGS), which was created by the Legislature five
years earlier. The Board was abolished in 1913, and reestablished as the State Mining Board
in 1929. During these early years, the State Mining Board provided general policy for guidance
to the Governor and the Division of Mines. These responsibilities recognize the impacts that
California’s complex geology, large amounts of federally managed lands, high mineralization,
and potential for geologic hazards have on the State’s economy, land use, and public safety. As
with the survey, the State Mining Board would evolve with time, and renamed the State Mining
and Geology Board (SMGB) in 1965. Focus was primarily on development of the state’s mineral
resources until the mid-1970s. By 1975, the SMGB was granted additional powers and duties,
and became involved with the implementation of policy pertaining to geologic hazards and surface mining. Today’s SMGB is housed within the Department of Conservation and is composed of
nine members appointed by the Governor, and confirmed by the Senate, for four-year terms. By
statute, SMGB members must have specific professional backgrounds in geology, mining engineering, environmental protection, groundwater hydrology and rock chemistry, urban planning,
landscape architecture, mineral resource conservation, and seismology, with one non-specialized
member representing the public. The SMGB is granted certain autonomous responsibilities and
obligations under several statutes. In concert with the Department of Conservation, the CGS and
the Office of Mine Reclamation (OMR), the SMGB has been fully engaged in implementing the
legislative mandates of the Surface Mining and Reclamation Act of 1975 (SMARA), the AlquistPriolo Earthquake Fault Zoning Act (A-P Act), and the Seismic Hazards Mapping Act (SHMA).
47-3
9:20 AM
Saucedo, George J.
[173170]
GEOLOGIC MAPPING AT THE CALIFORNIA GEOLOGICAL SURVEY – HISTORY,
EVOLUTION, AND METHODS
SAUCEDO, George J., California Geological Survey, 345 Middlefield Road, MS 520,
Menlo Park, CA 94025, [email protected] and WILLS, Christopher J.,
California Geological Survey, 801 K Street, MS 12-32, Sacramento, CA 95814
Geologic mapping has been an integral part of the California Geological Survey’s (CGS) history. As societal needs for geologic information have evolved, so has CGS’s commitment to
the citizens of California, to provide pertinent and accurate products to meet these challenges.
The Preliminary Mineralogical and Geological Map of the State of California (1891) and the
Geological Map of the State of California (1916), both at 1:750,000 scale, were the first maps to
depict the geology of the entire State. As the need for more detailed maps arose, subsequent
series of larger-scale geologic maps were prepared. The Geological Map of California (1938)
SESSION NO. 47
was published at 1:500,000-scale in 6 sections followed by the 1:250,000-scale Geologic Atlas
of California (1958-70) published as 27 sheets. The detail depicted in the Geologic Atlas Series,
along with other additions, served as sources for the Geologic Map of California (1977). In
1979, the Regional Geologic Map Series (1:250,000-scale) was introduced to replace the Atlas
Series with updated mapping and a new format. Six sheets were published before aligning with
the USGS National Cooperative Geologic Mapping Program’s suggested scale of 1:100,000 for
geologic map compilations.
Following priorities established by the State Geologist and an advisory committee, CGS maps
and compiles the geology of the State at 1:24,000 and 1:100,000 scale respectively, supported
in part by USGS-STATEMAP funds. CGS compiles regional geologic maps at 1:100,000-scale
based on 1:24,000-scale mapping in urban or developing areas and best available mapping
elsewhere. Compilation of a regional geologic map can be an arduous task especially in areas
where multiple mapping sources exist. Source materials are collected, evaluated, and converted
into digital format where necessary. Decisions are made on map sources, amount of detail to
show, and conflicts along map borders. One of the most challenging aspects is creating a single
map explanation from a myriad of geologic units shown on the source maps. Once completed,
the maps and accompanying materials are peer reviewed and placed on the CGS Preliminary
Geologic Map website for further comment and review. Geologic maps produced by CGS are the
foundation on which a variety of derivative products, including regulatory zone maps, are built.
47-4
9:40 AM
Wills, Chris J.
[173112]
DEVELOPING MAPS OF POTENTIAL EARTHQUAKE SHAKING FOR CALIFORNIA
WILLS, Chris J., California Geological Survey, 801 K Street, ms 12-32, Sacramento, CA
The science of seismic shaking hazard analysis has grown and matured in the years since the
California Division of Mines and Geology published Map Sheet 23 “Maximum Credible Rock
Acceleration from Earthquakes in California” in 1973. That map showed maximum earthquake
magnitudes based on the length of faults and estimates of shaking. Very little was known about
the rates of earthquakes on any of the faults beyond what was recorded in the short historic
record. Much has changed in the most recent successor to Map Sheet 23: Map Sheet 48
“Earthquake Shaking Potential for California” published by the California Geological Survey
in 2008. Most importantly, modern Probabilistic Seismic Hazard Analysis (PSHA) allows us to
consider data on the rates of earthquakes estimated from geologic slip-rate and paleoseismic
studies on individual faults, geodetic studies of deformation in a region, as well as seismic history.
In addition, PSHA allows consideration of uncertainties of the data. The location of faults and their
maximum earthquake magnitudes are still key to any evaluation of seismic shaking. Geologic slip
rate studies, in concept, are some of the primary data needed for this analysis. These studies can
have significant uncertainties and must be consistent with large scale geodetic data: the sum of
the fault slip across the plate boundary should equal the relative plate movement. Geodetic rates
can provide rates of movement across a fault or region, but there is debate about how a geodetic
rate measured over the past decade or two compares with the rates of movement that drive earthquakes over centuries. The Working Group on California Earthquake Probabilities, in which CGS
partners with USGS and SCEC, ensures that all the relevant data are considered. Coordination
with the USGS National Seismic Hazard Map program ensures consistency with seismic hazard
maps and building code design maps of the rest of the country.
47-5
10:20 AM
Clinkenbeard, John P.
[173260]
THE CALIFORNIA GEOLOGICAL SURVEY MINERAL RESOURCES PROGRAM - MINERAL
RESOURCES, MINERAL HAZARDS AND ENVIRONMENTAL GEOLOGY
CLINKENBEARD, John P., California Geological Survey, 801 K Street, MS 12-31,
Sacramento, CA 95814, [email protected]
Providing information on California’s mineral resources has been, and continues to be, an important task for the California Geological Survey Mineral Resources Program (MRP). However, just
as the California Geological Survey has changed and evolved over its 150-year history, the MRP
has also changed to meet society’s changing needs.
In addition to requests for information on California’s mineral resources, over the last two
decades the MRP has increasingly received requests for other types of information related to
environmental geology/mineralogy/geochemistry from state and local agencies, consultants,
industry representatives and the public. These requests have led to non-mineral resource projects
on topics such as geologic carbon sequestration, naturally occurring asbestos, heavy metals,
and radon.
As part of the West Coast Regional Carbon Sequestration Partnership, the MRP has been
working to provide baseline information for characterizing the potential for geologic sequestration
for carbon dioxide in California. Sequestration is one of several tactics being investigated to slow
the trend of global warming.
In the case of potential minerals-related public health and environmental issues, the MRP provides objective maps, technical information and advice on the occurrence and characteristics of
hazards such as naturally occurring asbestos, radon, and mercury. Such information has proven
very useful to the staffs at the California Air Resources Board, local Air Pollution Control Districts,
California Department of Transportation, CalFire, USGS, and county and city agencies as they
work to promote the health and safety of California citizens. This information has also been helpful
to private citizens trying to better understand local mineral-hazard issues.
47-6
10:40 AM
Miller, Russell V.
[173102]
MINERAL LAND CLASSIFICATION IN THE CALIFORNIA GEOLOGICAL SURVEY’S MINERAL
RESOURCES PROGRAM
MILLER, Russell V., Conservation, State of California, 206 S Thomas St, Orange, CA
California’s mineral resources have played an important part in the history and growth of the
state, and the collection and dissemination of mineral resource information has been an important
role of the California Geological Survey (CGS) since its inception in 1860. Since the late 1970s
the CGS Mineral Resources Program has identified mineral resources through the process of
Mineral Land Classification.
In the 1960s and 1970s, as the State’s population expanded and society’s priorities shifted,
land use decision makers in California were faced with the increasingly difficult task of balancing competing land uses while planning for future growth, the protection of the environment, and
the conservation and wise use of natural resources. The Surface Mining and Reclamation Act of
1975 (SMARA) was passed by the California State Legislature in response to the loss of significant mineral resources due to urban expansion, the need for current information concerning the
location and quantity of essential mineral deposits, and to ensure adequate mined-land reclamation. To address mineral resource conservation, SMARA mandated a two-phase process called
classification-designation.
SMARA directs the State Geologist to classify (identify and map) the non-fuel mineral
resources of the State to show where economically significant mineral deposits occur, and where
98 2010 GSA Abstracts with Programs they are likely to occur, based upon the best available scientific data. Designation as a mineral
resource of regional or statewide significance is a further step taken by the State Mining and
Geology Board to emphasize resource importance. Mineral Land Classification provides unbiased, scientific information about mineral resource occurrences in California to Federal, State
and local government agencies, industry, and the public. This information enables them to make
informed land-use and long term planning decisions that will impact the economic and environmental future of their communities, regions, and the State.
47-7
11:00 AM
Pompy, James
[173692]
ORIGINS OF CALIFORNIA’S SURFACE MINING & RECLAMATION ACT (SMARA)
POMPY, James, Office of Mine Reclamation, 801 K Street, M.S. 09-06, Sacramento, CA
As the California Geologic Survey celebrates its 150th anniversary and the State Mining and
Geology Board (SMGB) celebrates its 125th anniversary, it is fitting to reflect upon the crucial
role the SMGB and the State Geologist played in how mining and reclamation is regulated
today. In April of 1964, in Roanoke, Virginia, the Council of State Governments held a conference on surface mining, attended by state and federal legislative and administrative officials,
mining industry representatives, and conservationists. This meeting compelled to the Council
of State Governments to assist the states in dealing with surface mining problems. In 1967,
the California Senate called for a study of uniform control and standards for strip mining. The
subject was referred to the Senate Committee on Natural Resources for consideration. The
Senate Committee on Natural Resources looked to California’s SMGB for direction. The SMGB
adopted Resolution B, triggering the formation of a study group to “…inquire into the problems
presented by surface mining as identified by the Department of the Interior of the United States of
America…” The SMGB looked to Norman B. Livermore, Jr., Secretary of Resources, to organize
the Surface Mining Committee to study and recommend “such regulations as may be needed
to avoid ‘collisions’ between urbanization and the mining industry.” The findings of the Surface
Mining Committee were summarized in “The Report of the Committee on Surface Mining for the
State of California” (the report) was forwarded to both the Senate Standing Committee on Natural
Resources and the Assembly Committee on Natural Resources.
In Washington, the US Congress was on track to adopt the Surface Mining Control and
Recovery Act and the National Environmental Protection Act. California’s Surface Mining
Committee concluded that State regulation of mining would be preferable to Federal regulations.
The findings of the Committee set in motion events in the California legislature which led to the
adoption of California’s Surface Mining and Reclamation Act of 1975 (SMARA). SMARA was
amended 15 years later giving the State enforcement authority and leading to the creation of the
Office of Mine Reclamation.
47-8
11:20 AM
Kustic, Tim
[173041]
A HISTORY OF CALIFORNIA’S DIVISION OF OIL, GAS, AND GEOTHERMAL RESOURCES
KUSTIC, Tim, California Division of Oil, Gas, and Geothermal Resources, 801 K Street,
MS 20-20, Sacramento, CA 95814, [email protected]
Thousands of years after humans’ first use of California’s petroleum and 50 years after drilling
California’s first oil well, the California Legislature in 1915, with the support of the petroleum
industry, created a State-level regulatory agency to curtail abuse of this natural resource.
Preventing reservoir damage from wells lacking competent water zone isolation and collecting
well and production records were initial goals for the Department of Petroleum and Gas of the
State Mining Bureau.
Historically, the Division of Oil, Gas, and Geothermal Resources (Division) authority and
enforcement has been reactionary to issues involving California’s oil industry. Revisions in 1929
addressed the unreasonable waste of gas, which was a common practice to get to the oil hydrocarbons. California’s “law of capture” for oil fields generated haphazard townlot drilling of wells
and overproduction which were addressed in 1931 statutory amendments that detailed spacing
requirements. This 1931 amendment also introduced the first bonding requirement to address
wells that operators deserted. Although offshore wells were drilled as early as 1897, it was not
until 1921 that the State Legislature passed a tidelands leasing act. This allowed the more orderly
development of the offshore reserves. In the 1960’s the Geysers Geothermal field in Sonoma and
Lake Counties was developed. In September 1965 the regulation of geothermal wells was added
to the Division. In 1970, Division authority was expanded considerably to prevent “…damage to
life, health, property, and natural resources…” this trend continues today. In 1990, the Division
improved its idle/orphan well abatement program by increasing financial insurance requirements,
thereby, decreasing the State’s future liability for deserted oil and gas wells, and providing incentives to allow an operator to rework an orphaned well in an attempt to regain production.
As the Division looks to the future, its core programs will continue to protect the citizens of the
State, the environment, and natural resources. Ongoing and additional challenges include the
elimination of long-term idle wells and the remediation of derelict/idle lease facilities.
48-1
BTH 1
Haugerud, Ralph A.
[173694]
NCGMP09 -- A DATABASE SCHEMA FOR DIGITAL PUBLICATION OF GEOLOGIC MAPS
SOLLER, David R., U.S. Geological Survey, 926-A National Center, Reston, VA 20192-0001,
[email protected], HAUGERUD, Ralph A., U.S. Geological Survey, Dept Earth and Space
Sciences, University of Washington, Box 351310, Seattle, WA 98195, [email protected],
RICHARD, Stephen M., Arizona Geological Survey, 416 W. Congress, #100, Tucson,
AZ 85701-1381, and THOMS, Evan E., U.S. Geological Survey, 4200 University Drive,
Anchorage, AK 99508-4667
After two decades experience with geologic-map GIS, the earth science community has yet to
evolve a widely accepted schema for the GIS representation of a geologic map. Benefits of a
standard schema would include better communication with map users, easier development of
tools for creating and analyzing geologic maps, lower training costs, and easier map compilation.
We are developing a schema for the publication of a single geologic map. Creation of a singlemap database, collection of field data, cartography, and databases for multiple maps are different
(though related) problems. We began our effort with experience that included participation in
previous and ongoing standards efforts (NGMDB, NADM, FGDC), use and construction of GIS
SESSION NO. 48
tools for geologic map creation (ALACARTE and derivatives), extensive geologic mapping experience in diverse terrain, and much production GIS work. Our work is supported by the National
Cooperative Geologic Mapping Program of the USGS.
Salient features of the schema include: (1) inclusion of both traditional, hierarchical Description
of Map Units with free-form descriptions AND strongly-structured, tabular earth materials descriptions, (2) extensive feature-level metadata, (3) prescribed naming of all database elements, and
(4) the schema is native to ArcGIS. We have translated existing databases into this schema.
We have written tools that create an empty database, (partially) validate a database, check a
database for certain geometric inconsistencies, and translate a database to open file formats.
Documentation, example databases, and tools are online at http://ngmdb.usgs.gov/Info/standards/
NCGMP09/.In the coming months we plan another round of revision and will write more tools to
facilitate database creation. We solicit feedback on the database schema and collaboration in tool
development.
48-2
BTH 2
Brown, Howard J.
[171147]
GEOLOGIC MAP OF THE FAIRVIEW VALLEY AREA, SAN BERNARDINO COUNTY,
CALIFORNIA
BROWN, Howard J., Omya California, P.O. Box 825, Lucerne Valley, CA 92356,
[email protected]
Previous geologic mapping in the Fairview Valley area of west central Mojave Desert has been
mostly small scale or reconnaissance level. For this work Fairview Valley area was mapped in
detail at a scale of 1:12,000. Google Earth and other air photos and GPS were also used to verify
locations. Bedrock includes Late Proterozoic and Paleozoic carbonate dominated metasedimentary rocks, Permo-Triassic, Jurassic and Cretaceous intrusives, Jurassic Fairview Valley
Formation and Lower Sidewinder volcanic rocks. Several alluvial units are also present. Geologic
structure is complex, the result of multiple Mesozoic folding, metamorphic, intrusive, compression
and extension deformational events. Cenozoic activity includes debris flows, landslides and active
faulting continuing into modern time.
One of the most prominent features in the Fairview Valley area is the Helendale Fault Zone
(HFZ), identified on the California State Alquist Priolo fault map as active (Hart 1977). The HFZ
is considered to be a right lateral strike slip fault, postulated to have up to several kilometers of
movement, and is one of several major northwest trending lateral faults. The HFZ has been traced
for about 90 km. and has evidence of recurrent surface rupture in Holocene time (200-10,000 yrs).
Alluvial and basement rocks in Fairview Valley all indicate about the same amount of displacement, and have been displaced together by right lateral faulting in a zone of faulting >2km wide
that contains many faults, active during Pleistocene thru recent time.
Regional and local structural grain trends northwest parallel to the long axis of the valley. Aksoy
(1993) interpreted the valley to be a graben, gravity data suggesting right stepping en echelon
strands formed a pullapart basin up to 3 kilometers wide. His cross sections suggest Fairview
Valley is fault bounded on the west and east. Recent detailed mapping indicates the HFZ is a long
lived zone of structural weakness in which many faults are present within the valley and adjacent
bedrock, some of which predate and or have been reactivated by the modern Helendale Fault.
Accumulated evidence in Fairview Valley indicates the modern HFZ forms a zone >2.5 km wide
in which numerous faults and fractures are present, some of which have been episodically active
during Pleistocene thru recent time.
48-3
BTH 3
Brown, Howard J.
[172214]
LATE PROTEROZOIC, PALEOZOIC, AND MESOZOIC ROCKS AND GEOLOGIC STRUCTURES
IN THE VICTORVILLE AND HELENDALE 7.5’ QUADRANGLES WEST CENTRAL MOJAVE
DESERT, CALIFORNIA
BROWN, Howard J., Omya California, P.O. Box 825, Lucerne Valley, CA 92356,
[email protected] and HERNANDEZ, Janis L., California Geological Survey,
888 S. Figueroa Street, Suite 475, Los Angeles, CA 90017
The geology of the Victorville, California area was described in 1977 by Elizabeth Miller. New
1:6,000-scale bedrock mapping of the Victorville and Helendale 7.5’ quadrangles expanded
on Miller’s work by delineating additional detailed stratigraphic and structural relations, which
improved the understanding of the complex geologic history of the area. From this new mapping,
the California Geological Survey prepared two new 1:24,000-scale geologic maps.
Miogeoclinal strata of Late Proterozoic and Paleozoic age in the Quartzite Mountain area
were complexly folded (F-1, F-2), faulted and metamorphosed prior to or during Permo-Triassic
time. Early Jurassic Fairview Valley Formation and a transitional sequence of volcaniclastic and
quartz-rich sandstones were deposited and then locally folded (F-3) and metamorphosed. Lower
Sidewinder Volcanics were subsequently deposited during Early Middle Jurassic time.
Detailed mapping at Sparkhule Mountain identified an allochthon of about 3 km2 consisting
of Paleozoic limestone and Fairview Valley Upper limestone conglomerate resting discordantly
on lowest Sidewinder andesite and ignimbrites. The allochthon was emplaced during Lower
Sidewinder deposition, perhaps as a gravity slide related to caldera collapse.
New mapping also redefined the detailed stratigraphy of the Sidewinder Volcanics and associated deformation events, previously described by Schermer and Busby (1994). Younger Lower
Sidewinder ignimbrites and flows were deposited, followed by episodes of north- and NW-dipping
low-angle extensional faulting. After Lower Sidewinder deposition, Jurassic granitics were
emplaced, followed by north-trending high-angle faulting, hydrothermal activity, and uplift and
erosion.
Emplacement of Late Jurassic Upper Sidewinder shallow intrusive plugs and dikes and formation of NW-trending, west-dipping (east-verging) foliation/cleavage was followed by NW-trending
folding (F-4) and faulting. This occurred prior to intrusion of Late Cretaceous batholithic rocks.
The Jurassic events described above occurred in a short period of time (163 - 148 m.y.) and
are roughly coeval with Mid-Jurassic compression events in other parts of the Mojave region, and
similar to extension coeval with shortening in numerous convergent margin settings on a global
scale.
48-2
BTH 4
Masana, Eulalia
[173159]
COMBINING NEW AIRBORNE LIDAR DATA AND PROVENANCE OF ALLUVIAL FAN
DEPOSITS TO CONSTRAIN LONG-TERM OFFSETS ALONG THE ELSINORE FAULT IN THE
COYOTE MOUNTAINS, IMPERIAL VALLEY, CALIFORNIA
MASANA, Eulalia1, ROCKWELL, Thomas K.1, and STEPANCIKOVA, Petra2, (1) Geological
Sciences, San Diego State University, 5500 Campanile Dr, San Diego, CA 92182-1020,
[email protected], (2) Institute of Rock Structure and Mechanics, Academy of
Sciences of the Czech Republic, V Holesovickach 41, Prague, 182 09, Czech Republic
The Elsinore-Laguna Salada fault is part of the San Andreas fault (SAF) system in southern
California, extending 250 km from the Los Angeles Basin southeastward into Mexico. The slip
rate on the southern Elsinore fault is believed to be low, based on recent InSAR observations,
although a recent study near Fossil Canyon suggests a rate in the range of 1-2 mm/yr. However,
the fault is well-expressed in the geomorphology in the Coyote Mountains, which argues for a
reassessment of the long-term rate along this branch of the SAF system. For this study, we used
the new, recently acquired airborne LiDAR dataset (EarthScope Southern & Eastern California,
SoCal) to map alluvial offsets in the Coyote Mountains in western Imperial Valley. We reprocessed
the point clouds to produce DEMs with 0.5m and 0.25m grids. We varied the hill shade and insolation angles to illuminate and map the various fault strands and alluvial deposits. This allowed us
to detect not only the major offsets along the primary fault strands, but also the many secondary
minor faults. We identified numerous offset features, such as rills, channel bars, channel walls,
alluvial fans, beheaded channels and small erosional basins that varied in displacement from 1 to
350 m. These are compared to measurements on many of the same features in the field. For the
larger offsets, we recognize that older alluvium that is offset greater amounts is commonly buried
beneath younger pulses of alluvial fan deposition, and are separated by buried soils. To determine
the actual source canyon of various alluvial elements, we quantified the clast assemblage of
each source basin and each alluvial fan on both sides of the fault. To accomplish this, we used a
portable grid and classified more than 300 clasts at each of more than 35 sites along the fault. We
found a very good fit between displaced alluvial fan elements and their inferred source canyons,
but a poor match with the alluvium from neighboring canyons, which allows us to resolve longterm offset. Future dating of the pedogenic carbonate associated with these buried soils will allow
resolution of the long term slip rates over multiple time frames to test the constancy of fault slip
rate during the late Quaternary, as well as to test the lateral variations in rate along the length of
the fault.
48-5
BTH 5
Green, Joe
[173659]
ANALYSIS OF THE MICROSEISMICITY (1996-2007) OF THE SANTA MONICA MOUNTAINS
AND ASSOCIATED MALIBU COAST, SANTA MONICA-DUME, AND SANTA MONICA BAY
FAULTS
GREEN, Joe, Geological Sciences, CSUN, 18111 Nordhoff St, Northridge, CA 91330,
[email protected] and SIMILA, Gerry, Geological Sciences, California State University
Northridge, 18111 Nordhoff St, Northridge, CA 91330-8266
The Santa Monica Mountains, in the western Transverse Ranges, are separated from
Los Angeles and offshore Santa Monica sedimentary basins by the E-W, now predominantly
left-lateral Raymond-Hollywood-Santa Monica-Dume fault system. The western ~80 km-long
stretch of this fault system has been investigated by Sorlien et al (2006) using seismic reflection and earthquake data. Previous investigators proposed thrust slip on a low-angle blind fault
beneath the Santa Monica-Dume fault to account for the Santa Monica anticlinorium. The onshore
Malibu Coast fault (MCF) and the onshore Santa Monica fault are probably oblique left-reverse
faults. The Malibu Coast fault shows evidence of reverse-oblique slip with a left-lateral strike-slip
component along north-dipping strands ranging from 30-70 degrees. Though Holocene surface
displacements have been officially recognized across only two strands of the MCF zone to date,
the MCF is still considered active and capable of producing a magnitude 6.5 to 7.0 earthquake.
The microseismicity (1996-2007; M=1-3, 307 events) for the region has been relocated using
HYPOINVERSE 2000 and the SCEC/LARSEII crustal velocity structure. The results show seismicity (map view and cross-sections) associated with the Malibu Coast, Santa Monica-Dume, and
Santa Monica Bay faults, as well as scattered events in the eastern region of the Santa Monica
Mountains. The focal mechanisms show primarily reverse and some left-lateral slip faulting.
48-6
BTH 6
Anderson, Thomas H.
[173235]
IS THERE A CASE FOR A MAJOR LATE JURASSIC SHEAR ZONE IN THE PENINSULAR
RANGES?
ANDERSON, Thomas H.1, CAMPBELL, Patricia A.2, POWELL, Robert E.3, and MOLDE,
Brooke2, (1) Geology and Planetary Science, Univ of Pittsburgh, Pittsburgh, PA 15260,
[email protected], (2) Geography, Geology and the Environment, Slippery Rock University,
Slippery Rock, PA 16057, (3) U.S. Geological Survey, Geology and Geophysics Science
Center, 520 N Park Ave, Tucson, AZ 85719
Near Winchester, CA, strongly foliated rocks crop out among foliated and unfoliated plutonic
rocks of the southern California batholith (Morton, 2003). The plutons intrude two distinct rock
suites separated by a major “suture” or fault, which strikes north-northwest. To the east the rocks
include mafic and intermediate schist, amphibolite, and augen gneiss derived from porphyritic
granodiorite. To the west the exposed rocks consist of quartzose sandy and silty rocks and matrixrich conglomerate probably derived from debris flows. Southwest of Winchester in French Valley
and near Julian, the youngest interpreted ages of detrital zircon from metasedimentary units are
Late Triassic (Kimbrough et al., 2007). The structural relations near Winchester resemble those
along the Mojave-Sonora megashear in NW Mexico where Late Triassic and older strata of the
Caborca block crop out west of mid-Jurassic volcanic rocks. However, the “suture” has not been
mapped beyond the Winchester quadrangle nor has the linkage between inferred fault segments
been shown. Nevertheless, thinly laminated gneisses and schists formed by recrystallization of
mylonitic rocks extend south where they are mapped as part of the Julian Schist. Locally, the
fine-grained, strongly foliated, metasediment containing rootless folds comprises inclusions in
moderately foliated Late Jurassic granitoids (Todd, 1995). Southeast of Julian, much deformation
in the schist is attributed to Cretaceous tectonism (Thomson and Girty, 1994). However, diverse
orientations of foliation in the inclusions and moderately plunging fold hinges commonly recording
sinistral shear show rotation of previously deformed rocks. Powell (1993) has shown that carbonate-rich sedimentary sections and associated basement in the Transverse Ranges and Mojave
Desert distinguish domains that may be recognized in the Santa Rosa-San Jacinto Mts. These
domains provide constraints on the position of major pre-Tertiary fault structures. Restoration of
displacement along the San Andreas fault reveals a significant westward jog in the inferred MSms
trace, which may reflect a Jurassic releasing bend, southwestward-directed Cretaceous faulting,
Tertiary extension or some combination of these.
48-7
BTH 7
Clay, Pamela Jamie
[173622]
TECTONIC IMPLICATIONS OF DUCTILE SHEAR ZONES IN THE JURASSIC KEITHS DOME
PLUTON, NORTHERN SIERRA NEVADA BATHOLITH, CALIFORNIA
CLAY, Pamela Jamie, Department of Geology, San Jose State University, One Washington
Square, San Jose, CA 95192-0102, [email protected] and MILLER, Robert B., Geology
Department, San Jose State University, One Washington Square, San Jose, CA 95192
Structural data were collected on four Jurassic and Cretaceous plutons near Lake Tahoe, to
facilitate interpretation of regional structure and to evaluate changing tectonic regimes inferred
for the arc to the south; transpressional during the Mid-Late Jurassic (Saleeby and Busby-Spera,
1992), and neutral to weakly extensional in the mid-Cretaceous (Tobisch et al., 1995). Steep
(>70°), N-NW striking, <1 cm to >30 m wide ductile shear zones deform the Jurassic Desolation
Valley and Keiths Dome plutons of the Crystal Range Suite, and Mesozoic metavolcanic and
metasedimentary host rocks. The highest concentration (85% of all measured zones) is in the
Keiths Dome pluton. Rakes of lineations in the zones are mostly >45°. West-side up, reverse
motion is dominant, whereas the strike-slip component is inconsistent. Deformation temperatures
ranging from ~300 °to >550° are suggested by fragmented plagioclase, bent biotite grains and
SESSION NO. 48
small, recrystallized quartz in lower-T zones, and subgrains, grain boundary migration, and larger,
equant, recrystallized quartz and feldspar in higher-T zones. The shear zones locally deform
steep (≥77°), E-NE striking mafic dikes which cut the Keiths Dome pluton and other Jurassic
plutons of the Crystal Range Suite, including the ~164 Ma Pyramid Peak granite (Loomis, 1983;
Sabine, 1992). Temporal resolution of major ductile shear is restricted by limited geochronologic
data; shear zones deform <164 Ma dikes and are truncated by the ~91 Ma Echo Lake intrusion.
Orientations of the ductile shear zones in the Jurassic plutons and host rocks are largely concordant to those of the regional foliation, and discordant to pluton contacts in places, indicating that
the shear zones record tectonic strain rather than emplacement. The strain field inferred from the
N-NW striking reverse shear zones and E-NE striking subvertical dikes is one of E-NE contraction combined with N-NW subhorizontal extension (from dikes) and subvertical stretching (from
lineations). This is compatible with regional transpression, such as proposed to the south in the
Mid-Late Jurassic.
48-8
BTH 8
Simila, Gerry
[173655]
HIGH RESOLUTION FAULT KINEMATICS OF THE SAN PEDRO BASIN FAULT, CALIFORNIA
SIMILA, Gerry, Geological Sciences, California State University Northridge, 18111 Nordhoff
St, Northridge, CA 91330-8266, [email protected] and FRANCIS, Robert D., Department of
Geological Sciences, California State Univ Long Beach, 1250 Bellflower Blvd, Long Beach,
CA 90840
The California Continental Borderland is an unusual coastal zone that is undergoing transition
from a convergent continental margin to an oblique transform margin, dominated by the San
Andreas and similar faults. Major Borderland features are NNW-SSE trending seafloor basins
and ridges, many bounded by strike-slip faults. The San Pedro Basin fault is located between the
Palos Verdes peninsula and Catalina Island. Seismic reflection provides high resolution images
of the upper part of the fault, showing the seafloor expression. In addition, there are significant
differences on either side of the fault. There are onlaps on both sides, but on the SW side (toward
Catalina), the onlapping sediments are lower in the section than on the NE side. This corresponds
to an earlier time when Catalina may have been uplifting more than Palos Verdes, but the opposite is true at the present time which may represent a change in the motion along the fault. The
microseismicity of the San Pedro Basin is characterized by a low-level activity rate, magnitudes
smaller than three, spatially scattered events with minor clustering, and localized alignment, but
offset, with the San Pedro Basin fault. We are relocating the events and correlating with the seismic reflection interpretations of the fault location and orientation.
48-9
BTH 9
Sorlien, Christopher C.
[173137]
THRUST-REACTIVATED NORMAL FAULTS AND THRUST-FOLDING CALIFORNIA
BORDERLAND AND HAITI
SORLIEN, Christopher C.1, BRAUDY, Nicole2, CORMIER, Marie-Helene3, DAVIS, Marcy4,
DE BOW, Sam5, DEMING, Jacob6, DIEBOLD, John7, DIEUDONNE, Nicole8, DOUILLY,
Roby9, GULICK, Sean S.P.10, HORNBACH, Matthew11, JOHNSON, Harold3, MCHUGH,
Cecilia12, MISHKIN, Katherine13, SEEBER, Leonardo7, STECKLER, Michael7, SYMITHE,
Steeve Julien9, TEMPLETON, John7, and WILSON, Robert5, (1) Institute for Crustal Studies,
University of California Santa Barbara, Santa Barbara, CA 93106, [email protected],
(2) Geology, Brooklyn College, 2900 Bedford Ave, Brooklyn, NY 11210, (3) Department of
Geology, University of Missouri, Columbia, MO 65211, (4) University of Texas, Institute for
Geophysics, Austin, TX 78758, (5) URI Graduate School of Oceanography, Narragansett,
RI 02882-1197, (6) Seafloor Systems, El Dorado Hills, CA 95762, (7) Lamont-Doherty
Earth Observatory, 61 Route 9W, PO Box 1000, Palisades, NY 10964-8000, (8) Bureau
des Mines et Energie, Port-au-Prince, 000000, Haiti, (9) Faculte des Sciences (Universite
d’Etat d’HAITI, Port-au-Prince, HT-6120, Haiti, (10) Institute for Geophysics, University of
Texas at Austin, J.J. Pickle Research Campus (ROC), 10100 Burnet Rd. (R2200), Austin, TX
78758-4445, (11) Jackson School of Geosciences, University of Texas at Austin, J.J. Pickle
Research Campus, Building 196, 10100 Burnet Road (R2200), Austin, TX 78758-4445,
(12) School of Earth and Environmental Sciences, Queens College, C.U.N.Y, 65-30 Kissena
Blvd, Flushing, NY 11367, (13) Queens College, Flushing, NY 11367
Along the southern California margin and offshore, there are active anticlines growing above blind
thrust faults. These faults generally reactivate Miocene extensional faults. Some such California
faults, including large parts of the Holocene-active Oak Ridge fault beneath Santa Barbara
Channel, are characterized by slow subsidence of the upthrown side of the fault, with more
rapid subsidence of the downthrown side. Thus regional subsidence can mask the growth an
anticline with respect to sea level. Offshore southern California fold limbs also commonly exhibit
progressive tilting (rotation about a horizontal axis). If the tilt rate is constant across the width of
the limb and vertical motion is known at one spot, then varying vertical motion across dip can be
determined. In Haiti, an anticline forms the WNW-ESE St. Marc Peninsula north of Port-au-Prince.
Another 40 km by 150 km-long anticline that includes Gonave Island is located between the
northern and southern peninsulas of Haiti. Uplifted marines terraces are present on the coasts of
both anticlines with the ~120,000 year terrace dated using corals at both locations. This terrace is
folded and uplifted at the St. Marc Peninsula. Offshore industry seismic reflection profiles image
highly extended rocks beneath an unconformity. These profiles also image blind N-dipping faults
beneath both anticlines, with telltale signs that they are reactivated normal faults. The unconformity separating the extension and contraction may correlate to an onshore unconformity between
Eocene and Miocene rocks at both St. Marc Peninsula and Gonave Island. Both limbs of both
anticlines are also progressively tilted. They, along with intervening secondary anticlines, appear
to be part of a SSW-verging fold and thrust complex. Both anticlines exhibit evidence for subsidence of their offshore plunge, mainly as unconformities and other planar surfaces now in deep
water. The offshore sections of the St. Marc anticline image folding of the youngest strata of the
basin at the base of its backlimb. Thus, the parallelism of this transpressional system to southern
California is striking. The hanging-wall St. Marc Peninsula could be exposed to strong ground
motion if the fault proves to be active. The large size of the submerged part of Gonave Island
anticline suggests a tsunami hazard if active.
48-10
BTH 10
Koster, Kelvin L.
[173179]
SPACED CLEAVAGE DEVELOPMENT AT McCartney MOUNTAIN, MONTANA
KOSTER, Kelvin L., Grand Valley State University, 1 Campus Drive, Allendale, MI 49401,
[email protected]
At the McCartney Mountain salient in southwest Montana, spaced cleavage is exposed exclusively in two thin silty orange brittle dolostone layers in the lower gastropod member of the
Kootenai formation. Characterization and classification of cleavage morphology, orientation, and
domain spacing is used to assess the attributes of the strain field in terms of minimum elongation
direction and homogeneity of deformation distribution. Controls on spaced cleavage development
are explored, including lithology, structural proximity, and insoluble content. Results from stereonet analysis show that our initial field hypothesis that spaced cleavage reflected early bedding
100 2010 GSA Abstracts with Programs parallel shortening, with minimum elongation trending east-west, is not supported by the observations, which show shortening trending north-south. Structural analysis, chemical dissolution, and
microscopic observations are used to build a descriptive and kinematic history of spaced cleavage development.
48-11
BTH 11
Dutra, Steven M.
[173227]
THERMOBAROMETRY OF ECLOGITE-FACIES SHEAR ZONES IN THE LOFOTEN ISLANDS,
NORWAY
DUTRA, Steven M., Geosciences, San Francisco State University, San Francisco, CA 94132,
[email protected], SHULMAN, Deborah J., Geosciences, San Francisco State University,
50 Upper Terrace, San Francisco, CA 94117, and LEECH, Mary, San Francisco, CA 94132
The exhumed lower crustal rocks of the Lofoten Islands in northern Norway provide a rare
opportunity to study deep crustal processes forming eclogite-facies shear zones (ESZ) during
Caledonian continental collision. The 2-5 cm-wide ESZ found in Nusfjord and Flakstad, on the
island of Flakstadøy, are within metastable gabbroic host rocks, specifically gabbroic gneiss and
gabbronorite. These ESZ contain relict eclogite-facies omphacite along garnet grain boundaries
but are generally overprinted by a retrograde amphibolite-facies metamorphic event. This is the
first report of positively-identified relict omphacite for Flakstadøy shear zones. Peak metamorphic
P-T conditions are not well-constrained, but will be determined using Fe-Mg exchange between
omphacite and garnet pairs in the ESZ. Average omphacite chemistries are Aeg12.5Jd41Di46.5
and garnet chemistries adjacent to the omphacite are Alm47Pyr37Grs17 based on quantitative
analyses from an EDS on an FE-SEM at San Francisco State University. Preliminary P-T estimates for the eclogite-facies metamorphism calculated for Fe-Mg exchange equilibria are 1.5 GPa
and 820 °C, somewhat higher temperature than previous estimates. EBSD mapping will be used
in conjunction with mineral chemistries to assess the role ductile deformation may have played in
eclogitization reactions.
48-12
BTH 12
LaFromboise, Eli
[173700]
NEOTECTONICS OF THE NICOYA PENINSULA, COSTA RICA
LAFROMBOISE, Eli1, MARSHALL, Jeff2, SIMILA, Gerry1, PROTTI, Marino3, and
QUINTERO, Ronnie4, (1) Geological Sciences, California State University Northridge,
18111 Nordhoff St, Northridge, CA 91330-8266, [email protected], (2) Geological
Sciences Department, Cal Poly Pomona University, Pomona, CA 91768, (3) OVSICORI,
Universidad Nacional, Heredia, Costa Rica, (4) OVSICORI, Universidad Nacional, Apartado
Postal: 2346-3000, Heredia, Costa Rica
The Pacific margin of Costa Rica sits atop the leading edge of the Middle America Trench where
steep subduction of old, dense crust in the northern region transitions to shallow subduction of
hotspot thickened crust and ridge collision in the south. This transition, initiated by an acute bathymetric change in the incoming Cocos Plate, profoundly influences upper plate vertical tectonism
and regional seismicity. The Nicoya Peninsula represents an emergent portion of the outer forearc
that lies 50 km inboard of the trench. It sits above a locked section of the seismogenic zone
responsible for past earthquakes in excess of Mw ~ 7.5 with the last event in 1950 and an estimated recurrence interval of 50 years. Immediately south of the peninsula, the subducting Cocos
Plate exhibits extreme changes in vertical relief as a series of seamounts and aseismic ridges
collide with the overriding Caribbean Plate resulting in a greater earthquake frequency. The peninsula’s trench-parallel coast exhibits multiple suites of uplifted late Quaternary marine terraces
revealing varying rates of vertical tectonism in response to differing subduction styles. The Nicoya
Peninsula is an ideal location to study the Caribbean-Cocos Plate interaction through the harvest
of seismic data and examination of uplifted geomorphic surfaces. Marine and fluvial terrace correlation from the northern, central, and southern coastlines of the peninsula reveal uplift rates an
order of magnitude greater in the southern region (1.0-2.0 m/ky) than along the northern pacific
beaches (0.1-0.5 m/ky). The uplift rates correspond to the differences in character of the incoming
plate. Radiocarbon ages of uplifted beachrock horizons confirm uplift rates for several locations. In
addition, the seismic strong motion array project (SSMAP) for the Nicoya Peninsula is composed
of 10 - 13 sites including Geotech A900/A800 accelerographs (three-component), Ref-Teks
(three-component velocity), and Kinemetric Episensors. This network records strong subduction
zone earthquakes and moderate to strong upper plate earthquakes. Data from these instruments were used in conjunction with data recorded by the Earthquake and Volcano Observatory
(OVSICORI) to refine locations for several large magnitude (Mw>4.0) events.
48-13
BTH 13
Hacker, Christopher
[173018]
INCISED MEANDERING STREAMS AS INDICATOR OF TERTIARY-QUATERNARY REGIONAL
UPLIFT IN NORTHWEST THAILAND
HACKER, Christopher, Department of Geological Sciences, California State University,
Fullerton, P.O. Box 6850, Fullerton, CA 92834, [email protected]
In northern Thailand’s Western Ranges, field and map observations show that many deeply
incised streams are highly sinuous and meandering - typical of rivers that form in flat flood plains,
not mountainous regions. These streams likely formed in early Tertiary paleobasins, of which few
relicts remain in the mountainous areas, during a period of tectonic quiescence. The streams
then incised directly downward during homogeneous, regional uplift during the late Tertiary to the
present, in most cases retaining the meanders rather than diverting. Most standard techniques
of tectonic geomorphology, such as dating of terraces, are ineffective in jungle regions with high
rates of surface erosion. Results have been obtained using DEM- and GIS-derived geomorphology data, determining relationships between sinuosity, amount of incision, hypsometry, and longitudinal and cross-sectional elevation profiles. The tectonic activity suggested by these relationships is likely related to the India-Asia convergence zone. While that convergence is the primary
driver of recent tectonic activity in Southeast Asia, little previous work has been done constraining
this activity. These results suggest that previous tectonic models for Thailand and Southeast Asia
may be missing periods of activity that have been obscured from more standard techniques, but
which should be expected from the relatively constant effect the India-Asia convergence has on
the region.
48-14
BTH 14
Rice, Karin
[173347]
GEOLOGICAL RECONNAISSANCE OF THE MALANGIYN GOL AND TöHöMIYN NUUR
VALLEYS, CENTRAL MONGOLIA: IMPLICATIONS FOR POTENTIALLY ACTIVE FAULTING
RICE, Karin1, KELTY, T.K.1, SAUERMANN, Robert1, and DASH, Batulzii2, (1) Geological
Sciences, CSULB, 1250 Bellflower Blvd, Long Beach, CA 90840, [email protected],
(2) School of Geology, Mongolian University of Science and Technology, PO Box 46/520,
Ulaanbaatar, 210646, Mongolia
Remote sensing and geologic field observations reveal potentially active faulting in the Malangiyn
Gol and Töhömiyn Nuur Valleys, approximately 190 km southwest of Ulaanbaatar, Mongolia. The
Malangiyn Gol Valley trends N60°W, is approximately 80 km long and 10 km wide and is defined
SESSION NO. 49
by left-stepping strike-slip faults. The average strike of these faults is N55°W. The strike-slip faults
form scarps, sag ponds, and linear valleys and truncate alluvial fans. One of the fault segments
curves to the east and changes strike to E-W. The Malangiyn Gol Valley is directly northwest and
adjacent to the Töhömiyn Nuur Valley.
The Töhömiyn Nuur Valley is roughly rectangular in shape, covering approximately 2,300 km2.
The northern edge of the Töhömiyn Nuur Valley is bounded by a set of strike-slip faults that
extend north into the Malangiyn Gol Valley. These faults change strike from N55°W to E-W near
the town of Buren. The western and southwestern sections of the Töhömiyn Nuur Valley display
a set of N-S- and NW-striking normal faults and a set of NW-striking strike-slip faults. The normal
faults appear to be older and truncated by the strike-slip faults. Geologic and geomorphic evidence for normal faulting includes triangular facets, fault benches, slickenlines and meter-wide
breccia zones. Sets of E-W to E-NE-striking igneous dikes are abundant in the southern part of
the valley and impart a fabric to the topography visible in remote sensing images.
In general, historic seismicity in Mongolia occurs along E-W-striking, left-lateral strike-slip faults
and NW-striking, right-lateral strike-slip faults. Results of this study indicate more complicated
fault kinematics. The faults in this area appear to be late Quaternary in age and may be capable
of producing destructive earthquakes. Although the study area is sparely populated, the proximity
of these faults to Ulaanbaatar may have important ramifications for seismic hazard assessment.
48-15
BTH 15
Kelty, T.K.
[173707]
EARTHQUAKE FAULTS OF CENTRAL MONGOLIA: IMPLICATIONS FOR THE SEISMIC
SAFETY OF ULAANBAATAR
KELTY, T.K.1, DASH, Batulzii2, DAY, Paul P.1, RICE, Karin1, DAUBENMIRE, Emily1, CHINN,
Logan1, and CHAVEZ, J.1, (1) Geological Sciences, CSULB, 1250 Bellflower Blvd, Long
Beach, CA 90840, [email protected], (2) School of Geology, Mongolian University of Science
and Technology, PO Box 46/520, Ulaanbaatar, 210646, Mongolia
Four earthquakes have been recorded in Mongolia since 1906 in the range of M7.4 to M8.1.
These earthquakes occurred along strike-slip faults in sparsely populated regions and caused
little damage to Ulaanbaatar, the capitol of Mongolia. About 35% of Mongolia’s three million
people live in the Ulaanbaatar. Many live in multi-story, soviet-style apartment buildings. Seismic
hazard assessment, including the identification of potentially active faults, is critically important to
the population and economic stability of this city.
The neotectonic architecture of Mongolia is delineated by sets of faults that accommodate the
Tertiary and Quaternary shortening of this part of central Asia. Seismicity in Mongolia over the
past 100 years is puzzling because the low rates of crustal movement unexpectedly produce
large magnitude earthquakes. Two of the largest historic earthquakes occurred on the well studied
Bulnay and Bogd strike-slip faults. However, there are many other faults capable of generating significant earthquakes and they remain relatively unexplored and potential hazards to the
growing population centers of Mongolia. Recent field studies by California State University, Long
Beach (CSULB) and the Mongolian University of Science and Technology (MUST) have identified several seismically active faults within 300 km of Ulaanbaatar. These research efforts have
used state-of-the-art remote sensing techniques and geological field mapping to characterize the
seismic activity and kinematics of poorly understood faults. Four seismically active fault zones
have been identified and include the: (1) Deren fault zone, (2) Hustain fault, (3) Buren fault, and
(4) Harhorin fault. These fault zones have three distinctive strike directions (NW, NE and E) and
exhibit active geomorphic features. A recent earthquake has occurred in the vicinity of the Deren
fault zone in January, 2010 (M5.4). There are also at least three more faults in the study area that
warrant further investigation.
T4. Advances in Understanding Magma Petrogenesis
and Eruption Dynamics at Basaltic Monogenetic
Volcanoes (Posters) (Cordilleran Section GSA)
49-1
49-2
48-16
BTH 16
Dermond, Jeffrey A.
[173612]
DUCTILE DEFORMATION PATTERNS IN THE LOWER PLATE OF THE NORTHERN SNAKE
DETACHMENT: DEFORMATION TEMPERATURE, VORTICITY, QUARTZ C-AXIS FABRIC
PATTERN, AND FINITE STRAIN STUDIES
DERMOND, Jeffrey A., Department of Geological Sciences, Central Washington University,
400 E University Way, Ellensburg, WA 98926, [email protected] and LEE, Jeff,
Central Washington University, 400 East University Way, Ellensburg, WA 98926
The Snake Range, NV metamorphic core complex is composed of a low angle fault, the northern
Snake Range detachment (NSRD), which juxtaposes a hanging wall of unmetamorphosed, normal faulted rocks upon a footwall of ductilely thinned and stretched metamorphic rocks. Published
work (Lee et al., 1987) suggests that lower plate rocks record dominantly pure shear and relatively low strains, well preserved in the northwest, overprinted by top-SE simple shear and very
high strains, now well preserved in the southeast. To test this hypothesis, we combined deformation temperature, mean vorticity number (Wm) from rotated rigid grain and oblique grain shape
(OGS) measurements, quartz c-axis data, and finite strain calculations for 20 samples spanning
the northern Snake Range from the Prospect Mountain quartzite, the structurally highest quartzite
in the footwall. From northwest to southeast, bulging recrystallization in quartz and purely brittle
deformation of feldspar grades eastward to sub-grain rotation of quartz and both ductile and brittle
feldspar deformation, indicating a temperature range of ~300° to ~450° C. In thin section, top-SE
kinematic indicators are ubiquitous except for the western most samples. Wm measurements
from rotated feldspar porphyroclasts indicate 71-64% pure shear in the northwest decreasing to
60-57% pure shear in the southeast. Wm measurements from OGS indicate nearly 100% pure
shear in the northwest decreasing to 27-16% pure shear in the southeast. Quartz c-axis fabric
patterns are consistent with OGS results, with samples from the northwest yielding symmetrical
cross-girdle patterns, indicating pure shear, which transition to asymmetric single-girdle patterns,
indicating top-SE shear, in the southeast. Finite strain ratios (Rxz) increase from 5.8 in the northwest to ~100 in the southeast. A deformation history in the lower plate of the NSRD characterized
by an initial phase of dominantly pure shear deformation superimposed on an eastward dipping
sequence largely overprinted by a top-down to the SE simple shear concentrated to the southeast
explains: (a) the increase in deformation temperature to the southeast, (b) pure shear deformation on the northwest that switches to simple shear on the southeast, and (c) an increase in finite
strain northwest to southeast across the range.
BTH 17
Schreck, Beth A.
[172870]
COMPLEX CINDER CONE ERUPTIVE SEQUENCE AT O’Neill CRATER, SAN FRANCISCO
VOLCANIC FIELD, ARIZONA
SCHRECK, Beth A., Geology Department, Northern Arizona University, Flagstaff, AZ 86011,
[email protected] and RIGGS, Nancy R., Geology Department, Northern Arizona University,
Flagstaff, AZ 86011-4099
The San Francisco Volcanic Field (SFVF) in northern Arizona covers the 4,700 km2, and has
been active for six million years. In that time over 600 volcanoes have formed, dominantly as
basaltic cinder cones; volcanism has moved from west to east. Ongoing field work indicates that
few of these cones erupted in cone-to-flow progression of a classic cinder cone model, and that
cone breaching may be a common characteristic of SFVF eruptions. In many cases the cone
was rebuilt after breaching, but at O’Neill and other craters, rebuilding did not occur. These cones
provide insight into complex processes that occur at cinder cones.
Previous studies of O’Neill Crater indicate that three magma compositions make up the cinder
cone, plug, and lava extrusions. These include a dacitic dome, basaltic-andesite, and a more
mafic clinopyroxene-rich basalt. Further, it has been suggested that a cone-building eruptive
phase was followed by a basaltic-andesite lava flow that breached the cone, with dacitic dome
extrusion being the last stage of eruption to occur and without cone rebuilding around the dacite
dome. However, evidence for further eruptive events has been found as spatter and cinder welded
to dacitic dome fragments suggesting that a change in conduit regime prevented re-growth of
the cone.
Basaltic-andesite inclusions are found within the dacite suggesting intermingling of the dacite
and basaltic-andesite magmas within the conduit. Welded basaltic-andesite cinder and spatter
is found on the interior slope of part of the crater. In addition, basaltic-andesite cinder welded to
fragments of dacite has been found locally along the top suggesting that pulsating lava eruption
occurred after the extrusion of the dome.
We propose that at O’Neill crater, the more viscous dacite trapped within the conduit erupted
with more fluidal basaltic-andesite that did not have sufficient time for degassing to occur and
allow a further cone-building eruptive stage. Instead, insufficiently degassed lava erupted as a
more homogenous-phase flow in which magma coupled with gas erupted in a low fountain and
deposited only locally within the breached crater. In addition, an inadequate volume of magma in
this final eruptive stage prevented the re-growth of the crater.
BTH 18
Smith, A.L.
[173136]
COMPARISON OF THE 1902 ERUPTION TO THE OTHER HISTORIC ERUPTIONS OF
SOUFRIERE, ST. VINCENT, LESSER ANTILLES
SMITH, A.L.1, MATTIOLI, Glen S.2, STORNI, Natasha1, FRYXELL, J.E.1, SALAZAR,
Joseph S.3, HULETT, Ashley3, and VELASQUEZ, Christina4, (1) Geological Sciences,
California State Univ, San Bernardino, CA 92407, [email protected], (2) Department of
Geosciences, University of Arkansas, Fayetteville, AR 72701, (3) Geology, California State
University, San Bernardino, 5500 University Pkwy, San Bernardino, CA 92407, (4) Geological
Sciences, California State University, San Bernardino, 5500 University Parkway,
San Bernardino, CA 92407
Soufriere volcano on St. Vincent, Lesser Antilles erupted in 1718, 1812, 1902, 1971, and 1979.
The most famous of these began on May 6, 1902 with a series of phreatic explosions, entered
into its climactic phase on May 7, and continued with sporadic explosions until April 1903.
Stratigraphic studies on the west coast indicate that the initial deposit, which rests directly on the
pre-1902 paleosol, are roof tiles, these are overlain by a series of surge deposits, often rich in
accretionary lapilli that pass upwards into a succession of scoria and ash flow and surge deposits.
At the base of the flow-surge sequence is a layer rich in carbonized and non-carbonized wood.
This flow-surge sequence is itself overlain by numerous thin ash and lapilli fall beds. Both fall and
flow deposits are composed of juvenile clasts, lithic fragments, crystals and accretionary lapilli.
Although the presence of accretionary lapilli indicates a significant hydrologic component throughout the eruption, the variations in their amounts between different beds suggests that the watermagma interaction fluctuated significantly during the eruption. The pre-1902 eruptions were both
explosive, with that of 1812 producing a new crater. In contrast, the 1971 eruption was entirely
non-explosive resulting in the extrusion of a dome into the summit crater lake. The final historic
eruption in 1979, began with an explosive phase that destroyed the 1971 dome, and terminated
with the extrusion of a new dome. Clasts lithologically similar to the 1971 dome in both the pre1902 and 1902 deposits lends support to the idea of the extrusion of domes into the crater lake
prior to these eruptions. The deposits from the pre-1902, 1971 and 1979 eruptions as well as
the initial deposits from the 1902 eruption all show a similar restricted range in major and trace
element composition, in contrast the later 1902 deposits are considerably more basic. This difference suggests that the pre-1902, 1971 and 1979 eruptions only tapped magma that was present
in the upper levels of the magma chamber, some of this magma may have also seeped out as
the domes noted above. In contrast the larger compositional range in the 1902 deposits suggest
either the eruption tapped deeper levels of the magma chamber as it progressed or the eruption
involved the influx of new basic magma into the chamber.
49-3
BTH 19
Vitale, Michelle
[173219]
TEXTURAL AND MINERALOGICAL OBSERVATIONS OF QUENCHED BASALTIC INCLUSIONS
IN LOW-SILICA ANDESITE FROM THE 2006 ERUPTION OF AUGUSTINE VOLCANO, ALASKA
VITALE, Michelle and BROWNE, Brandon L., Department of Geological Sciences,
[email protected]
Quenched basaltic inclusions account for approximately 1 volume % of material emplaced during
the 2006 eruption of Augustine Volcano (Alaska), which corroborates several proposed models
from previous geological and geophysical studies calling for intrusion of a basaltic magma into
the subvolcanic reservoir followed by limited mixing between basalt and resident andesite magma
prior to, and possibly during, the 4-month-long eruption. Inclusions are observed exclusively in
SESSION NO. 49
variably dense blocks of the low-silica andesite (‘LSA’ from Larsen et al., In Press) lithology. In
outcrop, inclusions are dark black in color and characterized by vesicular interiors (approximately
20 volume % vesicles), quenched and cuspate margins and porphyritic texture. Inclusion mineralogy is dominated by 1-4mm-diameter plagioclase crystals and acicular hornblende, with lesser
clinopyroxene and magnetite, ilmenite, orthopyroxene, olivine and apatite. Plagioclase crystal
textures are characterized as either: (1) larger crystals (>0.25 mm diameter) with oscillatory
zoned interiors surrounded by a dusty sieved layer that is finally enclosed by clear and euhedral
overgrowths at the crystal rims; (2) smaller plagioclase (<0.1 mm diameter) crystals that either
display acicular or anhedral forms; and (3) larger crystals (0.20 mm diameter) with coarselysieved interiors characterized by 0.01 to 0.02 mm diameter melt inclusions and/or similarly sized
inclusions of clinopyroxene, orthopyroxene or hornblende. Future work aims to investigate major
and trace element compositions of common mineral phases from basaltic inclusions in order to
better understand the petrogenesis of basalt in the subvolcanic magma plumbing system and its
role in the generation of lava lithologies at Augustine Volcano.
49-4
BTH 20
Beach, Megan
[173644]
PHYSICAL VOLCANOLOGY OF THE MULE CREEK RHYOLITE, ARIZONA AND NEW MEXICO
BEACH, Megan, Geology Program, School of Earth Sciences and Environmental
Sustainability, Northern Arizona University, Flagstaff, AZ 86001, [email protected] and
RIGGS, Nancy R., Geology Program, School of Earth Sciences and Environmental
Sustainability, Northern Arizona University, Flagstaff, AZ 86011-4099
Tertiary delamination of the subducted Farallon plate led to asthenospheric upwelling and largescale rhyolitic volcanism in Arizona and New Mexico. Most of this volcanism occurred as highly
explosive, caldera-forming eruptions. However, several rhyolitic eruptions occurred on a smaller
scale and involved effusive, dome-forming lava. One such event was the formation of the Mule
Creek Rhyolite, exposed just west of the town of Mule Creek, New Mexico.
In this study, pyroclastic and lava facies were mapped and a model was developed to explain
the eruption of the Mule Creek Rhyolite, including the number of vents, the types of eruptions,
and the style of dome growth. Trace elements of different lavas were compared using inductivelycoupled plasma mass spectrometry. These analyses were used in addition to field relations to
determine the number of vents. Pyroclast morphologies were described using scanning electron microscopy to determine the extent of phreatic involvement in the explosive phases. The
developed model was compared to existing models of rhyolite domes and dome fields, including
those of Glass Mountain, Obsidian Dome, and the nearby Taylor Creek Rhyolite and Enebro
Mountain Rhyolite.
The model for the Mule Creek Rhyolite includes an initial explosive phase of pyroclastic flow,
fallout and minor surge. Phreatic contribution to the explosive eruption was minimal. A second phase consisted of effusion of lava, which formed an autobrecciated carapace, a layer of
quenched vitrophyre, and a massive or flow-foliated core that devitrified. Much of the vitrophyre
was later hydrated and perlitized. The high aspect ratio of the domes suggests exogenous growth,
and although multiple flow lobes are associated with a single dome, each vent was the source of
a single edifice. This model differs from others in that there is no evidence of major vesiculation of
lava and there was no sharing of vents between domes.
T10. Theory and Practice: Engineering Geology in the
Cordillera (Posters) (Cordilleran Section GSA)
50-1
50-3
49-5
BTH 21
Vazquez, J.A.
[173688]
TIMING OF LATE PLEISTOCENE VOLCANISM AT BIG PINE VOLCANIC FIELD: INSIGHTS
FROM VOLCANIC STRATIGRAPHY, COSMOGENIC 36CL DATING, AND PALEOMAGNETISM
VAZQUEZ, J.A.1, WOOLFORD, J.M.2, ZOHAR, A.2, NAGY-SHADMAN, E.A.3, and
CHAMPION, D.E.1, (1) U.S. Geological Survey, 345 Middlefield Road MS 910, Menlo Park,
CA 94025, [email protected], (2) Geological Sciences, CSU-Northridge, 18111 Nordhoff
St, Los Angeles, CA 91330, (3) Natural Sciences Division - Geology, Pasadena City College,
1570 E. Colorado Blvd, Pasadena, CA 91106-2003
The Big Pine volcanic field (BPVF) is one of several Quaternary volcanic fields located along the
tectonically active Owens Valley of eastern California. Previous geochronology establishes an
~1.3 Ma history of volcanism, but the ages and distribution of volcanic products associated with
the youngest eruptions are poorly resolved. To delimit the timing and products of the youngest
volcanism at BPVF, we combine field mapping, cosmogenic 36Cl dating, and paleomagnetism of
lavas and pyroclastic deposits in the area surrounding the town of Aberdeen where basaltic lavas
with well-preserved flow structures and morphology are concentrated. Mapping and petrography
reveal that ~ fifteen vents and six principal flow fields occur in the Aberdeen area. Discrete basalt
units are distinguishable using phenocryst-xenolith composition and mode, and overlapping flow
margins establish the relative ages of most of the flows. For 36Cl dating, samples were taken from
pahoehoe flow surfaces, near-vent tumuli, and the tops of meter-scale accretionary lava balls.
Using the scaling model of Desilets and Zreda (2003) and assuming erosion rates of <3 mm/ka,
36
Cl ages for lava flows from the top, middle, and bottom of the volcanic stratigraphy are ca. 15 ka,
25 ka, and 40 ka, suggesting multiple episodes of late Pleistocene volcanism. These ages agree
with cosmogenic 3He and 40Ar/39Ar ages from previous studies, and are relatively insensitive to
choice of scaling model or erosion rate. Samples from the three stratigraphically youngest flows,
which cover much of the area south of Taboose Creek and north of Division Creek, yield 36Cl ages
of ca. 15 ka. This youngest episode of volcanism erupted olivine to plagioclase-pyroxene phyric
basalt from at least four vents along the Sierran front and separated by up to 5 km. Paleomagnetic
directions for the lavas are consistent with the distinct episodes of volcanism implied by the 36Cl
ages. The youngest lavas yield nearly indistinguishable paleomagnetic directions, suggesting that
the youngest episode may have erupted compositionally diverse basalt over decadal to centurial
timescales. The young 36Cl ages and high concentration of vents relative to other areas of BPVF
indicate that late Pleistocene volcanism has migrated to the west-central portion of the volcanic field.
102 2010 GSA Abstracts with Programs BTH 22
Vincett, James D.
[173263]
NEW EVIDENCE FOR THE TUNGSTEN HILLS, NEAR BISHOP, CA, AS A LANDSLIDE
DEPOSIT
VINCETT, James D., Department of Geological Sciences, California State University,
Los Angeles, Los Angeles, CA 90032, [email protected]
Several years ago it was proposed that the Tungsten Hills, near Bishop, CA, is a possible landslide
deposit. The principal evidence proposed is primarily geomorphic: the hummocky, hackled, and
jointed surface of the Tungsten Hills quartz monzonite contrasts sharply with the surface texture
of the surrounding bedrock. Mapping of plutonic rocks by Bateman (1965, 1992) suggests a
source area in the Sierra Nevada either to the west or to the south. However, new structural and
stratigraphic evidence from Miocene basalt flows in and south of the Tungsten Hills provides new
evidence for the landslide hypothesis and the location of the source area. The Tungsten Hills are
24 square km in extent and composed primarily of Triassic quartz monzonite; they have hummocky
and hackly appearance, with the quartz monzonite heavily cross-jointed. In the northwestern
portion of the Tungsten Hills are three basalt flows of Miocene age, all within 1.5 km of each
other, each from 200 to 500 square meters in extent, and 1600 to 1800 m in elevation. Phillips
et al. (in press) determined an age of 11.7 Ma for these three flows, and that these three basalt
flows are the same age as a large flat-lying basalt sheet located on the northern edge of Coyote
warp 10.6 km to the south and 2700 m in elevation. Contrasting structural deformation within and
between the three basalt flows in the Tungsten Hills, combined with a stratigraphic comparison
between these flows and the large basalt sheet on the Coyote warp, is believed to be evidence
consistent with the landslide hypothesis. The Tungsten Hills basalt deposits consists of flows,
tephra, and lahars. Deformation of the basalt deposits includes faulting and tilting. Because of the
deformation, sharp structural discordance exists between outcrops separated by as little as a few
meters. At one outcrop, steeply dipping basalt deposits are truncated by a nearly horizontal fault
that separates the basalt from the underlying granitic rocks. The strong structural deformation of
the Tungsten Hills basalt contrasts with that of the non-deformed basalt of the same age on Coyote
warp. A simple explanation for the deformation contrast between the two areas is that the Tungsten
Hills are a landslide deposit and the basaltic deformation is a result of the landsliding process.
BTH 24
Bell, Angie
[173180]
APPLICATION OF A DEBRIS FLOW POTENTIAL MODEL ON THE 2008 PANTHER FIRE ON
THE KLAMATH NATIONAL FOREST, NORTHERN CALIFORNIA
BELL, Angie1, DE LA FUENTE, Juan A.1, and BELL, Chad B.2, (1) Klamath National Forest,
USDA, 1312 Fairlane Road, Yreka, CA 96097, [email protected], (2) Klamath Basin Wildlife
Refuge, US Fish and Wildlife Service, 4009 Hill Road, Tulelake, CA 96134
Debris flows are a destructive force in the steep landscape of the Klamath Mountains in Northern
California. Wildfires exacerbate the debris flow potential and volume by altering the characteristics of the hillslopes. These wildfire related debris flows can damage downstream facilities and
block major roadways. The US Forest Service responds to fire events by deploying a Burned
Area Emergency Response (BAER) Team to rapidly assess the threats to life and property. The
assessment often includes an evaluation of debris flow potential and recommends mitigations.
The mitigation measures for debris flows can be costly and it is imperative to have a tool to allow
for the immediate prioritization of debris flow mitigation in burned areas. An existing post-fire
debris flow model, calibrated for the Intermountain West, was applied to the 2008 Panther Fire on
the Klamath National Forest in to evaluate its utility for BAER assessments in Northern California.
The model predicts the probability of a debris flow event based on parameters easily obtained in
existing spatial data. These include fire severity, slope, rainfall intensity, and soil characteristics.
Two small debris flows were documented in the fire area due to a storm event in May 2009. The
outcome of the model was compared to the field data collected to determine its applicability to
fires on the Klamath National Forest. The debris flows occurred in the drainage basins with the
highest debris flow probability indicating that, at the very least, the model could be used to relatively prioritize BAER restoration activities in the fire perimeter.
50-4
BTH 25
Shaller, Philip J.
[173248]
THE JANUARY 10, 2005 LA CONCHITA LANDSLIDE
SHALLER, Philip J.1, SHRESTHA, Parmeshwar L.1, DOROUDIAN, Macan1, HAMILTON,
Douglas L.1, and SYKORA, David W.2, (1) Exponent, Inc, 320 Goddard, Suite 200, Irvine, CA
92618, [email protected], (2) Exponent, Inc, 9 Strathmore Road, Natick, MA 01760
This presentation reports the findings of a geologic/geomorphologic investigation and a FLO-2D
modeling analysis of the January 10, 2005 La Conchita landslide. The 2005 La Conchita landslide occurred about 130 km northwest of Los Angeles, California, following two weeks of heavy
rainfall. The landslide mobilized over 30,000 m3 of wet debris, forming two distinct lobes. The
main lobe, comprising 90% of the deposit, moved into place as a large-scale debris flow. This
lobe entered a residential community at the foot of the slope, killing 10 persons and damaging
or destroying 36 residences. The source area exhibited numerous unfavorable geologic characteristics. Movement was triggered by the addition of water from several sources. The main lobe
eroded and entrained over 4,000 m3 of material along its path. Video and eyewitness accounts
indicate it was moving at around 6 to 10 m/s in the mid slope area, dropping to 5 m/s or less in
the community. The main lobe exhibits textures characteristic of debris flows elsewhere, including raised lateral levees and a surface pattern of ridges and troughs. The minor lobe, comprising
about 10% of the total landslide volume, instead exhibits a hummocky, irregular surface texture.
Runout of the landslide was modeled using FLO-2D, a commercial software package used to
model the movement of water or sediment-water slurries over a fixed substrate. The model space
for the analysis consisted of 25,614 square grid cells, each measuring 1.52 m on a side, and
was developed using digitized pre- and post-event topographic maps. Model inputs included an
inflow hydrograph, sediment concentration, saturated density, yield strength, dynamic viscosity and Manning’s bottom roughness. A series of simulations were performed to evaluate travel
path variations for three differing wall and slope configurations present in the area between 1995
and 2005. Sensitivity analyses were performed for each of the simulations by varying the yield
strength, dynamic viscosity and debris volume. The FLO-2D program was very successful in
SESSION NO. 50
predicting the runout of the main lobe of the debris flow. The spatial distribution of the minor lobe,
however, generally differed from that predicted by the analysis due to travel through heavy brush,
the deposition of the debris in pulses, and other complicating factors.
50-5
BTH 26
Behl, Richard J.
[173628]
GEOMORPHIC EXPRESSION OF A MIOCENE DIKE COMPLEX, SAN JOAQUIN HILLS,
CALIFORNIA, USA
BEHL, Richard J.1, TA, Linda1, WILLIAMS, Dana2, WERNER, Alison3, BERNARDINO,
Melissa1, PETERSON, Randall4, MCCORMICK, Chelsea5, and NAGY, Brian6, (1) Geological
Sciences, California State University Long Beach, 1250 Bellflower Blvd, Department of
Geological Sciences; PH1-104, Long Beach, CA 90840, [email protected], (2) Earth Sciences,
California State University, Dominguez Hills, 1000 E. Victoria Street, Carson, CA 90747,
(3) Long Beach City College, 1305 East Pacific Coast Highway, Long Beach, CA 90806,
(4) Woodrow Wilson High School, 4400 East 10th Street, Long Beach, CA 90804, (5) Avalon
School, P.O. Box 557, Avalon, CA 90704, (6) Geography, California State University Long
Beach, 1250 Bellflower Blvd, Department of Geological Sciences; PH1-104, Long Beach,
CA 90840
Miocene transtension during development of the North American-Pacific plate boundary in southern California coincided with extensive magmatism and emplacement of a 15-16 Ma basaltic to
andesitic dike and sill complex in the San Joaquin Hills, Orange County. Intrusions cut through
and altered a thick Mesozoic to Cenozoic marine and nonmarine siliciclastic sedimentary succession. Hydrothermally altered sandstone within 20 meters of the contact is cemented with secondary microcrystalline quartz and illite, and locally with calcite. Cementation plus removal of iron
oxides from redbeds rendered the altered sandstones more resistant to erosion than the highly
weathered dikes or unaltered sedimentary strata.
These Miocene dikes exert a profound influence on modern topography due to differential susceptibilities of the dikes and altered wall rock to chemical and physical weathering. At vegetated
inland sites, where chemical weathering is important, plagioclase feldspar in dolerite intrusions
alter to smectitic clays, and the dikes weather to recessive, brush-covered soils on valleys and
slopes. In contrast, altered and hardened sedimentary wall rocks stand up in resistant relief. Many
of the wall rocks form the high ridges of the uplifted and dissected San Joaquin Hills and control
the geometry of drainages by forming resistant ledges that set local base level and by offsetting
stream drainages. Differential erosion of the soft weathered mafic dikes and hard, resistant wall
rocks produced a sharp contrast that formed most of the steepest slopes in the study area.
Coastal exposures of andesitic dikes, where physical weathering dominates, display a contrary
behavior. Igneous dikes are more resistant to wave erosion and form prominent headlands jutting out into the ocean, whereas sedimentary wall rocks are eroded back to form flanking cliffs or
sand-covered beaches.
50-6
BTH 27
Johnson, Philip L.
[173636]
THE HIDDEN COMPLEXITY OF A DEEP-SEATED LANDSLIDE COMPLEX IN RICHMOND,
CALIFORNIA
JOHNSON, Philip L., Cotton, Shires & Associates, Inc, 330 Village Lane, Los Gatos, CA
Detailed subsurface investigation of landslides often reveals complexity that is not apparent at
the surface. A case in point comes from the proposed Castro Ranch development, located in the
eastern San Francisco Bay Area. Our photogeologic mapping led to recognition of a landslide
complex consisting of several large, deep-seated landslides that failed away from a linear strike
ridge and into an incised drainage. Based upon geomorphology, we initially interpreted these
features as deep-seated, translational landslides consisting entirely of displaced blocks of Tertiary
sedimentary rock. Based upon that interpretation, we compiled a preliminary cross section that
showed a shallowly dipping basal rupture surface that projected to the present elevation of the
incised stream. During subsurface investigation (downhole logging of large-diameter borings), we
found that the depth of the basal rupture surface was much greater than predicted by the preliminary cross section. Thus, the preliminary landslide model did not fit the subsurface data. The
borings within the downslope half of the landslide complex encountered displaced sedimentary
rock over a planar rupture surface, but within the upslope half, the borings encountered a thick
succession of unconsolidated colluvium, consisting of multiple stacked deposits of sandy silt
with angular siltstone fragments separated by buried soil horizons. These deposits appear to fill
a deep graben that is not expressed at the surface. After completion of the subsurface investigation, it became apparent that the landslides failed into the incised stream channel and displaced
the channel laterally, raising the channel elevation. The present channel elevation led to the initial
misinterpretation of the landslide rupture surface elevation on the preliminary cross section.
Multiple debris or earth flows generated on steep slopes above the landslide complex filled the
graben with unconsolidated deposits. These details were revealed only through careful subsurface
investigation using downhole logging methods.
50-7
BTH 28
Fife, Donald L.
[173665]
PERALTA HILLS FAULT A PREVIOUSLY UNRECOGNIZED ACTIVE TRANSVERSE RANGE
“BLIND THRUST” ORANGE COUNTY, CA
FIFE, Donald L., Donald L. Fife & Associates, Box 1054, Tustin, CA 92781-1054,
[email protected] and SHLEMON, Roy, Geology, UC Davis, One Shields Ave,
Davis, CA 95616
The Peralta Hills fault is an east-west a “blind thrust” except where it surfaces as a low angle
thrust in Anaheim Hills. Two tree stumps radiocarbon dated at 3,500 years BP (Fife and Bryant,
1983), have been displaced 15 m. in the lower plate of the fault.
Many structures have been constructed on or near the trace or multiple traces of this active
fault as a result of the failure to place the Peralta Hills fault in an Earthquake Hazard Studies
Zone.
When the California Geological Survey contracted with the U.S. Geological Survey to digitize
their Geological/Landslide Hazard Map of the Orange Quad (Tan, 1995) the Survey “moved” the
Peralta Hills fault trace “around” Reservoir 1-A, a 5 million gallon semi-buried hillside steel tank
and apparently through or adjacent to a second buried hillside 3.500 gallon steel tank.
The Orange City Department of Public Works continues to fill the 5 million gallon tank, possibly
jeopardizing down slope structures should the fault rupture. The fault trace forms a perfect diameter through the middle of the 200-foot diameter tank with differential settlement along the contact
with Holocene gravels and Miocene siliceous shale.
The fault passes through portions of the Edison Serrano Substation and a key transmission
tower atop the upper plate and will likely sustain damage during a major earthquake. The fault
passes through a gas station and Eisenhower Lake above commercial and residential structures.
Many homes in Anaheim Hills are set back from the fault trace to avoid fault rupture, while other
homes are built on areas where multiple thrust fault traces and thrust fault-rooted landslides have
been buried. The 15 m set-back from the fault trace that is commonly required for structures may
not be sufficient when a low angle thrust passes less than 15 m. beneath the structure.
The Peralta Hills fault has a known sinuous trace of about 10 km. The fault consists, in some
locations; of multiple imbricate thrusts. Based on fault length it is estimated that the Peralta Hills
fault is capable of a 6 to 7 magnitude earthquake and several meters of left oblique surface rupture.
50-8
BTH 29
Colburn, Ivan P.
[174104]
GRAIN SIZE ANALYSIS AND MECHANICS OF THE 2008 MOUNT WHITNEY FISH HATCHERY
MUDFLOW ON THE EASTERN SLOPE OF THE SIERRA NEVADA, INDEPENDENCE,
CALIFORNIA
COLBURN, Ivan P., Department of Geological Sciences, California State University,
Los Angeles, CA 90032, [email protected]
On July 5th 2007 a wild fire flared in the hills west of the Mt. Whitney Fish Hatchery grounds
located on the eastern slope of the Sierra Nevada Mountains in Independence, California. In the
summer of 2008 intense rainfall subsequently mobilized the regolith on those hills into mudflows
that raced down Oak Creek. The north fork mudflow coursed down to California Highway 395
leaving an unbroken layer of mud four miles long with a drop in elevation of more than 2,000 feet.
On site written and photographic records were made of the flow and six representative samples
spaced along the length of the mudflow were taken. Samples were collected for sediment lab
grain size analysis at CSULA.
Results of the sample size analyses follow: mud (clay and silt size) ranged from 5-22% with
an avg. of 15%; sand size ranged from 53-74 % with an avg. of 64.2%; gravel size ranged from
8-35% with an avg. 20.7%.
Each sample studied exhibited clear grain size grading from gravel to mud size. Small air pockets measuring 1-2 mm in diameter were noted to make up 10 % of the flow by volume.
A thin film (1-2mm thick) of clay formed as a top layer giving the flow a lustrous sheen.
Prominent shrinkage cracks developed all over the surface of the mudflow as it hardened further
indicating a high clay content. On top of the flow various human and animal foot prints have been
preserved illustrating that the flow hardened over time.
Laboratory density measurements were made on the mudflow samples and compared to the
density of a representative set of various rocks. The mudflow specimens were significantly less
dense.
50-9
BTH 30
Wagner, David L.
[172797]
THE OAK CREEK MUDFLOWS AND DEBRIS FLOWS OF JULY 12, 2008, OWENS VALLEY,
INYO COUNTY CALIFONRIA
WAGNER, David L., California Geological Survey, 801 K Street, Sacramento, CA 95814,
[email protected] and DEROSE, Margie, US Forest Service, 351 Pacu Lane,
Bishop, CA 93514
On July 12, 2008 the remains of hurricane Bertha moved from the Gulf of Mexico across the
southwestern United States bringing tropical moisture to the eastern Sierra Nevada. Over 32
mm/hr (1.25 in/hr) of precipitation fell on the Oak Creek drainage north of Independence, in Inyo
County, California, which had been burned during the Inyo Complex fire of July 6, 2007, generating debris and mudflows that ran out 6 to 7 km from the mountain front, destroying 25 homes,
damaging another 25, severely damaging the historic Mt. Whitney Fish Hatchery, and disrupting
traffic on State Highway 395 for nearly a week. Although slopes were extensively rilled, most of
the estimated 1.53 million cubic meters of sediment was scoured from channels and deposited
over an area of more than 3 km2, mostly on younger alluvial fans. Mudflow surges moved down
the north fork of Oak Creek at estimated speeds of 2 m/sec (~6 m/hr) to 5.4 m/sec (~16 m/hr) and
were one to three meters high. Sand-rich, hyperconcentrated mudflows followed the active channel of the north fork of Oak Creek and abandoned channels on the fan filling them, and spread
laterally across the interfluves. On the south fork of Oak Creek, boulder-rich debris flows clogged
the active channel, leaving a boulder field of at least 1500 m long and 75 m wide, blocking the
channel and forcing the south fork to a new course to the west. The largest boulders moved during the storm ranged from 3300 kg (~1300 lbs) to 17,000 kg (11,800 lbs). Nearly all the damage
to private property and infrastructure was long the active stream channels where the hazard is
the highest. Older uplifted alluvial fans were unaffected and are the least hazardous areas, while
younger fans were greatly affected and should be considered, for the most part, highly hazardous.
Mitigation strategy should emphasize avoidance and education to promote public awareness.
50-10
BTH 31
Bishop, Kim M.
[173200]
EVIDENCE FOR A 45 km2 SIERRA NEVADA LANDSLIDE, NORTHERN OWENS VALLEY,
CALIFORNIA
BISHOP, Kim M., Geological Sciences, California State University, Los Angeles,
5151 State University Dr, Los Angeles, CA 90032, [email protected]
Based on anomalous geomorphology including hummocky topography, hackly surface texture,
and overall low slope gradient, the existence of a 45 km2 landslide on the Sierran escarpment
south of Bishop, California was proposed several years ago. Other than geomorphic expression,
however, evidence for the landslide was sparse. Recently acquired structural data from Neogene
basalt flows on and off the landslide mass provides new evidence supporting the landslide
hypothesis.
Structurally, the slope area containing the landslide is a relay ramp between two large normal
faults and is commonly referred to as the Coyote warp. Slope relief is 1500 m. Important basalt
outcrops occur at five locations on the warp. The eastern three of these outcrops occur within
2 km of one another and are on the proposed landslide, whereas the western two outcrops occur
just off the proposed landslide.
Basalt deposits at the three outcrops on the proposed landslide are faulted and moderately to
steeply tilted down to the north, whereas the two outcrops west of the landslide are eroded but
not deformed. Phillips et al. (in press) determined an Ar-Ar age of 3.4 Ma for the basalt of the
three outcrops on the landslide and 11.7 Ma for the two basalt outcrops west of it. The contrast in
deformation of the basalts on and off the proposed landslide supports the landslide interpretation.
In principal, the deformation of the three eastern basalt outcrops could be from either tectonic
activity or landsliding. However, given the degree of deformation of the 3.4 Ma outcrops, it seems
unlikely that such strong tectonic deformation could have affected the area of these basalts without also affecting the area of the 11.7 Ma basalts. The more reasonable explanation for the localized deformation is that the younger basalt flows were deformed by landsliding.
Recognition that the landslide interpretation is correct lends support that other landslides previously proposed for the Sierran escarpment bordering Owens Valley are real. For example, the
Sierran slope above the town of Big Pine, previously proposed to be the Big Pine landslide, has
geomorphic characteristics quite similar to the Bishop landslide. Two other similar features are the
Independence landslide west of the town of Independence and the Olancha landslide southwest
of the town of Olancha.
SESSION NO. 51
T11. New Insights into the Petrology of Mesozoic
Cordilleran Batholiths (Posters)
51-1
BTH 32
Clausen, Benjamin L.
[173063]
MAFIC-FELSIC MAGMA MIXING IN CONTINENTAL CRUST FORMATION: AN EXAMPLE
FROM LOW-INITIAL SR GRANITOIDS OF THE NORTHWESTERN PENINSULAR RANGES
BATHOLITH, SOUTHERN CALIFORNIA
CLAUSEN, Benjamin L., Geoscience Res Inst &, Dept Earth and Biological Sciences,
Loma Linda Univ, Loma Linda, CA 92350, [email protected], MORTON, Douglas M.,
U.S. Geol Surv &, Dept Earth Sciences, Univ of California, Riverside, CA 92521, KISTLER,
Ronald W., U.S. Geol Surv, 345 Middlefield Rd, Menlo Park, CA 94025, and LEE, Cin-Ty A.,
Dept Earth Science, Rice Univ, MS 126, 6100 Main St, Houston, TX 77005
A 1000 km2 area within the western Peninsular Ranges Batholith (PRB) near Escondido,
California is made up of granitoids having a uniformly low initial 87Sr/86Sr isotope ratio of Sri<0.704,
but a wide range of SiO2 compositions ranging from 46 to 78 wt.%. The systematically sampled
Escondido plutons are made up of three distinct groups consisting of 20% gabbros, 35% tonalites,
and 45% granodiorites. The linear data pattern on Harker diagrams is interpreted as resulting from
the mixing of mafic magma from partial melting of the mantle and felsic magma from partial melting of the lower crust to produce magma of intermediate SiO2 composition. These three magma
types subsequently fractionated and were emplaced at shallow levels. The early Cretaceous
western PRB granitoids formed in association with island arc basalts accreted to the North
American craton, and this especially low Sri portion displays negligible contamination from old
continental crust. These Escondido granitoids are unique in having undergone a cycle of mantle
melting to give arc basalts, a cycle of arc basalt (or gabbroic underplate) melting to give a range
of SiO2 granitoids, but no third cycle of continental crust melting and assimilation to yield high Sri.
Therefore, these granitoids provide a simplified Phanerozoic example of the petrogenetic process
for forming continental crust. Simple partial melting, mixing, and fractional crystallization calculations were performed to quantitatively understand the relative importance of each process during
differentiation. Mass balance calculations indicate that the volume of ultramafic restite left after
differentiation of the lower crust is about twice the volume of the fractionated Escondido granitoids.
51-2
BTH 33
Todd, Victoria R.
[172879]
A RECONNAISSANCE STUDY OF GRANITE SUITES ACROSS SAN DIEGO COUNTY USING
176
Hf/177Hf FROM SINGLE ZIRCON GRAINS: EVIDENCE OF MAGMA MIXING BETWEEN
MANTLE-DERIVED AND CRUSTAL-DERIVED MELTS
SHAW, Stirling E., GEMOC National Key Centre, Department of Earth and Planetary
Sciences, Macquarie University, New South Wales, 2109, Australia, sshaw@
laurel.ocs.mq.edu.au and TODD, Victoria R., 1740 Clarion Drive, Williamsport, PA
Magma mixing was important in the genesis of granites from the Peninsular Ranges batholith,
San Diego County. Depleted mantle ages (Hf TDM) calculated from zircon 176Hf/177Hf ratios for 16
plutons indicate a significant crustal component in granites from both western and eastern zones.
Fundamental differences in crustal structure are indicated –a Neoproterozoic crustal component
in western-zone granites and a more complex, possibly layered crust of Neoproterozoic and older
aged components to the east.
Zircon U-Pb age determinations for four western-zone I-type granite suites and one gabbro
suite yield Early Cretaceous emplacement ages between ~114 Ma and 101 Ma. Combined zircon
εHf values for these five suites vary between +2.5 and +11.2 representing depleted mantle model
ages between ~650 Ma and ~300 Ma. As the older model-aged zircons may have crystallized
from hybrid magma rather than from a crustal-derived melt, the calculated age for the crustal
end-member is considered a minimum. Given that the samples have low initial 87Sr/86Sr and
low to moderate δ18O, the range of TDM ages for five I-type western suites suggests a dominant
Neoproterozoic, low LILE partial melt of mafic crustal material mixed with a Cretaceous mantlederived fractionated melt component.
Zircon U-Pb data from the eastern zone verify the presence of Jurassic I- and S-type plutons
(~160 Ma) and Early to Late Cretaceous I-type plutons (~109 to 94 Ma). For a Jurassic I-S-type
granite, zircon εHf values vary between -2.5 and +3.4 representing TDM model ages between ~900
Ma and ~650 Ma. For three Cretaceous suites of the eastern zone, zircon εHf values vary between
-21.2 and +12.2 representing depleted mantle model ages between ~1,550 Ma and ~280 Ma.
The range of zircon TDM ages indicates several crustal source components: 1) a lower crustal
Mesoproterozoic component, in part eclogitic, for the Late Cretaceous high Sr/Y La Posta granite;
2) a Neoproterozoic crustal component for Jurassic I-S-type plutons; and 3) a Mesozoic metasedimentary component derived from reworked Proterozoic

Table of Contents - Geological Society of America

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