Eleuthera Field Seminar, Sept 2015

Post Meeting Field Trip: Eleuthera Island, Bahamas
September 15/16–19, 2015
Leaders
Gregor P. Eberli, Peter K. Swart, Sevag Mehterian, Paul M. (Mitch) Harris
Rationale and Overview
The lateral and vertical heterogeneity in platform margin grainstone complexes is
the result of a repeated interplay between physical, chemical and stratigraphic
processes. All of these processes can be examined in close proximity in the
Schooners Cays-Eleuthera area.
The modern ooid shoals of the Schooners Cays sand body occur as a very large
tidal bar belt whose size and heterogeneity is largely driven by currents and their
interaction with platform margin morphology, antecedent and newly created
topography. Early meteoric cementation on Holocene islands and marine
cements in the shallow subsurface are the first chemical overprint on these
shoals.
Sea-level fluctuations produce stacks of grainstone complexes along the platform
margin. In Eleuthera, two vertically stacked shallowing-upward sequences of
oolitic coastal deposits are exposed in spectacular exposures at the windward
margin. These two successions of beach facies and eolian deposits were
deposited during the last interglacial (MIS 5e) and document the higher sea level
compared to today and give further evidence of a sea-level oscillation within MIS
5e.
The large amplitude of the Pleistocene sea-level fluctuations repeatedly exposed
the platform top. Thus, karst features and meteoric diagenesis are ubiquitous in
the Pleistocene strata. The size and dimensions of sinkholes and their
connectivity to horizontal caves are illustrated by visiting two sinkholes. Flank
margin caves are common in carbonate eolian grainstones. The Hatchet Bay
Cave in Eleuthera is the study site for geochemical experiments by the CSL,
where speleothems are analyzed with clumped isotopes and fluid inclusions.
Logistics
The CSL field trip officially starts and stops in Nassau.
Travel:
Participants fly to Nassau, Bahamas, on Tuesday afternoon, September 15 and
stay overnight in Nassau.
Participants are responsible for booking their own roundtrip ticket from
Miami to Nassau. The following flights are possible but we recommend the
American flights:
September 15: Miami to Nassau:
American Airlines #4296,
Departs Miami 4:50 PM, in Nassau 5:49 PM
Or
Bahamas Air #228,
Departs Miami 4:40 PM, in Nassau 5:40 PM
September 19: Nassau to Miami:
American Airlines #4296
Departs Nassau 6:38 PM, in Miami 7:40 PM
Or
Bahamas Air #229
Departs Nassau 7:00 PM, in Miami 7:55 PM
For the segment from Nassau to Eleuthera you are already booked on:
September 16: Nassau to Eleuthera (Governors Harbor):
Pineapple Air #972
Departs Nassau at 11:45, in Eleuthera 12:10PM
September 19: Eleuthera (Governors Harbor) to Nassau
Pineapple Air #972
Departs Eleuthera at 12:15, in Nassau 01:00PM
There are limited flights to and from Eleuthera and thus our layover in Nassau on
September 19 is a bit long. If the flight is on time, we will visit downtown Nassau.
We will clear U.S. immigrations and customs in Nassau before departing for
Miami. This will shorten your connecting time in Miami, if you fly out that night.
Hotels:
Nassau 9/15: Sandyport Beaches Resort (http://www.sandyport.com)
Eleuthera 9/16 -9/19: Sky Beach Club (http://skybeachclub.com)
Itinerary and Field Trip Stops
TRAVEL SCHEDULE
We will travel from Miami to Nassau the afternoon of September 15, 2015. Please
book your flight in time. We will stay at the Sandyport Beaches Resort Hotel. The
morning of September 16th we will depart for Eleuthera.
Tuesday, September 15
PM
Flight to Nassau
Overnight: Sandyport Beaches Resort
Wednesday, September 16
The sedimentary record of the last interglacial MIS 5e at Clifton Pier
AM Clifton Pier: MIS 5e succession with subtidal facies and beach deposits.
Introduction to the theme of platform margin heterogeneity caused by sealevel oscillations within sea level highstands
11:45 Flight from Nassau to Governors Harbor in Eleuthera. Transfer from
airport to Hotel Sky Beach Club, Eleuthera
PM
Introduction to the field trip and safety briefing
Hatchet Bay Cave: Formation and distribution of sinkholes and flank
margin caves.
Rainbow Bay: Beach processes on the leeward side of the islands
Overnight: Sky Beach Club
Thursday, September 17
Schooners Cays: Facies and Geometries of the Tidal Bar Belt of the
Schooners Cays
AM
Drive to Cape Eleuthera Island School to get the boat for the day
Main focus: Formation, size and distribution of ooid tidal bars in relation to
platform morphology and tidal energy. Stops include:
• Holocene islands with beach rock, storm beach deposits, and
Goniolithon growth in shallow subtidal.
• Sand flat with hardgrounds and coral patches
• Tidal bar with ooid sand waves
• Subtidal channel
PM
Platform edge and drop off to deep water
Tunnel reef to explore spur and groove morphology on fore reef area
Overnight: Sky Beach Club
Friday, September 18
Stratigraphic complexity of platform margin grainstone bodies
Main focus: The stratigraphic architecture of marginal grainstone bodies,
and their potential to record oscillations of sea level within highstands. The
erosional processes of the beach-eolian system during transgressions is
examined in the Holocene succession and in the sedimentary record of
middle Pleistocene strata. Size and distribution of marginal grainstone
complex.
Stops include:
1) Two Pines Outcrop: Subaerial carbonate deposition, paloesols and
dissolution processes.
2) North Twin Coves Cliffs: Cemented Holocene eolian dune and modern
beach with beach rock.
3) Tombolo and Bluff Cay: MIS 5e sequence boundary, exposed reef with
exposure horizon and ravinement surface produced by the Holocene
transgression.
4) The Cliffs: Eolianites separated by reddish pedogenic horizons
deposited during multiple glacial / interglacial cycles with a ooid
grainstone shoal of MIS 5e age on the bank side.
5) Bight of Eleuthera: Cow and Bull boulders erosional remnants of
eolianites of a Pleistocene transgression.
6) Boiling Point: Examination of the beach/eolian successions deposited
during the MIS 9 or 11 and the interglacial of MIS 5e. The outcrop
summarizes the stratigraphy of the previous field stops and is ideal to
discuss the implication for vertical heterogeneity and fluid flow units.
7) Glass Window: Grainstone bodies separated by reddish pedogenic
horizons and the seaward erosion of the marginal cliffs.
Overnight: Sky Beach Club
Saturday, September 19
Karst features on the island
Main focus: The formation of large karst feature such as deep sinkholes
and flank margin caves.
Stops include:
1) Ocean Hole
12:15 Return to Nassau
Depending on time we will visit downtown Nassau
Clear immigration and customs in Nassau
18:38 Return to Miami
TRAVEL DOCUMENTS
There are no visa requirements for U.S. and Canadian Citizens. However, you
must have a valid passport.
If you are a citizen of any other country, please check on what requirements are
necessary for you.
CLOTHING AND FIELD EQUIPMENT
For the field, you will need two types of clothing; one for the island geology and
one for the open water geology on day two.
Island geology: A good pair of shoes with a sturdy sole for walking across
microkarst (hiking boots); hat with brim; long trousers and long-sleeved shirt for
field use as protection against the sun and insects, sun glasses (polarized) and
light rain jacket or poncho. One pair of old shorts and a T-shirt that you can
discard after visiting the Hatchet Bay Cave.
Open water: Swim suit or two, sunscreen, canvas shoes for wading, hat with
brim, long trousers and long-sleeved shirt for field use as protection against the
sun and insects, sun glasses (polarized) and light rain jacket or poncho. You
might also want to bring a water shirt (rash guard or normal t-shirt to wear during
snorkeling to protect from sun exposure).
Evening: Casual clothing (shorts, slacks and short-sleeved shirts).
ITEMS WE WILL PROVIDE
Guidebooks, sample bags, snorkeling equipment upon request.
Flash lights for Hatchet Bay Cave.
OPTIONAL ITEMS
Camera, underwater camera, canvas gloves for protection.
EXPENSES & RESERVATIONS
The cost of this field seminar is US $4,200.00. An invoice has been sent to you.
We accept checks, wire transfers and credit card payments. All expenses,
except long-distance phone calls and personal items are covered from arrival in
Nassau on Tuesday, September 15 through the return to Nassau on Saturday,
September 19. All reservations have been made.
EMERGENCY CONTACT INFORMATION
On September 15th you will be at the Sandyport Beaches Resort in Nassau. If
there is an emergency, one could call Sandyport Beaches Resort +1 (242) 3274279 and ask them to give a message to you. Alternatively, one could call Dr.
Gregor Eberli’s cell phone, 786-564-6032.
From September 16th – 19th you will be staying at the Sky Beach Club in
Governor’s Harbour, Eleuthera. The phone number is +1 (242) 332-2974. The
Club provides free WiFi for e-mail and Skype.
SUGGESTIONS FOR A SAFE AND COMFORTABLE VISIT
SUNBURN: The combination of direct sun and its reflection from the water
can produce a painful burn in a surprisingly short time. Use waterproof
sun cream and put on a long-sleeved shirt whenever possible.
GETTING IN AND OUT OF BOATS: Take it slow and deliberately. Use the
boarding ladders to get into boats from the water.
SWIMMING: If you are not familiar with mask, fins, and snorkel, you should
do some practicing in a pool. In open water we use the buddy system.
DANGEROUS ANIMALS: There are only a few harmful critters to watch out
for, we will point them out.
OVEREXERTION AND OVEREATING: We have a strenuous schedule in
what, for most of you, is an unusually hot and humid climate. Take it easy
in the field, get as much rest as you can, and avoid excessive eating and
drinking; in this climate it's hard on the heart.