The uptake of Ti in experimentally grown, hydrothermal quartz

Transcription

Goldschmidt Conference Abstracts
13
The uptake of Ti in
experimentally grown,
hydrothermal quartz
M. ACOSTA*, J. WATKINS AND M.H. REED
Department of Geological Sciences, University of
Oregon (*[email protected])
([email protected])
([email protected])
Characterization of the concentration of titanium
in quartz is particularly valuable because it is the
basis of the TitaniQ geothermobaromater [1], the
cause of quartz cathodoluminesent centers (CL), and
a measure of quartz cooling history [2]. The
partitioning of Ti between quartz and a fluid depends
on the P and T of crystallization, the activity of Ti4+
in solution, and the crystal growth rate [3].
We are growing quartz in cold-seal pressure
vessels to determine the influence of crystal growth
rate on TitaniQ. A Pt capsule containing a seed
crystal is placed within a gold capsule packed with
silica glass beads, water, and powdered rutile. The
experiments are isothermal (800°C) and isobaric (1
kbar). The silica glass supplies Si4+ and the rutile
supplies Ti4+. The growth rate is varied by using
different sieve sizes of glass. After an experiment, we
collect
scanning
electron
microscope
cathodoluminescence (SEM-CL) images of the quartz
overgrowth and newly formed crystals in the outer
capsule. Ti measurements are made by electron probe
microanalysis (EPMA).
We observe a relationship between the sieve size
of silica glass and the morphology of the quartz. In
experiments with large silica glass fragments
(.24892-.17526 mm), the overgrowth covers a smaller
portion of the seed crystal and we observe dissolution
textures on residual fragments of silica glass. In
experiments with small silica glass fragments
(.06096-.04318 mm), the overgrowth covers a larger
portion of the seed crystal and has a high density of
open-ended fluid inclusions. We find that quartz does
not grow uniformly around the seed crystal, which
complicates the measurement of growth rate.
Titanium concentrations range from 434 ppm to 602
ppm for three of the experiments, which is higher
than the values predicted by TitaniQ of 274- 476
ppm.
[1] Thomas, Watson, Spear, Shemella, Nayak &
Lanzirotti (2010), Contributions to Mineralogy and
Petrology 160, 743-759. [2] Mercer, Reed & Mercer
(2015), Economic Geology 110, 587-602. [3] Huang
& Audetat (2012), Geochimica et Cosmochimica
Acta 84, 75-89.
100
Dolomite fluorescence color
variation, chemical or thermal
effect, LA-ICP-MS evidence
O. H. ARDAKANI1*, H. SANEI1, S. E. JACKSON2, Z.
YANG2 AND I.S. AL-AASM3
Geological Survey of Canada, Calgary, AB, Canada
(*Correspondence:
[email protected])
2
Geological Survey of Canada, Ottawa, ON, Canada
3
Earth and Environmental Sciences Department,
University of Windsor, Windsor, ON, Canada
1
This study presents preliminary results of laser
ablation
inductively
coupled
plasma
mass
spectrometry (LA-ICP-MS) analysis of scattered
dolomite crystals in Upper Ordovician Utica Shale
from southern Québec to investigate the cause of
dolomite fluorescence zonation in samples of
different thermal maturity. Utica Shale dolomite
crystals show zonation under ultraviolet (UV) light,
with a shift from higher red/green quotient (R/G Q) in
crystal cores to lower R/G Q in the crystal rims. In
addition, the R/G Q shows an increase with thermal
maturity of the shale, where the cores of dolomite
crystals of over-mature samples with equivalent
vitrinite reflectance (VRoeqv.) > 2% tend to have
higher R/G Q in comparison to mature samples with
VRoeqv. ~ 1% (red shift). These two parameters show
a strong positive correlation that suggests that
dolomite fluorescence color variation is possibly
controlled by temperature [1].
LA-ICP-MS results shows that major and minor
(Ca, Fe, Mn, Na), trace (Sr, Zn, Cu) and rare earth
(La, Ce, Nd, Sm, Gd, Dy, Er, Yb) elements generally
show consistently higher concentrations in crystal
rims than cores, while the Mg concentration is
consistently higher in the crystal cores (~ 10%) than
rims (~ 7%). Concentrations of Fe show a decreasing
trend from mature to over-mature samples, especially
in the crystal rims. Over-mature samples have
relatively higher concentrations of LREE (La, Ce,
Nd, Sm) in the crystal rim, while the other elements
do not show any trend with thermal maturity.
Consistently lower Mg concentrations in the
crystal rims in comparison to the cores suggest Mg
depletion of dolomitizing fluids during dolomite
precipitation. Depletion of Mg, one of the major
constituents of dolomite, likely causes increases in
the concentrations of other elements. However,
variations in concentration of Fe and LREE with
thermal maturity suggest that temperature can
possibly have an overarching effect on chemistry of
dolomite that ultimately controls the crystal zonation.
[1] Haeri-Ardakani & Sanei (2015) IJCG 135
165-171.
2687
Fluid inclusion and genesis of
Yukarıgöçek amethyst vein
system, Bigadiç-Balıkesir (NW
Turkey); relationship to the
granite
H. ŞAHİN1 AND Z. ASLAN2*
Balıkesir University, Dursunbey Vocational School,
10800, Dursunbey, Balıkesir, Turkey
2
Balıkesir University, Department of Geology, 10145
Balıkesir, Turkey
(*correspondence: [email protected])
1
Amethyst crystals are exists as a vein system in
the ophiolitic rocks in the Yukarıgöçek (BigadiçBalıkesir), NW Turkey. Upper Cretaceous age
ophiolitic rocks consist of generally serpantinite and
metabazite which including high Fe2O3 content (89%wt). These rocks cuy by Musalar pluton. The
pluton has granite and granodioritic composition and
contains 5-10 cm in size and rounded in shape mafic
microgranular enclaves. The Musalar pluton show
madium-grained, poikilitic textures, and contain
plagioglase, orthoclase, quartz, biotite, hornblende.
Geochemically, major and trace element variations
diagrams can be attributed to the importance of
fractional crystallisation which was mainly controlled
by plagioclase and hornblende. Primitive mantle
normalized spider diagrams of granitic samples
exhibit significant enrichments in large-ion lithophile
elements (LILEs); as well as depletion of high field
strength elements (HFSE). Chondrite-normalized
rare-earth element patterns of the pluton and
ophiolitic rocks samples are concave upwards with
low- to-medium enrichment. The Musalar pluton has
high-K series and characterised by a calc-alkaline
granodiorite-series trend. It is I-type and has
volcanic-arc granitoids. Pluton is peraluminous with
ratio of A/CNK > 1.
The amethyst crystals size are between 0.3-1.5
cm, and have lilac colors. The amethyst crystals
settled into the cracks in the ophiolitic rocks.
Analysis of fluid inclusions vein amethyst showed
that average homogenization temperatures (Th) range
from 232 to 278 oC (mean 260 oC). In cracks
amethyst crystals were formed during hydrothermal
stage, depending on to the emplacemet of pluton.
This work was financially supported by the Scientific
Research Projects’ Foundation of Balıkesir
University.
498
Geochemistry, petrogenesis and
gold occurrence of Rixen
Deposit in Ulu Sokor area,
Peninsular Malaysia
CHONG KHAI YUEN1*, JASMI HAFIZ BIN
ABDUL AZIZ
1
1
Department of Geology, University of Malaya,
50603, Kuala Lumpur, Malaysia
(*correspondence: [email protected];
[email protected])
Rixen deposit is one of the gold occurrences in
Ulu Sokor area, which is in the northern part of
Central Belt in Peninsular Malaysia and around 50km
to the east of Bentong- Raub Suture Zone [1], a major
terrane boundary that marks the collision of
Sibumasu and East Malaya blocks at the Triassic
Indosinian Orogeny. Peninsular Malaysia is situated
on two tectono-stratigraphic continental terranes,
namely Sibumasu and East Malaya blocks. Rifting of
the north-eastern margin of ancient Gondwana during
Late Permian to Early Jurassic is the possible origin
of these blocks. The gold mineralization is heavily
controlled by the regional structures and closely
related to Bentong- Raub Suture. In this study, rare
earth elements (REE) such as Th, Ta and Yb are more
emphasized in classification to lower the
metamorphism and alteration effect (i.e. silicification,
chloritisation and sericitisation). Rixen deposit is
consisted of a set of calc-alkali series aluminiumoversaturated volcanic rocks, and enriched in large
ionic lithophile elements (LILE) and lightly enriched
in light rare earth elements (LREE). The protolith is a
set of intermediate- acidic volcanic rocks, ranging
from andesite to rhyolite, with rare mafic rocks.
Tectonic setting is in active continental marginsvolcanic island arc area, and possibly related to
subduction. Gold occurred as electrum with variable
Ag content (20-46%) and rare Ag-rich gold grains
(Ag content 10-12%). Most of the gold grains are
hosted by pyrite and associated with very rare galena
and chalcopyrite, disseminating in quartz.
[1] Hutchison C. S. (2009), Geology of Peninsular
Malaysia, 309.
510
Metallic gold from the
Suurikuusikko Mine (Kittilä,
Finland): Geochemistry and
metallogenetic implications
MIHAELA-ELENA CIOACĂ 1 MARIAN MUNTEANU
2
, JUKKA VÄLIMAA3
Geological Institute of Romania, Bucharest,
Romania [email protected]
2
Geological Institute of Romania, Bucharest,
Romania, [email protected]
3
Agnico Eagle Finland Oy, Kittilä, Finland
[email protected]
1
At the Suurikuusikko Mine, gold mineralization
is related to a tectonic lineament and can be classified
as orogenic/shear-zone type. Most gold is known to
occur either as submicronic inclusions or as atoms
trapped in the lattice of arsenopyrite and pyrite, while
metallic gold is a minor type (ca. 4% of total Au).
Several ore samples from the Suurikuusikko Mine
have been investigated with the optical and electron
microscope, while mineral composition was
measured using energy-dispersive spectroscopy and
wavelength-dispersive
spectroscopy.
The
mineralization is dominated by pyrite and
arsenopyrite, followed by gudmundite (FeSbS).
Pyrite is arsenian (0.2-4% As), anhedral to euhedral,
occurs as grains that can be larger than 200 μm across
and include arsenopyrite, chalcopyrite or galena.
Most arsenopyrite is euhedral, acicular (ca. 10-20 μm
across) and inclusion-free. Coarser (>100 μm),
subeuhedral arsenopyrite occurs in zones of fractured
rock, where sulfides are fragmented ± recrystallized.
Ni minerals have been found in two samples,
occurring as tiny grains (< 20 μm in size), some with
ullmannite composition (NiSbS) but other ones
showing compositions that correspond to the formula
Ni2Sb2S.
Metallic gold has been found mostly as inclusions in
the pyrite (± associated with galena inclusions) and
arsenopyrite from the fractured rock, sometimes
filling the cracks of the fragmented sulfides. Gold
grains not associated directly with sulfides were
found in carbonate veinlets. Metallic gold is allied
with Ag and Hg (27-68 wt% Au; 28-53 wt% Ag and
1.5-19 wt% Hg).
The investigated samples provided indications of
a relative Sb enrichment of the mineralizing
solutions. The common occurrence of metallic Au in
association with relatively large ± recrystallized
arsenopyrite grains or with carbonate veinlets,
suggests metallic Au precipitation in a distinct
metallogenetic stage that probably postdated the main
Au-bearing mineralization.
This research is part of the projects SUSMIN
(contr. 3004/2014) and Maxi (contr. 3006/2014).
512
The Application of Geochemical
and Isotope Tracers for the
Identification of Source
Contributors to Mineral (Scale)
Precipitation in Petroleum
Reservoirs
C. CISZKOWSKI1, M. NIGHTINGALE1, M.
SHEVALIER1,
B. MAYER1,
1
Applied Geochemistry Group, Department of
Geoscience, University of Calgary, Calgary, AB,
Canada T2N 1N4
([email protected])
Mineral (scale) precipitation can significantly
hinder production in petroleum reservoirs. This
includes steam assisted gravity drainage (SAGD)
operations used for bitumen recovery in the
Athabasca oil sands region of north-eastern Alberta,
Canada. Variations in scale compositions and their
formation conditions have been observed throughout
SAGD facilities and often require costly and
laborious mechanical and/or chemical treatment
efforts. Hence, we investigate methods to prevent or
at least minimize scale formation by applying select
geochemical and isotopic tracers to identify source
contributors to mineral precipitation. Pore water,
bottom formation water, and steam condensate and
returned emulsions (produced bitumen and water)
were sampled from a SAGD reservoir in Alberta and
analysed for geochemical and isotope parameters.
Results indicate distinct concentrations of dissolved
Na and Cl and δ18O and δ2H values for the three fluid
sources. Significant differences in δ13CDIC, δ11B, δ34S
values and 87Sr/86Sr ratios were also observed
between bottom formation water and steam
condensate and returned water samples, and hence
constitute excellent tracers for bottom water influx.
Scale sampled from multiple steam injector and
production wells has been analysed for δ18O, 13CDIC,
δ34S, δ11B, 87Sr/86Sr and trace elements and results are
assessed to determine the fluid sources and reservoir
dynamics that contributed to its formation.
591
Geochemical types of intrusionrelated gold deposits in the
south-eastern part of East
Sayan (Russia)
B. B. DAMDINOV
Geological Institute SB RAS, Ulan-Ude, Russia,
[email protected]
There are many gold deposits in the southeastern part of East Sayan which earlier were
classified as gold-quartz, gold-sulphide and goldquartz-sulphide ore formations. In this region
orogenic gold deposit are most wide-spread but some
deposits attributed to intrusion-related gold deposits
are known. They classified as gold-telluric, goldbismuth-telluric, gold-bismuth and gold-antimony
geochemical types based on mineral and chemical
compositions of most efficient ore paragenesises.
Gold-telluric type deposits are related to islandarc granites which have two different stages of
formation – 850 Ma and 500 Ma. These deposits
characterized by prevalence of pyrite, native gold and
gold, silver, lead, bismuth and nickel tellurides in the
ores. Gold-bismuth-telluric deposits are associated
with active continental margin granites. Formation of
this geochemical ore specialization is related with
two stages of ore-forming process. At first stage AuCu-Mo-(Bi)-porphyry system are formed (about 500
Ma) and later (about 325 Ma) intrusion of volcanicplutonic association dykes and low-temperature AuHg-Te mineralization formation are occurred. With
the same active continental margin granites goldantimony type deposits are related. These deposits
have such widespread minerals as stibnite in
association with native gold and Sb-sulphosalts –
andorite, zinkenite, chalcostibite. Gold-bismuth
mineralization is associated with collision-type
leucogranites with age about 500 Ma. This type
deposits are characterized by association of native
gold with arsenopyrite and Bi-minerals –
bismuthinite, galenobismutite lillianite.
Common characteristic features of the southeastern part of East Sayan intrusion-related gold
deposits are spatial and genetic relationships with
island-arc, active continental margin and collisiontype granitoids, the primary role of Te, Bi, Sb in ore
compositions, the wide range of temperature
conditions of ore formation.
592
The metal contents of solutions
formed fluorite-leucophanitemelinophane-eudidymite ores of
Ermakovka beryllium deposit
using LA-ICP-MS (West
Transbaikalia, Russia)
L. DAMDINOVA1, B. DAMDINOV1, N.
BRYANSKY2
1
Geological Institute SB RAS, Ulan-Ude, Russia,
[email protected], [email protected]
2
Institute of Geochemistry SB RAS, Irkutsk, Russia
[email protected]
Ermakovka F-Be deposit which located in the
Transbaikalia is characterized by the highest average
grade of BeO (1.3%) in the world. Berillium ores in
this deposit have different mineral types which differ
from each other in abundance, grade, mineral
assemblages and morphology. Fluorite-leucophanitemelinophane-eudidymite ores form relatively small
ore body and have a specific very rare composition
(fluorite, phenakite, eudidymite, melinophane,
leucophanite, albite, calcite, in small amounts apatite,
bavenite, helvite, phlogopite are present). Formation
of eudidymite and melinophane/leucophanite is the
result of phenakite replacement, which related to
increasing of sodium and reducing of beryllium
activities in the solutions. Primary fluid inclusions
(FI) in fluorite were studied. They have a three-phase
composition: gas + water solution + calcite crystal.
Inclusion sizes varies from 15 to 35 µm. Based on the
complex of thermobarogeochemical methods are
observed that these ores are formed by high-F and
low-salinity (4-11% equiv. NaCl) alkaline
hydrothermal solutions without CO2. Ore deposition
occurs in the temperature range from ≥320 to 136°C
and pressures about 5-77 MPa by means of the
solution cooling. Using LA-ICP-MS in the analyzed
fluid inclusions increased contents of such elements:
Li, Be, Na, Mg, Al, Fe, Cu, Zn, Nb, Mo, Ag, Sn, W,
Pb are determined. Be content (0.0002-1.04 g/kg) in
the ore-forming solutions is similar to Be content in
solutions forming main phenakite-bertrandite-fluorite
ores (0.06-3.82 g/kg).
This work was supported by RFBR grant: № 1405-00339-a.
662
Onyx From Ain Smara (NorthEastern Algeria): A Natural
Stone To Be Considered As A
Global Heritage Stone
DIAB HAMIDA
Engineer status in sedimentary geology
National Office of Geological and Mining
Research (ORGM), Tebessa-Algeria
[email protected]
Large amounts of the finest quality onyx are
extracted from the Ain Smara quarry, in north east
Algeria. It is used for decorating buildings around the
world. In 1814, during the restoration of the White
House, in Washington, experts used large blocks of
onyx
from
this
quarry.
This onyx, in contrast to many other types, is
characterized by bright colours and structures. Onyx
was very popular in ancient Greece and Rome where
it was carved with highly valued images and scenes.
There, onyx was considered to be linked with instinct
and intuition and has been associated with business
and management capabilities in some areas since
ancient
times.
Different societies had different legends about this
material and many used it to decorate their most
precious buildings. Information from geochemical,
petrographical, and other studies will help us to
characterize this natural stone, compare it with onyx
from many other places and to make a case for
proposing it as a candidate Global Heritage Stone
Resource. This will improve present knowledge of
this material and help the stone extraction industry in
Algeria
The picture : onyx, striped, semiprecious variety
of the silica mineral agate with white and black
alternating bands.
720
Paragenetic associations of PbZn, Au-Ag and Mo
mineralizations in Qingchengzi
orefield
XIAOXIA DUAN 1 , QINGDONG ZENG2, BIN CHEN1
1
Tunxi Road No.193, Hefei, China;
[email protected]
2
Beituchengxilu No.19, Beijing, China;
Qingchengzi orefield in Liaoning province is an
important large-scale Pb-Zn-Au-Ag-Mo polymetallic
orefield which clusters several Pb-Zn deposits, AuAg deposits and Mo deposit.The paragenetic
relationships between different metals are unsettled.
Constrained by mineralized granite porphyry and
lamprophyre
dykes
through
cross-cutting
relationships, Pb-Zn mineralization age is settled at
227-233Ma, coeval with the Triassic magmatic
activities. The Re-Os age of Mo mineralization is
164.8±6.4 Ma which is consistent with emplacement
age of Yaojiagou granite(165.7±1.3Ma) . This
indicates the Mo mineralization is genetically related
to Jurassic magmatic activities. As indicated by Pb
isotope analysis, Ag ores have distinctively enriched
Pb isotopes compared to Pb-Zn ores. And Ag ores
show linear correlation with Jurassic intrusion and
schist, implying their links with Jurassic magmatism
while Pb-Zn ores show linear correlation with
Triassic magmatic rocks and schist. Therefore, we
infer Au-Ag and Mo mineralization are both
associated with Jurassic magmatic activities and
together they form the combination of skarn Mo
mineralization with epithermal Au-Ag mineralization
of porphyry system. On the other hand, The Pb-Zn
mineralization is genetically linked to Triassic
magmatic activities.
779
Occurance and origins of
Arsenic in the Hokusetsu area,
Japan
EMILIE EVEN1, HARUE MASUDA1, TAKAHIRO
SHIBATA1, YUSUKE SAKAMOTO1, TOMOAKI
MURASAKI1, TAKAFUMI HIRATA2, HITOSHI
CHIBA3
Osaka City University, [email protected]
Kyoto University, [email protected]
3
Okayama University, [email protected]
1
2
Arsenic (As) contamination have been
chronically reported since 1994 in ground and river
waters of the Hokusetsu area, Osaka, Japan. In order
to asses the spread of As contamination and its
origins, a broad geochemical investigation of river
waters and bed sediments have been conducted.
Former studies have targeted sulfides hosted in
Mesozoic to Paleozoic sedimentary rocks as the
source of As[1]. Upon the sulfide hypothesis, As and
the associated trace elements in the sulfides in the
sedimentary rocks and the nearby ore deposits related
to Late Cretaceous granitic magmatism were
compared to document the genetic relationship
between As-bearing minerals and numerous
xenothermal and mesothermal ore deposits of the
area.
The geochcemical mapping of As was achieved
through ICP-MS analysis of river water and alkalifused bed sediments. Imaging of As and trace
elements within the sulfides from sedimentary rocks,
contact-metamorphosed rocks and ore deposits were
compared using LA-ICP-MS.
The As contamination was restrained to the
sedimentary rocks around an igneous intrusion, but
the most contaminated waters appeared nearby faults.
It is likely that the dissolution of As-bearing sulfides
by groundwater was enhanced by the increasing
surface contact of the sheared host-rocks. The As
level of water was lower in the area of sedimentary
rocks indurated by contact-metamorphism than in the
area of non-metamorphosed sedimentary rocks,
probably due to the potential dissolution rate of Asbearing sulfides.
In the contaminated areas, sulfur isotopes
confirmed that the disseminated sulfides (mainly
pyrite, pyrrhotite and chalcopyrite) in the contactmetamorphosed rocks were induced by the igneous
intrusion. Ni and Co were found in these
disseminated sulfides and in some felsic magma
related ore deposits, corroborating the common
origins. But some sulfides in the Paleozoic
sedimentary rocks were related to the submarine
hydrothermal ore deposits. As was detected in both
kinds of sulfides, and also in Mn-hornfels likely from
Paleozoic times and later metamorphosed by the
Cretaceous magmatic activities.
[1] Ito et al. (2003) J. Groundw. Hydrol 45, 3-18. (In
Japanese with english abst.)
801
Magmatic-meteoric water
interaction during
hydrothermal ore deposition
SZANDRA FEKETE1, PHILIPP WEIS1,2, THOMAS
DRIESNER1, LUKAS BAUMGARTNER3, ANNESOPHIE BOUVIER3, CHRISTOPH A. HEINRICH1
Institute of Geochemistry and Petrology, ETH
Zurich,
Switzerland (*correspondence:
[email protected])
2
GFZ German Research Centre for Geosciences,
Potsdam,
Germany
3
Institute of Earth Sciences, University of Lausanne,
Switzerland
1
Hydrothermal convection of ambient fluids can
induce significant cooling of as well as mixing with
magmatic fluids in the upper crust, both being
potentially efficient mechanisms driving ore
deposition. Fluid inclusion evidence from the tinmineralized Yankee Lode (Mole Granite, Australia)
deposit suggests that meteoric water incursion into
the evolving mineralizing magmatic-hydrothermal
system triggered cassiterite precepitaion. To trace
meteoric water interaction in the Yankee Lode, we
carried out high resolution, in situ oxygen isotope
measurements (SIMS analyses) in combination with
scanning electron microscope cathodo-luminescence
(SEM-CL) imaging on a previously well-studied
quartz crystall. Growth temperatures are provided
from texturally controlled fluid inclusion studies by
Audétat et al. (1998) [1]. Calculated δ18O values of
the fluid over successive quartz generations decrease
from magmatic isotopic composition with δ18O
values of ~10 ‰ to very light δ18O values of about 15 ‰. The main cassiterite formation event agrees
with a progressive drop in the fluid’s δ18O value
demonstrating that tin precipitated from a hot saline
magmatic fluid upon gradual inmixing of cooler
meteoric water.
In contrast, porphyry copper ore formation has
been linked to entirely magmatic fluids and meteoric
water incursion has generally been attributed to
peripheral parts of the system or post-ore stages.
However, recent numerical simulations imply a
significant role of meteoric water for the copper
enrichment processes. After validation of the
methodology with the Yankee Lode sample, we will
also apply it to hydrothermal quartz samples from
two significant porphyry copper deposits (Bingham
Canyon, USA and Elatsite, Bulgaria) to investigate a
potential role of meteoric water incursion in porphyry
copper ore precipitation.
[1] Audétat, Günther & Heinrich (1998), Science
279, 2091-2094.
830
Volcanogenic beryllium deposits
at Spor Mountain, Utah, USA:
impact on past production and
material flow cycles
NORA FOLEY, ROBERT AYUSO, GRAHAM
LEDERER, AND BRIAN JASKULA
1
United States Geological Survey, Reston, Virginia,
20192 USA, (*correspondence:
[email protected])
Beryllium ores are used to make strong alloys,
metals, and ceramics that are critical for computer,
telecommunication, aerospace, medical, and defense
industries. Data on changes in Be sources,
production cycles, and material flow pathways over
time is required for interpreting trends in global
supply and demand. Both beryl (Be3Al2Si6O18) and
bertrandite (Be4Si2O7(OH)2) are currently mined to
ensure a stable supply of Be; beryl is mainly derived
from Li-Cs-Ta-type pegmatites; bertrandite is
obtained from a single volcanic-hosted resource at
Spor Mountain, Utah, USA [1]. Since the Spor
Mountain mine opened in 1968, this single deposit
has accounted for more than two-thirds of global
beryllium production [1]. At Spor Mountain, the Be
ores occur in lithic-rich, phreato-magmatic basesurge deposits situated mainly along the ring fracture
of an Oligocene caldera [2]. The Be ores are part of a
sequence of lithophile element-rich, topaz-bearing
rhyolite lava flows, pyroclastic deposits, and fluoritebearing pipes. Ore nodules containing Mn-oxides,
calcite, opal (~100 ppm Be), and fluorite, and ~1-2%
bertrandite occur in mineralized tuff. New
geochemical modeling indicates that alteration
assemblages, fluorite, and bertrandite likely formed
under pH-buffered, isothermal to cooling conditions
(200º-100ºC), when F-, Mn-, Li-, Si-, and Be-bearing
fluids reacted with dedolomitized carbonate clasts in
the base-surge deposits. Geochemical evaluation of
Be transport and accumulation processes, including
direct release of Be (plus volatiles) from cooling
hypabyssal rhyolite (or a pluton at depth), and
remobilization of Be from vitric tuff [3], is the focus
of this work. Quantifying the timing and flux of Be
and the relative roles of magmatic fluids and meteoric
water leading to precipitation of bertrandite, fluorite,
and other minerals are the subject of ongoing studies.
Widespread occurrence of geochemically similar
volcanic rocks in the southwestern US indicates
potential for additional deposits of volcanic-hosted
Be. Such discoveries can safeguard a long-term,
reliable, and stable supply of US-produced Be to
global markets.
[1] Jaskula (2015) USGS 2013 Minerals Yearbook
28-29. [2] Burt et al. (1982) Economic Geology 77,
1818-1836. [3] Foley et al. (2012) USGS-SIR 20125070-F, 43.
888
Magmatism and Mineral
Occurrences of the Eastern
Greater Caucasus, Georgian
Segment
N. GAGNIDZE1, A.OKROSTSVARIDZE2, K.
AKIMIDZE, S. L. CHUNG3
1
Ilia state University, Tbilisi 0162, Georgia,
(*correspondence:[email protected])
2
Javakhishviuli State University, Tbilisi 0138,
Georgia
([email protected])
3
Institute of Earth Science, Academia Sinica, Taipei
11529, Taiwan ([email protected])
The eastern part of the Greater Caucasus orogen,
Georgian segment, is underlain mainly with highly
deformed Lower-Middle Jurassic shales, sandstones
and volcaniclastic rocks, associated with numerous
intrusive bodies. All these rocks contain a variety of
mineral deposit types and surrounding zones of
hydrothermal alteration.
Conducted researches showed important new
information on the evolution of the region. Three
main stages of magmatic activity are now clearly
identified. The oldest magmatism in Early Jurassic
was related to extensional tectonism, and resulted in
rhyolitic, through dacitic and andesitic, to basaltic
rocks; Additional extensional processes in Bajocian
were characterized by intrusion of a gabbro/diorite
dike system into late Early-early Middle Jurassic
sedimentary formations; and the third magmatic
event was associated with Middle Jurassic folding
and uplift, during which multiphase diorite plutons
were emplaced [1].
Our metallogenic study carried out in the research
area has shown that a wide range of mineral
occurrences, largely in terms of composition and
style, is represented. Most are just locally exposed
and the potential for important resources remaining to
be discovered at shallower depths is high, particularly
under the cover of sedimentary formations and where
altered zones are exposed at the surface. According to
a number of parameters, these occurances are
hydrothermal in origin and are likely genetically
linked to productive magmatic centers [2].
Related intense hydrothermal activity was
responsible
for
principal
polymetallic
mineralization, with more than 100 recognized
outcrops. A detailed study of 11 of these ore
occurrences has indicated anomalous concentrations
of gold, thorium, yttrium, cobalt, cadmium, and
bismuth. In addition, several new and potentially
significant ore mineral occurrences were discovered,
including Gelia and Lechuri.
[1] Okrostsvaridze et al.(2016) J. Eisodes (in print).
[2] Ridley (2013) Cambridge Un. Pr. 398 p.
891
Magmatic aspects of oil - gas
bearing
Y. GALANT
1
Independent Researcher. P.O.Box 164. YokneamMoshava. 20600. ISRAEL ( [email protected] )
Currently, the petroleum geology postulated the
existence of oil in the all the different genetic types of
rocks: igneous, sedimentary, and metamorphic.
Oil in igneous rocks. Oil and gas deposits are
found in Vietnam in the area of the White Tiger and
the other in the basement granitoids. . In Sicily there
is oil and gas field Galliano and other fields around
the volcano Etna. Oil reserves in Azerbaijan
(Muradkhanli) and Georgia (Samgori) were found in
volcanoes.
Oil in sedimentary rocks . In Azerbaijan - Oil: Oil
Rocks, Surakhani concentrated in the productive
strata, folded alternating clay, sand and sandstone. In
Japan, the oil fields are located on the island of
Honshu, and the Sea of Japan in the Miocene and
Pliocene rocks. Australia contains industrial reserves
of oil in the Permian continental sedimentary basins Gipslend.
Oil in metamorphic rocks. In Venezuela, in the
fields of La Paz and Mara in metamorphic rocks
found deposits of oil. In the West Javanese basin of
Indonesia revealed industrial gas accumulation in the
metamorphic rocks of the pre - Tertiary crystalline
basement. In Morocco in seven fields : Baton Tisserand, Ued - Mellac, Lower Sidi - Fili, Mers-elKarets, Bled – adl - Def and Lower Bled ad-Dum oil
produced from the fractured shales and quartzites of
the Paleozoic.
Finding oil in the genetically diverse geological
objects, and based on the primary magmatic
processes that form the Earth's Crust propose
magmatic model of genesis, location and existence of
oil deposits in the Globe.
971
A secondary (PGE-Au) ± Ni-SAs-Sb-Pb mineralization in
serpentinite shear zones from
Central Chile
JOSÉ M. GONZÁLEZ-JIMÉNEZ1, LEONARDO N.F.
GARRIDO1, RURIK ROMERO1, EDUARDO
SALAZAR1, FERNANDO BARRA1, MARTIN REICH1,
TAKAKO SATSUKAWA2, VANESSA COLÁS3
1
Department of Geology and Andean Geothermal
Center of Excellence (CEGA), Universidad de
Chile, Plaza Ercilla # 803, Santiago de Chile,
Chile.
2
ARC Centre of Excellence for Core to Crust Fluid
Systems (CCFS), and GEMOC National Key
Centre, Department of Earth and Planetary
Sciences, Macquarie University, Sydney, NSW
2109, Australia.
3
Instituto de Geología, Universidad Nacional
Autónoma de México. Ciudad Universitaria, 04510
México, D.F. (Mexico)
The ultramafic rocks hosted in the Paleozoic
Coastal Accretionary Complex of Central Chile host
small meter-size pods of chromite ores within in
shear zones filled by schistose antigorite (±talc) that
isolate blocks of non-deformed olivine-lizardite
dunites. The chromite ores appreciable amounts of
the platinum-group elements (up to 347 ppb total)
and gold (up to 24 ppb), which has its expression in
the mineralogy by the presence of specific phases of
the six platinum-group elements (i.e., platinum-group
minerals, PGM) as well as native gold. The PGM
identified include native osmium, laurite (RuS2),
irarsite (IrAsS), osarsite (OsAsS), omeiite (OsAs2),
Pt-Fe alloy (possibly isoferroplatinum) and a suite of
inadequately identified phases such as PtSb (possibly
stumpflite), PdHg (possibly potarite), RhS, Ir-Ni and
Ir-Ni-Ru compounds. Only a few grains of osmium
and laurite were identified in unaltered cores of
chromite and therefore considered as magmatic
formed during the high-T event of crystallization of
the chromitite in the upper mantle. The other PGM
were located in porous chromite associated with
chlorite or the base-metal minerals (BMM) that often
fill the pores of this secondary chromite or are
intergrowth with antigorite in the host serpentinized
ultramafic rock. The assemblage of BMM identified
in the studied rocks include sulphides [millerite
(NiS), polydymite (Ni3S4), violarite (FeNi2S4), galena
(PbS), sphalerite (ZnS), chalcocite (CuS)], arsenides
[(nickeline (NiAs), orcelite (Ni5-xAs2), maucherite
(Ni11As8)], the sulpharsenides gersdorfitte (NiAsS),
and native bismuth. We suggest the origin of these
PGE-Au) ± Ni-S-As-Sb-Pb minerals as a result of
the reaction of magmatic PGMs with fluids rich in
metalloids such as As, Sb, Pb, Zn and Hg emanated
from the country metasediments that have penetrated
the ultramafic rocks through active shear zones. This
secondary mineralization took place coevally with the
formation of prograde antigorite within the shear
zones once the ultramafic bodies became tectonically
mixed with the host metasediments. During this a
secondary gold mineralization was produced in the
studied rocks.
1008
Geology, mineralogy and fluid
inclusion data from the
Tumanpınarı volcanic rockhosted Fe-Mn-Ba deposit,
Balıkesir, Turkey
A.H.GULTEKIN
1
1
, NURGUL BALCı1
Department of Geological Engineering, Istanbul
Technical University, Istanbul, Turkey.
The Tumanpınarı mineralization is a volcanic
rock-hosted hydrothermal deposit located in 35 km
west of Dursunbey, Balıkesir. The deposit constitutes
one of the most important deposits of the HavranDursunbey metallogenic sub-province in which
numerous Early Miocene Fe-Mn-Ba deposits are
distributed. The geology of the study area consists
mainly of andesite that form a part of the West
Anatolian calc-alkaline volcanism of Miocene age.
The Mn-Fe-Ba deposits in the Dursunbey area
associated with andesite. These rocks display a large
variation of K2O from approximately 2 % to 6 %.
SiO2 content ranges between 55 % and 63 %. These
chemical results signify a high-K calc-alkaline
spectrum. Early hydrothermal activity was
responsible for three types of hypogene alteration in
decreasing intensity: silicification, hematization and
argillic alteration. The ore stage clearly postdates
hydrothermal alteration, as indicated by the
occurrence of ore minerals in vuggy cavities and
fractures in silica bodies. The mineral assemblage
includes pyrolusite, psilomelane, barite, hematite, and
magnetite as well as minor manganite, poliannite,
braunite, bixbyite, pyrite, limonite, and goethite.
Mineralogical, it was recognized three ore types as
dominant pyrolusite ore, pyrolusite + psilomelane
ore, and psilomelane + hematite + barite+ limonite
ore with pyrolusite. High As, Pb, Zn contents of the
ore seem to be an important geochemical
characteristic of the Tumanpınarı deposits. Average δ
34
S values for barite are
2,92 and 6,24 o/oo,
respectively, suggesting an igneous source for both
the sulphur and metals. Fluid inclusions in main-stage
quartz and barite homogenize at 134o to 417 oC with
salinities ranging from 1.3 to 21,2 eq. wt % NaCl.
The deposits formed during the interaction of two
aqueous fluids: a higher-salinity fluid (probably
magmatic) and a dilute meteoric fluid.
1024
Vein Petrography and
Geochemistry of the North
Amethyst Au-Ag epithermal
Deposit, Creede, Colorado USA
GUZMAN, MA1 AND MONECKE, TM1
1
Department of Geology and Geological
Engineering, Colorado School of Mines, 1516
Illinois Street, CO 80401 ([email protected])
The Oligocene Creede mining district represents
one of the most prolific intermediate sulfidation-state
epithermal silver and base metal mining districts
worldwide. The district is located in the Central San
Juan Mountains of southwestern Colorado. The North
Amethyst deposit consists of epithermal veins which
filled dilatant zones of the Amethyst and Equity
faults at or near the intersection of the two major
structures.
The mineralogical and textural characteristics of
the vein stages were determined by optical
microscopy and back-scatter electron imaging on a
scanning electron microscope. Electron microprobe
analysis was performed on sulfide minerals to
determine the geochemical characteristics of the vein
stages. Particular emphasis was placed on the
compositional analysis of sphalerite to constrain the
temperature and sulfidation state of the hydrothermal
liquids which formed the various ore bearing vein
stages.
Four sulfide bearing vein stages were observed at
the North Amethyst deposit and are each punctuated
by a breccia or a gangue stage. The earliest of the
four sulfide bearing veins is the Alpha stage which
was observed from the deep to shallow elevations of
the deposit. The hydrothermal liquids forming the
Alpha stage are interpreted to have cooled as they
ascended from deep to shallow levels of the deposit,
acquiring a higher sulfidation state (1.3 to 0.24 mole
% FeS). Following the Alpha stage, the precious
metal (Au-Ag) bearing vein stage known as Beta
stage was formed. The Beta stage is weakly
mineralized at depth but is well developed in the
shallow portions of the deposit. Beta stage veins are
spatially associated with Alpha stage veins.
Compositional variations in the sphalerite are less
pronounced. However, the paragenesis of Beta stage
indicates a shift from high to low sulfidation states
through the transition from argentite-acanthite to
native silver at the end of the mineral deposition
sequence. The late base metal sulfide-rich Stage-1
was observed in the deep part of the deposit and the
Fe-poor Base Metal Sulfide stage was observed at
mid-elevation of the North Amethyst deposit. These
two base metal and silver stages correlate with those
recognized in the central and southern parts of the
Creede mining district.
1044
Silica recovery from Sumikawa
geothermal brines in Japan by
additon of cationic flocculants
ERI HANAJIMA
1
1
AND AKIRA UEDA1
Graduate School of Science and Engineering for
Education, University of Toyama, 3190 Gofuku,
Toyama 930-8555, Japan, ([email protected], [email protected])
Silica in geothermal brines deposits as a scale
in pipes and injetion wells at geothermal plant and
redues the capacity of the injection rates of brines.
This is due to depotion of excess silica (ca. 600mg/L)
in the geothermal brines. Currently, a pH adjustment
method by addition of sulfate into brines has been
carried out in the world. However, there are some
problems such as corrosion of pipes and other scale
generation such as anhydrite in the production well.
In addition, most silica scales in Japan include a large
amount of aluminum. The solubility of Al-containg
amorphous silica is by 150 mg/L lower than pure
amorphous silica. This means the pH adjusting
method can not sufficiently inhibit scale precipitation.
We examined a recovery method for the excess
silica by addition of cationic flicculants into the
brines to prohibit the silica scaling by checking the
clarity of geothermal brine after the treatment and the
economy. The experiments of silica recovery were
carried out using geothermal brine in Sumikawa
geothermal power plant (50MW), Akita, Japan. We
examined several experimental conditions such as
effect of concentration of the cationic flocculant and
retaining time of the brine before the addition of the
flocculant. We measured the total silica concentration
and turbidity of the brines.
Our results show that the cationic flocculant
used in this study reacts with polymeric silica rather
than monomer silica and that 50 mg/L of the cationic
flocculants is enough to reduce the silica
concentration to the solubility (ca. 380 mg/L) of
amorphous silica at 95℃. At this treatment, the
turbidity of the brine is low than 10mg/L. The
sedimentation rates of precipitated silica by addition
of cationic flocculants were also measured. The rate
of precipitate reacted with monomer silica is faster
than that with polymeric silica.
The geothermal brine used in this study is
characterized by the low Cl concentration (less than
1,000 mg/L). To examine the application of our
method to other geothermal brines, we also examined
a salinity effect of our cationic flocculants to brines
with different Cl concentrations. The result shows
that the cationic flocculant can effectively remove
silica in brines with higher Cl concentration.
1079
Oxygen isotope study of silica
sinter from the Osorezan
geothermal field, northeast
Japan
KEN-ICHIRO HAYASHI1
1
Graduate School of Life and Environmental
Sciences, University of Tsukuba, Tsukuba, Japan
Silica sinter developed on the northern
shore of Lake Usoriyama in the Osorezan geothermal
field was examined for the occurrence, texture, and
crystallinity of silica minerals, and the concentrations
of trace elements and oxygen isotopes. The silica
sinter of this study consists of two parts, a thick
eastern mound (layer A) and a thin western part
(layer B). Layer A’s maximum thickness is 150 cm,
and it consists of alternating white to light gray layers
about 1 cm thick interspersed with yellowish and
reddish layers. A red to reddish gray layer with a
unique stromatolitic texture, having aggregates of
stratified concentric layers extending upward, appears
in the middle of layer A. Layer B is characterized by
alternating loose white layers about 1 mm thick. The
mineralogical constituents of the sinter are dominated
by silica minerals. Layer B consists of opal-A, while
layer A contains opal-A and opal-CT.
We measured trace elements such as Au,
Hg, As, and Sb. Au content ranges from 5 to 310 ppb,
and Hg content is between 0.8 and 30.1 ppm, with
high concentrations observed in the colored layers of
layer A. The concentration of As varies between 40
and 201 ppm, and an exceptionally high
concentration of As, 650 ppm, was observed in newly
formed white silica sinter around an active vent.
The δ18O of the silica minerals in layer A
vary between 13 and 26‰, while those of layer B are
higher, from 19 to 33‰. The δ18O of the water
estimated from the δ18O of the silica sinter is heavier
than that of local meteoric water, but approximately
overlaps with the δ18O range observed in present-day
hot spring waters. This overlap suggests that the
origin of the water from which the 150 cm thick silica
sinter of this study is not different from present day
hot spring water.
1174
The Daye Iron Deposit, East
China: a Possible Missing Link
between Kiruna-type and Iron
Skarn Ores
HAO HU1, JIAN-WEI LI1,2, ZHUANG DUAN2
State Key Laboratory of Geological Processes and
Mineral Resources, , China University of
Geosciences, Wuhan 430074, China
2
Faculty of Earth Resources, China University of
Geosciences, Wuhan 430074, China
1
Kiruna-type deposits, often referred to iron
oxide–apatite (IOA) deposits, typically contain
abundant F-apatite and V- and/or Ti-rich magnetite.
Despite having been described as an independent
style of mineralization, origin of many Kiruna-type
deposits remains hotly debated. Two contrasting
models have been proposed to explain their
formation: (1) they crystallized from immiscible iron
melts, and (2) they formed as a result of hydrothermal
metasomatism as is the case of iron skarn systems.
The Daye iron deposit provides an opportunity to
reconcile these contrasting models. This deposit is
localized within the contact zone between an early
Cretaceous dioritic intrusion and Triassic marine
carbonate rocks. Magnetite and hematite from the
iron ore bodies have close paragenetic relationships
with skarn assemblages mainly consisting of diopside
and garnet. As such, the Daye deposit has long been
considered as a typical iron skarn system. In a recent
study, we have recognized apatite-rich diopside
skarns and theire associated iron ores (up to 20 vol. %
apatite) in the Daye deposit, with mineral
assemblages and geochemistry resembling Kirunatype ores. Apatite has two types of occurrences: (1) it
forms mass of aggregates coexisting with magnetite
or prograde skarn minerals such as diopside and
garnet, and (2) it occurs as veinlets crosscutting the
magnetite. Many magnetite grains are characterized
by orientated ulvospinel exsolutions. The diopside
and garnet have chemical compositions typical of
iron skarn deposits. However, apatite contains high F
(up to 2.9 wt. %), LREE (8694 ppm), and magnetite
with ulvospinel inclusion have up to 2.14 wt. % Ti
and 0.36 wt. % V, characters similar to the Kirunatype deposits. We suggest that the IOA ores from the
Daye deposit have a similar origin to the Kiruna
deposits and possibly represent a missing link
between Kiruna-type and iron skarn mineralization.
Our findings also indicate that the Kiruna-type iron
deposit may have formed from high temperature
magmatic-hydrothermal fluids.
1188
Helium Isotopic Compositions
of Ore-Forming Fluid from the
Xintianling Tungsten Deposit
and the Furong Tin Deposit, the
Nanling Range: Implications for
the origin and evolution of the
ore-forming fluid of the
Qitianling pluton
CHAO.HUANG* AND B.CHEN
School of Resources and Environmental
Engineering, Hefei University of Technology,
Hefei 230009, China,
[email protected]（*presenting author),
[email protected]
The Furong deposit, located in the southern
Qitianling pluton, is a giant tin deposit. The
Xintianling tungsten deposit located in northern
Qitianling pluton. They are genetically associated
with the granite of Qitianling pluton. Direct Re-Os
dating on molybdenites collected from the skarn type
ore in the Xintianling deposit have been carried4
out，the result shows that the Re-Os dating of six
molybdenite samples collected from skarn type ore
yields
a
187Re-187Os
model
age
of
162.9±1.9Ma(MSWD=0.21). It is suggested that the
mineralization of the Xintianling tungsten deposit is
spatially and temporally related to the early stage
hornblende-biotite monzonitic granite of Qitianling
pluton.While based on previous studies,the Furong
tin deposit may be closely related to the late stage
biotite monzonitic granite. Therefore, we analyzed
the helium and argon isotopic compositions of fluid
inclusions in pyrites and arsenopyrites collected from
these two deposits. It is shown that，3He/4He ratios
of fluid inclusions in pyrites and arsenopyrites
collected from Furong deposit fall in the range of
0.09-0.50
Ra
and
1.353.91Ra，respectively，obviously higher than that of
the crust,but lower than that of the mantle, indicating
that the ore-forming fluid in this deposit is a mixture
of mantle- and crustal-derived fluids. The 3He /4He
ratios of fluid inclusions in pyrites collected from
Xintianling deposit fall in the range of 6.90-10.94 Ra,
obviously higher than that of the mantle,indicating
that the ore-forming fluid in this deposit is mantlederived fluids. According to the results. The
emplacement of the Qitianling A-type granite and
associated tungsten-tin polymetallic mineralization is
a continuous evolution process, which are the
products of large-scale mineralization of the Nanling
in Middle-Late Jurassic. Tungsten deposit and tin
deposit are associated with mantle-derived fluids and
a mixture of mantle- and crustal-derived fluids,
respectively.
1242
Investigations of several
inhibitors for silica scale control
in Sumikawa geothermal brine,
Japan
RISA IKEDA1, AKIRA UEDA1, TAKEHIKO
ISHIDUKA2 AND KAZUO ISHIMI3
Enviromental Biology and Chemistry, Graduate
School of Science and Engineering for Education,
University of Toyama, 3190 Gofuku, Toyama
930-8555, Japan, ([email protected], [email protected])
2
BWA JAPAN CO. LTD., Tobutateno Bldg. 8F, 210-27 Kitasaiwai, Nisi-ku, Yokohama, Kanagawa
220-0004, Japan, ([email protected])
3
Techno Office, Isutokoa Hikibune Nibankan
No.2808, 1-1-2 Kyojima, Sumidaku, Tokyo 1310046, Japan, ([email protected])
1
In geothermal power plants, silica in brines
precipitates as scale in pipes and injection wells and
decreases the amount of injecting brine. A pH
adjustment method has been applied to prevent the
silica scaling so far, but this method can not
completely prohibit the scaling. There is a problem
that added sulfate for the pH adjustment promotes
anhydrite (CaSO4) precipitation in production wells.
The purpose of this study is to develop a new
method to prevent silica scale with chemical reagents.
We examined nine organic inhibitors by passing brine
with the reagent through columns. The brine used in
this study is taken from well SC-4 under an
atmospheric pressure (pH:6.48, Cl:1,100mg/L,
SiO2:980 mg/L) at Sumikawa geothermal power plant
(50MW), Akita, Japan. The intermal diameter and
length of the column in our experiments are 15mm
and 40cm, respectively. A teflon pipes is set in the
column and filled with glass beads with a diameter of
1mm. The mixed geothermal brine (1L/min) and
inhibitor solution (2, 10, and 25mg/L) were passed
through the column for 4 days. The flow rates , pH
and EC were monitored.
The flow rates of brines in all columns decreased
with time, whereas those of the brine without addition
of any inhibitors quickly decreased up to 0 L/min
within 3 days. The results indicate that the cationic
inhibitors showed an aggregation effect of silica in
brines and the inhibitor concentration is critical to
control the silica precipitation. The best concentration
for the prohibition of silica scaling in this study is
2mg/L. This inhibitor can reduce by 10 to 20% of the
silica precipitation rates compared to no addition test
into the brine. Therefore, we concluded that the
effective inhibitor condition is 1) anionic inhibitor
and 2) the low concentration.
1267
Geochemical study on
geothermal resources in OkuHida Hot Spring area, Gifu
Japan
REONA ISAJI1 AND AKIRA UEDA1
1 Enviromental Biology and Chemistry, Graduate
School of Science and Engineering for Education,
University of Toyama, 3190, Gofuku, Toyama,
930-8555, Japan ([email protected], [email protected])
There are many high-temperature hot springs
with > 90 ℃ in the vicinity of Yakidake volcano
across the border of Gifu and Nagano Prefectures.
Koji et al. (2012) reported the chemical and isotopic
(δD and δ18O) compositions of 30 hot spring waters
and 5 river waters in this area. Most hot springs were
of meteoric origin and of Na+-Cl－・HCO3－ and Na+HCO3－ types with low salinity (less than 30 meq/L).
The estimated underground temperatures by
geothermometers are 150 to 200℃ at the depth of ca.
1km. The total geothermal resources in the study area
are estimated to be ca. 400 MWe for producing the
electricity.
Recently, geothermal well was drilled in the
study area (1,200 m in depth). The Sr concentration
and isotopic ratios of both hot springs and rocks are
analyzed. The purpose of this study is to estimate the
depth of the reservoirs which issue the hot spring
waters by using Sr concentration and its isotopic
composition (87Sr/86Sr) in hot spring waters and rocks
obtained from a newly drilled well. In this
preliminary report, the Sr concentrations of the hot
spring waters collected by Koji et al (2012) were
analyzed.
The results show that the hot spring waters in the
southern part of the study area have slightly higher Sr
concentration than those in the northern part. The Sr
concentration increases with increasing of Ca
concentration in the southern area, whereas those in
the Northern part show an almost constant value.
These results show that Sr concentration in hot spring
waters reflect those of reservoir rocks.
1490
Unusual uranium
mineralization from central
Jordan
*HANI N. KHOURY
Department of Geology, The University of Jordan,
Amman
Uranium Mineralization
Unusual uranium resources are widely distributed
in central Jordan. The outcropping rocks consist
mainly of organic-rich bituminous limestone and
marl (oil shales) that overlie phosphorite beds and
underlie the varicolord marble. The sequence is
overlain by travertine and regolith deposits of
Pleistocene – Recent age. The rocks are unusually
enriched with reduced sensitive elements (U, Cr, Ti,
Mn, Ni, Cr, Cu, Mo, V, Ba, Ag, Cd, Zn, Zr, Cl, F, Se
and REE).
Discussion of Results
Secondary yellow uranium minerals (uranyl
vanadates) together with unique green smectites (Crrich smectite/volkonskoite) are hosted by the thick
altered varicolored marble, travertine and regolith
either as encrustations, impregnations, or filling joints
and cavities [1].
Tyuyamunite Ca(UO2)2V5+2O8•3(H2O)-strelkinite
Na2(UO2)2V2O8•6(H2O)
solid
solution
series
(uranmica) are the major components. The surficial
uranium deposits in central Jordan have resulted from
the interplay of tectonic, climatic, hydrologic, and
depositional events. The deposits are related to the
highly alkaline circulating water (hydroxide–sulfate
type) enriched with redox sensitive elements among
which were U and V [1].
The varicolored marbles are strongly altered in
fractured and weak zones, where high-temperature
minerals are partially or totally replaced by secondary
Ca-carbonate, CSH’s, and sulfate minerals (most
often gypsum, barite, hashemite and ettringite). New
primary calcium uranate phases (CaUO4, Ca2UO5,
Ca3UO6, Ca3U2O9, Ca4UO7, Ca5UO8, and Ca6UO9), Ubearing lakargiite Ca(Zr,Ti,U)O3, tululite (Cazincate-aluminate), Ca-Cd Oxide, oldhamite (Ca S),
Fe-Ni phosphides were identified in the varicolored
marble [2]. Primary calcium uranate phases are the
result of combustion of phosphorus-rich bituminous
marl and the oxidation of U+4 at high temperature into
U+6under high oxygen fugacity. The varicolored
marbles closely resemble cement-immobilized waste,
exposed to supergene weathering and alteration over
time spans are considered as unique natural analogs.
[1] Khoury et al. (2014) Applied Geochemistry, 43,
49–65. [2] Khoury et al. (2015) Canadian
Mineralogist, 53(1), 61–82
1668
Study On Geological
Characteristics And Genesis Of
Nancha Gold Deposit In
Tonghua City,Jilin Province.
LAN TIAN
[email protected]
This research is mainly concerned with a study of
The Geological Characteristics And Genesis Of
Nancha Gold Deposit In Tonghua City,Jilin
Province.The procedure were as follows by studying
the regional mineralization geological background of
mineral deposit、ore district and the mineral
deposit's geological characteristics,and also based on
that,we combined with the test analysis of the fluid
inclusion to discuss the contributing factors of
mineral deposit.The technique applied is referred to
as the test analysis of the fluid inclusion.The results
of the experiment indicated that the ore-controlling
structure is XiaoSiPing-HuangHou mountainNanCha"S" fracture type and its secondary fracture
and fold structure.Through the test analysis of the
fluid inclusion get the homogenization temperature
between 150℃ and 260℃,peak value centers
between 190℃ and 200℃ ,reflecting the
mineralization
temperature
is
middle-low
temperature;Metallogenic pressure range is between
9.49 Mpa and 20.55Mpa; Metallogenic depth is
between 0.95 km and 2.06km;The density of oreforming fluid is between 0.81 g/cm3 and 0.94 g/cm3 ,
peak value centers between 0.88 g/cm3 and 0.9
g/cm3;The salinity of ore-forming fluid is between
0.18 wt%NaCl and 0.59 wt%NaCl, peak value
centered between4 and 4.6.These findings of the
research led the author to the conclusion that what
we confirmed is that the NanCha gold deposit is the
Medium temperature hydrothermal altered rock type
gold deposit which controlled by the fracture and fold
structure.
1801
Source of ore fluids of the
Yangshan gold deposit, Western
Qinling belt, China: evidence
from microthermo-metry, noble
gas isotopes and in-situ sulfur
isotopes of Au-bearing pyrite
JINLONG LIANG1, WEIDONG SUN2, SHIJUN NI1
1No.1 Dongsanlu, Erxianqiao, Chengdu, Sichuan,
China; [email protected]
2No.11 Kehuajie, Wushan, Tianhe District,
Guangzhou, China; [email protected]
The issue of ore-forming fluids sources and
genesis model of sediment-hosted disseminated gold
deposits including Carlin-type and some orogenic
gold deposits has been debated for several decades.
Although Yangshan gold deposit was taken as the
largest Carlin-type gold deposit in China ten years
ago, there are still experts who propose that
Yangshan belongs to orogenic type gold deposit [1].
The microthermometric measurements show the
homogenization temperature from 221°C to 303.5 °C
and low salinities of 2.0~7.2 wt.% NaCl equiv of the
H2O-CO2 system. 3He/4He ratios of fluid inclusions
ranging from 0.0330 to 0.0809 Ra, shows no mantle
sources. The measured 40Ar/36Ar values of fluid
inclusion in pyrite and quartz range from 434.1 to
863, higher than the ratio of 40Ar/36Ar of air-saturated
water (295.5). The 40Ar*/4He values (0.0227-0.0539)
for the pyrite samples are far below the crustal and
mantle values (0.2 and 0.5 respectively).The in-situ
sulfur isotopes of Au-bearing pyrite results using
Nano-SIMS is as the following: framboidal pyrites
show low δ34S values of -23.8~-20.9‰; the pyrites
from mineralized plagiogranite dikes have a narrow
δ34S range of -4.4~1.3‰; and the inner part of zoned
pyrites form the main ore rocks of
black
carbonaceous phyllites have the similar δ34S feature
to the framboidal pyrites, whereas the rims enriched
in gold have δ34S values around 0‰, similar to the
pyrites in mineralized plagiogranite dikes.
Based on the characteristics mentioned above, we
concluded that: first, ore-forming fluids own typical
feature of orogenic gold deposit; second, recycled
meteoric water heated by magmatic heat source may
be a component of ore fluids instead of mantle matter
involvement; third, in-situ sulfur isotope analyses
indicate that the exact ore-related sulfur sources are
magmatic sulfur.
[1]Liang J.L., Sun W. D., et al. 2014, Journal of
Asian Earth Sciences. 40-52.
1965
The Silurian igneous rocks from
the Santander Massif
(Colombia) and its metallogenic
significance
LUIS C. MANTILLA F.*1, JUAN D. COLEGIAL G.1,
FABIAN BOTELLO1, YENNY Y. HERNÁNDEZ D.¹
AND CARLOS A. QUIROZ¹
1
Universidad Industrial de Santander (UIS),
Bucaramanga, Colombia (*correspondence:
[email protected]).
The Santander Massif (SM), located in the
Colombian Eastern Cordillera, registers different
Phanerozoic magmatic events. Except for the
Neogene magmatism (related to porphyry Mo-Cu and
epithermal Au-Ag mineralization) no metallogenic
potential has been attributed to these rocks.
The mapped ‘Durania Granite Unit’ (DGU),
outcropping in the central part of the SM is a pluton
composed by different lithologies: from plagioclaserich metaluminous to muscovite-garnet-bearing
peraluminous granite rocks (associated with high
pegmatite dikes formation). The chemistry of these
rocks are also variable: from tholeiitic to mediumhigh potassium calk-alkaline affinities. This wide
composition across this pluton is interpreted as
related to several magmatic pulses that took place
along with a changing tectonic setting: starting with a
locally more extensional and finishing with a more
compressional
environment
(continental
arc
magmatism). The transition towards compressive
settings (with a progressive crustal thickening and
crustal contamination) favored the formation of more
differentiated magmatic rocks (more felsic and more
peraluminous granite rocks with enriched light REE
relative to heavy REE, based on chondrite normalized
plots). The local abundance of tourmaline and
greisen-type hydrothermal alteration confined mainly
to the pegmatite dikes cutting the metamorphic rocks
of the Silgara Schist Unit (Early Ordovician in age;
Fammatinian
Orogeny)
suggests
a
coeval
development of magmatic-hydrothermal processes
with a probable metallogenic significance (W-Sn?).
The Zircon U-Pb geochronology indicates a GDU’
crystallization age of 442.6 Ma +7.4/-6.0 Ma (Early
Silurian). Similar Silurian igneous bodies
outcropping in the Merida Andes (Venezuela) allows
to suggest that the progressive crustal thickening
event was a regional episode which affected the
Colombia and Venezuela Andes.
2097
Implicit approach as a new age
in geological modelling
MITROFANOV ALESKANDR1, BAIANOVA
TAMARA2
1
2
[email protected]
[email protected]
Implicit modelling has been firstly invented in the
early 2000s and over the last years it has become the
well developed and highly promising technology for
geological wireframe modelling. Improved time
efficiency, visually more pleasing shapes of
geological features and ease of dynamic updating are
among the reasons for the success of this technology.
This type of modelling is fully based on Radial
Basic Functions (RBF), a mathematical function
whose value essentially depends on the distance from
a sample point (Stewart M. et al., 2014). The
techniques allow rapid creation of boundaries with
arbitrary geometry to describe for example faults,
weathering and lithological contacts from a variety of
data sources including drill holes, geological,
geophysical and geotechnical survey and mining
plans. The modeller is able to manipulate these
surfaces to create volumes and domains, which in a
geological context may represent features such as
mineralised zones, lithological and structural
domains, mining blocks or zones of geochemical
contamination.
The way of modelling based on spatial data has
been in many ways revolutionised by implicit
approach. Much less time is required to model
complex systems (weeks instead of months) and to
dynamically update of these models in light of new
data. This modelling can be applied at any stage of
project development, from early scoping studies (for
quick pre-resource estimation and operative
corrections of exploration programmes) up to
operational mining (for creating a model which can
be dynamically and automatically updated with a new
data). As an addition, implicit techniques can be
successfully implemented for lithological modeling
and particularly for developing models for large
strategic
PGE-bearing
intrusives
on
Fennoscandinavian shield.
At the same time, this approach often demands a
higher level of competency from the modelling team
and failure cost in that case increase dramatically. But
once the modeller has successfully navigated this
mathematical jungle, it should allow creation of
models that properly reflect an interpretation of the
underlying data, without the necessary limitations of
classical (explicit) approach.
The work was supported by RFBR (The Russian
Foundation for Basic Research) number 16-05-00305
and SRK Consulting.
2134
Fe - Mn Metamorphic Ore in
Sanandaj- Sirjan Zone, Iran:
Implication of Pull- Apart Basin
during Upper Jurassic Age
REZA MONSEF1 AND IMAN MONSEF2
Department of Geology, Shiraz branch, Islamic Azad
University, Shiraz, Iran ([email protected])
2
Department of Earth Sciences, Institute for Advanced
Studies in Basic Sciences (IASBS), Zanjan, Iran
(*Correspondance: [email protected])
1*
The Sanandaj–Sirjan Zone (SSZ) is a complex
dynamic structural zone between Zagros fold-thrust
belt bordered by the Zagros thrust in the southwest
and the Urumieh-Dokhtar magmatic arc in the
northeast. It has a length of 1500 km with a width of
150–250 km from the southeast to the northwest of
Iran and joins the Taurus belt in Turkey. As a whole
the rock units exposed in the SSZ Shahrekord,
southwest Iran, are predominantly composed of
amphibolite, gneiss, and amphibole schist of
Neoproterozoic age. This belt is characterized by the
consistent Zagros trend of the belt, the nearly
complete lack of Tertiary volcanic rocks, the poor
development of Tertiary formations in general, the
mostly Mesozoic age of the rocks except the
Paleozoic rocks exposed in the southeast, and
metamorphic deformed rocks associated with
abundant deformed and undeformed plutons in
addition to widespread Mesozoic volcanic rocks. The
Jurassic metamorphic and igneous rocks of SSZ in
Shahrekord contain Fe-Mn metamorphic ore with Mn
rich slate shale (Mean 30.2 %) and quartz- calcite
veins with Au mineralization (Mean 1.1 PPM). These
rocks display banding structure and hydrothermal
metamorphic input is indicated by the low LREE
contents and high HREE contents of hydrothermal
end-member composition, relative to MORB, a large
range in V/As ratio, and low U and Th contents.
These Mn-Fe rich complexes were originally
interpreted as pull-apart basin during middle to upper
Jurassic.
Reference
Berberian, M. and King, G. C. P. (1981).
Towards a paleogeography and tectonic evolution of
Iran. Can. J. Earth Sci., 18, 210–265.
2187
Ni and Fe bearing phases and
redox during the weathering of
the New Caledonia ophiolite
MANUEL MUÑOZ1, MARC ULRICH2, MICHEL
CATHELINEAU3, OLIVIER MATHON4
Univ. Grenoble Alpes, ISTerre, France,
[email protected]
2
Univ. Strasbourg, EOST, France,
[email protected]
3
Univ. Nancy, Géoressources, France,
[email protected]
4
ESRF, Grenoble, France, [email protected]
1
We investigate the mineralogy and crystal
chemistry of a boulder (~20 cm diameter) sampled in
the saprolite rocks of the Koniambo massif (New
Caledonia), which reflects early stages of bed-rock
weathering. A polished cross-section of the boulder
reveals
radial
weathering
profile.
“Fresh”
serpentinized-harzburgite is localized in the center
(zone 1), while a gradually increasing alteration
degree is observed from the center to the edge (zone
2 to 3). Large-scale µXRF maps performed on the
polished surface reveal a dense network of Ni-rich
mineral veins in the external part of the boulder. Thin
sections corresponding to the different alteration
zones were characterized by optical microscope,
electron microprobe (BSE, micro-analyses, X-ray
maps), and Raman spectroscopy. In addition, Fe and
Ni-K edge XANES spectra were collected in order to
determine, respectively, the oxidation state and the
speciation of these two cations.
In zone 1, lizardite – most likely formed during
oceanic hydrothermal alteration – is observed,
including ~0.2 to 0.4 wt% of NiO and a ferric-to-total
iron ratio (i.e., XFeIII) of ~0.5. In zone 2, oceanic
lizardite is still observed, together with partially
recrystallized/neoformed lizardite enriched up to ~1.5
wt% of NiO ; XFeIII increases up to 0.6-0.7. Zone 3
shows a dense network of phyllosilicate veins, mainly
composed of three different types of lizardite with
various chemical composition, i.e., 0.8 to 5 wt% NiO,
and 0.4 to 2 wt% Al2O3. Petrological observations
show a reactivation of the lizardite network through
the precipitation of highly concentrated Ni-talk-like
(kerolite) in the central part of the veins. A first
generation concentrates nickel up to ~20 wt% NiO,
which appears to be subsequently replaced by a
kerolite vein with ~36 wt% NiO; both minerals are
highly depleted in iron (0.4 and 0.1 wt%,
respectively). XFeIII ranges from 0.8 to 1 in those
veins, showing a clear correlation between the
occurence of Ni-bearing phases and the XFeIII ratio in
neoformed phyllosilicates.
2190
Pb isotope ratios of the Akeshi
Au deposit, Kagoshima, Japan:
Implication for gold
mineralization
SHUMPEI MURAKAMI1, KOICHIRO FUJINAGA2,1,
SHUHEI ARAKI3, JUNICHIRO OHTA4, KAZUTAKA
YASUKAWA1,2, KENTARO NAKAMURA1,
YASUHIRO KATO1,2,4*, KYOHEI KUROKAWA5,
HIKARU IWAMORI4,6, KAZUYA NAGAISHI7,
TSUYOSHI ISHIKAWA4
1
School of Engneering, Univ. of Tokyo
(shumpei-m�egeo.t.u-tokyo.ac.jp)
2
Chiba Institute of Technology
3
Mitsui Mineral Development Engineering Co.,
LTD.
4
JAMSTEC
5
Mitsui Kushikino Mining Co., Ltd.
6
Dept. Earth Planet. Sci., Tokyo Institute of
Technology
7
Marine Work Japan Co., Ltd.
(*Corresponding: [email protected])
Elucidating the origin of the deposits can provide
a crucial key constraint in exploration for new
mineral deposits. For epithermal deposits, it is
commonly considered that ore-forming fluids
originated from hydrous magmas and/or created by
circulation of the meteoric water within the shallow
crust play an essential role. The previous
mineralization models have been proposed on the
basis of isotopic study of relatively light elements
(e.g., H and O) in ore-forming fluid [1]. However,
recent isotopic studies on heavy metals (e.g., Pb and
Nd) suggest the involvement of another important
component, i.e., slab-derived fluid, to the formation
of epithermal ore deposits [2].
In order to detect direct information of source of
metals contributing to the formation of epithermal
gold deposits, we study Pb isotopic compositions of
sulfide ores from the Hishikari and Akeshi gold
deposits both in Kagoshima, Japan. Analytical results
suggest that some ore samples are consistent with the
previous ore-forming model indicating shallow fluid
circulation. However, several ore samples imply that
slab-derived fluid contributes to mineralization of
hydrothermal ore deposits as was recently suggested
[2]. The relationship between Pb isotopic ratio and
the Au concentration also suggests that both the bed
rock and the slab-derived fluid contribute to the Au
mineralization.
[1] Hedenquist and Lowenstern (1994) Nature 370,
519-527.
[2] Fujinaga et al. (2013) GEOFLUID 3.
2411
Genetical modelling of the Hg,
Sb and Au deposits in the
continetal rift zone of the Küçük
Menderes, Western Anatolia,
Turkey
NEVZAT ÖZGÜR
Süleyman Demirel University, Faculty of
Engineering, Department of geological
Engineering, 32260 Isparta, Turkey
([email protected])
Within the Menderes Massif, the continental rift
zones of the Büyük Menderes, Küçük Menderes and
Gediz were formed by extensional tectonic regimes
from Early to Middle Miocene which strike E-W
generally and are represented by a great number of
epithermal Hg, Sb and Au mineralizations,
geothermal waters and volcanos from Middle
Miocene to recent. The epithermal mineralizations
and geothermal waters are related to faults which
strike preferentially NW-SE and/or NE-SW and
locate diagonal to the E-W general strike of the
continental rift zones. These faults are probably
generated by compressional tectonic stress which
leads to deformation of uplift between two
extensional rift zones.
The epithermal Hg, Sb and Au minaralizations
are located in the eastern part of the continental rift
zone of the Küçük Menderes within the Menderes
Massive. The ore mineralizations of these deposits
are associated with Paleozoic mica schists. At the
surface, the host rocka are intensively altered by
interaction with the circulation of geothermal fluids.
Therefore, the ore fields can be recognized by a
distinct color change of the host rocks. The
hydrothermal alteration is noticable at the surface
clearly which is distinguished by phyllic, argillic and
silicic alterations zones.
The isotopic ratios of δ18O and δ2H in fluid inclusions
of quartz and stibnite samples from Hg deposit of
Halıköy, Sb depsoit of Emirli and arsenopyrite-Au
deposit of Küre in the continental rift zone of the
Küçük Menderes show a similarity with active
geothermal
systems.
By
using
geological,
geochemicl, isotope geochemical, ore and rock
microscopical and microthermometric methods, these
epithermal Hg, Sb and Au deposits in the continental
rift zone of the Küçük Menderes have been modelled
genetically and can be considered as fossile
geothermal systems.
(1) Özgür, N., 1998, Aktive und fossile
geothermalsyteme in den kontinentalen Riftzonen des
Menderes Massives, W-Anatolien, Türkei. Freie
Universität Berlin, Habilitatiionsschrift, 171 p.
1659
The origin of ore-forming fluids
of the Wandao gold deposit,
southeastern Guangxi, China
X. LAI1, B. PANG1*, Q. ZHANG1, Y. LI1, J. LV1
AND Y. ZHOU1
1
Guilin University of Technology, Guilin, 541004, China
The Wandao gold deposit is located in
Dayaoshan polymetallic metallogenic belt of
southeastern Guangxi. The exposed strata in Wandao
ore district is middle Cambrian Huangdongkou
Formation which is of low-grade metamorphic
argillaceous sandstone and carbonaceous slate. The
Dawangchong and Gulinao granite porphyry bodies,
formed in Caledonian, are output in or near mining
area. Ore bodies are mainly controlled by the nearly
EW-striking structural fracture zone. A single ore
body occurs in quartz vein or quartz lenticular in
frature zone which elongates into granite porphyry or
in contact zone between granite porphyry and strata.
some previous workers proposed that the ore-forming
fluid was predominantly magmatic in origin. In
contrast, we argued that metamorphic fluid is an
alternatively source of the ore-forming fluid based on
a
preliminary
study
of
fluid
inclusion
microthermometry and Raman spectrum.
According to cutting relationship of ore-bearing
quartz veins, the Wandao gold deposit can be divided
into main mineralization stage and late mineralization
stage. Quartz veins in main stage are smoky gray or
milky and often associated with pyrite. Quartz veins
in late stage are white and cut main stage quartz
veins. The size of fluid inclusions in quartz in two
stages ranges from 2 μm to 7 μm. The
homogenization temperatures of fluid inclusions in
the main stage and late stage quartz range from
323.5℃ to 384℃ and from 237.7℃ to 309.6℃,
respectively. The main mineralization stage
inclusions show salinity range of 1.06-3.23wt% NaCl
equiv and trapping pressure estimated between 213252×105Pa. The late mineralization stage inclusions
show salinity range of 1.57-3.87wt% NaCl equiv
trapping pressure estimated between 157-203×105Pa.
To sum up, ore-forming fluids in the Wandao gold
deposit are middle to high temperature, low salinity
and low density ones.
The δD value of inclusion water in two stages
changes from -68‰ to -31‰, and δ18Oquartz value of
quartz changes between 12.6‰ and 15.0‰.
According to the formula (Clayton et al, 1972) , the
δ18Owater value are from 5.03‰ to 9.46‰. Laser
Raman Spectrum analysis indicate that gases in fluid
inclusions are mainly CO2, H2O and a small amount
of CH4. Hydrogen and oxygen isotope analysis and
Laser Raman Spectrum analysis suggest that the oreforming fluids in the Wandao gold deposit are mainly
metamorphic water and the deposit type should be
orogenic gold deposit.
Acknowledgments This project is supported by
NSFC(41362006) , CGS(12120114052501) and
GXNSF(2013GXNSFAA019275)
2517
Mafic rocks vs. Sbmineralisation: a role in the
early metal distribution
processes? Insights from the
Variscan Armorican belt
(France)
ANTHONY POCHON1*, ERIC GLOAGUEN23,
12
1
YANNICK BRANQUET , MARC POUJOL , CHARLES
2
23
GUMIAUX , FLORENCE CAGNARD , DENIS
GAPAIS
1
Géosciences Rennes, UMR 6118, OSUR, Université
de Rennes 1, 35042 Rennes Cedex, France
2
ISTO, UMR 7327, Université d’Orléans, 1A rue de
la Férollerie, 45071 Orléans Cedex 2, France
3
BRGM, UMR 7327, 3 avenue Claude-Guillemin,
BP 36009, 45060 Orléans Cedex 02, France
1
The Armorican belt is part of the western
European Variscan belt. Although the region was one
of the world leader producers of antimony at the
beginning of the 20th century, the geological controls
behind these deposits remain badly constrained. Here
we present a spatial statistical analysis of the Sbmineralisation, together with geophysical and
geological data [1]. Results show that the Sbmineralisation is spatially associated with strong
positive gravity and magnetic anomalies which must
be linked to the presence of mafic/ultramafic bodies
at depth. This spatial link is further supported by the
numerous outcropping occurrences of dolerite dykes
and sills close to the Sb-deposits and sometimes
hosting the mineralisation. This mafic magmatism,
dated by in-situ U-Pb analyses on apatite at ca. 360
Ma, appears as a regional-scale event at the
Devonian-Carboniferous boundary. In addition, new
data suggests that mafic magmatism may have
probably played a role in the early distribution or
redistribution processes of metal stock in the
subsequent history of the antimony in the Variscan
Armorican belt.
[1] Pochon et al. (2016). Terra Nova, doi:
10.1111/ter.12201
2635
Recent investigation on Agbearing minerals at the River
Reef Zone, the Poboya Prospect,
Central Sulawesi, Indonesia
T.A. RIVAI1*, K. YONEZU1, SYAFRIZAL2, D.
KUSUMANTO3 AND K. WATANABE1
Department of Earth Resources Engineering, Kyushu
University, Fukuoka 819-0395, Japan
2
Earth Resources Exploration Research Group,
Faculty of Mining and Petroleum Engineering,
Institut Teknologi Bandung, Bandung 40191,
Indonesia
3
Bumi Resources Minerals, Jakarta 12920, Indonesia
1
Epithermal deposits are generally known to have
Au-Ag [1] thus in this study the importance of Agbearing minerals are focused to understand the
mineralization condition in addition to electrum. Agbearing minerals were analyzed through ore
microscopy and scanning electron microscopy with
energy dispersive X-ray.
As the results, several principal Ag-bearing
minerals have been recognized, such as electrum,
naumannite-aguilarite,
selenopolybasite
and
freibergite. Ag, either as a main or supplementary
element, is also contained in other minerals:
aguilarite-acanthite,
argyrodite,
pyrargyrite,
chalcopyrite, sphalerite and pyrite in various
proportion (Table 1). Besides being identified as free
grains, these minerals are often coexisted with other
minerals in forms of simple-spotty mutual grains and
inclusion-host
minerals.
Further
study
on
characteristics of the ore-forming fluid will give us an
insight of physicochemical environment of the
mineralization.
Mineral
Ag Content (at.%)
Electrum
52.75 - 85.56
Naumannite-aguilarite
64.91-70.54
Aguilarite-acanthite
64.02
Argyrodite
55.68
Selenopolybasite
48.69 - 55.23
Pyrargyrite
40.96 - 46.09
Freibergite
14.40 - 20.82
Chalcopyrite
4.03 - 5.40
Sphalerite
1.02
Pyrite
1.85
Table 1: Ag content in each Ag-bearing mineral.
[1] Hedenquist et al. (1996), Resource Geol. Spec.
Publ. 1.
2694
Re-Os systematics of löllingite
and arsenopyrite in granulite
facies garnet rocks: Insights into
the thermal evolution of the
Broken Hill block during the
Early Mesoproterozoic
N.J. SAINTILAN1*, R.A. CREASER1, P. G. SPRY2
Department of Earth and Atmospheric Sciences,
University of Alberta, Edmonton, Canada
(*correspondence: [email protected],
[email protected])
2
Iowa State University, Ames, IO, USA
([email protected])
1
Löllingite and euhedral arsenopyrite crystals are
reported from granulite facies spessartine-almandine
garnet rocks closely associated with the Pb- and Znsulfide orebodies at the Broken Hill deposit, Southern
Curnamona Province (SCP), New South Wales,
Australia [1,2]. Sulfide minerals comprise löllingite
and coexisting arsenopyrite ± galena ± tetrahedrite
interestitial to garnet crystals. Löllingite formed first
whereas gold-bearing löllingite, now occurring as
relicts in arsenopyrite, was destroyed to produce
arsenopyrite ± gold microinclusions.
Standard mineral separation procedures produced
pure separates of löllingite, arsenopyrite and
arsenopyrite ± löllingite. Re-Os data of these mineral
fractions show a very narrow range of 187Re/188Os (7
to 11) and 187Os/188Os ratios (0.8505 to 0.9650) but in
187
Os/188Os vs. 187Re/188Os space define a Model 1
isochron (n = 14) with an age of 1534 ± 33 Ma (2σ;
MSWD = 0.78, initial 187Os/188Os ratio of 0.672 ±
0.005). Os and Re contents are extremely high for all
sulfide phases (Re = 120‒475 ppb; Os = 65‒345 ppb)
likely as a result of concentration of Re and Os in
these minerals during granulite facies metamorphism,
from the inferred exhalite protolith.
In the polydeformational and polymetamorphic
history of the granulite facies rocks of the SCP,
monazite grew from lower amphibolite facies at ca.
1657 Ma to granulite facies at ca. 1602 Ma [3]. The
current age of sulfide mineralization implies a
cooling rate of 3 to 4ºC/Ma in the SCP from ca.
780ºC (monazite precipitation) to ca. <550ºC and
formation of arsenopyrite from the destruction of
gold-bearing löllingite during late retrograde
metamorphism [3, this study].
[1] Spry, P.G., Wonder, J.D. (1989) Can Miner
27, 275-292.
[2] Plimmer, I.R. (2006) Miner Petro 88, 443-478
[3]McFarlane, C.R.M., and Frost, B.R., (2009) J
Metamorphic Geol 27, 3-17
2792
New 40Ar/39Ar ages of Sn- and
W-polymetallic mineralization
in the Erzgebirge / Krušné hory
(DE, CZ)
THOMAS SEIFERT1*, GALINA G. PAVLOVA2
1
TU Bergakademie Freiberg, D-09599 Freiberg,
Germany
2
Inst. Geol. & Mineral. SB RAS, Novosibirsk
630090, Russia
The Erzgebirge/Krušné hory (DE, CZ) is known
for different types of late-Variscan greisen
mineralization with high potential for rare metals.
Four greisen types (GT) can be distinguished: GT1,
Sn-Li(-W-Mo)-greisen with quartz, topaz, Li-micas,
fluorite, cassiterite, wolframite, sulfides (e.g. Krupka,
Zinnwald); GT2, Sn-greisen with quartz, topaz,
(Li)muscovite, fluorite, cassiterite, wolframite,
sulfides (e.g. Gottesberg); GT3: Sn(-W-Mo-Li-ZnCu-In)-greisen with quartz, Li-mica, topaz, fluorite,
chlorite, cassiterite, sulfides (e.g. Sadisdorf); GT4:
W(-Mo-Bi)-greisen/veins with quartz, (Li)muscovite,
wolframite, scheelite, sulfides (e.g. Pechtelsgrün).
New 40Ar/39Ar analyses of greisen-micas show
well defined plateau ages: Sn-W-Mo deposit Knötel
(Krupka), protolithionite in quartz-mica greisen with
molybdenite and wolframite: 312±3.1 Ma; Li-Sn-W
deposit Zinnwald, zinnwaldite in quartz-mica greisen
(massive greisen and vein-greisen): 311.4±3.0 Ma
and 312.5±3.1 Ma; Sn(-W-Mo-Cu-Zn-In) deposit
Sadisdorf, Li-mica from the mica-quartz-topazgreisen (“Innengreisen”): 310.0±3.5 Ma; W-Mo-Bi
deposit Pechtelsgrün (290 m level), muscovite in
mica-quartz-greisen with W-Bi mineralization:
318.2±3.1 Ma and with W-Mo-mineralization:
320.4±3.0 Ma.
Prevoius [1, 2, 3, 4] and new age data indicate
that the W-Mo association (GT4: 320 Ma and 318
Ma) is the first late-Variscan mineralization stage in
the Erzgebirge. The Sn(-W) association with GT1
(315-309 Ma) and GT3 (310 Ma) show younger age
data. In summary the above mentioned data confirm
that the W-Mo and Sn-W association are spatially
and temporally related to different post-collisional
granite/rhyolitic and lamprophyric intrusions (320290 Ma).
[1] Seifert & Kempe (1994) Beih. Eur. J. Miner. 6,
125-172. [2] Baumann, Kuschka, Seifert (2000)
Lagerstätten des Erzgebirges, Enke Verlag, 300 pp.
[3] Seifert (2008) Metallogeny and Petrogenesis of
Lamprophyres in the Mid-European Variscides, IOS
Press, 303 pp. [4] Seifert et al. (2011) Mineralogical
Magazine 75, 1833.
2803
Hydrothermal processes in
Sangdong W-Mo deposit, Korea
SEO, JUNG HUN1*, YOO, BONG CHUL2, LEE, JUN HEE1,
LEE, TONG HA1, KIM, CHAN SU1, MOON, KUN JOO3
1
Department of Energy Resource Engineering, Inha
University, Korea, [email protected] (* presenting author)
2
Korea Institute of Geoscience & Mineral Resources
(KIGAM)
3
Sangdong Mining co.
Sangdong W-Mo deposit located in NE of S.
Korea consists of stratabound orebodies mostly in the
intercalated carbonate layers in the Cambrian
Myobong slate. The scheelite-molybdenite ores are
associated by the Upper Cretaceous hydrothermal
activity (82-83 Ma) [1], while no exposed outcrops of
associated intrusions. The major ore-bearing layers
consist of ‘footwall orebody’, ‘main orebody’, and
‘hangingwall orebody’. Each layers are skarnized
earlier hosting minor scheelite, and the central part of
the skarns are subsequently crosscut by the swarms of
quartz veins hosting major scheelite-molybdenite
ores. Two types of alterations around the quartz veins
overprint the earlier garnet-pyroxene skarn, 1)
amphibole alteration and 2) quartz-mica (biotitemuscovite) alteration. Recent drill core exploration
located the molybdenite-bearing quartz veinlets with
sericite alteration in the Jangsan quartzite underneath
the Myobong slate [2].
Fluid inclusions in the quartz veins from the
footwall orebody, the main orebody, and the deep
quartz-molybdenite veins are mostly liquid–rich
aqueous inclusions having bubble size of 10-20
vol.%, salinities of 2-8 wt% NaCleqv., and
homogenization temperatures of 150-350 °C.
Densities of the aqueous inclusions are 0.70-0.94
g/cm3. No brine inclusions were observed in the vein,
which indicates no phase separation of the
hydrothermal fluids. The fluid isochore are combined
with Ti-in-quartz geothermometry to constrain the PT conditions during the ore formations.
The fluid inclusions were subsequently analysed
by the LA-ICP-MS. The similar Rb/Sr ratios in the in
fluid inclusions of the respective orebodies indicate
same fluid or igneous source, while changing Cs
concentrations in the fluids indicate a batholith-scale
fractionation of the associated magma. REE patterns
and the concentrations of the redox–sensitive trace
elements such as Mo, U, and Th in the scheelite
suggest a redox change in the hydrothermal oreforming fluids, which might control the molybdenite
precipitation in Sangdong deposit.
[1] Farrar E. et al. (1978) Econ. Geol. 73, 547-566.
[2] Moon K.J. (1991) J. Geochem. Explor. 42, 205221.
2855
F and Cl in sericite evidence of
volatiles fugacity of
hydrothermal fluids in Hamand
porphyry copper deposit, SW
Birjand, Iran
K.SIAHCHESHM AND A.A. CALAGARI 12
1,2
Department of Earth Sciences, University of
Tabriz,, Iran. (*correspoundance:
[email protected]) ,
([email protected])
The systematic compositional variations of
sericite through the different alteration zones within
Hamand porphyry copper deposit used as an evidence
for specifying halogen fugacity ratios of associated
hydrothermal fluids. Sericite from the potassic zone
(XSer = 0.94) possesses a moderate F content (0.1 to
0.69 wt.%) that is significantly higher than in argillic
zone (0.08 to 0.31 wt.%), producing a positive
correlation with XMg and negative correlation with Cl.
The systematic variation of the logarithmic halogen
ratios reflects a systematic variation of the F/Cl in
sericites through different alteration zones. With a
decrease in temperature, the log (fH2O/fHF) and log
(fH2O/fHCl) values calculated for fluids equilibrated
with sericite increase progressively from potassic to
phyllic to argillic zones. The decrease in halogen
content of hydrothermal fluids towards outer parts of
the deposits reflects an increase in the degree of
mixing between magmatic fluid and meteoric water.
Experimental
equilibrium
constants
are
following:
log
Ksericite
=
log
(Xx/XOH)sericite
+
log
(fH2O/fHX)fluid,log K*sericite = 2100/T + 1.523(XMg) +
0.416(XFe) - 0.11(XAl),
The fugacity ratios of halogen-hydroxyl
exchanges in the hydrothermal fluids are calculated
using a combination of both equilibrium constant
formulas. These are:
log (fH2O)/(fHF) = log K* - log (XF/XOH), and
log (fH2O/(fHCl) = log K* - log (XCl/XOH).
8.00
7.00
)l
C
H
f( 6.00
)/
O
2
H 5.00
(f
g
lo
potassic
phyllic-‐Igdr
phyllic-‐Qmz
argillic
4.00
3.00
3.0
3.5
4.0
4.5
5.0
log(f H2O)/(f HCl)
5.5
6.0
Figure 1. Log (fH2O)/(fHF) against log
(fH2O)/(fHCl) plot, defining the fugacity ratios of
hydrothermal fluids.
2967
Tourmaline boron isotopic
evidences of fluid mixing in
IOCG deposits in the Kangdian
district, China
ZHIKUN SU1, XINFU ZHAO1 *
1
State Key Laboratory of Geological Processes and
Mineral Resources, and Faculty of earth
resources, China University of Geoschiences,
Wuhan 430074,China (*correspondence:
[email protected], [email protected])
The sources of ore-forming fluids of iron oxidecopper-gold (IOCG) deposits remain highly debated.
Alternative models invoke either magmatic origin or
circulation of basinal brines, and some studies
suggest that ore fluids of IOCG deposits might have
more than single source. Boron isotopes of
tourmaline, having large variation at different
reservoirs, potentially provide an approach to unravel
this problem.
Three types of tourmaline have been identified in
the IOCG deposits of Kangdian region. Type 1
tourmaline occurs in the cement of breccia body
associated with the orebody. Type 2 tourmaline is
disseminated grain in massive Fe ores. Type 3 occurs
as barren veins in albitite country rocks nearby the
Cu-Fe orebodies. The δ11B values of the three types
of tourmaline, analyzed by LA-MC-ICPMS, span
from -15.4‰ to +19.5‰. Type 1 tourmaline yields
δ11B values from -15.4‰ to -4.6‰, within the range
of tourmaline of pegmatite and granite worldwide,
indicating a magmatic source. In contrast, type 3
tourmaline has δ11B values from +10.8‰ to +19.5‰
with an average value of +16.7‰, indicating a source
from marine evaporate or basinal brine. Type 2
tourmaline from massive Fe ores has intermediate
values from -2.5‰ to +0.6‰, which are plotted
between the Type 1 and Type 3 tourmaline and are
hence interpreted as mixing of fluids from the
magmatic and marine-derived sources.
Our work highlights that the incorporation of
external fluids may act as key triggers for formation
of IOCG deposits and the utility of tourmaline B
isotopes as indicator of fluid sources.
2978
Trace Metals in Crude Oil: An
Alternative Geochemical
Interpretation
I. SUGIYAMA1* AND A.E. WILLIAMS-JONES1
Department of Earth and Planetary Sciences, McGill
University
[email protected] (*primary author)
1
Crude oils are known to contain elevated
concentrations of metals such as nickel (Ni),
vanadium (V), zinc (Zn), iron (Fe), molybdenum
(Mo), and chromium (Cr) [1,2,3,4]. Elevated metal
concentrations in crude oils are thought to be
controlled by the composition of the crude oil (eg.
Porphyrin abundance, aspahltene content, etc.),
protolith shale geochemistry or basin architecture
(open vs. closed) [1,2,3,4,5]. The relative importance
of the aforementioned parameters remains poorly
understood and the possible contribitions of other
processes have been under exlplored.
In order to test some potential processes that
might affect metal profiles in crude oils, we analyzed
17 crude oils from various locations (Canada and
Norway) for Ni, V, Mo, Zn, nitrogen (N), and sulfur
(S). We also isotlated the asphaltene fraction from
one of the heavy crude oils and performed trace metal
analyses to test the proportion of metals in the
asphaltene fraction.
Based on our results, Ni and V showed strong
linear correlations with S and moderate correlation
with N, while Mo and Zn did not show a significant
correlation. Furthermore,
Ni and S ratios
significantly differed from a 1:1 nickel sulfide (NiS)
stoichiometric ratio, which is thought to be one of the
favorable species likely to occur in crude oils [1,2,4].
Finally, the majority of the Ni and V resides within
the asphaltene fraction (>90%), indicating that sulfur
macromolecules
and/or
other
organosulfur
compounds might be playing a key role in controlling
the Ni and V concentrations in crude oils.
[1] Manning, D. A., & Gize, A. P. (1993). The role of
organic matter in ore transport processes. In Organic
Geochemistry (pp. 547-563). Springer US. [2]
Lewan, M., Factors controlling the proportionality of
vanadium to nickel in crude oils, Geochimica et
Cosmochimica Acta 48.11 (1984): 2231-2238. [3]
Parnell, J. (1988). Metal enrichments in solid
bitumens: a review. Mineralium Deposita, 23(3),
191-199. [4] Filby, R. H. (1994). Origin and nature of
trace element species in crude oils, bitumens and
kerogens: implications for correlation and other
geochemical studies. Geological Society, London,
Special Publications, 78(1), 203-219. [5] Rooney, A.
D., Selby, D., Lewan, M. D., Lillis, P. G., & Houzay,
J. P. (2012). Evaluating Re–Os systematics in
organic-rich sedimentary rocks in response to
petroleum generation using hydrous pyrolysis
experiments. Geochimica et Cosmochimica Acta, 77,
275-291.
3109
Fluctuations in the Chemical
Composition of Electrum at the
Lebong Tambang Gold Deposit,
Southern Sumatra, Indonesia
K. TERASHIMA1*, K. YONEZU1, T. TINDELL1, E.
SURYANI2, M. F. ROSANA 3
Department of Earth Resources Engineering,
Kyushu University, Fukuoka, 819-0395, Japan
2
PT Tansri Madjid Energi, Indonesia
3
Faculty of Geology, Padjadjaran University,
Bandung, Indonesia
1
Lebong Tambang is a low-sulfidation epthermal
gold deposit located at Lebong District, Southern
Sumatra, Indonesia. There are many gold prospects in
the area. Among them, Lebong Tambang has been
well known for its high-grade gold and much amount
of gold ore reserve. The main veins of the Lebong
Tambang deposit have already been mined out,
however exploration of its extension is being
conducted. This study is to understand the
characteristics of gold mineralization as an initial
stage of study of the deposit. The oldest formations
recognized in the area consist of mudstone referred to
as the Jurassic-Cretaceous Woyla Group. Woyla
group is unconformably overlain by andesitic to
basaltic lava and tuff of the Neogene Hulusimpang
Formation. Most veins are hosted by Woyla Group.
In contrast, only a few veinlets are found in the
Hulusimpang Formation.
Based on observed mineral association and
results of fluid inclusion microthermometry, it is
estimated that the temperature of ore-forming fluid
was 170° ~ 190°C and the fluid was neutral to
slightly alkaline. Characteristic mineral assembladges
and their textures suggest that ore-forming fluid
boiled since early stage of mineralization and was
resulted in electrum deposition in some parts in the
deposit. Association of uytenbogaardtite and argentite
suggests that there was later lower temperature and
oxidizing fluid affect after primary deposition.
Presence of gold rich electrum surrounding relatively
silver rich electrum and Ag-Se-S minerals is
consistent with the change in gold content in electrum
which is expected based on mineral stability with
respect to fugacity and temperature of the later fluid.
In addition, gold rich electrum associated with iron
hydroxides and malachite was found in high-grade
gold ore. Therefore, there is the possibility that highgrade gold ore was formed as a result of
remobilization of gold and/or silver by the later fluid.
3134
Characteristics of the Au-Ag-Te
Mineralization in the Kencana
Epithermal Gold Deposit,
Halmahera
THOMAS TINDELL1*, TAKASHI HASE1, KOTARO
YONEZU1, SYAFRIZAL2 AND KOICHIRO
WATANABE1
Department of Earth Resources Engineering, Kyushu
University, Fukuoka, 819-0395, Japan
2
Department of Mining Engineering, Institute of
Technology Bandung
1
The Kencana epithermal deposit is situated in the
north-eastern extreme of the archiopelago of
Indonesia, located on Halmahera Island, between
Sulawesi to the west and New Guinea to the east.
Formed as a group of vein type mineralizations, it
makes up the highest grade gold deposit of the
Gosowong mining area. Which is composed of a
number of prospects and operating deposits. The
island of Halmahera is split simply into the Western
and Eastern Provinces, in which the Eastern Province
is composed of Cretaceous ultramafics and ophiolites.
Bounded by Tertiary limestones and andesite and
basaltic rocks. Later Teriary volcanic rocks of
andesite, dacite and rhyolite form the main host of
mineralization in the Gosowong District, and which
is roughly the north-south striking ancient analog of
the present Halmahera Arc, situated presently off the
western coast.
Kencana is composed of 3 principle ore veins;
K1, K2 and K-link. This study focuses on the
mineralization of the K1 vein. K1, strikes in a NWSE direction, almost contiguous with the T-Fault,
though the nature of this connection is unknown. The
upper zones of the K1 vein are composed of
crustiform colloform bands at 100-150m depth and
Au grades in excess of 1000g/t. Below (150-200m),
the vein is largely composed of hydrothermal breccia,
initially of weakly banded to massive quartz, and a
latter crustiform colloform quartz band. Cockade
texture is common in this breccia, with host rocks of
the Gosowong Volcaniclatics, typically showing
strong chlorite alteration of the hematitic mudstones
and andesites. Measured Au grades here reach
2000g/t, with the majority of the gold present as
electrum (>70at.%) in the earlier stage massive
quartz, with few tellurides (hessite being the most
encountered). The crustiform band that follows the
main mineralization event is composed of repeating
bands of chalcopyrite (ubiquitous), hessite, petzite,
sylvanite, electrum and stuzite. Base metals are
composed of galena and Cd-rich sphalerite anb a
form of zincian-greenockite. The base of this vein is
composed of sheeted quartz veins, locally amethystic,
with an upper grade of 7g/t.
3369
Trace element and sulfur
isotopic evidence for redox
changes during formation of the
Wallaby gold deposit, Western
Australia
JOSEPHINE WARD1*, JOHN MAVROGENES2,
AMBERLEY MURRAY AND PETER HOLDEN
Research School of Earth Sciences, The Australian
National University, Canberra, 0200 ACT,
Australia (*Correspondence:
[email protected])
2
Research School of Earth Sciences, The Australian
National University, Canberra, 0200 ACT,
Australia
1
Wallaby, WA, is a gold deposit with an estimated
resource of 7 million ounces of gold. It has a wellestablished paragenesis displaying mineral evidence
of a redox change across five vein sets, each of which
contains pyrite. Pyrite from each vein generation has
undergone microanalysis techniques to show a
progressive and gradual change in redox conditions.
The sulfur isotope composition has a δ34S range of 7.7 to +9.8 ‰ using 3 micron spots on the SHRIMPSI. Negative values indicative of an-oxidized sulfur
signature are found in the earliest generation of pyrite
which contains high concentrations of As, Ni, Zn,
Ag, Sb, Cu and Pb. Conversely, positive values
representative of reduced sulfur signatures are found
in later generations of pyrite which has lower
concentrations of As, Ni, Sb, Cu, Zn and Pb. These
later pyrite crystals display higher ratios of As to Ni,
As to Sb, and As to Bi, and conversely a lower Cu to
Te ratio. The geochemical trends are clearly related to
minor and trace elements held within the pyrite that
are believed to be redox controlled. Previous
suggestions of a single orogenic event, under
oxidizing conditions formed the Wallaby gold deposit
are supported by the present study. We have
demonstrated that pyrite from the Wallaby gold
deposit formed via sulfidation and a gradual change
in redox conditions within an evolving fluid and did
not result by the mixing of two separate fluids as
previously advocated. This study also demonstrates
the use of pyrite as a valuable mineral tracer in goldbearing fluid systems.
3393
Fluorine Geochemistry of
Baogutu Intermediate - Acidic
intrusive bodies, West Jungger
(Xinjiang, NW China)
SHAONI WEI
College of Geology and Environment, Xi’an
University of Science and Technology, Xi’an
710054, Shaanxi, China ([email protected])
Fluorine, one of the most common mineralizing
elements, is important for understanding the
magmatic-hydrothermal mineralization process [1-2].
Experimental data show that, in intermediate-acidic
magmatic systems (SiO2 between 45 wt. % and 65
wt. %), fluorine is preferentially incorporated into
fluid phase (DFfluid/melt＞1) [3-5]. The intermediate acidic intrusive bodies in Baogutu area (West
Jungger, Xinjiang) show large differences of
mineralization features [6-7]. The fluorine content of
weakly, moderately and strongly mineralized
intrusions are 204ppm ~ 512ppm (average value of
369ppm), 287ppm ~ 573ppm (average value of
427ppm) and 466ppm ~ 811ppm(average value of
639ppm) respectively. Obviously higher values in
strongly mineralized intrusions signify the
importance
of
fluorine
during
magmatichydrothermal mineralization process. In addition,
higher fluorine content is well coincided with copper
mineralization, suggesting that fluorine is helpful on
copper migration.
[1] Webster JD (1990) Contrib. Mineral. Petrol. 104,
424-438. [2] Keppler H (1993) Contrib. Mineral.
Petrol. 114, 479-488. [3] Xiong et al. (1998)
Geochimica 27, 66-73. [4] Chevychelvo et al. (2008)
Chemical Geology 256, 172-184. [5] Borodulin et al.
(2009) Doklady Earth Science 427, 233-238. [6] Shen
et al. (2009) Acta Petrologica Sinica 25, 777-792. [7]
Cao et al. (2013) Ore Geology Reviews 56, 159-180.
3546
Simulation of Water-rock
Reaction Theory of Gold Ore In
GanSu DaShui
YANG BIN1 PENG XIUHONG2* SHI ZEMING3 NI
SHIJUN4 ZHENGHAO5
College of earth science of ChengDu University of
Technology,China SiChuan ChengDu,610059;
([email protected])
2 .Learn key laboratory of nuclear technology of
ChengDu University of Technology,China
SiChuan ChengDu,610059
Revolutionary New Method
In the ore-forming fluid caused by
hydrotherm，the solubility of calcite will increase
gradually with the temperature decrease gradually
and the concentration of CO2 in gas increase.In a
closed system，calcite will not deposit if it is the
cooling action caused only by the falling of
temperature.The ore-forming fluid with high
temperature and the surrounding rock occur strong
interaction，making the ore-forming fluid lose large
number of hydrogen ion and take in plenty of calcium
ion，magnesium ion，iron ion.In this process，the
ore-forming fluid and surrounding rock will generate
strong isotope exchange reaction.Under this
reaction，the calcite will deposit with the gradual
saturation of the ore-forming fluid.Therefore，the
linear relation ofδ13C、δ18O in calcite may be the
results of water-rock reaction[Figure 1].From this
perspective，the characteristic of carbon-oxygen
isotope composition may be the result of water-rock
reaction，which explains that the water-rock reaction
theoretical simulation can be used to study the source
of the ore-forming fluid in DaShui gold ore[1,2].
Discussion of Results
The value of δ13C shows the carbon in early
mineralization stage of DaShui Gold ore mainly
comes from the deep，otherwise the calcite relates to
the dissolution of carbonate obviously.Carbon isotope
shows that the ore-forming fluid in DaShui Gold ore
could relate to magmation. InAddition, marine face
carbonate is also the indispensable composition. The
value of δ18O shows the ore-forming fluid is
magmation in early mineralization stage and
atmospheric precipitation in later mineralization
stage. It is out of question that atmospheric
precipitation is the main role in the entire
process,，which agrees with preamble.
[1]Seward T M.1982. The transport and
deposition of gold in hydrothermal systems. In:
Foster R.P, ed. Proc. Gold 82: The geology,
geochemistry and genesis of gold mineral deposits.
Univ.Zimbabwe. 165～181.
[2]Terrence P. Mernagh. 2008.Transport and
Precipitation of Gold in Phanerozoic Metamorphic
Terranes from Chemical Modeling of Fluid-Rock
Interaction. Economic Geology, 103:1613-1640.
3553
A Study on Banded Pyrite in
Tiegelongnan Copper(GoldSilver) Deposit, Tibet, China
HUANHUAN, YANG.1
1
Institute of Mineral Resources, Chinese Academy of
Geological Sciences. Beijing 100037, China.
Email: [email protected].
Tiegelongnan copper (gold-silver) deposit in
Duolong ore-concentrated area is the first discovered
epithermal deposits in Tibet, China. Pyrites in this
deposit
develop
extensively
with
obvious
characteristics. For example, pyrites which are
located in shallower parts of drillings develop band
structure and they are relative rarity in other deposits.
Field drilling geological record, microscopic
identification and electron microprobe analysis have
been done to study the mineralogical characteristics,
trace elements and unique band structure of pyrites in
the ore area. The experimental results show that
banded pyrites in Tiegelongnan ore area are the result
of discontinuous growth. The Co/Ni and element
contents of Au, Cu and Se show rhythm changes
from core to edge of banded pyrite. Temperature of
fluid during formation of the external band is higher
than that of the internal band. Contents of Au, Cu and
Se in the liquid during formation of the external band
are higher than those of the internal band. Au in the
banded pyrite gets into pyrite crystal lattice via Au+
replacing Fe2+. While part of Cu get into pyrite
crystal lattice via Cu2+ replacing Fe2+ to form CuS2
and part of Cu get into pyrite via copper sulfide
inclusions. The banded pyrites developed in the
shallow of ore-body, which approach to the strong
copper mineralization and Au, Ag and Cu grades in
the position where banded pyrite developed are high.
Therefore, the banded pyrite is the indication for
concentrating Au, Ag and Cu elements in
Tiegelongnan deposit.
3561
Low-salinity liquid-rich or
vapor-like fluids in a porphyrytype Mo deposit, South Korea
HYUNGSUK KIM1, KYOUNGHEE YANG1,*,
DAVID LENTZ2
Dept. of Geological Sciences, Pusan National
University, Busan, 609-735, South Korea
(* corresponding author, email:
[email protected])
2
Dept. of Earth Sciences, University of New
Brunswick, Fredericton, NB E3B 5A3, Canada
1
Small
porphyry-type
molybdenum
(Mo)
mineralization, the Geumeum deposit, South Korea is
associated with the crystallization of a Cretaceous
granodiorite, exsolution of magmatic hydrothermal
fluids, and related hydrofracturing. Quartz and
molybdenite occur with minor amounts of
uneconomic chalcopyrite, pyrite, sphalerite, and
galena that precipitated from exsolved magmatic
fluids and formed hydrothermal fissure-filling vein
ores. Three distinct fluid inclusion assemblages
responsible for the precipitation of molybdenite are
present in vein quartz. The earliest fluid is
represented by low-salinity liquid-rich Type I fluid
inclusions,
which
displayed
homogenization
temperatures ranging from 298 to 352oC, and
salinities from ~ 0 to 9 wt% NaCl equiv. The
intermediate fluid is represented by CO2-bearing
vapor-rich Type IV inclusions, which totally
homogenized by vapor disappearance at 327-340°C
or vapor bubble expansion at 327-369°C, exhibiting
near-critical behaviors. The latest fluid can be
represented by vapor-rich Type II fluid inclusions.
No microthermometric data were obtained for these
latest assemblages as no visible amounts of liquid
phases are evident in small inclusions. The oxygen
and hydrogen isotopic fluid compositions of the vein
quartz (δ18OSMOW = 4.3 to 6.9 ‰ and δDSMOW = -65 to
-84 ‰ at 400°C) is consistent with a magmatic origin
with a possible slight influence from meteoric water.
Mo mineralization at Geumeum is a product of
hypogene hydrothermal processes that was strongly
fracture-controlled, highlighting the importance of
low-salinity liquid-rich to vapor-like supercritical
fluids for the mineralization. It seems likely that the
magmas responsible for the formation of the deposit
at Geumeum were emplaced at greater depths than
those reported for economic porphyry copper
deposits in the world. The deposit could thus have
survived long periods of erosion, representing the
weakly mineralized “base” of porphyry systems in
the Gyeongsang Basin, South Korea.
3714
Geochemical characteristics of
the Damaya gold deposit,
Sichuan province, China
ZHANG ZHIJUN
Tianjin North China Geological Exploration Bureau,
Tianjin, 300170, PRC
Damaya gold deposit is a typical quartz vein disseminated-type gold deposit in the Daduhe gold
orefield, which is located in the north of the well
know Sanjiang ore cluster area. Wall rocks are
amphibolite with pyrite sericite quartzalteration. The
altered rocks have an obvious negative Eu anomaly
compared with the wall rocks in the deposit. The δ34S
average is 0.1‰ for pyrite and 2.3‰ for chalcopyrite.
Fluid inclusion homogenization temperature are
primarily 280°C-300°C; salinities are at 4-6wt% and
densities vary between 0.79 and 0.99g/cm3. The
source of sulfur is inferred to be the mantle, with
mixing additional sulfur from the crust. CO2
dominates in the compositions of some fluid
inclusions. The date suggests that the Damaya gold
deposit fit with its field setting as an orogenic
deposit.
Keywords: mineralizing fluid, Daduhe gold
field, Damaya gold deposit
3716
Stale isotope characteristcs of
iron ore deposits in the western
Tianshan Mountain,NW China
1
ZHANG ZUOHENG1, DUAN SHIGANG2, JIANG
ZONGSHENG3
Institute of Mineral Resources, CAGS, Beijing
100037, China, [email protected]
2
3
Several medium-large scale iron ore deposits
were gradually discovered in Chinese Western
Tianshan Mountain. In this study,we carried out some
oxygen and sulphur isotope analisis on these iron
deposit.
1. Oxygen isotope
Oxygen analysis were taken for magnetites from
Cha gangnuoer, Zhibo and Beizhan iron deposits
respectively. Five massive and breccia ores generated
during the magmatic phase and minerailzed andesite
show the δ18OV-SMOW value of magnetites ranging
from 0.6 ‰ to 5.5‰, with an average of 3.8‰. Five
magnetites of magmatic stage have that value
changing between 1.8‰ and 3.5 ‰, with an average
of 2.4 ‰. The value of magnetite of nine ore samples
from Beizhan iron deposit are between 0.6 ‰ and
4.6‰, which closing that value distributing within
orthomagmatic rocks, and they are similar as that
value presented in the magmatic water.
2. Sulphur isotope
The δ34S value of hydrothermal are 1‰ ~ 4‰ in
Beizhan, 6‰~8‰ in Dunde, -2‰~0‰ in Zhibo,
5‰~7‰ in Chagangnuoer, 0‰~ 1‰ in Wuling, -3
‰~2‰ in Songhu and -1‰ in Akesayi deposit.
Obvious variations of δ34S value show that the
oxygen fugacity is close or slightly higher than that of
SO2/H2S boundary. Considering that, we consider
that the sulphur source of these iron deposits may
come from magma, which also corresponds to the
close geological relationship between these iron
deposits and the volcanic and intrusive rocks in this
region.
Stable isotope characteristics of these iron
deposits show that ore forming material are derived
from deep magma.
Acknowledgments
This work was jointly supported by the National
Basic Research Program in China (2012CB416803),
National Science and Technology Support Program
in China (2011BAB06B02-05).

The uptake of Ti in experimentally grown, hydrothermal quartz

Transcription

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