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Sample records for hydrothermal sulfide deposits

  1. ESR dating of submarine hydrothermal activities using barite in sulfide deposition

    Science.gov (United States)

    Toyoda, S.; Fujiwara, T.; Ishibashi, J.; Isono, Y.; Uchida, A.; Takamasa, A.; Nakai, S.

    2012-12-01

    The temporal change of submarine hydrothermal activities has been an important issue in the aspect of the evolution of hydrothermal systems which is related with ore formation (Urabe, 1995) and biological systems sustained by the chemical species arising from hydrothermal activities (Macdonald et al., 1980). Determining the ages of the hydrothermal deposit will provide essential information on such studies. Dating methods using disequilibrium between radioisotopes such as U-Th method (e.g. You and Bickle, 1998), 226}Ra-{210Pb and 228}Ra-{228Th method (e.g. Noguchi et al., 2011) have been applied to date submarine hydrothermal deposits. ESR (electron spin resonance) dating method is commonly applied to fossil teeth, shells, and quartz of Quaternay period where the natural accumulated dose is obtained from the intensities of the ESR signals which are created by natural radiation. The natural dose is divided by the dose rate to the mineral/sample to deduce the age. Okumura et al., (2010) made the first practical application of ESR (electron spin resonance) dating technique to a sample of submarine hydrothermal barite (BaSO4) to obtain preliminary ages, where Kasuya et al. (1991) first pointed out that barite can be used for ESR dating. Knowing that ESR dating of barite is promising, in this paper, we will present how we have investigated each factor that contributes ESR dating of barite in submarine hydrothermal sulfide deposition. (1) The best ESR condition for measuring the SO3- signal in barite is with the microwave power of 1mW and modulation amplitude of 0.1mT. (2) As results of heating experiments, the signal was found to be stable for the dating age range of several thousands. (3) 226Ra replacing Ba in barite is the source of the radiation. The amount of radioactive elements in sulfide mineral surrounding barite is negligible. (4) The external radiation from the sea water is negligible even in the submarine hydrothermal area where the radiation level is much

  2. Hydrothermal alteration and the formation of aluminous haloes around sulfide deposits

    Science.gov (United States)

    Lemiere, B.; Delfour, J.; Moine, B.; Piboule, M.; Ploquin, A.; Isnard, P.; Tegyey, M.

    1986-04-01

    The sulfide deposits of Chizeuil (Saone et Loire) occur in a Late Devonian volcano-sedimentary sequence within an acid volcanic unit and close to a Carboniferous granite batholith. Sulfide bodies, mainly pyrite, are enclosed in andalusite-bearing siliceous rocks lacking primary textures and recrystallized by the granitic thermal metamorphism. Several genetic interpretations were proposed for these siliceous rocks and the associated mineralization, i.e., as either being related to the granite intrusion or of volcanogenic derivation. Detailed studies led to their identification as hydrothermal alterites. A petrographic study of these siliceous alterites reveals that the main mineral phases are only constituted of silica and alumina: quartz, andalusite, kaolinite and minor contents of muscovite, diaspore and corundum. Neither K-feldspar or biotite are present with andalusite. This implies that thermal metamorphism occurred on an already alkali-, calcium- and magnesium-depleted rock. These siliceous alterites show less mobile-element (Al, Ti, V, Zr, Nb) concentration ranges similar to those of acid volcanic host rocks. A metasomatic model is computed from chemical data on surrounding soda dacites, assuming that acid hydrolysis was the only phenomenon involved, and that Al was stable in this process. Although altered rock types grading to soda dacites do not crop out, their existence may be deduced from surficial bedrock multielement geochemical data. The zoned distribution of elements agrees with that deduced from reactions and experimental phase diagrams. The pyrite bodies are surrounded by two distinct concentric alteration zones; the inner one is advanced argillic and the outer one is sericitic. Such a pattern is unusual for volcanogenic sulfide deposits but commonly associated with porphyry deposits. It may be related to the strong acidity (pH≦3) of hydrothermal solutions. These siliceous rocks were produced by an in-situ alteration of brecciated dacitic lavas

  3. ESR dating of barite in sea-floor hydrothermal sulfide deposits at Okinawa Trough

    Science.gov (United States)

    Fujiwara, T.; Toyoda, S.; Uchida, A.; Ishibashi, J.; Nakai, S.; Takamasa, A.

    2013-12-01

    The temporal change of submarine hydrothermal activities has been an important issue in the aspect of the evolution of hydrothermal systems which is related with ore formation and biological systems sustained by the chemical species arising from hydrothermal activities (Macdonald et al., 1980). With this aspect, Okumura et al. (2010) made the first practical application of ESR (electron spin resonance) dating technique to a sample of submarine hydrothermal barite to obtain preliminary ages, while Kasuya et al. (1991) first pointed out that barite can be used for ESR dating. ESR is a method to observe radicals having unpaired electrons. As natural radiation creates unpaired electrons in minerals, the age is deduced by dividing the natural radiation dose (obtained from the amount of unpaired electrons) by the dose rate which is estimated by the amount of environmental radioactive elements. The samples were taken by the research cruises, NT12-10 and NT11-20 and NT12-06 operated by JAMSTEC from Hatoma, Yoron, Izena, North Iheya, and Yonaguni IV Knolls of Okinawa Trough. The blocks of sulfide deposits were cut into pieces, and about 2.0g was crushed. The samples were soaked in 12M hydrochloric acid, left for approximately 24 hours. Then, 13M nitric acid was added. Finally, after rinsing in distilled water, the sample was filtered and dried. Impurities were removed by handpicking. A X-ray diffraction study was made to confirm that the grains are pure barite. After γ-ray irradiation at Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, they were measured at room temperature with an ESR spectrometer (JES-PX2300) with a microwave power of 1mW, and the magnetic field modulation amplitude of 0.1mT. The equivalent natural radiation doses were obtained from the increase of ESR signal intensity of SO3- by irradiation. The bulk Ra concentration was measured by the low background pure Ge gamma ray spectrometer. Assuming that Ra is populated only in barite

  4. The formation of gold-rich seafloor sulfide deposits: Evidence from the Beebe hydrothermal vent field, Cayman Trough

    Science.gov (United States)

    Webber, Alexander P.; Roberts, Stephen; Murton, Bramley J.; Mills, Rachel A.; Hodgkinson, Matthew R. S.

    2017-06-01

    The Beebe vent field (BVF) in the Cayman Trough has built an auriferous massive sulfide deposit on the ultraslow spreading mid-Cayman spreading center. The genesis of auriferous sulfide deposits at mid-ocean ridges is not fully understood, although there is a growing recognition that slow and ultraslow spreading centers are conducive to gold mineralization. Analysis of hydrothermal precipitates from the BVF indicates that the highest gold contents are present within "beehive diffusers," which have developed a highly porous pyrrhotite framework. The beehive structure allows vent fluids to effuse slowly while allowing ingress of seawater to cool the fluid. The prevalence of pyrrhotite in the beehive samples, lack of sulfates, association between pyrrhotite and gold grains, and results of thermodynamic modeling suggest gold precipitation occurred under highly reduced conditions even during mixing with seawater. In contrast, high-temperature chimneys, with a single orifice, maintain high temperatures to the primary vent orifice and much of the gold is lost to seawater. Despite this, both chimney types are relatively gold-enriched, which points to a further underlying cause for high gold at the BVF such as interaction of hydrothermal fluids with ultramafic lithologies in the basement. The final gold composition of the deposit is partially controlled by loss of gold during mass-wasting of the material, with gold depletion most prevalent in blocks formed at beehive-type chimneys. The BVF demonstrates that the overall gold content of a massive sulfide deposit is the sum of basement, precipitation, and surface processes.Plain Language SummaryMineral deposits form on the seafloor at hydrothermal vent sites and are rich in metals including copper, zinc, lead, and sometimes precious metals like gold and silver. However, the processes controlling the amount of gold that ends up in these deposits is not clearly understood. In this article we show that as hydrothermal fluid vents

  5. Drilling the Snake Pit hydrothermal sulfide deposit on the Mid-Atlantic Ridge, lat 23/sup 0/22'N

    Energy Technology Data Exchange (ETDEWEB)

    Detrick, R.S.; Honnorez, J.; Adamson, A.C.; Brass, G.; Gillis, K.M.; Humphris, S.E.; Mevel, C.; Meyer, P.; Petersen, N.; Rautenschlein, M.; Shibata, T.; Staudigel, H.; Yamamoto, K.

    1986-12-01

    A major high-temperature hydrothermal area has been discovered in the Mid-Atlantic Ridge rift valley about 25 km south of the Kane Fracture Zone. The vent field consists of a wide area (> 40,000 m/sup 2/) of dark hydrothermal deposits, numerous sulfide chimneys and mounds, some up to 11 m high, and high-temperature black-smoker vents. Ten shallow holes, the first ever drilled in an active submarine hydrothermal area, recovered friable, unconsolidated Fe, Cu-Fe, and Zn sulfides and several large fragments of massive sulfide (mainly chalcopyrite) from the locally thick (> 13 m) hydrothermal deposits. The vents are also associated with an unusual biological community of smaller, more mobile organisms than reported from the East Pacific Rise.

  6. The mineralogy and the isotopic composition of sulfur in hydrothermal sulfide/sulfate deposits on the East Pacific Rise, 21 deg N latitude

    Science.gov (United States)

    Styrt, M. M.; Brackmann, A. J.; Holland, H. D.; Clark, B. C.; Pisutha-Arnond, V.; Eldridge, C. S.; Ohmoto, H.

    1981-01-01

    The mineralogy and isotopic composition of sulfur found in hydrothermal deposits associated with five groups of vents along the ridge axis of the East Pacific Rise near 21 deg N latitude are investigated. Solid samples of mixed sulfides and sulfates from mounds, chimneys and the surrounding sediment as well as fresh basaltic glass were examined with a portable X-ray fluorescence spectrometer and by scanning electron microscopy, X-ray diffractometry, and electron microprobe analysis. For the three vents of exit temperature close to 350 C, the chimneys are found to be rich in copper sulfides, while for those of temperatures around 300 C, zinc sulfide is found to predominate. The major sulfides found in the chimneys include wurtzite, chalcopyrite, pyrite and cubanite, with anhydrite the dominant sulfate. Significant mineralogical differences are found between active and inactive vents. The isotopic composition of sulfur in anhydrites from active vents is observed to be close to that of sea water and consistent with a derivation from sea water sulfate. The isotopic composition of sulfur in the sulfide minerals is explained in terms of precipitation from solutions with reduced sulfur derived from basalts or basaltic magmas, and sea water sulfate. Finally, the deposits are interpreted as the results of the mixing of H2S-dominated hydrothermal fluids with cold sea water near the sea floor.

  7. Suboxic deep seawater in the late Paleoproterozoic: Evidence from hematitic chert and iron formation related to seafloor-hydrothermal sulfide deposits, central Arizona, USA

    Science.gov (United States)

    Slack, J.F.; Grenne, Tor; Bekker, A.; Rouxel, O.J.; Lindberg, P.A.

    2007-01-01

    A current model for the evolution of Proterozoic deep seawater composition involves a change from anoxic sulfide-free to sulfidic conditions 1.8??Ga. In an earlier model the deep ocean became oxic at that time. Both models are based on the secular distribution of banded iron formation (BIF) in shallow marine sequences. We here present a new model based on rare earth elements, especially redox-sensitive Ce, in hydrothermal silica-iron oxide sediments from deeper-water, open-marine settings related to volcanogenic massive sulfide (VMS) deposits. In contrast to Archean, Paleozoic, and modern hydrothermal iron oxide sediments, 1.74 to 1.71??Ga hematitic chert (jasper) and iron formation in central Arizona, USA, show moderate positive to small negative Ce anomalies, suggesting that the redox state of the deep ocean then was at a transitional, suboxic state with low concentrations of dissolved O2 but no H2S. The presence of jasper and/or iron formation related to VMS deposits in other volcanosedimentary sequences ca. 1.79-1.69??Ga, 1.40??Ga, and 1.24??Ga also reflects oxygenated and not sulfidic deep ocean waters during these time periods. Suboxic conditions in the deep ocean are consistent with the lack of shallow-marine BIF ??? 1.8 to 0.8??Ga, and likely limited nutrient concentrations in seawater and, consequently, may have constrained biological evolution. ?? 2006 Elsevier B.V. All rights reserved.

  8. Magmatic-vapor expansion and the formation of high-sulfidation gold deposits: Structural controls on hydrothermal alteration and ore mineralization

    Science.gov (United States)

    Berger, Byron R.; Henley, Richard W.

    2011-01-01

    High-sulfidation copper–gold lode deposits such as Chinkuashih, Taiwan, Lepanto, Philippines, and Goldfield, Nevada, formed within 1500 m of the paleosurface in volcanic terranes. All underwent an early stage of extensive advanced argillic silica–alunite alteration followed by an abrupt change to spatially much more restricted stages of fracture-controlled sulfide–sulfosalt mineral assemblages and gold–silver mineralization. The alteration as well as ore mineralization stages of these deposits were controlled by the dynamics and history of syn-hydrothermal faulting.At the Sulfate Stage, aggressive advanced argillic alteration and silicification were consequent on the in situ formation of acidic condensate from magmatic vapor as it expanded through secondary fracture networks alongside active faults. The reduction of permeability at this stage due to alteration decreased fluid flow to the surface, and progressively developed a barrier between magmatic-vapor expansion constrained by the active faults and peripheral hydrothermal activity dominated by hot-water flow. In conjunction with the increased rock strength resulting from alteration, subsequent fault-slip inversion in response to an increase in compressional stress generated new, highly permeable fractures localized by the embrittled, altered rock. The new fractures focused magmatic-vapor expansion with much lower heat loss so that condensation occurred. Sulfide Stage sulfosalt, sulfide, and gold–silver deposition then resulted from destabilization of vapor phase metal species due to vapor decompression through the new fracture array. The switch from sulfate to sulfide assemblages is, therefore, a logical consequence of changes in structural permeability due to the coupling of alteration and fracture dynamics rather than to changes in the chemistry of the fluid phase at its magmatic source.

  9. Are the alteration halos of massive sulfide deposits syngenetic Evidence from U-Pb dating of hydrothermal rutile at the Kidd volcanic center, Abitibi subprovince, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Schandl, E.S.; Davis, D.W.; Krogh, T.E. (Royal Ontario Museum, Toronto, Ontario (Canada))

    1990-06-01

    The Kidd volcanic complex is composed of felsic volcanic and subvolcanic rocks of Archean age. Metasomatic events affecting the lithology of the Kidd volcanic complex include silicification, extensive CO{sub 2} metasomatism (carbonate), K-metasomatism (sericite-fuchsite), and chlorite and minor carbonate alterations. Petrographic evidence, supported by stable isotope and fluid inclusion studies, suggests that silicification and early carbonate alteration were synvolcanic, and therefore related to ore deposition. During subsequent extensive K-metasomatism, sericite precipitated in the rhyolite, and fuschsite precipitated in the ultramafic rocks. Although chlorite postdates K-metasomatism, the micas and chlorite are both found in anastomosing microfissures, commonly occupying the same set of fractures. Hydrothermal rutile formed by the breakdown of magnetite-ilmenite during K-metasomatism and chlorite alteration gives an age of 2624 {plus minus} 62 Ma (95% confidence level). It is therefore approximately 100 m.y. younger than syngenetic massive sulfide mineralization (2712 {plus minus} 2 Ma). Sulfide stringers within sericite and chlorite veins suggest some remobilization of the ores during these later events. This alteration assemblage, is identical to that found associated with many lode-gold deposits in the Superior province. Recent dating of micas and rutile associated with gold deposits in the Abitibi subprovince gives comparable ages to the rutile in the Kidd volcanic complex, which must therefore record a widespread, late hydrothermal event affecting mineralized rocks.

  10. Are the alteration halos of massive sulfide deposits syngenetic? Evidence from U-Pb dating of hydrothermal rutile at the Kidd volcanic center, Abitibi subprovince, Canada

    Science.gov (United States)

    Schandl, E. S.; Davis, D. W.; Krogh, T. E.

    1990-06-01

    The Kidd volcanic complex is composed of felsic volcanic and subvolcanic rocks of Archean age. The felsic rocks are intercalated with sedimentary rocks, and are in contact with komatiitic ultramafic rocks. Large diorite plutons were emplaced into the rhyolite, and the complex is overlain by younger basalts. Metasomatic events affecting the lithology of the Kidd volcanic complex include silicification, extensive CO2 metasomatism (carbonate), K-metasomatism (sericite-fuchsite), and chlorite and minor carbonate alterations. Petrographic evidence, supported by stable isotope and fluid inclusion studies, suggests that silicification and early carbonate alteration were synvolcanic, and therefore related to ore deposition. During subsequent extensive K-metasomatism, sericite precipitated in the rhyolite, and fuchsite precipitated in the ultramafic rocks. Although chlorite post-dates K-metasomatism, the micas and chlorite are both found in anastomosing microfissures, commonly occupying the same set of fractures. Hydrothermal rutile formed by the breakdown of magnetiteilmenite during K-metasomatism and chlorite alteration gives an age of 2624 ±62 Ma (95% confidence level) by Pb-Pb isotopic measurements. It is therefore approximately 100 m.y. younger than syngenetic massive sulfide mineralization (2717 ±2 Ma). Sulfide stringers within sericite and chlorite veins suggest some remobilization of the ores during these later events. This alteration assemblage, generally thought to be intimately associated with mineralization, is identical to that found associated with many lode-gold deposits in the Superior province. Recent dating of micas and rutile associated with gold deposits in the Abitibi subprovince gives comparable ages to the rutile in the Kidd volcanic complex, which must therefore record a widespread, late hydrothermal event affecting mineralized rocks.

  11. Feasibility study of application of ROV-towed loop-loop EM sensor for mapping seafloor marine hydrothermal sulfide massive deposit

    Science.gov (United States)

    Lee, S.; Ko, H.; Park, I.; Cho, S.; Won, I. J.; Funak, F.; Kim, H.

    2013-12-01

    Seafloor massive sulfide (SMS) deposits have gained much attention of scientific interest since 1970s. In recent years, as demand for metallic mineral resources such as copper, zinc, gold, and other rare earth material increases, together with modern enhancement of marine technology, SMS deposits become more competing and now being recognized as commercially viable mineral resources in near future. An off-shore experiment was performed with a new marine small loop electromagnetic (EM) survey system, which was developed primarily for exploration of seafloor hydrothermal deposits. The new marine system is a multi-frequency loop EM system so that it is designed to endure high pressure in deep sea up to 2000 m. To maintain altitude of the system from the seafloor in rough seafloor topography condition, the system was connected rigidly to ROV (Remotely Operated Vehicle), which then tows the whole system for survey. We performed offshore tests with the new loop EM system by keeping altitude of ROV 2 m above from the seafloor at a depth of 300 m near off-shore. The ROV position and attitude while moving (pitch, roll, yaw) and CTD (Conductivity, Temperature, Depth) data are also recorded simultaneously with electromagnetic responses. Experiments showed that EM anomaly was clearly identified at the true location of metallic object, and the pattern of the EM responses matches well with the theoretical responses from a 3-D integral equation EM modeling code. With the test in offshore, we confirmed that the method of operation of the EM survey system by ROV was readily feasible, and the system could effectively be used to map actual seafloor hydrothermal deposits in the highly conductive seafloor environment.

  12. Complexing and hydrothermal ore deposition

    CERN Document Server

    Helgeson, Harold C

    1964-01-01

    Complexing and Hydrothermal Ore Deposition provides a synthesis of fact, theory, and interpretative speculation on hydrothermal ore-forming solutions. This book summarizes information and theory of the internal chemistry of aqueous electrolyte solutions accumulated in previous years. The scope of the discussion is limited to those aspects of particular interest to the geologist working on the problem of hydrothermal ore genesis. Wherever feasible, fundamental principles are reviewed. Portions of this text are devoted to calculations of specific hydrothermal equilibriums in multicompone

  13. Volcanogenic massive sulfide occurrence model: Chapter C in Mineral deposit models for resource assessment

    Science.gov (United States)

    Shanks, W.C. Pat; Koski, Randolph A.; Mosier, Dan L.; Schulz, Klaus J.; Morgan, Lisa A.; Slack, John F.; Ridley, W. Ian; Dusel-Bacon, Cynthia; Seal, Robert R.; Piatak, Nadine M.; Shanks, W.C. Pat; Thurston, Roland

    2012-01-01

    Volcanogenic massive sulfide deposits, also known as volcanic-hosted massive sulfide, volcanic-associated massive sulfide, or seafloor massive sulfide deposits, are important sources of copper, zinc, lead, gold, and silver (Cu, Zn, Pb, Au, and Ag). These deposits form at or near the seafloor where circulating hydrothermal fluids driven by magmatic heat are quenched through mixing with bottom waters or porewaters in near-seafloor lithologies. Massive sulfide lenses vary widely in shape and size and may be podlike or sheetlike. They are generally stratiform and may occur as multiple lenses.

  14. Geology, sulfide geochemistry and supercritical venting at the Beebe Hydrothermal Vent Field, Cayman Trough

    Science.gov (United States)

    Webber, Alexander P.; Roberts, Stephen; Murton, Bramley J.; Hodgkinson, Matthew R. S.

    2015-09-01

    The Beebe Vent Field (BVF) is the world's deepest known hydrothermal system, at 4960 m below sea level. Located on the Mid-Cayman Spreading Centre, Caribbean, the BVF hosts high temperature (˜401°C) "black smoker" vents that build Cu, Zn and Au-rich sulfide mounds and chimneys. The BVF is highly gold-rich, with Au values up to 93 ppm and an average Au:Ag ratio of 0.15. Gold precipitation is directly associated with diffuse flow through "beehive" chimneys. Significant mass-wasting of sulfide material at the BVF, accompanied by changes in metal content, results in metaliferous talus and sediment deposits. Situated on very thin (2-3 km thick) oceanic crust, at an ultraslow spreading centre, the hydrothermal system circulates fluids to a depth of ˜1.8 km in a basement that is likely to include a mixture of both mafic and ultramafic lithologies. We suggest hydrothermal interaction with chalcophile-bearing sulfides in the mantle rocks, together with precipitation of Au in beehive chimney structures, has resulted in the formation of a Au-rich volcanogenic massive sulfide (VMS) deposit. With its spatial distribution of deposit materials and metal contents, the BVF represents a modern day analogue for basalt hosted, Au-rich VMS systems.

  15. Particle Geochemistry of Hydrothermal Systems and Implications for Mining Seafloor Massive Sulfides

    Science.gov (United States)

    Gartman, A.; Hein, J. R.

    2016-12-01

    Seafloor massive sulfide deposits form due to high-temperature hydrothermal venting that occurs globally, in every ocean basin, along plate boundaries and intra-plate hotspots. At these sites, the rapid mixing of hot, metal- and sulfur-rich reduced fluids into cold, oxygenated ocean water results in abundant mineral precipitation. The mining of seafloor massive sulfides is likely to occur in the near future and will generate a new class of mainly inorganic particulates, different from those formed in hydrothermal `black smoke.' While the major components of both black smoke & SMS tailings are Cu, Fe and Zn sulfides, many other minerals, including those containing technology critical elements, especially tellurium, are present. A comparison of these two classes of particulates will be presented, including chemical composition and reactivity to oxidative dissolution.

  16. Iron-sulfide crystals in probe deposits

    DEFF Research Database (Denmark)

    Laursen, Karin; Frandsen, Flemming

    1998-01-01

    : (1) impact of low viscous droplets of iron sulfide; and (2) sulfur diffusion. Previous research on the influence of pyrite on slagging focused on the decomposition of pyrite into pyrrhotite and especially on the oxidation stage of this product during impact on the heat transfer surfaces......Iron-sulfides were observed in deposits collected on a probe inserted at the top of the furnace of a coal-fired power station in Denmark. The chemical composition of the iron-sulfides is equivalent to pyrrhotite (FeS). The pyrrhotites are present as crystals and, based on the shape of the crystals...

  17. Sulfur and lead isotopic compositions of massive sulfides from deep-sea hydrothermal systems : implications for ore genesis and fluid circulation.

    OpenAIRE

    Zeng, Z.; Ma, Y.; Chen, S; Selby, D.; Wang, X.; X. Yin

    2017-01-01

    Studies of sulfur and lead isotopic compositions in hydrothermal deposits are an important tool to determine the source and processes of both sulfur and lead, and to understand the origin of hydrothermal ore deposits. Here, the sulfur and lead isotopic compositions of sulfide minerals have been studied for different hydrothermal fields in the East Pacific Rise (EPR), Mid-Atlantic Ridge (MAR), Central Indian Ridge (CIR), Southwest Indian Ridge (SWIR), and North Fiji Basin (NFB). The sulfur iso...

  18. Pyrrhotite mineralization as a search criterion for sulfide deposits at sediment-covered spreading centers

    Science.gov (United States)

    Bogdanova, O. Yu.; Lein, A. Yu.; Dara, O. M.; Ozhogina, E. G.; Lisitzin, A. P.

    2016-09-01

    Pyrrhotite ores forming the hydrothermal vents of the Hydrothermal Hills in the Southern Trough of the Guaymas depression were studied. A series of features pointing to the occurrence of surface and buried sulfide deposits of pyrrhotite mineralization was revealed: the presence of pyrrhotite associations to hydrocarbons of oil series; low concentrations of Cu, Zn, and Pb; the enrichment of sulfur of pyrrhotite and hydrogen sulfide of hydrothermal solutions in heavy 34S isotope by 5-7%; and the heavy isotope composition of carbon in naphthoid compounds. The results obtained allow one to suggest searching for large sulfide deposits at active rifts of high spreading and sedimentation rates, i.e., at near-continental rifts of the humid zone of avalanche sedimentation.

  19. Microbial lipids reveal carbon assimilation patterns on hydrothermal sulfide chimneys.

    Science.gov (United States)

    Reeves, Eoghan P; Yoshinaga, Marcos Y; Pjevac, Petra; Goldenstein, Nadine I; Peplies, Jörg; Meyerdierks, Anke; Amann, Rudolf; Bach, Wolfgang; Hinrichs, Kai-Uwe

    2014-11-01

    Sulfide 'chimneys' characteristic of seafloor hydrothermal venting are diverse microbial habitats. ¹³C/¹²C ratios of microbial lipids have rarely been used to assess carbon assimilation pathways on these structures, despite complementing gene- and culture-based approaches. Here, we integrate analyses of the diversity of intact polar lipids (IPL) and their side-chain δ¹³C values (δ¹³ C(lipid)) with 16S rRNA gene-based phylogeny to examine microbial carbon flow on active and inactive sulfide structures from the Manus Basin. Surficial crusts of active structures, dominated by Epsilonproteobacteria, yield bacterial δ¹³C(lipid) values higher than biomass δ¹³C (total organic carbon), implicating autotrophy via the reverse tricarboxylic acid cycle. Our data also suggest δ¹³C(lipid) values vary on individual active structures without accompanying microbial diversity changes. Temperature and/or dissolved substrate effects - likely relating to variable advective-diffusive fluxes to chimney exteriors - may be responsible for differing ¹³C fractionation during assimilation. In an inactive structure, δ¹³C(lipid) values lower than biomass δ¹³C and a distinctive IPL and 16S rRNA gene diversity suggest a shift to a more diverse community and an alternate carbon assimilation pathway after venting ceases. We discuss here the potential of IPL and δ¹³C(lipid) analyses to elucidate carbon flow in hydrothermal structures when combined with other molecular tools. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  20. Age and depositional environment of the Draa Sfar massive sulfide deposit, Morocco

    Science.gov (United States)

    Moreno, C.; Sáez, R.; González, F.; Almodóvar, G.; Toscano, M.; Playford, G.; Alansari, A.; Rziki, S.; Bajddi, A.

    2008-11-01

    The Draa Sfar mineralization consists of two main stratabound orebodies, Sidi M’Barek and Tazacourt, located north and south of the Tensift River (“Oued Tessift”), respectively. Each orebody is comprised by at least two massive sulfide lenses. The hosting rocks are predominantly black shales, although minor rhyolitic rocks are also present in the footwall to the southern orebody. Shales, rhyolitic volcanic rocks, and massive sulfides are all included into the Sarhlef Series, which is recognized as one of the main stratigraphic units of the Moroccan Variscan Meseta. Hydrothermal activity related with an anomalous thermal gradient, together with a high sedimentation rate in a tectonically driven pull-apart marine basin, favored the accumulation of organic-rich mud in the deepest parts of the basin and the sedimentary environment suitable for massive sulfide deposition and preservation. This took place by replacement of the hosting unlithified wet mud below the sediment-water interface. Geochemical data suggest a sedimentary environment characterized by oxic water column and anoxic sediment pile with the redox boundary below the sediment-water interface. The low oxygen availability within the sediment pile inhibited oxidation and pyritization of pyrrhotite. Biostratigraphic analysis, based on the palynological content of the hosting black shales, restricts the age of the sulfides to the Asbian substage (mid-Mississippian). This age is consistent with earlier geochronological constraints.

  1. Mixing from below in hydrothermal ore deposits

    Science.gov (United States)

    Bons, Paul D.; Gomez-Rivas, Enrique; Markl, Gregor; Walter, Bejamin

    2014-05-01

    Unconformity-related hydrothermal ore deposits typically show indications of mixing of two end-member fluids: (a) hot, deep, rock-buffered basement brines and (b) colder fluids derived from the surface or overlying sediments. The hydromechanics of bringing these fluids together from above and below remain unclear. Classical percolative Darcy-flow models are inconsistent with (1) fluid overpressure indicated by fracturing and brecciation, (2) fast fluid flow indicated by thermal disequilibrium, and (3) strong fluid composition variations on the mm-scale, indicated by fluid inclusion analyses (Bons et al. 2012; Fusswinkel et al. 2013). We propose that fluids first descend, sucked down by desiccation reactions in exhumed basement. Oldest fluids reach greatest depths, where long residence times and elevated temperatures allow them the extensively equilibrate with their host rock, reach high salinity and scavenge metals, if present. Youngest fluids can only penetrate to shallower depths and can (partially) retain signatures from their origin, for example high Cl/Br ratios from the dissolution of evaporitic halite horizons. When fluids are released from all levels of the crustal column, these fluids mix during rapid ascent to form hydrothermal ore deposits. Mixing from below provides a viable hydromechanical mechanism to explain the common phenomenon of mixed shallow and deep fluids in hydrothermal ore deposits. Bons, P.D., Elburg, M.A., Gomez-Rivas, E. 2012. A review of the formation of tectonic veins and their microstructures. J. Struct. Geol. doi:10.1016/j.jsg.2012.07.005 Fusswinkel, T., Wagner, T., Wälle, M., Wenzel, T., Heinrich, C.A., Markl, M. 2013. Fluid mixing forms basement-hosted Pb-Zn deposits: Insight from metal and halogen geochemistry of individual fluid inclusions. Geology. doi:10.1130/G34092.1

  2. Cuprous oxide thin films grown by hydrothermal electrochemical deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Majumder, M., E-mail: mousumi@cgcri.res.in; Biswas, I.; Pujaru, S.; Chakraborty, A.K.

    2015-08-31

    Semiconducting cuprous oxide films were grown by a hydrothermal electro-deposition technique on metal (Cu) and glass (ITO) substrates between 60 °C and 100 °C. X-ray diffraction studies reveal the formation of cubic cuprous oxide films in different preferred orientations depending upon the deposition technique used. Film growth, uniformity, grain size, optical band gap and photoelectrochemical response were found to improve in the hydrothermal electrochemical deposition technique. - Highlights: • Cu{sub 2}O thin films were grown on Cu and glass substrates. • Conventional and hydrothermal electrochemical deposition techniques were used. • Hydrothermal electrochemical growth showed improved morphology, thickness and optical band gap.

  3. Trace elements in tourmalines from massive sulfide deposits and tourmalinites: Geochemical controls and exploration applications

    Science.gov (United States)

    Griffin, W.L.; Slack, J.F.; Ramsden, A.R.; Win, T.T.; Ryan, C.G.

    1996-01-01

    Trace element contents of tourmalines from massive sulfide deposits and tourmalinites have been determined in situ by proton microprobe; >390 analyses were acquired from 32 polished thin sections. Concentrations of trace elements in the tourmalines vary widely, from inclusions. The highest base metal contents are in ore-related tourmaline samples from Kidd Creek (Ontario), Broken Hill (Australia), and Sazare (Japan). Tourmaline data from these and many other massive sulfide deposits cluster by sample and display broadly linear trends on Zn vs. Fe plots, suggesting chemical control by temperature and hydrothermal and/or metamorphic fluid-mineral equilibria. Significant Ni occurs only in samples from the Kidd Creek Cu-Zn-Pb-Ag deposit, which is associated with a large footwall ultramafic body. An overall antithetic relationship between Zn and Ni probably reflects fluid source controls. Mn is correlated with Fe in tourmalines from barren associations, and possibly in some tourmalines associated with sulfide vein deposits. Sn increases systematically with Fe content irrespective of association; the highest values are found in schorls from granites. Other trace elements are generally uncorrelated with major element concentrations (e.g., Sr-Ca). Base metal proportions in the tourmalines show systematic patterns on ternary Cu-Pb-Zn diagrams that correlate well with the major commodity metals in the associated massive sulfide deposits. For example, data for tourmalines from Cu-Zn deposits (e.g., Ming mine, Newfoundland) fall mainly on the Cu-Zn join, whereas those from Pb-Zn deposits (e.g., Broken Hill, Australia) plot on the Pb-Zn join; no data fall on the Cu-Pb join, consistent with the lack of this metal association in massive sulfide deposits. The systematic relationship between base metal proportions in the tourmalines and the metallogeny of the host massive sulfide deposits indicates that the analyzed tourmalines retain a strong chemical signature of their original

  4. Potential for biogeochemical cycling of sulfur, iron and carbon within massive sulfide deposits below the seafloor.

    Science.gov (United States)

    Kato, Shingo; Ikehata, Kei; Shibuya, Takazo; Urabe, Tetsuro; Ohkuma, Moriya; Yamagishi, Akihiko

    2015-05-01

    Seafloor massive sulfides are a potential energy source for the support of chemosynthetic ecosystems in dark, deep-sea environments; however, little is known about microbial communities in these ecosystems, especially below the seafloor. In the present study, we performed culture-independent molecular analyses of sub-seafloor sulfide samples collected in the Southern Mariana Trough by drilling. The depth for the samples ranged from 0.52 m to 2.67 m below the seafloor. A combination of 16S rRNA and functional gene analyses suggested the presence of chemoautotrophs, sulfur-oxidizers, sulfate-reducers, iron-oxidizers and iron-reducers. In addition, mineralogical and thermodynamic analyses are consistent with chemosynthetic microbial communities sustained by sulfide minerals below the seafloor. Although distinct bacterial community compositions were found among the sub-seafloor sulfide samples and hydrothermally inactive sulfide chimneys on the seafloor collected from various areas, we also found common bacterial members at species level including the sulfur-oxidizers and sulfate-reducers, suggesting that the common members are widely distributed within massive sulfide deposits on and below the seafloor and play a key role in the ecosystem function. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  5. Weathering of post-impact hydrothermal deposits from the Haughton impact structure: implications for microbial colonization and biosignature preservation.

    Science.gov (United States)

    Izawa, M R M; Banerjee, Neil R; Osinski, G R; Flemming, R L; Parnell, J; Cockell, C S

    2011-01-01

    Meteorite impacts are among the very few processes common to all planetary bodies with solid surfaces. Among the effects of impact on water-bearing targets is the formation of post-impact hydrothermal systems and associated mineral deposits. The Haughton impact structure (Devon Island, Nunavut, Canada, 75.2 °N, 89.5 °W) hosts a variety of hydrothermal mineral deposits that preserve assemblages of primary hydrothermal minerals commonly associated with secondary oxidative/hydrous weathering products. Hydrothermal mineral deposits at Haughton include intra-breccia calcite-marcasite vugs, small intra-breccia calcite or quartz vugs, intra-breccia gypsum megacryst vugs, hydrothermal pipe structures and associated surface "gossans," banded Fe-oxyhydroxide deposits, and calcite and quartz veins and coatings in shattered target rocks. Of particular importance are sulfide-rich deposits and their associated assemblage of weathering products. Hydrothermal mineral assemblages were characterized structurally, texturally, and geochemically with X-ray diffraction, micro X-ray diffraction, optical and electron microscopy, and inductively coupled plasma atomic emission spectroscopy. Primary sulfides (marcasite and pyrite) are commonly associated with alteration minerals, including jarosite (K,Na,H(3)O)Fe(3)(SO(4))(2)(OH)(6), rozenite FeSO(4)·4(H(2)O), copiapite (Fe,Mg)Fe(4)(SO(4))(6)(OH)(2)·20(H(2)O), fibroferrite Fe(SO(4))(OH)·5(H(2)O), melanterite FeSO(4)·7(H(2)O), szomolnokite FeSO(4)·H(2)O, goethite α-FeO(OH), lepidocrocite γ-FeO(OH) and ferrihydrite Fe(2)O(3)·0.5(H(2)O). These alteration assemblages are consistent with geochemical conditions that were locally very different from the predominantly circumneutral, carbonate-buffered environment at Haughton. Mineral assemblages associated with primary hydrothermal activity, and the weathering products of such deposits, provide constraints on possible microbial activity in the post-impact environment. The initial period of

  6. Mapping hydrothermal altered mineral deposits using Landsat 7 ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 121; Issue 4. Mapping hydrothermal altered mineral ... To evaluate the conventional methods for mapping hydrothermal altered deposits by using Landsat 7 ETM+ image in and around Kuju volcano is the prime target of our study. The Kuju volcano is a mountainous ...

  7. The coupled geochemistry of Au and As in pyrite from hydrothermal ore deposits

    Science.gov (United States)

    Deditius, Artur P.; Reich, Martin; Kesler, Stephen E.; Utsunomiya, Satoshi; Chryssoulis, Stephen L.; Walshe, John; Ewing, Rodney C.

    2014-09-01

    The ubiquity of Au-bearing arsenian pyrite in hydrothermal ore deposits suggests that the coupled geochemical behaviour of Au and As in this sulfide occurs under a wide range of physico-chemical conditions. Despite significant advances in the last 20 years, fundamental factors controlling Au and As ratios in pyrite from ore deposits remain poorly known. Here we explore these constraints using new and previously published EMPA, LA-ICP-MS, SIMS, and μ-PIXE analyses of As and Au in pyrite from Carlin-type Au, epithermal Au, porphyry Cu, Cu-Au, and orogenic Au deposits, volcanogenic massive sulfide (VHMS), Witwatersrand Au, iron oxide copper gold (IOCG), and coal deposits. Pyrite included in the data compilation formed under temperatures from ∼30 to ∼600 °C and in a wide variety of geological environments. The pyrite Au-As data form a wedge-shaped zone in compositional space, and the fact that most data points plot below the solid solubility limit defined by Reich et al. (2005) indicate that Au1+ is the dominant form of Au in arsenian pyrite and that Au-bearing ore fluids that deposit this sulfide are mostly undersaturated with respect to native Au. The analytical data also show that the solid solubility limit of Au in arsenian pyrite defined by an Au/As ratio of 0.02 is independent of the geochemical environment of pyrite formation and rather depends on the crystal-chemical properties of pyrite and post-depositional alteration. Compilation of Au-As concentrations and formation temperatures for pyrite indicates that Au and As solubility in pyrite is retrograde; Au and As contents decrease as a function of increasing temperature from ∼200 to ∼500 °C. Based on these results, two major Au-As trends for Au-bearing arsenian pyrite from ore deposits are defined. One trend is formed by pyrites from Carlin-type and orogenic Au deposits where compositions are largely controlled by fluid-rock interactions and/or can be highly perturbed by changes in temperature and

  8. Hydrothermal synthesis and photoluminescent properties of stacked indium sulfide superstructures.

    Science.gov (United States)

    Xing, Yan; Zhang, Hongjie; Song, Shuyan; Feng, Jing; Lei, Yongqian; Zhao, Lijun; Li, Meiye

    2008-03-28

    Unusual hierarchical stacked superstructures of cubic beta-In2S3 were fabricated via a facile hydrothermal process in the presence of a surfactant cetyltrimethylammonium bromide CTAB; the 3D superstructures were developed by helical propagation of surface steps from microflakes of 10-20 nm thickness.

  9. Textural, mineralogical and stable isotope studies of hydrothermal alteration in the main sulfide zone of the Great Dyke, Zimbabwe and the precious metals zone of the Sonju Lake Intrusion, Minnesota, USA

    Science.gov (United States)

    Li, C.; Ripley, E.M.; Oberthur, T.; Miller, J.D.; Joslin, G.D.

    2008-01-01

    Stratigraphic offsets in the peak concentrations of platinum-group elements (PGE) and base-metal sulfides in the main sulfide zone of the Great Dyke and the precious metals zone of the Sonju Lake Intrusion have, in part, been attributed to the interaction between magmatic PGE-bearing base-metal sulfide assemblages and hydrothermal fluids. In this paper, we provide mineralogical and textural evidence that indicates alteration of base-metal sulfides and mobilization of metals and S during hydrothermal alteration in both mineralized intrusions. Stable isotopic data suggest that the fluids involved in the alteration were of magmatic origin in the Great Dyke but that a meteoric water component was involved in the alteration of the Sonju Lake Intrusion. The strong spatial association of platinum-group minerals, principally Pt and Pd sulfides, arsenides, and tellurides, with base-metal sulfide assemblages in the main sulfide zone of the Great Dyke is consistent with residual enrichment of Pt and Pd during hydrothermal alteration. However, such an interpretation is more tenuous for the precious metals zone of the Sonju Lake Intrusion where important Pt and Pd arsenides and antimonides occur as inclusions within individual plagioclase crystals and within alteration assemblages that are free of base-metal sulfides. Our observations suggest that Pt and Pd tellurides, antimonides, and arsenides may form during both magmatic crystallization and subsolidus hydrothermal alteration. Experimental studies of magmatic crystallization and hydrothermal transport/deposition in systems involving arsenides, tellurides, antimonides, and base metal sulfides are needed to better understand the relative importance of magmatic and hydrothermal processes in controlling the distribution of PGE in mineralized layered intrusions of this type. ?? Springer-Verlag 2007.

  10. Geology of volcanogenic massive sulfide deposit near Meli ...

    African Journals Online (AJOL)

    Bheema

    ABSTRACT. Results of a preliminary study conducted on the volcanogenic massive sulfide (VMS) deposit near Meli/Rahwa, northern Ethiopia are presented in the paper. The study area forms part of. Neoproterozoic basement of northern Ethiopia and southern part of the Arabian Nubian Shield. (ANS). Selected surface rock ...

  11. Magnetic properties and phase transformations of iron sulfides synthesized under the hydrothermal method

    Science.gov (United States)

    Li, S. H.; Chen, Y. H.

    2016-12-01

    The iron sulfide nano-minerals possess advantages of high abundance, low cost, and low toxicity. These advantages make them be competitive in the magnetic, electronic, and photoelectric applications. Mackinawite can be used in soil or water remediations. Greigite is very important for paleomagnetic and geochemical environment studies and the anode materials for lithium ion batteries. Besides, greigite is also utilized for hyperthermia and biomedicine. Pyrrhotite can be applied as geothermometry. Due to the above-mentioned reasons, iron sulfide minerals have specific significances and they must be further investigated, like their phase transformations, magnetic properties, and etc. In this study, the iron sulfide minerals were synthesized by using a hydrothermal method. The ex-situ and in-situ X-ray diffraction (XRD) was used to examine the crystal structure and phase transformation of iron sulfide minerals. The Transmission electron microscopy (TEM) and superconducting quantum interference device (SQUID) were carried out to investigate their morphology and magnetic properties, respectively. The results suggested that the phase transformation sequence was followed the order: mackinawite → greigite → (smythite) → pyrrhotite. Two pure mineral phases of greigite and pyrrhotite were obtained under the hydrothermal conditions. The morphology of the pure greigite is granular aggregates with a particle size of approximately 30 nm and pyrrhotite presented a hexagonal sheet stacking with a particle size of thousands nanometers. The greigite had a ferri-magnetic behavior and pyrrhotite was weak ferro-magnetic. Both of them had a pseudo-single magnetic domain (PSD) based on the Day's plot from SQUID data. The complete phase-transformation pathways and high magnetization of iron sulfide minerals are observed in this study and these kind of iron sulfide minerals are worthy to further study.

  12. Geochemistry of metalliferous, hydrothermal deposits in the Aeolian arc (Tyrrhenian Sea)

    Science.gov (United States)

    Savelli, C.; Marani, M.; Gamberi, F.

    1999-03-01

    In shallow-water areas of the submerged volcanic complex around the island of Panarea (Aeolian archipelago), hydrothermal precipitation of both low-temperature Fe-oxyhydroxide-rich red muds and crusts, and high-temperature, sediment-hosted massive sulfides was discovered during an integrated, high-resolution survey. Iron-rich crusts were also found on the bathymetric high of Secca del Capo, north of Salina island. The exhalative iron-rich sediments occur in small (closed) depressions or in proximity to faults and scarps at water depths ranging from 55 to 285 m. The principal chemical characteristics of these deposits are high, but variable, Fe content ranging from 12.2 to 45%, and low contents of the transition elements Mn, Cu, Zn, Ni and Co. The low contents of Cu, Ni and Co suggest a hydrothermal origin. The Fe-oxyhydroxide deposits are enriched in light rare earth element (REE) (35-110×chondrite) compared to heavy REE (10-25×chondrite). Their REE patterns are similar to those of associated calc-alkaline volcanics: negative slope of light REE and a horizontal distribution of the heavy ones. This contrasts with the pattern for iron and manganese oxides of hydrogenous origin, which have tilted trends of heavy REE paralleling that of seawater. The mineralogy of the polymetallic sulfide deposits consists of galena, sphalerite, pyrite and barite in the form of silt-sand grains and decimeter-sized fragments disseminated in clay, 30 cm below the seabed, at a waterdepth of 80 m. The chemistry of the Aeolian iron-rich, low-temperature deposits and of the high-temperature, Ba-rich Pb and Zn sulfides suggests that they are genetically analogous to, respectively, the kuroko-type iron formation (`tetsusekiei') and the black ore exposed in the Miocene Hokuroku district of Japan.

  13. Depth profiles of resistivity and spectral IP for active modern submarine hydrothermal deposits: a case study from the Iheya North Knoll and the Iheya Minor Ridge in Okinawa Trough, Japan

    Science.gov (United States)

    Komori, Shogo; Masaki, Yuka; Tanikawa, Wataru; Torimoto, Junji; Ohta, Yusuke; Makio, Masato; Maeda, Lena; Ishibashi, Jun-ichiro; Nozaki, Tatsuo; Tadai, Osamu; Kumagai, Hidenori

    2017-08-01

    Submarine hydrothermal deposits are one of the promising seafloor mineral resources, because they can store a large amount of metallic minerals as sulfides. The present study focuses on the electrical properties of active modern submarine hydrothermal deposits, in order to provide constraints on the interpretation of electrical structures obtained from marine electromagnetic surveys. Measurements of resistivity and spectral induced polarization (IP) were made using drillcore samples taken from the Iheya North Knoll and the Iheya Minor Ridge in Okinawa Trough, Japan. These hydrothermal sediments are dominantly composed of disseminated sulfides, with minor amounts of massive sulfide rocks. The depth profiles of resistivity and spectral IP properties were successfully revealed to correspond well to layer-by-layer lithological features. Comparison with other physical properties and occurrence of constituent minerals showed that resistivity is essentially sensitive to the connectivity of interstitial fluids, rather than by sulfide and clay content. This suggests that, in active modern submarine hydrothermal systems, not only typical massive sulfide rocks but also high-temperature hydrothermal fluids could be imaged as low-resistivity anomalies in seabed surveys. The spectral IP signature was shown to be sensitive to the presence or absence of sulfide minerals, and total chargeability is positively correlated with sulfide mineral abundance. In addition, the massive sulfide rock exhibits the distinctive IP feature that the phase steadily increases with a decrease of frequency. These results show the effective usage of IP for developing and improving marine IP exploration techniques.[Figure not available: see fulltext.

  14. The deep structure of a sea-floor hydrothermal deposit

    Science.gov (United States)

    Zierenberg, R.A.; Fouquet, Y.; Miller, D.J.; Bahr, J.M.; Baker, P.A.; Bjerkgard, T.; Brunner, C.A.; Duckworth, R.C.; Gable, R.; Gieskes, J.; Goodfellow, W.D.; Groschel-Becker, H. M.; Guerin, G.; Ishibashi, J.; Iturrino, G.; James, R.H.; Lackschewitz, K.S.; Marquez, L.L.; Nehlig, P.; Peter, J.M.; Rigsby, C.A.; Schultheiss, P.; Shanks, Wayne C.; Simoneit, B.R.T.; Summit, M.; Teagle, D.A.H.; Urbat, M.; Zuffa, G.G.

    1998-01-01

    Hydrothermal circulation at the crests of mid-ocean ridges plays an important role in transferring heat from the interior of the Earth. A consequence of this hydrothermal circulation is the formation of metallic ore bodies known as volcanic-associated massive sulphide deposits. Such deposits, preserved on land, were important sources of copper for ancient civilizations and continue to provide a significant source of base metals (for example, copper and zinc). Here we present results from Ocean Drilling Program Leg 169, which drilled through a massive sulphide deposit on the northern Juan de Fuca spreading centre and penetrated the hydrothermal feeder zone through which the metal-rich fluids reached the sea floor. We found that the style of feeder-zone mineralization changes with depth in response to changes in the pore pressure of the hydrothermal fluids and discovered a stratified zone of high-grade copper-rich replacement mineralization below the massive sulphide deposit. This copper-rich zone represents a type of mineralization not previously observed below sea-floor deposits, and may provide new targets for land-based mineral exploration.

  15. Pt-Os isotopic constraints on the age of hydrothermal overprinting on the Jinchuan Ni-Cu-PGE deposit, China

    Science.gov (United States)

    Yang, Shenghong; Yang, Gang; Qu, Wenjun; Du, Andao; Hanski, Eero; Lahaye, Yann; Chen, Jiangfeng

    2017-12-01

    Platinum group element (PGE) mineralization occurs associated with mafic-ultramafic rocks in different environments. Although the PGE enrichment is primarily caused by magmatic processes, remobilization of Pd and Pt by hydrothermal fluids has likely been an important mechanism in increasing the precious metal grade in many cases. However, the timing of PGE enrichment by hydrothermal fluid processes is commonly difficult to constrain. The Jinchuan ultramafic intrusion in Northwest China is ranked the world's third largest magmatic Ni-Cu sulfide deposit. Besides the main ore body consisting of net-textured and disseminated sulfides, there is hydrothermal mineralization associated with sheared contact zones of the intrusion, which shows elevated Cu and Pt concentrations. The unusually high Pt is hosted mainly in sperrylite within altered silicates. In this study, we applied the Pt-Os geochronometer to a Cu-Pt-rich ore body, yielding an isochron age of 436 ± 23 Ma. This age is significantly younger than the main ore formation age of ca. 825 Ma, but similar to that of the continental collision event between the Qaidam-Qilian Block and Alax Block of North China. This indicates that the intrusion may have been uplifted during the Paleozoic orogenic processes from deeper crust, resulting in the generation of the Cu-Pt-rich hydrothermal ore body. Our new data provide the first strong age constraints on the hydrothermal PGE enrichment, showing that the Pt-Os isotope system is potentially a powerful tool for dating hydrothermal overprinting on Ni-Cu-PGE sulfide deposits.

  16. Oxygen-free atomic layer deposition of indium sulfide

    Science.gov (United States)

    Martinson, Alex B.; Hock, Adam S.; McCarthy, Robert; Weimer, Matthew S.

    2016-07-05

    A method for synthesizing an In(III) N,N'-diisopropylacetamidinate precursor including cooling a mixture comprised of diisopropylcarbodiimide and diethyl ether to approximately -30.degree. C., adding methyllithium drop-wise into the mixture, allowing the mixture to warm to room temperature, adding indium(III) chloride as a solid to the mixture to produce a white solid, dissolving the white solid in pentane to form a clear and colorless solution, filtering the mixture over a celite plug, and evaporating the solution under reduced pressure to obtain a solid In(III) N,N'-diisopropylacetamidinate precursor. This precursor has been further used to develop a novel atomic layer deposition technique for indium sulfide by dosing a reactor with the precursor, purging with nitrogen, dosing with dilute hydrogen sulfide, purging again with nitrogen, and repeating these steps to increase growth.

  17. Application of the Re-Os isotopic system to the study of Precambrian magmatic sulfide deposits of Western Australia

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, D.D.; Frick, L.R. [Monash University, Clayton, VIC (Australia). VIEPS Department of Earth Sciences; Foster, J.G. [Monash University, Clayton, VIC (Australia). VIEPS Department of Earth Sciences]|[Western Mining Corporation Limited, Kambalda, WA (Australia); Hoatson, D.M. [Australian Geological Survey Organisation, Canberra, ACT (Australia); Purvis, A.C. [I.R. Pontifex and Associates, Norwood, SA (Australia)

    1998-04-01

    Mafic and ultramafic rocks that host magmatic Fe-Ni-Cu-platinum-group element (PGE) sulfide deposits are an important feature of the Archaean Yilgarn and Pilbara Cratons of Western Australia. In order to constrain better the genesis of these magmatic ore systems the Re-Os isotopic geochronometer and tracer was applied to four komatiite-hosted Ni sulfide deposits, one Merensky Reef-style Cu-Ni-PGE disseminated sulfide accumulation in a mafic layered intrusion, and a Cu-Ni sulfide-rich siliceous high-MgO basalt dyke swarm . Significant post-crystallisation Re and/or Os mobility is observed in some of the isotopic data. This open-system behaviour and disturbance of the Re-Os system is attributed to hydrothermal alteration, sulfide recrystallization during deformation and metamorphism, and/or metasomatism associated with mesothermal lode-gold mineralisation. However, less tectonised and metamorphosed ores and a host komatiite lava from Kambalda as well as olivine-sulfide cumulates from Perseverance and Mt Keith yield a magmatic Re-Os isochron age of 2706 + 36 Ma, in good agreement with U-Pb zircon ages of 2709-2702 Ma for metasediments from Kambalda, demonstrating that the Re-Os isotopic systematics in these samples have remained closed for 2.7 Ga. This isochron can also be used as a tracer of the magmatic processes that brought the host komatiites to sulfide saturation. These Os isotopic data in combination with trace element and Nd isotopic data demonstrate that the major ore-forming komatiites in Western Australia were derived from chemically depleted mantle without significant contamination (< 3%) by crust either prior to eruption or during turbulent flow at the surface. Details of sample preparation and analytical methods are given in the appendix 120 refs., 1 tab., 5 figs.

  18. Lithologic controls on mineralization at the Lagunas Norte high-sulfidation epithermal gold deposit, northern Peru

    Science.gov (United States)

    Cerpa, Luis M.; Bissig, Thomas; Kyser, Kurt; McEwan, Craig; Macassi, Arturo; Rios, Hugo W.

    2013-06-01

    The 13.1-Moz high-sulfidation epithermal gold deposit of Lagunas Norte, Alto Chicama District, northern Peru, is hosted in weakly metamorphosed quartzites of the Upper Jurassic to Lower Cretaceous Chimú Formation and in overlying Miocene volcanic rocks of dacitic to rhyolitic composition. The Dafne and Josefa diatremes crosscut the quartzites and are interpreted to be sources of the pyroclastic volcanic rocks. Hydrothermal activity was centered on the diatremes and four hydrothermal stages have been defined, three of which introduced Au ± Ag mineralization. The first hydrothermal stage is restricted to the quartzites of the Chimú Formation and is characterized by silice parda, a tan-colored aggregate of quartz-auriferous pyrite-rutile ± digenite infilling fractures and faults, partially replacing silty beds and forming cement of small hydraulic breccia bodies. The δ34S values for pyrite (1.7-2.2 ‰) and digenite (2.1 ‰) indicate a magmatic source for the sulfur. The second hydrothermal stage resulted in the emplacement of diatremes and the related volcanic rocks. The Dafne diatreme features a relatively impermeable core dominated by milled slate from the Chicama Formation, whereas the Josefa diatreme only contains Chimú Formation quartzite clasts. The third hydrothermal stage introduced the bulk of the mineralization and affected the volcanic rocks, the diatremes, and the Chimú Formation. In the volcanic rocks, classic high-sulfidation epithermal alteration zonation exhibiting vuggy quartz surrounded by a quartz-alunite and a quartz-alunite-kaolinite zone is observed. Company data suggest that gold is present in solid solution or micro inclusions in pyrite. In the quartzite, the alteration is subtle and is manifested by the presence of pyrophyllite or kaolinite in the silty beds, the former resulting from relatively high silica activities in the fluid. In the quartzite, gold mineralization is hosted in a fracture network filled with coarse alunite

  19. Geology, geochemistry, and genesis of the Greens Creek massive sulfide deposit, Admiralty Island, southeastern Alaska

    Science.gov (United States)

    Taylor, Cliff D.; Johnson, Craig A.

    2010-01-01

    precious-metal-rich silica-barite-carbonate white ores began at low temperature in a shallow, subaqueous setting, probably a thin carbonate shelf on the flanks of the Alexander landmass. Epigenetic carbonate replacement textures in the footwall dolostones are overlain by stratiform silica-carbonate-barite-rich ores and indicate that early mineralization formed at and just beneath the paleo sea floor by mixing of a reduced, precious-metal-rich, base-metal-poor hydrothermal fluid with oxygenated seawater. As rifting intensified, the shelf was downfaulted and isolated as a graben. Isolation of the basin and onset of starved-basin shale sedimentation was concurrent with emplacement of mafic-ultramafic intrusives at shallow levels in the rift, resulting in an increasingly higher temperature and progressively more anoxic ore-forming environment. The formation of the main stage of massive sulfide ores began as the supply of bacterially reduced sulfur increased in the accumulating shales. As the main-stage mineralization intensified, shale sedimentation inundated the hydrothermal system, eventually forming a cap. Biogenic sulfate reduction supplied reduced sulfur to the base of the shales where mixing occurred with hot, base-metal-rich hydrothermal fluids. Ore deposition continued by destruction and epigenetic replacement of the early white ores in proximal areas and by inflation and diagenetic replacement of unlithified shale at the interface between the white ores and the base of the shale cap. Ore deposition waned as the shales became lithified and as the supply of bacterially reduced sulfur to the site of ore deposition ceased. The final stages of rifting resulted in the emplacement of mafic-ultramafic intrusive rocks into the Greens Creek system and extrusion of voluminous basaltic flows at the top of the Triassic section. Greenschist facies metamorphism during the Jurassic-Cretaceous accretion of the Alexander terrane to the continental margin resulted in recrystalli

  20. Sulfur, carbon, and oxygen isotope variations in submarine hydrothermal deposits of Guaymas Basin, Gulf of California, USA

    Science.gov (United States)

    Peter, J.M.; Shanks, Wayne C.

    1992-01-01

    Sulfur, carbon, and oxygen isotope values were measured in sulfide, sulfate, and carbonate from hydrothermal chimney, spire, and mound samples in the southern trough of Guaymas Basin, Gulf of California, USA. ??34S values of sulfides range from -3.7 to 4.5%. and indicate that sulfur originated from several sources: 1. (1) dissolution of 0??? sulfide contained within basaltic rocks, 2. (2) thermal reduction of seawater sulfate during sediment alteration reactions in feeder zones to give sulfide with positive ??34S, and 3. (3) entrainment or leaching of isotopically light (negative-??34S) bacteriogenic sulfide from sediments underlying the deposits. ??34S of barite and anhydrite indicate sulfur derivation mainly from unfractionated seawater sulfate, although some samples show evidence of sulfate reduction and sulfide oxidation reactions during mixing within chimneys. Oxygen isotope temperatures calculated for chimney calcites are in reasonable agreement with measured vent fluid temperatures and fluid inclusion trapping temperatures. Hydrothermal fluids that formed calcite-rich chimneys in the southern trough of Guaymas Basin were enriched in 18O with respect to seawater by about 2.4??? due to isotopic exchange with sedimentary and/or basaltic rocks. Carbon isotope values of calcite range from -9.6 to -14.0??? ??34CpDB, indicating that carbon was derived in approximately equal quantities from the dissolution of marine carbonate minerals and the oxidation of organic matter during migration of hydrothermal fluid through the underlying sediment column. Statistically significant positive, linear correlations of ??34S, ??34C, and ??18O of sulfides and calcites with geographic location within the southern trough of Guaymas Basin are best explained by variations in water/rock ( w r) ratios or sediment reactivity within subsurface alteration zones. Low w r ratios and the leaching of detrital carbonates and bacteriogenic sulfides at the southern vent sites result in relatively

  1. Thiotaurine and hypotaurine contents in hydrothermal-vent polychaetes without thiotrophic endosymbionts: correlation With sulfide exposure.

    Science.gov (United States)

    Yancey, Paul H; Ishikawa, Joanne; Meyer, Brigitte; Girguis, Peter R; Lee, Raymond W

    2009-07-01

    Invertebrates at hydrothermal vents and cold seeps must cope with toxic H(2)S. One proposed protection mechanism involves taurine derivatives: At vents and seeps, many animals have high levels of hypotaurine and thiotaurine (a product of hypotaurine and HS), originally found in animals with thiotrophic endosymbionts. To further test the role of these compounds, we analyzed them in vent polychaetes without endosymbionts: Paralvinella sulfincola, P. palmiformis and P. pandorae (paralvinellids) and Nicomache venticola (maldanid). P. sulfincola were collected from a high temperature (42-68 degrees C) and a warm site (21-35 degrees C). P. palmiformis and pandorae were from cool sites (12-18 degrees C) and N. venticola were from a cold site (4 degrees C). H(2)S concentrations in vent effluent largely correlate with temperature. Some specimens were frozen; other ones were kept alive in laboratory chambers, with and without sulfide. Tissues were analyzed for taurine derivatives and other solutes that serve as organic osmolytes. The major osmolyte of all species was glycine. Thiotaurine contents were significantly different among all species, in the order P. sulfincola hot>P. sulfincola warm>P. pandorae>P. palmiformis>N. venticola. P. sulfincola also had high levels of sarcosine; others species had none. Sarcosine and hypotaurine contents of P. sulfincola's branchiae were higher, while glycine contents were lower, than in main body. In P. palmiformis kept in pressure chambers with sulfide, thiotaurine contents were higher and hypotaurine lower than in those kept without sulfide. These results support the hypothesis that conversion of hypotaurine to thiotaurine detoxifies sulfide in vent animals without endosymbionts. 2009 Wiley-Liss, Inc

  2. Geochemical and Sulfur-Isotopic Signatures of Volcanogenic Massive Sulfide Deposits on Prince of Wales Island and Vicinity, Southeastern Alaska

    Science.gov (United States)

    Slack, John F.; Shanks, Wayne C.; Karl, Susan M.; Gemery, Pamela A.; Bittenbender, Peter E.; Ridley, W. Ian

    2007-01-01

    Stratabound volcanogenic massive sulfide (VMS) deposits on Prince of Wales Island and vicinity, southeastern Alaska, occur in two volcanosedimentary sequences of Late Proterozoic through Cambrian and of Ordovician through Early Silurian age. This study presents geochemical data on sulfide-rich samples, in situ laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of sulfide minerals, and sulfur-isotopic analyses of sulfides and sulfates (barite) for identifying and distinguishing between primary sea-floor signatures and later regional metamorphic overprints. These datasets are also used here in an attempt to discriminate the VMS deposits in the older Wales Group from those in the younger Moira Sound unit (new informal name). The Wales Group and its contained VMS deposits have been multiply deformed and metamorphosed from greenschist to amphibolite grade, whereas the Moira Sound unit and related VMS deposits are less deformed and generally less metamorphosed (lower to middle greenschist grade). Variations in the sulfide mineral assemblages and textures of the VMS deposits in both sequences reflect a combination of processes, including primary sea-floor mineralization and sub-sea-floor zone refining, followed by metamorphic recrystallization. Very coarse grained (>1 cm diam) sulfide minerals and abundant pyrrhotite are restricted to VMS deposits in a small area of the Wales Group, at Khayyam and Stumble-On, which record high-grade metamorphism of the sulfides. Geochemical and sulfur-isotopic data distinguish the VMS deposits in the Wales Group from those in the Moira Sound unit. Although base- and precious-metal contents vary widely in sulfide-rich samples from both sequences, samples from the Moira Sound generally have proportionately higher Ag contents relative to base metals and Au. In situ LA-ICP-MS analysis of trace elements in the sulfide minerals suggests that primary sea-floor hydrothermal signatures are preserved in some samples (for

  3. Gold enrichment and the Bi-Au association in pyrrhotite-rich massive sulfide deposits, Escanaba trough, Southern Gorda Ridge

    Science.gov (United States)

    Tormanen, T.O.; Koski, R.A.

    2005-01-01

    High gold contents (to 10.1 ppm, avg 1.4 ppm, n = 34) occur in pyrrhotite-rich massive sulfide samples from the sediment-covered floor of the Escanaba trough, the slow-spreading, southernmost segment of Gorda Ridge. These concentrations reflect the presence of primary gold, formed during high-temperature hydrothermal activity in mounds and chimneys, and secondary gold deposited during sea-floor weathering of massive sulfide. Primary gold occurs as fine-grained (2 ??m) secondary gold grains have a porous, flaky morphology and occur in samples in which pyrrhotite is oxidized and replaced by Fe oxyhydroxides, Fe sulfate, and sulfur. Mounds and chimneys dominated by pyrrhotite and containing lesser amounts of isocubanite, chalcopyrite, and Fe-rich sphalerite were formed by high-temperature (estimated range 325??-275??C), reduced, low-sulfur vent fluids. The mineral and fluid compositions during this main stage of hydrothermal venting reflect subsurface interaction between circulating hydrothermal fluids and turbiditic sediment containing as much as 1.1 percent organic carbon. As the deposition of pyrrhotite, Cu-Fe sulfides, and sphalerite waned, a volumetrically minor suite of sulfarsenide, arsenide, Bi, and Au minerals was deposited from highly reduced, late main-stage fluids diffusing through mounds and chimneys. The low solubility of Au as a bisulfide complex and the absence of fluid mixing during this stage of hydrothermal activity apparently inhibited the precipitation of gold directly from solution. Instead, gold precipitation is thought to be linked to elevated concentrations of Bi in the late main-stage fluids. The textural relationships of Au and Bi minerals in pyrrhotite-rich samples, low melting point of native bismuth (271.4??C), and recent experimental results on Au and Bi in hydrothermal fluids contribute to the hypothesis that gold was effectively scavenged from the Escanaba trough vent fluids by coexisting droplets of liquid bismuth. Additional phase

  4. Magmatic-vapor expansion and the formation of high-sulfidation gold deposits: Chemical controls on alteration and mineralization

    Science.gov (United States)

    Henley, R.W.; Berger, B.R.

    2011-01-01

    from any external contemporary hydrothermal activity. Subsequent fracturing is localized by the embrittled wallrock to provide high-permeability fracture arrays that constrain vapor expansion with minimization of heat loss. The Sulfide Stage vein sequence is then a consequence of destabilization of metal-vapor species in response to depressurization and decrease in vapor density. The geology, mineralogy, fluid inclusion and stable isotope data and geothermometry for high-sulfidation, bulk-tonnage and lode deposits are quite different from those for epithermal gold-silver deposits such as McLaughlin, California that formed near-surface in groundwater-dominated hydrothermal systems where magmatic fluid has been diluted to less than about 30%. High sulfidation gold deposits are better termed 'Solfataric Gold Deposits' to emphasize this distinction. The magmatic-vapor expansion hypothesis also applies to the phenomenology of acidic geothermal systems in active volcanic systems and equivalent magmatic-vapor discharges on the flanks of submarine volcanoes. ?? 2010.

  5. Silver sulfotellurides from volcanic-hosted massive sulfide deposits in the Southern Urals

    Science.gov (United States)

    Novoselov, K. A.; Belogub, E. V.; Zaykov, V. V.; Yakovleva, V. A.

    2006-07-01

    This paper addresses Ag-sulfotellurides occurring in volcanic-hosted massive sulfide deposits of the Southern Urals. Cervelleite-like minerals were identified in ores from the Gayskoe, Yaman-Kasy, Severo-Uvaryazhskoe, Tash-Tau, and Babaryk deposits, where they occur in ores containing chalcopyrite, galena, sphalerite, tennantite ± bornite. Other Ag- and Te-bearing minerals (electrum, hessite, stromeyerite and Ag-bearing chalcocite) are present in the association. A benleonardite-like mineral associated with sylvanite and native tellurium was found as a metastable phase in paleohydrothermal tubes relics from the Yaman-Kasy deposit. Formation of the sulfotellurides indicates relative low fTe2 in the hydrothermal systems, insufficient for formation of most S-free tellurides. The significant Cu enrichment in cervelleite relates to the association with bornite. Broad variations in composition and physical properties of cervelleite-like sulfotellurides allow the supposition of the presence of several, as yet unnamed mineral species, which can be distinguished by Cu contents, Te/S ratios, and presumably by crystal structure.

  6. Biomolecule-assisted hydrothermal synthesis and properties of manganese sulfide hollow microspheres

    Science.gov (United States)

    Ma, Wei; Chen, Gen; Zhang, Dan; Zhou, Kechao; Qiu, Guanzhou; Liu, Xiaohe

    2012-11-01

    Gamma-manganese sulfide (γ-MnS) hollow microspheres have been successfully synthesized via a biomolecule-assisted hydrothermal process in the presence of L-cysteine and urea at 180 °C for 24 h. In the synthesis system, L-cysteine was employed as not only a sulfur source, but also a coordination agent. The structure, morphology and optical properties of as-prepared products have been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and photoluminescence (PL) spectrum. Reaction parameters such as ratio of L-cysteine to urea, surfactants and reaction time played a significant role in controlling the morphology of as-prepared products. The probable formation mechanism of the γ-MnS hollow microsphere was proposed on the basis of the experimental results.

  7. Mineralogical Distribution of Germanium, Gallium and Indium at the Mt Carlton High-Sulfidation Epithermal Deposit, NE Australia, and Comparison with Similar Deposits Worldwide

    Directory of Open Access Journals (Sweden)

    Fredrik Sahlström

    2017-11-01

    Full Text Available Germanium, gallium and indium are in high demand due to their growing usage in high-tech and green-tech applications. However, the mineralogy and the mechanisms of concentration of these critical elements in different types of hydrothermal ore deposits remain poorly constrained. We investigated the mineralogical distribution of Ge, Ga and In at the Mt Carlton high-sulfidation epithermal deposit in NE Australia, using electron probe microanalysis and laser ablation inductively-coupled plasma mass spectrometry. Parageneses from which selected minerals were analyzed include: Stage 1 acid sulfate alteration (alunite, Stage 2A high-sulfidation enargite mineralization (enargite, argyrodite, sphalerite, pyrite, barite, Stage 2B intermediate-sulfidation sphalerite mineralization (sphalerite, pyrite, galena and Stage 3 hydrothermal void fill (dickite. Moderate to locally high concentrations of Ga were measured in Stage 1 alunite (up to 339 ppm and in Stage 3 dickite (up to 150 ppm. The Stage 2A ores show enrichment in Ge, which is primarily associated with argyrodite (up to 6.95 wt % Ge and Ge-bearing enargite (up to 2189 ppm Ge. Co-existing sphalerite has comparatively low Ge content (up to 143 ppm, while Ga (up to 1181 ppm and In (up to 571 ppm are higher. Sphalerite in Stage 2B contains up to 611 ppm Ge, 2829 ppm Ga and 2169 ppm In, and locally exhibits fine colloform bands of an uncharacterized Zn-In mineral with compositions close to CuZn2(In,GaS4. Barite, pyrite and galena which occur in association with Stage 2 mineralization were found to play negligible roles as carriers of Ge, Ga and In at Mt Carlton. Analyzed reference samples of enargite from seven similar deposits worldwide have average Ge concentrations ranging from 12 to 717 ppm (maximum 2679 ppm. The deposits from which samples showed high enrichment in critical elements in this study are all hosted in stratigraphic sequences that locally contain carbonaceous sedimentary rocks. In

  8. Highly dispersed NiW/{gamma}-Al{sub 2}O{sub 3} catalyst prepared by hydrothermal deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hao [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249 (China); Fan, Yu.; Bao, Xiaojun [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249 (China); The Key Laboratory of Catalysis, China National Petroleum Corp., China University of Petroleum, Beijing 102249 (China); Shi, Gang; Liu, Haiyan [The Key Laboratory of Catalysis, China National Petroleum Corp., China University of Petroleum, Beijing 102249 (China); Liu, Zhihong [Science and Technology Management Department, PetroChina Company Ltd., World Tower, 16 Andelu, Dongcheng District, Beijing 100011 (China)

    2007-07-30

    This article describes a novel hydrothermal deposition method for preparing highly dispersed NiW/{gamma}-Al{sub 2}O{sub 3} catalysts and demonstrates its advantages over the conventional impregnation method. Via the hydrothermal precipitation reactions between sodium tungstate and hydrochloric acid and between nickel nitrate and urea, respectively, the active species W and Ni were deposited on {gamma}-Al{sub 2}O{sub 3}. In the hydrothermal deposition of WO{sub 3}, a surfactant hexadecyltrimethyl ammonium bromide (CTAB) was used to prevent the aggregation of WO{sub 3}. The characterization results obtained by means of X-ray photoelectron spectroscopy (XPS), N{sub 2} adsorption and high-resolution transmission electron microscopy (HRTEM) measurements showed that compared with the catalyst prepared by the conventional impregnation method, the catalyst with the same metal contents prepared by the hydrothermal deposition had much higher W and Ni dispersion, higher specific surface area, larger pore volume, the significantly decreased slab length and slightly increased stacking degree of sulfided W species, leading to the significantly enhanced dibenzothiophene (DBT) hydrodesulfurization (HDS) activity. The DBT HDS assessment results also revealed that the catalyst containing 17.7 wt% WO{sub 3} and 2.4 wt% NiO prepared by the hydrothermal deposition method had the similar DBT HDS activity as a commercial NiW/{gamma}-Al{sub 2}O{sub 3} catalyst containing 23 wt% WO{sub 3} and 2.6 wt% NiO, resulting in the greatly decreased amount of active metals for achieving the same HDS activity. (author)

  9. Influence of deposition time on the properties of chemical bath deposited manganese sulfide thin films

    Directory of Open Access Journals (Sweden)

    Anuar Kassim

    2010-12-01

    Full Text Available Manganese sulfide thin films were chemically deposited from an aqueous solution containing manganese sulfate, sodium thiosulfate and sodium tartrate. The influence of deposition time (2, 3, 6 and 8 days on the properties of thin films was investigated. The structure and surface morphology of the thin films were studied by X-ray diffraction and atomic force microscopy, respectively. In addition, in order to investigate the optical properties of the thin films, the UV-visible spectrophotometry was used. The XRD results indicated that the deposited MnS2 thin films exhibited a polycrystalline cubic structure. The number of MnS2 peaks on the XRD patterns initially increased from three to six peaks and then decreased to five peaks, as the deposition time was increased from 2 to 8 days. From the AFM measurements, the film thickness and surface roughness were found to be dependent on the deposition time.

  10. Hydrothermal uranium deposits containing molybdenum and fluorite in the Marysvale volcanic field, west-central Utah

    Science.gov (United States)

    Cunningham, C.G.; Rasmussen, J.D.; Steven, T.A.; Rye, R.O.; Rowley, P.D.; Romberger, S.B.; Selverstone, J.

    1998-01-01

    Uranium deposits containing molybdenum and fluorite occur in the Central Mining Area, near Marysvale, Utah, and formed in an epithermal vein system that is part of a volcanic/hypabyssal complex. They represent a known, but uncommon, type of deposit; relative to other commonly described volcanic-related uranium deposits, they are young, well-exposed and well-documented. Hydrothermal uranium-bearing quartz and fluorite veins are exposed over a 300 m vertical range in the mines. Molybdenum, as jordisite (amorphous MoS2, together with fluorite and pyrite, increase with depth, and uranium decreases with depth. The veins cut 23-Ma quartz monzonite, 20-Ma granite, and 19-Ma rhyolite ash-flow tuff. The veins formed at 19-18 Ma in a 1 km2 area, above a cupola of a composite, recurrent, magma chamber at least 24 ?? 5 km across that fed a sequence of 21- to 14-Ma hypabyssal granitic stocks, rhyolite lava flows, ash-flow tuffs, and volcanic domes. Formation of the Central Mining Area began when the intrusion of a rhyolite stock, and related molybdenite-bearing, uranium-rich, glassy rhyolite dikes, lifted the fractured roof above the stock. A breccia pipe formed and relieved magmatic pressures, and as blocks of the fractured roof began to settle back in place, flat-lying, concave-downward, 'pull-apart' fractures were formed. Uranium-bearing, quartz and fluorite veins were deposited by a shallow hydrothermal system in the disarticulated carapace. The veins, which filled open spaces along the high-angle fault zones and flat-lying fractures, were deposited within 115 m of the ground surface above the concealed rhyolite stock. Hydrothermal fluids with temperatures near 200??C, ??18OH2O ~ -1.5, ?? -1.5, ??DH2O ~ -130, log fO2 about -47 to -50, and pH about 6 to 7, permeated the fractured rocks; these fluids were rich in fluorine, molybdenum, potassium, and hydrogen sulfide, and contained uranium as fluoride complexes. The hydrothermal fluids reacted with the wallrock resulting in

  11. Formation of Zn- and Fe-sulfides near hydrothermal vents at the Eastern Lau Spreading Center: implications for sulfide bioavailability to chemoautotrophs

    Directory of Open Access Journals (Sweden)

    Yucel Mustafa

    2008-05-01

    Full Text Available Abstract Background The speciation of dissolved sulfide in the water immediately surrounding deep-ocean hydrothermal vents is critical to chemoautotrophic organisms that are the primary producers of these ecosystems. The objective of this research was to identify the role of Zn and Fe for controlling the speciation of sulfide in the hydrothermal vent fields at the Eastern Lau Spreading Center (ELSC in the southern Pacific Ocean. Compared to other well-studied hydrothermal systems in the Pacific, the ELSC is notable for unique ridge characteristics and gradients over short distances along the north-south ridge axis. Results In June 2005, diffuse-flow ( 250°C vent fluids were collected from four field sites along the ELSC ridge axis. Total and filtered Zn and Fe concentrations were quantified in the vent fluid samples using voltammetric and spectrometric analyses. The results indicated north-to-south variability in vent fluid composition. In the high temperature vent fluids, the ratio of total Fe to total Zn varied from 39 at Kilo Moana, the most northern site, to less than 7 at the other three sites. The concentrations of total Zn, Fe, and acid-volatile sulfide indicated that oversaturation and precipitation of sphalerite (ZnS(s and pyrite (FeS2(s were possible during cooling of the vent fluids as they mixed with the surrounding seawater. In contrast, most samples were undersaturated with respect to mackinawite (FeS(s. The reactivity of Zn(II in the filtered samples was tested by adding Cu(II to the samples to induce metal-exchange reactions. In a portion of the samples, the concentration of labile Zn2+ increased after the addition of Cu(II, indicating the presence of strongly-bound Zn(II species such as ZnS clusters and nanoparticles. Conclusion Results of this study suggest that Zn is important to sulfide speciation at ELSC vent habitats, particularly at the southern sites where Zn concentrations increase relative to Fe. As the hydrothermal

  12. Shape-controlled synthesis and properties of manganese sulfide microcrystals via a biomolecule-assisted hydrothermal process

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Jinghui; Yu Runnan; Zhu Jianyu; Yi Ran; Qiu Guanzhou [School of Resources Processing and Bioengineering, Central South University, Changsha, Hunan 410083 (China); He Yuehui [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Liu Xiaohe, E-mail: liuxh@mail.csu.edu.cn [School of Resources Processing and Bioengineering, Central South University, Changsha, Hunan 410083 (China); State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China)

    2009-06-15

    An effective biomolecule-assisted synthetic route has been successfully developed to prepare {gamma}-manganese sulfide (MnS) microtubes under hydrothermal conditions. In the synthetic system, soluble hydrated manganese chloride was employed to supply Mn source and L-cysteine was used as precipitator and complexing reagent. Sea urchin-like {gamma}-MnS and octahedron-like {alpha}-MnS microcrystals could also be selectively obtained by adjusting the process parameters such as hydrothermal temperature and reaction time. The phase structures, morphologies and properties of the as-prepared products were investigated in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), and photoluminescence spectra (PL). The photoluminescence studies exhibited the correlations between the morphology, size, and shape structure of MnS microcrystals and its optical properties. The formation mechanisms of manganese sulfide microcrystals were discussed based on the experimental results.

  13. Carlin-type Au Deposits in Nevada: Unique Hydrothermal Systems?

    Science.gov (United States)

    Cline, J. S.

    2006-05-01

    Carlin-type gold deposits (CTGD) in Nevada have huge Au endowments that have made Nevada one of the leading Au producers in the world. Although they form one of the three most productive Au districts in the world, the deposits were not discovered until the early 1960's owing primarily to the lack of visible Au. Numerous studies have provided a detailed geologic picture of the deposits, yet a comprehensive and widely accepted genetic model remains elusive because of 1) difficulties in identifying and analyzing the fine-grained, volumetrically minor, and common ore and gangue minerals, 2) approximately contemporaneous mineralization that overprinted or was overprinted by Carlin-type mineralization, and 3) post-ore weathering and oxidation. Geologic data from all districts indicate compelling similarities, suggesting that all deposits formed in response to similar geologic processes. Yet, stable isotope studies suggest multiple sources for ore fluids and components. Because of these inconsistencies, current models relate deposits to 1) metal leaching and transport by convecting meteoric water, 2) hydrothermal fluids exsolved from epizonal intrusions, and 3) deep metamorphic and/or magmatic fluids. Proterozoic to early Paleozoic rifting produced a passive margin sequence of reactive calcareous host rocks, and NNW- and WNW-striking basement and Paleozoic normal faults that may control the trends. Following rifting, the host rocks were subjected to compressional orogenies, developing a pre-mineral architecture of steeply dipping fluid conduits and shallow dipping traps. NNW- and WNW-striking basement and Paleozoic normal faults were inverted during these compressional events and formed structural culminations including anticlines and domes that served as depositional sites for ore fluids. Au-bearing pyrite precipitated 42-36 m.y. ago as northwesterly to westerly extension reopened favorably oriented older structures. Fluid flow and mineral deposition appear to have been

  14. Effects of greenschist-facies metamorphism and related deformation on the Mobrun massive sulfide deposit, Québec, Canada

    Science.gov (United States)

    Larocque, A. C. L.; Hodgson, C. J.

    1995-10-01

    The Mobrun Zn-Cu-Ag-Au deposit in the Noranda mining camp is hosted by Archean mafic and felsic submarine volcanic rocks. The deposit comprises three massive sulfide complexes: the Main and Satellite Lenses near surface, and the 1100 orebody at depth. The rocks have been subjected to lower greenschist-facies metamorphism and related deformation, which resulted in changes in ore textures, development of shear zones and veins systems, remobilization of gold, and formation of a new mineral (electrum) within the orebodies. Both mechanical and chemical processes operated to produce secondary textures and structures resulting from brittle deformation, ductile deformation, and annealing. The specific deformation mechanisms include brittle failure and cataclastic flow, dislocation glide, dislocation creep and solution-precipitation creep. The Main and Satellite Lenses are characterized by excellent preservation of primary sulfides deposited from and reworked by synvolcanic hydrothermal fluids. These orebodies were affected to a limited degree by mechanical processes of deformation. In contrast, the 1100 orebody is characterized by a higher degree of development of textures and structures related to metamorphism and deformation, especially those formed by chemical processes. The differences may be due to the greater depth of the 1100 orebody relative to the other lenses, as regional metamorphic isograds are subhorizontal, and more extensive interaction between metamorphic fluids and the 1100 Lens.

  15. Sulfur and oxygen isotopes in barite deposits of the western Brooks Range, Alaska, and implications for the origin of the Red Dog massive sulfide deposits

    Science.gov (United States)

    Johnson, C.A.; Kelley, K.D.; Leach, D.L.

    2004-01-01

    Sulfur and oxygen isotope analyses have been obtained for barite samples from the giant stratiform sulfide barite deposits at Red Dog in the western Brooks Range of Alaska, from stratiform barite deposits elsewhere in the Red Dog district, and from stratiform and vein and breccia barite occurrences in the central Brooks Range. Twelve of the 15 deposits studied lie within middle to Upper Mississippian black shale and chert units. The data reveal two different patterns on ?? 34S versus ??18O plots. The first, which is best illustrated by the barite deposit at Anarraaq, shows linear trends with slopes that vary with barite texture. For most samples, ??34S and ??18O values are both higher than the values characteristic of Mississippian marine sulfate. The second pattern, which is evident at the Red Dog deposits, shows no correlation between ??34S and ??18. In most samples, ??18O is below the value for Mississippian marine sulfate. Comparisons with sulfate in modern marine environments suggest a possible model for the mineralizing process. Anarraaq-type barite formed at sea-floor vents where ascending fluids carrying barium and methane encountered sulfate-bearing pore waters or bottom waters. Barite deposition was accompanied by the reduction of sulfate to H2S by means of microbially mediated anaerobic methane oxidation. Red Dog-type barite was formed in a manner similar to Anarraaq-type barite but was over-printed by a massive sulfide-forming event. Red Dog sulfides precipitated where metal-bearing hydrothermal fluids encountered pore waters that had been charged with H2S by anaerobic methane oxidation. Textural and isotopic evidence indicates that the sulfide bodies grew by consuming the available H2S and then by reductively dissolving barite. Dissolution of barite caused barium to be released to higher stratigraphic levels where it was reprecipitated on encountering sulfate. Isotopic evidence is pre sented for a link between methane venting and barite formation and

  16. Geochemical features of sulfides from the Deyin-1 hydrothermal field at the southern Mid-Atlantic Ridge near 15°S

    Science.gov (United States)

    Wang, Shujie; Li, Huaiming; Zhai, Shikui; Yu, Zenghui; Cai, Zongwei

    2017-12-01

    In this study, geochemical compositions of elements in sulfide samples collected from the Deyin-1 hydrothermal field near the 15°S southern Mid-Atlantic Ridge (SMAR) were analyzed by the X-ray fluorescence spectrometry (XRF) and inductively coupled plasma mass spectrometry (ICP-MS) to examine the enrichment regulations of ore-forming elements and hydrothermal mineralization. These sulfide precipitates can be classified macroscopically into three types: Fe-rich sulfide, Fe-Cu-rich sulfide and Fe-Zn-rich sulfide, and are characterized by the enrichment of base metal elements along with a sequence of Fe>Zn>Cu. Compared with sulfides from other hydrothermal fields on MAR, Zn concentrations of sulfides in the research area are significantly high, while Cu concentrations are relatively low. For all major, trace or rare-earth elements (REE), their concentrations and related characteristic parameters exhibit significant variations (up to one or two orders of magnitude), which indicates the sulfides from different hydrothermal vents or even a same station were formed at different stages of hydrothermal mineralization, and suggests the variations of chemical compositions of the hydrothermal fluid with respect to time. The hydrothermal temperatures of sulfides precipitation decreased gradually from station TVG10 (st.TVG10) to st.TVG12, and to st.TVG11, indicating that the precipitation of hydrothermal sulfides is subjected to conditions changed from high temperature to low temperature, and that the hydrothermal activity of study area was at the late stage of a general trend of evolution from strong to weak. The abnormally low concentrations of REE in sulfides and their similar chondrite-normalized REE patterns show that REEs in all sulfides were derived from a same source, but underwent different processes of migration or enrichment, or sulfides were formed at different stages of hydrothermal mineralization. The sulfides collected from the active hydrothermal vent were

  17. The interplay of evolved seawater and magmatic-hydrothermal fluids in the 3.24 Ga panorama volcanic-hosted massive sulfide hydrothermal system, North Pilbara Craton, Western Australia

    Science.gov (United States)

    Drieberg, Susan L.; Hagemann, Steffen G.; Huston, David L.; Landis, Gary; Ryan, Chris G.; Van Achterbergh, Esmé; Vennemann, Torsten

    2013-01-01

    The ~3240 Ma Panorama volcanic-hosted massive sulfide (VHMS) district is unusual for its high degree of exposure and low degree of postdepositional modification. In addition to typical seafloor VHMS deposits, this district contains greisen- and vein-hosted Mo-Cu-Zn-Sn mineral occurrences that are contemporaneous with VHMS orebodies and are hosted by the Strelley granite complex, which also drove VHMS circulation. Hence the Panorama district is a natural laboratory to investigate the role of magmatic-hydrothermal fluids in VHMS hydrothermal systems. Regional and proximal high-temperature alteration zones in volcanic rocks underlying the VHMS deposits are dominated by chlorite-quartz ± albite assemblages, with lesser low-temperature sericite-quartz ± K-feldspar assemblages. These assemblages are typical of VHMS hydrothermal systems. In contrast, the alteration assemblages associated with granite-hosted greisens and veins include quartz-topaz-muscovite-fluorite and quartz-muscovite (sericite)-chlorite-ankerite. These vein systems generally do not extend into the overlying volcanic pile. Fluid inclusion and stable isotope studies suggest that the greisens were produced by high-temperature (~590°C), high-salinity (38–56 wt % NaCl equiv) fluids with high densities (>1.3 g/cm3) and high δ18O (9.3 ± 0.6‰). These fluids are compatible with the measured characteristics of magmatic fluids evolved from the Strelley granite complex. In contrast, fluids in the volcanic pile (including the VHMS ore-forming fluids) were of lower temperature (90°–270°C), lower salinity (5.0–11.2 wt % NaCl equiv), with lower densities (0.88–1.01 g/cm3) and lower δ18O (−0.8 ± 2.6‰). These fluids are compatible with evolved Paleoarchean seawater. Fluids that formed the quartz-chalcopyrite-sphalerite-cassiterite veins, which are present within the granite complex near the contact with the volcanic pile, were intermediate in temperature and isotopic composition between the greisen

  18. Microbial lipid remnants within sulfide chimneys reveal organic matter transport in seafloor hydrothermal systems

    Science.gov (United States)

    Reeves, E.; Goldenstein, N. I.; Yoshinaga, M. Y.; Pjevac, P.; Bach, W.; Hinrichs, K.

    2013-12-01

    , with presumed hyperthermophilic archaeal lipid remnants more prevalent in interior and more mesophilic lipids in outer regions of the inactive chimney. Diffuser interior samples, however, are highly unusual, in that they contain presumed mesophilic archaeal core lipids, despite uninhabitable temperatures. Thermal degradation of an in situ microbial community (e.g. due to transient fluid flow variability) is a possible explanation, but the nature of these lipids suggests they may instead reflect transport and pyrolysis of microbial material from lower temperature mixing zones within the crustal aquifer. Not only does this study broaden our understanding of lipid biomolecule distribution in the interiors of sulfide edifices, it provides an initial evaluation of possible sources and implications for carbon cycling in seafloor hydrothermal systems.

  19. U-Pb dating of minerals in alteration halos of Superior Province massive sulfide deposits: syngenesis versus metamorphism

    Science.gov (United States)

    Davis, D. W.; Schandl, E. S.; Wasteneys, H. A.

    1994-02-01

    U-Pb geochronology of igneous zircon from rhyolitic host rocks to the Archean Kidd Creek, Geco and Winston Lake massive sulfide deposits, in the Superior Province of Ontario, shows that volcanism, which accompanied mineralization, occupied a narrow time span (2717±2 Ma, 2720±2 Ma and 2723±2 Ma, respectively). Precise ages of hydrothermal monazite, allanite and rutile from alteration zones surrounding the above deposits indicate that these minerals crystallized 40 70 million years after volcanism. Monazite from Kidd Creek mine is 2659±3 Ma old, in agreement with spatially associated 2664±25 Ma old rutile. Monazite from a biotite schist at Geoco mine gives a similar age of 2661±1 Ma. However, monazite from a sericite schist, which hosts the ore at Geco mine, is 2675±2 Ma old. Abraded large monazite grains from three units in the Winston Lake deposit are coeval with biotite crystallization and record an age of 2677±2 Ma, approximately the same as monazite in the sericite schist at Geco. Data points from allanite fractions from both the Winston Lake and Geco deposits fall on a Pb-Pb isochron that gives an age of 2672±5 Ma. Rutile from Winston Lake gives a younger age of 2651±6/-2 Ma and may date retrograde alteration of biotite to chlorite. The ca. 2676 Ma age of monazite from Winston Lake and in the sericite schist at Geco mine probably dates a regional metamorphic event that affected most of the southern Superior Province. The ca. 2660 Ma old monazite in the biotite schist at Geco mine and in the chlorite-sericite alteration at Kidd Creek may date later K-metasomatism caused by metamorphically derived fluids that were focussed along old fault structures. Such fluids were also responsible for local sulfide remobilization. Monazite and rutile are spatially associated with chlorite and sericite alterations at Kidd Creek. Their young ages indicate that these originally syngenetic mineral assemblages may have been significantly affected by regional metamorphism

  20. Clear Evidence for Hydrothermal Deposits within Gusev Crater Established by the Mars Exploration Rover Spirit

    Science.gov (United States)

    Yen, A. S.; Gellert, R.; Morris, R. V.; Clark, B. C.; Athena Science Team

    2011-12-01

    The Spirit rover ended its science mission on the martian surface after operating for 2210 sols and covering over 7.7 km across geologically diverse terrain. A multitude of discoveries have been made along the traverse, including compelling evidence for past hydrothermal activity at the surface of Mars. Several light-toned deposits excavated by the rover wheels were analyzed in detail by the Mössbauer and Alpha Particle X-ray Spectrometers (APXS), which determined that they are dominated by ferric sulfates in association with magnesium sulfates, silica and occasionally calcium sulfates and phosphates. Based on modeling of scatter peaks within the APXS data, these samples are hydrated and contain up to 18 wt% water. They also exhibit the chemical signatures of nearby rocks (e.g. corresponding phosphate enrichments) and have a Fe:Mn ratio far from the value measured for the majority of samples analyzed by the rovers, clearly indicative of aqueous interactions. Variability in the deposits over centimeter to meter scales indicates that these precipitates did not develop under large-scale equilibrium conditions. Based upon the observations of up to 35 wt% SO3 and the abundance of measured cations in expected oxidation states, the occurrence of elemental sulfur, sulfuric acid, or sulfides cannot be ruled out. The likely mechanisms for the formation of these deposits involve sulfur-rich hydrothermal fluids and volcanic vapors reaching the surface and producing fumarolic condensates. In close association with the samples containing abundant hydrated ferric sulfates are other samples which are dominated by silica. In one example, the elemental chemistry data shows over 90 wt% SiO2. Elevated titanium concentrations in these silica-rich samples are suggestive of interactions with acidic fluids or vapors resulting in preferential retention of the least mobile elements. This is consistent with the acid sulfate processes indicated by the occurrence of the ferric sulfates

  1. Fungi associated with chimney and sulfide samples from a South Mid-Atlantic Ridge hydrothermal site: Distribution, diversity and abundance

    Science.gov (United States)

    Xu, Wei; Guo, Shuangshuang; Pang, Ka-Lai; Luo, Zhu-Hua

    2017-05-01

    Deep-sea hydrothermal vent ecosystems are known to support remarkably diverse microbial communities, ranging from chemoautotrophic prokaryotes to heterotrophic prokaryotes and microeukaryotes. While fungi have generally been identified as an important component of various microbial communities in the environment, little is known about the species richness and abundance of such microorganisms in deep-sea hydrothermal vent ecosystems. In this study, a combined culture-dependent and culture-independent sequence-based approach was used to investigate fungal distribution and diversity at a deep-sea hydrothermal vent site located at the Mid-Atlantic Ridge of the South Atlantic Ocean. Sequence analyses showed that the fungal community was dominated by members of the Ascomycota and the Basidiomycota. Several new phylotypes (28 of 65 total fungal OTUs and 2 of 19 culturable fungal phylotypes) were identified, contributing to the literally unknown diversity of fungi in this understudied habitat. The fungal community structures in the chimney samples were distinct from those in three sulfide samples. The qPCR results revealed that fungal LSU rRNA gene copy numbers ranged from 5.88×105 to 6.77×106 copies/gram rock (wet weight), and the Ascomycota was significantly more abundant 2-3 orders) than the Basidiomycota. Our findings provide new insights into the diversity and abundance of fungi in deep-sea hydrothermal vent ecosystems, which increases our knowledge and understanding of the fungal diversity in deep-sea environments.

  2. Mineralogy and geochemical environment of formation of the Perama Hill high-sulfidation epithermal Au-Ag-Te-Se deposit, Petrota Graben, NE Greece

    Science.gov (United States)

    Voudouris, Panagiotis Christos; Melfos, Vasilios; Spry, Paul G.; Moritz, Robert; Papavassiliou, Constantinos; Falalakis, George

    2011-11-01

    The Perama Hill deposit is a high-sulfidation Au-Ag-Te-Se epithermal system hosted in silicic- and argillic altered andesitic rocks and overlying sandstones, which were emplaced on the eastern margin of the Petrota graben, northeastern Greece. The deposit evolved from an early stage silica-pyrite rock and argillic alteration followed by the deposition of sulfide-, sulfosalt- and telluride-bearing quartz-barite veins and stockworks. Early ore formation is characterized by a high-sulfidation-type enargite-galena-bearing ore assemblage (consisting of enargite, watanabeite, Fe-free sphalerite, covellite, kesterite, bismuthinite, selenian bismuthinite, lillianite homologues, kawazulite-tetradymite, goldfieldite, and native gold), followed by the formation of an intermediate-sulfidation-type tennantite-bearing assemblage characterized by ferrian/zincian tennantite, tellurobismuthite, tetradymite, melonite, native tellurium, Au-Ag-tellurides (calaverite, krennerite, sylvanite, hessite, petzite, stützite), altaite and electrum. Quartz, barite, kaolinite, sericite and minor aluminum-phosphate-sulfate minerals are gangue minerals. Fluid inclusion data demonstrate that the ore system evolved from an initial high temperature (up to 330°C) and low salinity (up to 4.9 wt.% NaCl equiv.) fluid towards a cooler (200°C) and very low salinity (0.7 wt.% NaCl equiv.) hydrothermal fluid suggesting progressive cooling and dilution of the ore fluid. The ore minerals at Perama Hill reflect variable fS2 and fTe2 conditions during base and precious metal deposition. Early ore deposition took place at ~300°C, at log fS2 values between ≈-8.2 and -5.5, and log fTe2 from -11.8 and -7.8. Late ore deposition occurred at log fS2 = -11.8 to -9.8 and log fTe2 of ≈-9.2 and -7.8. These data and paragenetic studies indicate a shift towards higher log fTe2 and lower log fS2 and log fSe2 values for the mineralizing fluids with time. The kawazulite/tetradymitess-gold association at Perama Hill

  3. Geology, ore facies and sulfur isotopes geochemistry of the Nudeh Besshi-type volcanogenic massive sulfide deposit, southwest Sabzevar basin, Iran

    Science.gov (United States)

    Maghfouri, Sajjad; Rastad, Ebrahim; Mousivand, Fardin; Lin, Ye; Zaw, Khin

    2016-08-01

    . Chloritization, silicification, sericitization and epidotization are the main wall-rock alterations; alteration intensity increases towards the stringer zone. The δ34S composition of the sulfides ranges from -1.5‰ to +3.69‰ with a general increase of δ34S ratios of massive ore facies to stockwork zone. The heavier values indicate that some of the sulfur was derived from seawater sulfate that was ultimately thermochemically reduced in deep hydrothermal reaction zones. Sulfur isotopes, along with sedimentological, textural, petrological, mineralogical, and geochemical evidences, suggest that this deposit should be classified as a Besshi-type VMS ore deposit.

  4. Boiling and vertical mineralization zoning: a case study from the Apacheta low-sulfidation epithermal gold-silver deposit, southern Peru

    Science.gov (United States)

    André-Mayer, Anne-Sylvie; Leroy, Jacques; Bailly, Laurent; Chauvet, Alain; Marcoux, Eric; Grancea, Luminita; Llosa, Fernando; Rosas, Juan

    2002-06-01

    The Au-Ag (±Pb-Zn) Apacheta deposit is located in the Shila district, 600 km southeast of Lima in the Cordillera Occidental of Arequipa Province, southern Peru. The vein mineralization is found in Early to Middle Miocene calc-alkaline lava flows and volcanic breccias. Both gangue and sulfide mineralization express a typical low-sulfidation system; assay data show element zoning with base metals enriched at depth and higher concentrations of precious metals in the upper part of the veins. Three main deposition stages are observed: (1) early pyrite and base-metal sulfides with minor electrum 1 and acanthite; (2) brecciation of this mineral assemblage and cross-cutting veinlets with subhedral quartz crystals, Mn-bearing calcite and rhombic adularia crystals; and finally (3) veinlets and geodal filling of an assemblage of tennantite/tetrahedrite + colorless sphalerite 2 + galena + chalcopyrite + electrum 2. Fluid inclusions in the mineralized veins display two distinct types: aqueous-carbonic liquid-rich Lw-c inclusions, and aqueous-carbonic vapor-rich Vw-c inclusions. Microthermometric data indicate that the ore minerals were deposited between 300 and 225 °C from relatively dilute hydrothermal fluids (0.6-3.4 wt% NaCl). The physical and chemical characteristics of the hydrothermal fluids show a vertical evolution, with in particular a drop in temperature and a loss of H2S. The presence of adularia and platy calcite and of co-existing liquid-rich and vapor-rich inclusions in the ore-stage indicates a boiling event. Strong H2S enrichment in the Vw-c inclusions observed at -200 m, the abundance of platy calcite, and the occurrence of hydrothermal breccia at this level may indicate a zone of intense boiling. The vertical element zoning observed in the Apacheta deposit thus seems to be directly related to the vertical evolution of hydrothermal-fluid characteristics. Precious-metal deposition mainly occurred above the 200-m level below the present-day surface, in response

  5. Hydrothermal deposition on the Juan de Fuca Ridge over multiple glacial-interglacial cycles

    Science.gov (United States)

    Costa, Kassandra M.; McManus, Jerry F.; Middleton, Jennifer L.; Langmuir, Charles H.; Huybers, Peter J.; Winckler, Gisela; Mukhopadhyay, Sujoy

    2017-12-01

    Hydrothermal systems play an important role in modern marine chemistry, but little is known about how they may have varied on 100,000 year timescales. Here we present high-resolution records of non-lithogenic metal fluxes within sediment cores covering the last 500,000 years of hydrothermal deposition on the flanks of the Juan de Fuca Ridge. Six adjacent, gridded cores were analyzed by x-ray fluorescence for Fe, Mn, and Cu concentrations, corrected for lithogenic inputs with Ti, and normalized to excess initial 230Th to generate non-lithogenic metal flux records that provide the longest orbitally resolved reconstructions of hydrothermal activity currently available. Fe fluxes vary with global sea level over the last two glacial cycles, suggesting higher hydrothermal deposition during interglacial periods. The observed negative relationship between Fe and Mn indicates variable sediment redox conditions and diagenetic remobilization of sedimentary Mn over time. Thus, Mn fluxes may not be a reliable indicator for hydrothermal activity in the Juan de Fuca Ridge sediment cores. Cu fluxes show substantial high-frequency variability that may be linked to changes in vent temperature related to increased magmatic production during glacial periods. Deglacial hydrothermal peaks on the Juan de Fuca Ridge are consistent with previously published records from the Mid-Atlantic Ridge and the East Pacific Rise. Moreover, on the Juan de Fuca Ridge, the deglacial peaks in hydrothermal activity are followed by relatively high hydrothermal fluxes throughout the ensuing interglacial periods relative to the previous glacial period.

  6. Ore horizons, ore facies, mineralogy and geochemistry of volconogenic massive sulfide (VMS deposits of the Varandan Ba-Pb-Cu deposit, southwest of Qamsar - Iran

    Directory of Open Access Journals (Sweden)

    Fayeq Hashemi

    2017-11-01

    -horizons in Unit1, as lenticular to tabular ore bodies concordant to layering of the host rocks. Based on textural, structural and mineralogical studies, the Varandan deposit consists of five ore facieses including: 1 veins-veinlets (stringer zone that involves cross-cuting barite, quartz and sulfide veins-veinlets, 2 brecciated barite and massive pyrite (vent complex zone involving replacement texture, 3 massive barite and sulfide (massive zone, 4 alternations of barite- and galena- rich bands (Bedded-banded zone and; 5 iron-manganese-bearing hydrothermal-exhalative sediments. Primary ore minerals are barite, galena, chalcopyrite, pyrite, sphalerite, tetrahedrite, magnetite, oligiste, braunite, pyrolusite and bornite, accompanied with secondary minerals such as native copper, cuprite, digenite, covellite, chalcosite, goethite, hematite and malachite. Gangue minerals consist of chlorite, sericite, quartz and calcite. Major wall rock alterations in the deposit are chloritic and quartz- sericitic. For determining the type of ore of the Varandan deposit, the Cu/Zn ratio for the barite and sulfide ore of the first, second and third sub-horizon are 1.08, 0.12 and 11.08, respectively. This lies in the yellow ore for the first and third sub-horizon, and it falls in the black ore for the second sub-. Discussion According to the basic characteristics of mineralization such as geometry of ore bodies, textures and structures, ore facies, wall rock alterations, mineralogy, fluid inclusions data, metal zonation and geochemical features, the Varandan deposit could be classified as a bimodal-felsic or Kuroko-type voclanogenic massive sulfide (VMS deposit, similar to those of the Hokuroko basin in Japan (Ohmoto and Skinner, 1983; Hoy, 1995, Huston et al., 2011. The Varandan deposit has been formed in an intra-arc setting due to subduction of the Neo-Tethyan oceanic crust beneath the Iranian plate during the Middle Eocene. Acknowledgements The authors are grateful to the Grant Commission for

  7. Textural, compositional, and sulfur isotope variations of sulfide minerals in the Red Dog Zn-Pb-Ag deposits, Brooks Range, Alaska: Implications for Ore Formation

    Science.gov (United States)

    Kelley, K.D.; Leach, D.L.; Johnson, C.A.; Clark, J.L.; Fayek, M.; Slack, J.F.; Anderson, V.M.; Ayuso, R.A.; Ridley, W.I.

    2004-01-01

    The Red Dog Zn-Pb deposits are hosted in organic-rich mudstone and shale of the Mississippian Kuna Formation. A complex mineralization history is defined by four sphalerite types or stages: (1) early brown sphalerite, (2) yellow-brown sphalerite, (3) red-brown sphalerite, and (4) late tan sphalerite. Stages 2 and 3 constitute the main ore-forming event and are volumetrically the most important. Sulfides in stages 1 and 2 were deposited with barite, whereas stage 3 largely replaces barite. Distinct chemical differences exist among the different stages of sphalerite. From early brown sphalerite to later yellow-brown sphalerite and red-brown sphalerite, Fe and Co content generally increase and Mn and Tl content generally decrease. Early brown sphalerite contains no more than 1.9 wt percent Fe and 63 ppm Co, with high Mn (up to 37 ppm) and Tl (126 ppm), whereas yellow-brown sphalerite and red-brown sphalerite contain high Fe (up to 7.3 wt %) and Co (up to 382 ppm), and low Mn (sulfur isotope analyses show a progression from extremely low ??34S values for stage 1 (as low as -37.20???) to much higher values for yellow-brown sphalerite (mean of 3.3???; n = 30) and red-brown sphalerite (mean of 3.4; n = 20). Late tan sphalerite is isotopically light (-16.4 to -27.2???). The textural, chem ical, and isotopic data indicate the following paragenesis: (1) deposition of early brown sphalerite with abundant barite, minor pyrite, and trace galena immediately beneath the sea floor in unconsolidated mud; (2) deposition of yellow-brown sphalerite during subsea-floor hydrothermal recrystallization and coarsening of preexisting barite; (3) open-space deposition of barite, red-brown sphalerite and other sulfides in veins and coeval replacement of barite; and (4) postore sulfide deposition, including the formation of late tan sphalerite breccias. Stage 1 mineralization took place in a low-temperature environment where fluids rich in Ba mixed with pore water or water-column sulfate to

  8. Formation and evolution stages of gold rich Barika massive sulfide deposit, east of Sardasht, northern Sanandaj-Sirjan zone: based on structural, textural and fluid inclusion studies

    Directory of Open Access Journals (Sweden)

    Hossein Ali Tajeddin

    2010-05-01

    Full Text Available Barika gold (and silver rich massive sulfide deposit is located 18 km east of Sardasht, north western part of Sanandaj-Sirjan metamorphic zone. Rock units outcropped in this area are Cretaceous metamorphosed volcano-sedimentary rocks in green schist facies, and include association of meta-andesite, meta-tuffite, phyllite and slate rocks, where the meta-andesitic unit (Kmv1 is host rock to the deposit. Barika deposit is composed of stratiform ore and stringer zone. Stratiform part contains massive and banded sulfide and barite associated with subordinary silica bands underlain by stringer silicic zone. The massive and banded ore is surrounded by an extensive zone of silicic stringer veins and disseminated mineralization within strongly altered and deformed andesitic volcanic rocks. Ore mineral assemblages in stratiform part of the deposit are quite variable and consist of pyrite, sphalerite, galena, stibnite, a variety of sulfosalt minerals and gold (electrum. Ore mineral assemblages in silicic veins in the stringer zone are simpler and consist of pyrite, galena, sphalerite, tetrahedrrite and trace chalcopyrite. Average gold and silver grades in stratiform ore are 8.3 and 420 g/t respectively and in silicic stringer veins are 0.7 and 30 g/t. Base metal content in both parts of the deposit are less than 1%. Based on our research, Barika is an immature Kuroko type massive sulfide deposit, which contains only black ore. The Barika deposit underwent low-grade metamorphism and high grade deformation after the ore deposition event. Geologic processes appear to control the mode of occurrence of gold in the deposit. In synvolcanism stage, deposition of a gold–bearing low temperature (140-200°C and low salinity (1-9.6 wt% NaCl hydrothermal fluid formed a Kuroko black ore type deposit. In the stage of mineralization, invisible gold was concentrated in framboidal pyrite and other sulfide minerals. The main effect of progressive metamorphism (D1 on gold

  9. Hydrothermal barite mineralization at Chenarvardeh deposit, Markazi Province, Iran: Evidences from REE geochemistry and fluid inclusions

    Science.gov (United States)

    Ehya, Farhad; Mazraei, Shaghayegh Moalaye

    2017-10-01

    Barite mineralization occurs at Chenarvardeh deposit as layers and lenses in Upper Eocene volcanic and pyroclastic rocks. The host rocks are intensely saussuritized in most places. Barite is accompanied by calcite, Mn-oxides, galena and malachite as subordinate minerals. The amount of Sr in barites is low and varies between 0.11 and 0.30 wt%. The concentration of Rb, Zr, Y, Ta and Hf is also low (volcanic hydrothermal model for barite formation at the Chenarvardeh deposit. Mineral-forming fluids originated from solutions related to submarine hydrothermal activities deposited barite on seafloor as they encountered sulfate-bearing seawater.

  10. Geology of volcanogenic massive sulfide deposit near Meli ...

    African Journals Online (AJOL)

    VMS) deposit near Meli/Rahwa, northern Ethiopia are presented in the paper. The study area forms part of Neoproterozoic basement of northern Ethiopia and southern part of the Arabian Nubian Shield (ANS). Selected surface rock samples of ...

  11. Involvement of magmatic fluids at the Laloki and Federal Flag massive sulfide Cu-Zn-Au-Ag deposits, Astrolabe mineral district, Papua New Guinea: sulfur isotope evidence

    Science.gov (United States)

    Noku, Shadrach K.; Espi, Joseph O.; Matsueda, Hiroharu

    2015-01-01

    We present the first sulfur (S) isotope data of sulfides, sulfates, pyrite in host mudstone, and bulk sulfur of gabbroic rocks from the Laloki and Federal Flag massive Cu-Zn-Au-Ag deposits in the Astrolabe mineral district, Papua New Guinea. Early-stage pyrite-marcasite, chalcopyrite, and sphalerite from Laloki display wide range of δ34S values from -4.5 to +7.0 ‰ ( n = 16). Late-stage pyrite, chalcopyrite, and sphalerite have restricted δ34S values of -1.9 to +4.7 ‰ ( n = 16). The mineralizing stage these correspond to had moderately saline (5.9-8.4 NaCl eq. wt%) mineralizing fluids of possible magmatic origin. A single analysis of late-stage barite has a value of δ34S +17.9 ‰, which is likely similar to coexisting seawater sulfate. Pyrite from the foot-wall mudstone at Laloki has very light δ34S values of -36.1 to -33.8 ‰ ( n = 2), which suggest an organic source for S. Pyrite-marcasite and chalcopyrite from Federal Flag show δ34S values of -2.4 to -1.9 ‰ ( n = 2), consistent with a magmatic origin, either leached from intrusive magmatic rocks or derived from magmatic-hydrothermal fluids. The very narrow range and near-zero δ34S values (-1.0 to +0.6 ‰) of bulk gabbroic samples is consistent with mantle-derived magmatic S. Sulfur isotope characteristics of sulfides and sulfates are, however, very similar to base metal sulfide accumulations associated with modern volcanic arcs and sedimented mid-ocean ridges. The most reasonable interpretation is that the range of the sulfide and sulfate δ34S values from both Laloki and Federal Flag massive sulfide deposits is indicative of the complex interaction of magmatic fluids, seawater, gabbroic rocks, and mudstone.

  12. Mapping hydrothermal altered mineral deposits using Landsat 7 ...

    Indian Academy of Sciences (India)

    and low cost (Yetkin 2003). There are many studies around the world related to hydrothermal alteration mapping .... for many years in remote sensing to display spectral variations effectively (e.g., Goetz et al. 1983). It is based on ... affect the viewer's interpretations and may lead to misguided results. Therefore, the band ratio.

  13. Non-stoichiometry in sulfides produced by pulsed laser deposition

    DEFF Research Database (Denmark)

    Canulescu, Stela; Cazzaniga, Andrea Carlo; Ettlinger, Rebecca Bolt

    Pulsed laser deposition or PLD is known as a technique by which complex materials can be stoichiometrically transferred from a target to a substrate, providing that the ablation threshold is exceeded. For a multi-target component, it frequently happens that there is loss of the lightest and the m...

  14. Comparative studies of spray pyrolysis deposited copper sulfide ...

    Indian Academy of Sciences (India)

    Abstract. CuxS thin films with different Cu to S molar ratios (0·33 and 0·43) have been deposited by spray pyro- lysis method on glass and FTO coated glass substrates using an aqueous solution of copper (II) acetate and thiourea at a substrate temperature of 285◦C. The structural, surface morphological, optical and ...

  15. Tellurium-bearing minerals in zoned sulfide chimneys from Cu-Zn massive sulfide deposits of the Urals, Russia

    Science.gov (United States)

    Maslennikov, V. V.; Maslennikova, S. P.; Large, R. R.; Danyushevsky, L. V.; Herrington, R. J.; Stanley, C. J.

    2013-02-01

    Tellurium-bearing minerals are generally rare in chimney material from mafic and bimodal felsic volcanic hosted massive sulfide (VMS) deposits, but are abundant in chimneys of the Urals VMS deposits located within Silurian and Devonian bimodal mafic sequences. High physicochemical gradients during chimney growth result in a wide range of telluride and sulfoarsenide assemblages including a variety of Cu-Ag-Te-S and Ag-Pb-Bi-Te solid solution series and tellurium sulfosalts. A change in chimney types from Fe-Cu to Cu-Zn-Fe to Zn-Cu is accompanied by gradual replacement of abundant Fe-, Co, Bi-, and Pb- tellurides by Hg, Ag, Au-Ag telluride and galena-fahlore with native gold assemblages. Decreasing amounts of pyrite, both colloform and pseudomorphic after pyrrhotite, isocubanite ISS and chalcopyrite in the chimneys is coupled with increasing amounts of sphalerite, quatz, barite or talc contents. This trend represents a transition from low- to high sulphidation conditions, and it is observed across a range of the Urals deposits from bimodal mafic- to bimodal felsic-hosted types: Yaman-Kasy → Molodezhnoye → Uzelga → Valentorskoye → Oktyabrskoye → Alexandrinskoye → Tash-Tau → Jusa.

  16. Copper isotope fractionation during sulfide-magma differentiation in the Tulaergen magmatic Ni-Cu deposit, NW China

    Science.gov (United States)

    Zhao, Yun; Xue, Chunji; Liu, Sheng-Ao; Symons, David T. A.; Zhao, Xiaobo; Yang, Yongqiang; Ke, Junjun

    2017-08-01

    Although it has been recently demonstrated that Cu isotope fractionation during mantle melting and basaltic magma differentiation is limited, the behavior of Cu isotopes during magmatic differentiation involving significant sulfide segregation remains unclear. Magmatic Ni-Cu deposits, which formed via sulfide segregation from basaltic or picritic magmas, are appropriate targets to address this issue. Here we report Cu isotope data for sulfides (chalcopyrite) from the Tulaergen Ni-Cu sulfide deposit in Xinjiang, NW China. Sulfides, including sparsely disseminated (hosted by hornblende gabbro), moderately disseminated (hosted by hornblende olivine websterite), densely disseminated (hosted by hornblende lherzolite) and massive sulfides (sandwiched between country rocks and mafic-ultramafic rocks), were collected from adits at 1050 m, 1100 m and 1150 m levels. The sparsely and moderately disseminated sulfides on 1150 m and 1050 m levels have a restricted range of δ65Cu values from - 0.38‰ to 0.15‰, whereas disseminated and massive sulfides on 1100 m level have δ65Cu values ranging widely from - 1.98‰ to - 0.04‰ and from - 1.08‰ to - 0.52‰, respectively. The δ65Cu values of disseminated sulfides are negatively correlated with whole-rock S and Cu concentrations, and sulfides formed at later stages have heavier δ65Cu values. These observations suggest significant Cu isotope fractionation during sulfide-magma differentiation above 600 °C. During the formation of the Tulaergen magmatic Ni-Cu deposit, sulfide segregation and crystallization of olivine and pyroxene caused the increase of Fe3 + contents in the residual magmas, which would move the redox reaction Cu+ + Fe3 + = Fe2 + + Cu2 + toward larger amounts of Cu2 + in the melt. The presence of Cu2 + in melt allowed redox transformation to happen during sulfide segregation. The residual magmas are enriched in heavy Cu isotopes due to the removal of 65Cu-depleted sulfides, and sulfides formed at later

  17. Geologic setting and genesis of the Mule Canyon low-sulfidation epithermal gold-silver deposit, north-central Nevada

    Science.gov (United States)

    John, D.A.; Hofstra, A.H.; Fleck, R.J.; Brummer, J.E.; Saderholm, E.C.

    2003-01-01

    The Mule Canyon mine exploited shallow, low-sulfidation, epithermal Au-Ag deposits that lie near the west side of the Northern Nevada rift in northern Lander County, Nevada. Mule Canyon consists of six small deposits that contained premining reserves of about 8.2 Mt at an average grade of 3.81 g Au/tonne. It is an uncommon mafic end member of low-sulfidation Au-Ag deposits associated with tholeiitic bimodal basalt-rhyolite magmatism. The ore is hosted by a basalt-andesite eruptive center that formed between about 16.4 to 15.8 Ma during early mafic eruptions related to regionally extensive bimodal magmatism. Hydrothermal alteration and Au-Ag ores formed at about 15.6 Ma and were tightly controlled by north-northwest- to north-striking high-angle fault and breccia zones developed during rifting, emplacement of mafic dikes, and eruption of mafic lava flows. Hydrothermal alteration assemblages are zoned outward from fluid conduits in the sequence silica-adularia, adularia-smectite, smectite (intermediate argillic), and smectite-carbonate (propylitic). All alteration types contain abundant pyrite and/or marcasite ?? arsenopyrite. Field relations indicate that silica-adularia alteration is superimposed on argillic and propylitic alteration. Little or no steam-heated acid-sulfate alteration is present, probably the result of a near-surface water table during hydrothermal alteration and ore deposition. Two distinct ore types are present at Mule Canyon: early replacement and later open-space filling. Replacement ores consist of disseminated and vesicle-filling pyrite, marcasite, and arsenopyrite in argillically altered or weakly silicified rocks. Ore minerals consist of Au-bearing arsenopyrite and arsenian pyrite overgrowths on earlier-formed pyrite and marcasite. Open-space filling ores include narrow stockwork quartz-adularia veins, banded and crustiform opaline and chalcedonic silica-adularia veins, silica-adularia cemented breccias, and sparse carbonate-pyrite and

  18. The Marianas-San Marcos vein system: characteristics of a shallow low sulfidation epithermal Au-Ag deposit in the Cerro Negro district, Deseado Massif, Patagonia, Argentina

    Science.gov (United States)

    Vidal, Conrado Permuy; Guido, Diego M.; Jovic, Sebastián M.; Bodnar, Robert J.; Moncada, Daniel; Melgarejo, Joan Carles; Hames, Willis

    2016-08-01

    The Cerro Negro district, within the Argentinian Deseado Massif province, has become one of the most significant recent epithermal discoveries, with estimated reserves plus resources of ˜6.7 Moz Au equivalent. The Marianas-San Marcos vein system contains about 70 % of the Au-Ag resources in the district. Mineralization consists of Upper Jurassic (155 Ma) epithermal Au- and Ag-rich veins of low to intermediate sulfidation style, hosted in and genetically related to Jurassic intermediate composition volcanic rocks (159-156 Ma). Veins have a complex infill history, represented by ten stages with clear crosscutting relationships that can be summarized in four main episodes: a low volume, metal-rich initial episode (E1), an extended banded quartz episode with minor mineralization (E2), a barren waning stage episode (E3), and a silver-rich late tectonic-hydrothermal episode (E4). The first three episodes are interpreted to have formed at the same time and probably from fluids of similar composition: a 290-230 °C fluid dominated by meteoric and volcanic waters (-3‰ to -0‰ δ18Owater), with sulfur (-1 to -2 ‰ δ34Swater). Metal was mainly precipitated at the beginning of vein formation (episode 1) due to a combination of boiling at ˜600 to 800 m below the paleowater table, and associated mixing/cooling processes, as evidenced by sulfide-rich bands showing crustiform-colloform quartz, adularia, and chlorite-smectite banding. During episodes 2 and 3, metal contents progressively decrease during continuing boiling conditions, and veins were filled by quartz and calcite during waning stages of the hydrothermal system, and the influx of bicarbonate waters (-6 to -8.5 ‰ δ18Owater). Hydrothermal alteration is characterized by proximal illite, adularia, and silica zone with chlorite and minor epidote, intermediate interlayered illite-smectite and a distal chlorite halo. This assemblage is in agreement with measured fluid inclusion temperatures. A striking aspect of the

  19. Silver-bearing minerals in the Xinhua hydrothermal vein-type Pb-Zn deposit, South China

    Science.gov (United States)

    Wang, Minfang; Zhang, Xubo; Guo, Xiaonan; Pi, Daohui; Yang, Meijun

    2017-03-01

    Electron probe microanalysis (EPMA) results are reported for newly identified silver-bearing minerals from the Xinhua deposit, Yunkaidashan area, South China. The Xinhua deposit is a hydrothermal vein-type Pb-Zn deposit and is hosted in the Pubei Complex, which consists of a cordierite-biotite granite with a U-Pb zircon age of 244.3 ± 1.8-251.9 ± 2.2 Ma. The mineralization process is subdivided into four mineralization stages, characterized by the following mineral associations: mineralization stage I with quartz, pyrite, and sphalerite; mineralization stage II with siderite, galena, and tetrahedrite; mineralization stage III with quartz and galena; and mineralization stage IV with quartz, calcite, and baryte. Tetrahedrite series minerals, such as freibergite, argentotetrahedrite, and tennantite are the main Ag-bearing minerals in the Xinhua deposit. The greatest concentration of silver occurs in phases from mineralization stage II. Microscopic observations reveal close relationship between galena and tetrahedrite series minerals that mostly occur as irregular inclusions within galena. The negative correlation between Cu and Ag in the lattices of tetrahedrite series minerals suggests that Cu sites are occupied by Ag atoms. Zn substitution for Fe in argentotetrahedrite and Cd substitution for Pb in tetrahedrite are also observed. Micro-thermometric data reveal that both homogenization temperatures and calculated salinities of hydrothermal fluids decrease progressively from the early to the later mineralization stages. The metal ions, such as Ag+, Cu+, Pb2+, and Zn2+, are transported as chlorine complex ions in the early mineralization stage and as bisulfide complex ions in the late mineralization stage, caused by changes in oxygen fugacity, temperature, and pH of the hydrothermal fluids. Because of the varying solubility of different metal ions, Pb2+, Zn2+, and Cu2+ ions are initially precipitated as galena, sphalerite, and chalcopyrite, respectively. With

  20. Electrochemical deposition of iron sulfide thin films and heterojunction diodes with zinc oxide

    Energy Technology Data Exchange (ETDEWEB)

    Kawai, Shoichi, E-mail: shoichi-kawai@denso.co.jp; Sobue, Susumu; Okuno, Eiichi [DENSO CORP. Research Laboratories, Komenoki, Nissin, Aichi 470-0111 (Japan); Yamazaki, Ryuta; Ichimura, Masaya [Department of Engineering Physics, Electronics and Mechanics, Nagoya Institute of Technology, Nagoya 466-8555 (Japan)

    2014-03-01

    Iron sulfide thin films were fabricated by the electrochemical deposition method from an aqueous solution containing FeSO{sub 4} and Na{sub 2}S{sub 2}O{sub 3}. The composition ratio obtained was Fe:S:O = 36:56:8. In the photoelectrochemical measurement, a weak negative photo-current was observed for the iron sulfide films, which indicates that its conduction type is p-type. No peaks were observed in X-ray diffraction pattern, and thus the deposited films were considered to be amorphous. For a heterojunction with ZnO, rectification properties were confirmed in the current-voltage characteristics. Moreover, the current was clearly enhanced under AM1.5 illumination.

  1. Variable mineralization processes during the formation of the Permian Hulu Ni-Cu sulfide deposit, Xinjiang, Northwestern China

    Science.gov (United States)

    Zhao, Yun; Xue, Chunji; Zhao, Xiaobo; Yang, Yongqiang; Ke, Junjun; Zu, Bo

    2016-08-01

    The Permian Hulu Ni-Cu sulfide deposit is located at the southern margin of the Central Asian Orogenic Belt (CAOB) in Northern Xinjiang, Northwestern China. The host intrusion of the Hulu deposit is composed of a layered mafic-ultramafic sequence and a dike-like unit. The layered sequence is composed of harzburgite, lherzolite, pyroxenite, gabbro, gabbrodiorite and diorite. The dike-like body comprises lherzolite and gabbro. Sulfide orebodies occur mainly within the harzburgite, pyroxenite and lherzolite at the base of the layered sequence and within the lherzolite in the dike-like body. Sulfide mineralization from the Hulu deposit shows significant depletion of PGE relative to Cu and Ni. These elements show good positive correlations with S in the sulfide mineralization from the dike-like unit but relatively weak correlations in the sulfide mineralization from the layered sequence. The sulfide mineralization from the layered unit shows excellent positive correlations between Ir and Os, Ru or Rh, and poor relationships between Ir and Pt or Pd. On the contrary, sulfide mineralization from the dike-like unit shows good correlations in the diagrams of Os, Ru, Rh, Pt and Pd against Ir. Both high Cu/Pd ratios (8855-481,398) and our modeling indicate that PGE depletion resulted from sulfide removal in a deep staging magma chamber. The evolved PGE-depleted magmas then ascended to the shallower magma chamber and became sulfide saturation due to crustal contamination. Both low Se/S ratios (33.5 × 10-6-487.5 × 10-6) and a negative correlation between Se/S and Cu/Pd ratios are consistent with the addition of crustal S. A large number of sulfide liquids segregated with minor crystallization of monosulfide solid solution (MSS) in the shallower magma chamber. When new magma pulses with unfractionated sulfide droplets entered the shallower magma chamber, the sulfide slurry containing crystallized MSS may be disrupted and mixed with the unfractionated sulfide droplets. The

  2. The Muruntau gold deposit (Uzbekistan – A unique ancient hydrothermal system in the southern Tien Shan

    Directory of Open Access Journals (Sweden)

    Ulf Kempe

    2016-05-01

    Full Text Available The Muruntau gold deposit in the Central Kyzylkum, Uzbekistan is one of the largest single gold deposits worldwide. Data available from the literature are reviewed with the aim to (1 integrate the present knowledge on this unique deposit from Russian and English literature; (2 show the considerable progress made in the understanding of the genesis of the Muruntau deposit during the last decades; and (3 point to problems still open for future research. Deposit formation occurred through a multi-stage process involving sedimentation, regional metamorphism including thrusting, magmatism with formation of hornfels aureoles and several stages of hydrothermal activity. According to recent knowledge, synsedimentary or pure metamorphic formation of gold mineralization seems unlikely. The role of granite magmatism occurring roughly within the same time interval as the main hydrothermal gold precipitation remains uncertain. There are no signs of interaction of matter between the magma(s and the hydrothermal system(s. On the other hand, there was an intense, high-temperature (above 400 °C fluid – wall rock interaction resulting in the formation of gold-bearing, cone-like stockworks with veins, veinlets and gold-bearing metasomatites. Several chemical and isotope indicators hint at an involvement of lower-crustal or mantle-related sources as well as of surface waters in ore formation. Deposit formation through brecciation involving explosion, hydrothermal or tectonic breccias might explain these data. Further investigations on breccia formation as well as on the exact timing of relevant sedimentary, metamorphic, magmatic and hydrothermal events are recommended.

  3. Uranium-lead dating of hydrothermal zircon and monazite from the Sin Quyen Fe-Cu-REE-Au-(U) deposit, northwestern Vietnam

    Science.gov (United States)

    Li, Xiao-Chun; Zhou, Mei-Fu; Chen, Wei Terry; Zhao, Xin-Fu; Tran, MyDung

    2017-06-01

    The Sin Quyen deposit in northwestern Vietnam contains economic concentrations of Cu, Au and LREE, and sub-economic concentration of U. In this deposit, massive and banded replacement ores are hosted in Neoproterozoic metapelite. The paragenetic sequence includes sodic alteration (stage I), calcic-potassic alteration and associated Fe-REE-(U) mineralization (stage II), Cu-Au mineralization (stage III), and sulfide-(quartz-carbonate) veins (stage IV). The Sin Quyen deposit experienced an extensive post-ore metamorphic overprint, which makes it difficult to precisely determine the mineralization age. In this study, zircon and monazite U-Pb geochronometers and the Rb-Sr isochron method are used to constrain the timing of mineralization. Zircon grains in the ore are closely intergrown or texturally associated with hydrothermal minerals of stage II (e.g., garnet, allanite, and hedenbergite). They may contain primary fluid inclusions and display irregular zoning in cathodoluminescence (CL) images. Zircon grains are rich in U (688 to 2902 ppm) and poor in Th (0.2 to 2.9 ppm). Their δ18OV-SMOW values range from 11.9 to 14.0‰, higher than those of typical magmatic zircon. These textural and compositional features imply that zircon precipitated from 18O- and U-rich hydrothermal fluids, coeval with the minerals of stage II. Monazite occurs in close association with stage II magnetite and allanite and has low contents of Th (<2700 ppm), indicative of a hydrothermal origin. Hydrothermal zircon and monazite have indistinguishable U-Pb ages of 841 ± 12 and 836 ± 18 Ma, respectively, representing the timing of Fe-REE mineralization. There is no direct isotopic constraint on the timing of the Cu-Au mineralization, but geological observations suggest that the Cu-Au and Fe-REE ores most likely formed within a single evolved hydrothermal process. In the plot of 87Rb/86Sr vs. 87Sr/86Sr, the composition of bulk-ore and biotite separates from ore lie along a reference line for 30 Ma

  4. Influences of the Tonga Subduction Zone on seafloor massive sulfide deposits along the Eastern Lau Spreading Center and Valu Fa Ridge

    Science.gov (United States)

    Evans, Guy N.; Tivey, Margaret K.; Seewald, Jeffrey S.; Wheat, C. Geoff

    2017-10-01

    This study investigates the morphology, mineralogy, and geochemistry of seafloor massive sulfide (SMS) deposits from six back-arc hydrothermal vent fields along the Eastern Lau Spreading Center (ELSC) and Valu Fa Ridge (VFR) in the context of endmember vent fluid chemistry and proximity to the Tonga Subduction Zone. To complement deposit geochemistry, vent fluid analyses of Cu, Zn, Ba, Pb and H2,(aq) were completed to supplement existing data and enable thermodynamic calculations of mineral saturation states at in situ conditions. Results document southward increases in the abundance of mantle-incompatible elements in hydrothermal fluids (Ba and Pb) and SMS deposits (Ba, Pb, As, and Sb), which is also expressed in the abundance of barite (BaSO4) and galena (PbS) in SMS deposits. These increases correspond to a decrease in distance between the ELSC/VFR and the Tonga Subduction Zone that correlates with a change in crustal lithology from back-arc basin basalt in the north to mixed andesite, rhyolite, and dacite in the south. Barite influences deposit morphology, contributing to the formation of horizontal flanges and squat terraces. Results are also consistent with a regional-scale lowering of hydrothermal reaction zone temperatures from north to south (except at the southernmost Mariner vent field) that leads to lower-temperature, higher-pH vent fluids relative to mid-ocean ridges of similar spreading rates (Mottl et al., 2011). These fluids are Cu- and Zn-poor and the deposits formed from these fluids are Cu-poor but Zn-rich. In contrast, at the Mariner vent field, higher-temperature and lower pH vent fluids are hypothesized to result from higher reaction zone temperatures and the localized addition of acidic magmatic volatiles (Mottl et al., 2011). The Mariner fluids are Cu- and Zn-rich and vent from SMS deposits that are rich in Cu but poor in Zn with moderate amounts of Pb. Thermodynamic calculations indicate that the contrasting metal contents of vent fluids

  5. Poriferan chitin as a template for hydrothermal zirconia deposition

    Science.gov (United States)

    Wysokowski, Marcin; Motylenko, Mykhaylo; Bazhenov, Vasilii V.; Stawski, Dawid; Petrenko, Iaroslav; Ehrlich, Andre; Behm, Thomas; Kljajic, Zoran; Stelling, Allison L.; Jesionowski, Teofil; Ehrlich, Hermann

    2013-09-01

    Chitin is a thermostable biopolymer found in various inorganic-organic skeletal structures of numerous invertebrates including sponges (Porifera). The occurrence of chitin within calcium- and silica-based biominerals in organisms living in extreme natural conditions has inspired development of new (extreme biomimetic) synthesis route of chitin-based hybrid materials in vitro. Here, we show for the first time that 3D-α-chitin scaffolds isolated from skeletons of the marine sponge Aplysina aerophoba can be effectively mineralized under hydrothermal conditions (150°C) using ammonium zirconium(IV) carbonate as a precursor of zirconia. Obtained chitin-ZrO2 hybrid materials were characterized by FT-IR, SEM, HRTEM, as well as light and confocal laser microscopy. We suggest that formation of chitin-ZrO2 hybrids occurs due to hydrogen bonds between chitin and ZrO2.

  6. Trace metal-rich Quaternary hydrothermal manganese oxide and barite deposit, Milos Island, Greece

    Science.gov (United States)

    Hein, J.R.; Stamatakis, G.; Dowling, J.S.

    2000-01-01

    The Cape Vani Mn oxide and barite deposit on Milos Island offers an excellent opportunity to study the three-dimensional characteristics of a shallow-water hydrothermal system. Milos Island is part of the active Aegean volcanic arc. A 1 km long basin located between two dacitic domes in northwest Milos is filled with a 35-50 m thick section of Quaternary volcaniclastic and pyroclastic rocks capped by reef limestone that were hydrothermally mineralized by Mn oxides and barite. Manganese occurs as thin layers, as cement of sandstone and as metasomatic replacement of the limestone, including abundant fossil shells. Manganese minerals include chiefly δ-MnO2, pyrolusite and ramsdellite. The MnO contents for single beds range up to 60%. The Mn oxide deposits are rich in Pb (to 3.4%), BaO (to 3.1%), Zn (to 0.8%), As (to 0.3%), Sb (to 0.2%) and Ag (to 10 ppm). Strontium isotopic compositions of the Mn oxide deposits and sulphur isotopic compositions of the associated barite show that the mineralizing fluids were predominantly sea water. The Mn oxide deposit formed in close geographical proximity to sulphide-sulphate-Au-Ag deposits and the two deposit types probably formed from the same hydrothermal system. Precipitation of Mn oxide took place at shallow burial depths and was promoted by the mixing of modified sea water (hydrothermal fluid) from which the sulphides precipitated at depth and sea water that penetrated along faults and fractures in the Cape Vani volcaniclastic and tuff deposits. The hydrothermal fluid was formed from predominantly sea water that was enriched in metals leached from the basement and overlying volcanogenic rocks. The hydrothermal fluids were driven by convection sustained by heat from cooling magma chambers. Barite was deposited throughout the time of Mn oxide mineralization, which occurred in at least two episodes. Manganese mineralization occurred by both focused and diffuse flow, the fluids mineralizing the beds of greatest porosity and

  7. Constraints on mineralisation and hydrothermal alteration in the Nalunaq gold deposit, South Greenland

    DEFF Research Database (Denmark)

    Bell, Robin-Marie Fairbairn

    Summary: Nalunaq is located in South Greenland and is a small high gold-grade deposit, which for the majority of its operational life was Greenland's only metalliferous mine. Gold is hosted in narrow quartz veins which are cross-cut by late-stage faults. Gold-quartz veins are hosted by fine......-and - medium grained amphibolite of the Nanortalik Nappe. Detailed petrographic and geochronological studies have revealed a multi-stage hydrothermal alteration system, with alteration pre-and post-dating gold mineralisation. The hydrothermal alteration records a transition from upper-amphibolite facies...

  8. Geochemical and iron isotopic insights into hydrothermal iron oxyhydroxide deposit formation at Loihi Seamount

    Science.gov (United States)

    Rouxel, Olivier; Toner, Brandy; Germain, Yoan; Glazer, Brian

    2018-01-01

    Low-temperature hydrothermal vents, such as those encountered at Loihi Seamount, harbor abundant microbial communities and provide ideal systems to test hypotheses on biotic versus abiotic formation of hydrous ferric oxide (FeOx) deposits at the seafloor. Hydrothermal activity at Loihi Seamount produces abundant microbial mats associated with rust-colored FeOx deposits and variably encrusted with Mn-oxyhydroxides. Here, we applied Fe isotope systematics together with major and trace element geochemistry to study the formation mechanisms and preservation of such mineralized microbial mats. Iron isotope composition of warm (aged or less active deposits. These results are consistent with Fe(II) oxidation mediated by microbial processes considering the expected slow kinetics of abiotic Fe oxidation in low oxygen bottom water at Loihi Seamount. In contrast, FeOx deposits recovered at extinct sites have distinctly negative Fe-isotope values down to -1.77‰ together with significant enrichment in Mn and occurrence of negative Ce anomalies. These results are best explained by the near-complete oxidation of an isotopically light Fe(II) source produced during the waning stage of hydrothermal activity under more oxidizing conditions. Light Fe isotope values of FeOx are therefore generated by subsurface precipitation of isotopically heavy Fe-oxides rather than by the activity of dissimilatory Fe reduction in the subsurface. Overall, Fe-isotope compositions of microbial mats at Loihi Seamount display a remarkable range between -1.2‰ and +1.6‰ which indicate that Fe isotope compositions of hydrothermal Fe-oxide precipitates are particularly sensitive to local environmental conditions where they form, and are less sensitive to abiotic versus biotic origins. It follows that FeOx deposits at Loihi Seamount provides important modern analogues for ancient seafloor Fe-rich deposits allowing for testing hypotheses about the biogeochemical cycling of Fe isotopes on early Earth.

  9. Colloidal origin of colloform-banded textures in the Paleogene low-sulfidation Khan Krum gold deposit, SE Bulgaria

    Science.gov (United States)

    Marinova, Irina; Ganev, Valentin; Titorenkova, Rositsa

    2014-01-01

    We studied both colloform-banded macro- and micro-textures as well as the composition of electrum from the epithermal Khan Krum (or Ada Tepe) gold deposit, Bulgaria (5 Mt at 5.1 g/t Au + 2.7 g/t Ag) using optical and electron scanning microscopy, vibration spectroscopy, electron micro-probe analysis, and LA-ICP-MS. The individual textural bands differ in grain size, porosity, quartz-to-adularia ratio, and abundance of electrum, pyrite, and scattered dusty opaque micro-inclusions. The individual macro-bands have formed successively via intermittent fault dilation from episodic hydrothermal pulses, as a result of regional extension and most likely originated from colloidal solutions formed by vigorous boiling during rapid pressure drop and supersaturation with respect to amorphous silica in a closed or quasi-closed hydrothermal system. Electrum is highly concentrated in the finest quartz-adularia colloform micro-bands, which fill joints with widths up to 1-2 mm. We presume that the joints have filled in with more concentrated colloidal solutions than those in the macro-bands, most likely due to extreme boiling of fluids in open or quasi-open hydrothermal system. Electrum in the micro-bands forms transverse dendrite- and chain-like aggregates as well as oval clots along the banding, all of globular morphology. We explain these locations of electrum with reorientation of aggregated electrum globules during plastic deformation of a mixed electrum-silicate gel and in result from the consequent crystallization of silicates. At the same time, electrum is not present in pores and cracks of syneresis, which indicates that it had not been a soluble phase at the time of syneresis, rather colloidal particles. Electrum also forms dense sprinkles of globular morphology deposited in open space on the surfaces of some quartz-adularia bands, due to a condensation of gaseous phase, separated during the boiling of fluids. We found that the electrum-rich quartz-adularia micro

  10. A Palaeoproterozoic multi-stage hydrothermal alteration system at Nalunaq gold deposit, South Greenland

    Science.gov (United States)

    Bell, Robin-Marie; Kolb, Jochen; Waight, Tod Earle; Bagas, Leon; Thomsen, Tonny B.

    2017-03-01

    Nalunaq is an orogenic, high gold grade deposit situated on the Nanortalik Peninsula, South Greenland. Mineralisation is hosted in shear zone-controlled quartz veins, located in fine- and medium-grained amphibolite. The deposit was the site of Greenland's only operating metalliferous mine until its closure in 2014, having produced 10.67 t of gold. This study uses a combination of field investigation, petrography and U/Pb zircon and titanite geochronology to define a multi-stage hydrothermal alteration system at Nalunaq. A clinopyroxene-plagioclase-garnet(-sulphide) alteration zone (CPGZ) developed in the Nanortalik Peninsula, close to regional peak metamorphism and prior to gold-quartz vein formation. The ca. 1783-1762-Ma gold-quartz veins are hosted in reactivated shear zones with a hydrothermal alteration halo of biotite-arsenopyrite-sericite-actinolite-pyrrhotite(-chlorite-plagioclase-löllingite-tourmaline-titanite), which is best developed in areas of exceptionally high gold grades. Aplite dykes dated to ca. 1762 Ma cross-cut the gold-quartz veins, providing a minimum age for mineralisation. A hydrothermal calcite-titanite alteration assemblage is dated to ca. 1766 Ma; however, this alteration is highly isolated, and as a result, its field relationships are poorly constrained. The hydrothermal alteration and mineralisation is cut by several generations of ca. 1745-Ma biotite granodiorite accompanied by brittle deformation. A ca. 1745-Ma lower greenschist facies hydrothermal epidote-calcite-zoisite alteration assemblage with numerous accessory minerals forms halos surrounding the late-stage fractures. The contrasting hydrothermal alteration styles at Nalunaq indicate a complex history of exhumation from amphibolite facies conditions to lower greenschist facies conditions in an orogenic belt which resembles modern Phanerozoic orogens.

  11. Preparation and characterization of titania-deposited silica composite hollow fiber membranes with high hydrothermal stability.

    Science.gov (United States)

    Kwon, Young-Nam; Kim, In-Chul

    2013-11-01

    Hydrothermal stability of a porous nickel-supported silica membrane was successfully improved by deposition of titania multilayers on colloidal silica particles embedded in the porous nickel fiber support. Porous nickel-supported silica membranes were prepared by means of a dipping-freezing-fast drying (DFF) method. The titania layers were deposited on colloidal silica particles by repeating hydrolysis and condensation reactions of titanium isopropoxide on the silica particle surfaces. The deposition of thin titania layers on the nickel-supported silica membrane was verified by various analytical tools. The water flux and the solute rejection of the porous Ni fiber-supported silica membranes did not change after titania layer deposition, indicating that thickness of titania layers deposited on silica surface is enough thin not to affect the membrane performance. Moreover, improvement of the hydrothermal stability in the titania-deposited silica membranes was confirmed by stability tests, indicating that thin titania layers deposited on silica surface played an important role as a diffusion barrier against 90 degrees C water into silica particles.

  12. Antimony sulfide thin films prepared by laser assisted chemical bath deposition

    Energy Technology Data Exchange (ETDEWEB)

    Shaji, S., E-mail: sshajis@yahoo.com [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolás de los Garza, Nuevo León, 66455 (Mexico); CIIDIT—Universidad Autónoma de Nuevo León, Apodaca, Nuevo León (Mexico); Garcia, L.V. [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolás de los Garza, Nuevo León, 66455 (Mexico); Loredo, S.L. [Centro de Investigación en Materiales Avanzados (CIMAV), Unidad Monterrey, PIIT, Apodaca, Nuevo León (Mexico); Krishnan, B. [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolás de los Garza, Nuevo León, 66455 (Mexico); CIIDIT—Universidad Autónoma de Nuevo León, Apodaca, Nuevo León (Mexico); and others

    2017-01-30

    Highlights: • Antimony sulfide thin films were prepared by normal CBD and laser assisted CBD. • Characterized these films using XRD, XPS, AFM, optical and electrical measurements. • Accelerated growth was observed in the laser assisted CBD process. • These films were photoconductive. - Abstract: Antimony sulfide (Sb{sub 2}S{sub 3}) thin films were prepared by laser assisted chemical bath deposition (LACBD) technique. These thin films were deposited on glass substrates from a chemical bath containing antimony chloride, acetone and sodium thiosulfate under various conditions of normal chemical bath deposition (CBD) as well as in-situ irradiation of the chemical bath using a continuous laser of 532 nm wavelength. Structure, composition, morphology, optical and electrical properties of the Sb{sub 2}S{sub 3} thin films produced by normal CBD and LACBD were analyzed by X-Ray diffraction (XRD), Raman Spectroscopy, Atomic force microscopy (AFM), X-Ray photoelectron spectroscopy (XPS), UV–vis spectroscopy and Photoconductivity. The results showed that LACBD is an effective synthesis technique to obtain Sb{sub 2}S{sub 3} thin films for optoelectronic applications.

  13. Hydrothermal synthesis, characterization and optical properties of 3D flower like indium sulfide nanostructures

    Science.gov (United States)

    Ghaderi Sheikhi abadi, Parvaneh; Salavati-Niasari, Masoud; Davar, Fatemeh

    2013-01-01

    High-quality and high-yield 3D flower like indium sulfide (In2S3) nanostructures with cubic structure were synthesized by a wet chemical route, without using any surfactant and organic solvents at 160 °C for 12 h, by using InCl3 and 2-aminothiophenol (2-ATP) as starting reagents. The obtained In2S3 with different morphologies and size was characterized by X-ray diffraction pattern (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and ultraviolet-visible (UV-vis) spectroscopy. The effects of reaction parameters, such as temperature, precursor concentration and reaction time on the morphology, and particle size of products were investigated. Our experimental results showed that temperature and time reaction played key roles in the final morphology of In2S3. The morphology of In2S3 structures could be changed from one-dimensional (1D) structures to three-dimensional (3D) structures by increasing reaction time to 24 h. In the present study the optical properties 3D In2S3 structures were investigated.

  14. Magmatic-hydrothermal origin of the early Triassic Laodou lode gold deposit in the Xiahe-Hezuo district, West Qinling orogen, China: implications for gold metallogeny

    Science.gov (United States)

    Jin, Xiao-ye; Li, Jian-wei; Hofstra, Albert H.; Sui, Ji-xiang

    2017-08-01

    The Xiahe-Hezuo district in the West Qinling orogen contains numerous Au-(As-Sb) and Cu-Au-(W) deposits. The district is divided into eastern and western zones by the Xiahe-Hezuo Fault. The western zone is exposed at a shallow level and contains sediment-hosted disseminated Au-(As-Sb) deposits, whereas the eastern zone is exposed at a deeper level and contains Cu-Au-(W) skarn and lode gold deposits within or close to granitic intrusions. The Laodou gold deposit in the eastern zone consists of auriferous quartz-sulfide-tourmaline and minor quartz-stibnite veins that are structurally controlled by fault zones transecting the Laodou quartz diorite porphyry stock and enveloped by potassic and phyllic alteration. Both the veins and alteration halos commonly contain quartz, sericite, tourmaline, pyrite, and arsenopyrite, with minor galena, sphalerite, chalcopyrite, tetrahedrite, and enargite. Gold occurs mainly as invisible gold in pyrite or arsenopyrite and locally as inclusions less than 50 μm in diameter. The zircon U-Pb age of 247.6 ± 1.3 Ma (2 σ) on the host quartz diorite porphyry and the sericite 40Ar/39Ar plateau ages of 249.1 ± 1.6 and 249.0 ± 1.5 Ma (2 σ) on two ore-related hydrothermal sericite samples are within analytical errors of one another. At the formation temperature (275 °C) inferred from microthermometric measurements of fluid inclusion, sericite and tourmaline yield calculated δDH2O values of -70 to -45‰ and δ 18OH2O of 5.8 to 9.7‰, while quartz yields calculated δ 18OH2O values of 5.1˜5.7‰. Hydrothermal tourmaline in quartz-sulfide-tourmaline veins has δ 11B of -11.2 to -0.9‰ (mean of -6.3‰) that are similar to the values of magmatic tourmaline (-8.9 to -5.5‰ with a mean of -6.8‰) in the host quartz diorite porphyry. The δ 34S values of sulfide minerals range from -5.9 to +5.8‰ with a mean of -0.6‰ that is typical of magmatic sulfur. Pyrite from hydrothermally altered quartz diorite porphyry and quartz-sulfide

  15. A Palaeoproterozoic multi-stage hydrothermal alteration system at Nalunaq gold deposit, South Greenland

    DEFF Research Database (Denmark)

    Bell, Robin-Marie; Kolb, Jochen; Waight, Tod Earle

    2017-01-01

    Nalunaq is an orogenic, high gold grade deposit situated on the Nanortalik Peninsula, South Greenland. Mineralisation is hosted in shear zone-controlled quartz veins, located in fine- and medium-grained amphibolite. The deposit was the site of Greenland’s only operating metalliferous mine until its......-tourmaline-titanite), which is best developed in areas of exceptionally high gold grades. Aplite dykes dated to ca. 1762 Ma cross-cut the gold-quartz veins, providing a minimum age for mineralisation. A hydrothermal calcite-titanite alteration assemblage is dated to ca. 1766 Ma; however, this alteration is highly isolated...

  16. Evidence for de-sulfidation to form native electrum in the Fire Creek epithermal gold-silver deposit, north-central Nevada

    Science.gov (United States)

    Perez, J.; Day, J. M.; Cook, G. W.

    2012-12-01

    that the second phase of mineralization shows spatial and petrographic association with coarser silica and carbon phases. Conversely associations of electrum in Mule Canyon are typically with chalcedony or opal veins and hydrothermal breccia matrices (John et al. Econ. Geol. 98, 425-463, 2003). Opal and chalcedony phases do not appear within fracture-filled veins in Fire Creek, but occur as cap rocks on the surface. These associations are likely driven by impingement of basaltic dikes into ground waters in both the Fire Creek and Mule Canyon deposits. However, in the case of Fire Creek, our study demonstrates that there is a clear spatial dependence between the electrum, primary S-rich mineralized veins and phases of coarse carbonate and silica. We postulate that this occurs through increased brecciation and sub-surface boiling of hydrothermal fluids leading to de-sulfidation and a marked change in alteration and mineral assemblage.

  17. Scientific communications: Re-Os sulfide (bornite, chalcopyrite, and pyrite) systematics of the carbonate-hosted copper deposits at ruby creek, southern brooks range, Alaska

    Science.gov (United States)

    Selby, D.; Kelley, K.D.; Hitzman, M.W.; Zieg, J.

    2009-01-01

    New Re-Os data for chalcopyrite, bornite, and pyrite from the carbonate-hosted Cu deposit at Ruby Creek (Bornite), Alaska, show extremely high Re abundances (hundreds of ppb, low ppm) and contain essentially no common Os. The Re-Os data provide the first absolute ages of ore formation for the carbonate-hosted Ruby Creek Cu-(Co) deposit and demonstrate that the Re-Os systematics of pyrite, chalcopyrite, and bornite are unaffected by greenschist metamorphism. The Re-Os data show that the main phase of Cu mineralization pre dominantly occurred at 384 ?? 4.2 Ma, with an earlier phase possibly at ???400 Ma. The Re-Os data are consistent with the observed paragenetic sequence and coincide with zircon U-Pb ages from igneous rocks within the Ambler metallogenic belt, some of which are spatially and genetically associated with regional volcanogenic massive sulfide deposits. The latter may suggest a temporal link between regional magmatism and hydrothermal mineralization in the Ambler district. The utility of bornite and chalcopyrite, in addition to pyrite, contributes to a new understanding of Re-Os geochronology and permits a refinement of the genetic model for the Ruby Creek deposit. ?? 2009 Society of Economices Geologists, Inc.

  18. Whole-rock and sulfide-mineral geochemical data for samples from volcanogenic massive sulfide deposits of the Bonnifield district, east-central Alaska

    Science.gov (United States)

    Dusel-Bacon, Cynthia; Slack, John F.; Koenig, Alan E.; Foley, Nora K.; Oscarson, Robert L.; Gans, Kathleen D.

    2011-01-01

    This Open-File Report presents geochemical data for outcrop and drill-core samples from volcanogenic massive sulfide deposits and associated metaigneous and metasedimentary rocks in the Wood River area of the Bonnifield mining district, northern Alaska Range, east-central Alaska. The data consist of major- and trace-element whole-rock geochemical analyses, and major- and trace-element analyses of sulfide minerals determined by electron microprobe and laser ablation—inductively coupled plasma—mass spectrometry (LA-ICP-MS) techniques. The PDF consists of text, appendix explaining the analytical methods used for the analyses presented in the data tables, a sample location map, and seven data tables. The seven tables are also available as spreadsheets in several file formats. Descriptions and discussions of the Bonnifield deposits are given in Dusel-Bacon and others (2004, 2005, 2006, 2007, 2010).

  19. Mineralogy, stable isotopes (δ18O and δ34S and 40Ar-39Ar geochronology studies on the hydrothermal carapace of the Igarapé Manteiga W-Sn Deposit, Rondônia

    Directory of Open Access Journals (Sweden)

    Thais Marcela Fernandes do Nascimento

    Full Text Available ABSTRACT: The Igarapé Manteiga W-Sn deposit is formed by a granite stock that intrudes in the Paleoproterozoic basement. The mineralization is encapsulated in an alumino-siliceous hydrothermal carapace formed by greisen, vein-veinlets and breccia, developed in the apex zone of a granite stock. At this site, wolframite, cassiterite and sulfides-minerals, as well as siderite, monazite, xenotime, hematite and others, are spread out or in massive clusters associated with quartz, topaz, zinnwaldite and fluorite. Wolframite is not zoned and relatively rich in Fe, and poor in Nb and Ta. Cassiterite exhibits growth-zones with light-yellow to dark-orange colors, and is rich in Ta, and poor in Ti, W, Mn and U. Oxygen and sulfur (δ18O and δ34S isotope data on the ore- and sulfide-minerals indicates that it is a magmatic source, with closing temperatures from 230°C to 480°C. The hydrothermal phase was cyclical and protractedly active, promoting greisenization and hydrofracturing. The lowering of temperature and the change in the composition of fluids (from oxidized to reduced controlled the precipitation of the hydrothermal mineral assemblage. The 40Ar-39Ar analyses reveal a plateau age of 988 Ma, interpreted as the closure time for the hydrothermal processes responsible for mineralization, which is linked to the final magmatic evolution of the Rondônia Intrusive Suite (995-991 Ma.

  20. The nature of hydrothermal fluids in the Kahang porphyry copper deposit (Northeast of Isfahan based on mineralography, fluid inclusion and stable isotopic data

    Directory of Open Access Journals (Sweden)

    Salimeh Sadat Komeili

    2017-02-01

    Full Text Available Introduction The Kahang Cu- Mo deposit is situated approximately 73 Km northeast of Isfahan. Asadi (2007 identified a geological reserve of 40 Mt (proven reserve grading at 0.53 Cu, 0.02 Mo and estimated reserve of 120 Mt. All the rock types in the region have been subjected to hydrothermal solutions which gave rise to three different alteration facies. The dacite and rhyodacite volcanic rocks and granitic- granodioritic stocks have experienced phyllic alteration. Disseminated and stockwork siliceous veins are the major styles of mineralization in this zone. Intermediate argillitic alteration developed on a part of dacitic and rhyodacitic rocks whereas andesite and basaltic-andesite plus related pyroclastic rocks have been subjected to propyllitic alteration. This paper presents the results of geological and mineralogical studies carried out in the Kahang area. This preliminary information is integrated with additional data on ore mineralogy, fluid inclusions and stable isotopes in view of understanding the genesis of the Cu- Mo deposit and the nature of the fluids involved in ore formation. Materials and Methods A total of 18 polished thin sections were prepared at the University of Isfahan for optical study. Fluid inclusions study was carried out on 8 double polished quartz thin sections (stockworks containing ore mineralization from phyllic zone. H – O stable isotope analysis was performed on 4 quartz samples from siliceous stockworks (from phyllic altered zone and one vein epidote sample (from propyllitic zone. All isotopic analyses were performed at the University of Oregan, Oregan, USA. Discussion In the investigated mineralization area, the hypogene zone is characterized by the presence of pyrite, chalcopyrite, bornite and magnetite. Hematite, goethite, jarosite, malachite and azurite are the predominant minerals of supergene zone. The major textures of the primary sulfides are disseminated, vein and veinlet. Pyrite is the most common

  1. Effects of Buffer Salt Concentration on the Dominated Deposition Mechanism and Optical Characteristics of Chemically Deposited Cadmium Sulfide Thin Films

    Science.gov (United States)

    Kakhaki, Z. Makhdoumi; Youzbashi, A.; Sangpour, P.; Kazemzadeh, A.; Naderi, N.; Bazargan, A. M.

    2016-02-01

    Effects of buffer salt concentration on the rate of deposition, dominated deposition mechanism and subsequently the structural, morphological, and optical properties of cadmium sulfide (CdS) thin films deposited by chemical bath deposition (CBD) on glass substrate were investigated. The precursors were chosen to be cadmium chloride (CdCl2) as the cadmium source, thiourea (CS(NH2)2) as the sulfur source, ammonium nitrate (NH4NO3) as the buffer salt and ammonia as the complexing agent and the pH controller. The influence of the NH4NO3 concentration on the structure, morphology, film uniformity, stoichiometry and optical properties of CdS thin films was also studied by X-ray diffractometer (XRD), field emission scanning electron microscope (FE-SEM), energy dispersive X-ray (EDX) spectroscope, uv-visible and photoluminescence (PL) spectroscopes. The XRD studies revealed that all the deposited films exhibited a (002)h/(111)c preferred orientation. The crystallite size was increased from 20nm to 30nm by the increase of concentration of NH4NO3 from 0.5M to 2.5M. The morphology of CdS thin films were agglomerated spherical particles consisted of smaller particles. The surface of thin films deposited at the NH4NO3 concentration of 0.5M was compact and smooth. The increase of the concentration of NH4NO3 decreased the packing density of the films. The optical band gap was in the range of 2.25-2.4eV, which was decreased by the decrement of packing density. The PL spectra showed two peaks centered at 400nm and 500nm which are attributed to violet and band-to-band emissions, respectively.

  2. The origin of life near deep-sea hydrothermal systems during the Cambrian explosion: data from the Kyzyl Tashtyg sulphide deposit (Central Asia)

    Science.gov (United States)

    Simonov, Vladimir; Terleev, Alexander; Safonova, Inna; Kotlyarov, Alexey; Stupakov, Sergey; Tokarev, Dmitry

    2015-04-01

    On Earth the solar radiation and the hydrothermal circulation both affect life evolution. Recent extensive studies of the World Ocean have shown that the biodiversity of Earth is linked with hydrothermal activity on the oceanic floor. These deep-sea ecosystems use chemical energy, not solar radiation. In the last quarter of the XX century, a new type of hydrothermal systems, so-called black smokers, was discovered in mid-oceanic ridges. As black smokers form sulfide ores and are surrounded by abundant bio-oases or symbioses, identification of their analogues in ancient orogenic belts is necessary for studying life origin and evolution. Of special importance are problems of life associated with deep-sea hydrothermal systems acted at the Precambrian-Cambrian boundary - the time of Cambrian explosion (Maruyama et al., 2013). During that explosion life significantly evolved and diversified due to dramatic changes of Earth's environment. Consequently, the early Cambrian - late Precambrian Kyzyl Tashtyg sulphide deposit of East Tuva in the Central Asian Orogenic Belt is of special interest. This deposit was formed on the bottom of ancient back-arc deep-sea basin as a result of black smoker hydrothermal activity and is hosted by volcanogenic-sedimentary rocks altered by the high temperature solutions. The altered Kyzyl Tashtyg basalts have an amygdules (filled by albite, epidote and carbonates), contain brown-green microfossils, often attached to their walls. The microfossils are thin tubes 5 to 25 microns in diameter and 500 microns long. This tubes are empty and have straight, curved or branching shape. Chemically, the tube material is close to epidote. In consideration of microscopic dimensions, simple morphology and similarity with modern tubular microorganisms, the studied tube-shaped microfossils can be related to cyanobacteria. Almost the same fossils, associated with oceanic basalt complexes, were described earlier (Furnes et al., 2007; Mcloughlin et al., 2007

  3. Synthesis, Deposition, and Microstructure Development of Thin Films Formed by Sulfidation and Selenization of Copper Zinc Tin Sulfide Nanocrystals

    Science.gov (United States)

    Chernomordik, Boris David

    stoichiometric kesterite CZTS. The ~2 nm nanocrystals synthesized at 150 °C exhibit quantum confinement, with a band gap of 1.67 eV. Larger nanocrystals have the expected bulk CZTS band gap of 1.5 eV. Several micron thick films deposited by drop casting colloidal dispersions of ~40 nm CZTS nanocrystals were crack-free, while those cast using 5 nm nanocrystals had micron-scale cracks. We showed the applicability of these nanocrystal coatings for thin film solar cells by demonstrating a CZTS thin film solar cell using coatings annealed in a sulfur atmosphere. We conducted a systematic study of the factors controlling crystal growth and microstructure development during sulfidation annealing of films cast from colloidal dispersions of CZTS nanocrystals. The film microstructure is controlled by concurrent normal and abnormal grain growth. At 600 °C to 800 °C and low sulfur pressures (50 Torr), abnormal CZTS grains up to 10 microm in size grow on the surface of the CZTS nanocrystal film via transport of material from the nanocrystals to the abnormal grains. Meanwhile, the nanocrystals coarsen, sinter, and undergo normal grain growth. The driving force for abnormal grain growth is the reduction in total energy associated with the high surface area nanocrystals. The eventual coarsening of the CZTS nanocrystals reduces the driving force for abnormal crystal growth. Increasing the sulfur pressure by an order of magnitude to 500 Torr accelerates both normal and abnormal crystal growth though sufficient acceleration of the former eventually reduces the latter by reducing the driving force for abnormal grain growth. For example, at high temperatures (700-800 oC) and sulfur pressures (500 Torr) normal grains quickly grow to ~500 nm which significantly reduces abnormal grain growth. The use of soda lime glass as the substrate, instead of quartz, accelerates normal grain growth. Normal grains grow to ~500 nm at lower temperatures and sulfur pressures (i.e., 600 °C and 50 Torr) than those

  4. Facies-related baryte mineralization bearing Cu-Zn sulfides in Miocene estuarine deposits of the upper Rhein Graben (Wetterau, Central Germany)

    Science.gov (United States)

    Dill, H. G.; Berner, Z.; Kaufholt, S.; Weber, B.; Metz, U.

    2013-10-01

    Baryte with or without base metal sulfides is quite common in sediments deposited in open marine environments or in continental sedimentary basins. Its precipitation is caused by hydrothermal processes, related to diagenesis, and frequently mediated by biogenic processes. The current study is focused on siliciclastic sandstones of Miocene (Aquitanian) age in an estuarine environment in the Wetterau region of the Rhein Graben, central Germany. In the estuarine environment only the central basin and the landward delta are host to a diagenetic and subsequent hydrothermal mineralization. Diagenesis took place under near-ambient (T ≈ 25 °C) conditions and resulted in strong pyritization (- 0.75 5) in the central basin. Diagenesis is more landward represented by a pervasive silicification (pH Cu-Zn-(Sb) minerals (0.75 < Eh < 0/5 < pH < 11), silicification and kaolinization (2 < pH < 9.5) and eventually by the formation of gibbsite (3 < pH < 8). At the transition from the delta to the estuarine funnel, baryte is of very widespread occurrence. Its variegated texture and crystal morphology allow for a precise determination of the hydraulic system as marine phreatic, freshwater phreatic, and freshwater vadose. The narrow size of the rift graben and its sealing against the open sea fostered concentration of Ba and enhanced the redox processes. Hypogene brines along with Miocene volcanic activity provided the metals, and marine ingressions in this transitional environment supplied the sulfur. Sulfides were concentrated in the finer-grained rocks because of their enrichment in organic material, while sulfates accumulated in the more permeable coarser sandstones.

  5. The Chahnaly low sulfidation epithermal gold deposit, western Makran volcanic arc, southeastern Iran

    Science.gov (United States)

    Sholeh, Ali; Rastad, Ebrahim; Huston, David L.; Gemmell, J. Bruce; Taylor, Ryan D.

    2016-01-01

    The Chahnaly low-sulfidation epithermal Au deposit and nearby Au prospects are located northwest of the intermittently active Bazman stratovolcano on the western end of the Makran volcanic arc, which formed as the result of subduction of the remnant Neo-Tethyan oceanic crust beneath the Lut block. The arc hosts the Siah Jangal epithermal and Kharestan porphyry prospects, near Taftan volcano, as well as the Saindak Cu-Au porphyry deposit and world-class Reko Diq Cu-Au porphyry deposit, near Koh-i-Sultan volcano to the east-northeast in Pakistan. The host rocks for the Chahnaly deposit include early Miocene andesite and andesitic volcaniclastic rocks that are intruded by younger dacitic domes. Unaltered late Miocene dacitic ignimbrites overlie these rocks. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U-Pb zircon geochronology data yield ages between 21.8 and 9.9 Ma for the acidic-intermediate regional volcanism. The most recent volcanic activity of the Bazman stratovolcano involved extrusion of an olivine basalt during Pliocene to Quaternary times. Interpretation of geochemical data indicate that the volcanic rocks are synsubduction and calc-alkaline to subalkaline. The lack of a significant negative Eu anomaly, a listric-shaped rare earth element pattern, and moderate La/Yb ratios of host suites indicate a high water content of the source magma.

  6. Structural and optical studied of nano structured lead sulfide thin films prepared by the chemical bath deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Al Din, Nasser Saad, E-mail: nsaadaldin@yahoo.com; Hussain, Nabiha, E-mail: nabihahssin@yahoo.com [Damascus University Faculty of Science, Department of physics, Homs (Syrian Arab Republic); Jandow, Nidhal, E-mail: nidhaljandow@yahoo.com [Al –Mustansiriyah University, College of Education, Department of physics, Baghdad (Iraq)

    2016-07-25

    Lead (II) Sulfide PbS thin films were deposited on glass substrates at 25°C by chemical bath deposition (CBD) method. The structural properties of the films were studied as a function of the concentration of Thiourea (CS (NH{sub 2}){sub 2}) as Source of Sulfide and deposition time. The surface morphology of the films was characterized by X-ray diffraction and SEM. The obtained results showed that the as-deposited films Polycrystalline had cubic crystalline phase that belong to S.G: Fm3m. We found that they have preferred orientation [200]. Also the thickness of thin films decrease with deposition time after certain value and, it observed free sulfide had orthorhombic phase. Optical properties showed that the thin films have high transmission at visible range and low transmission at UV, IR range. The films of PbS have direct band gap (I.68 - 2.32 ev) at 300 K the values of band energy decreases with increases thickness of the Lead (II) Sulfide films.

  7. Characteristics of hydrothermally deposited nanostructured (NiZn) Fe2O4 films.

    Science.gov (United States)

    Pramoda, K P; Mun, Tang Seow; Goh, G K L; Lok, B K; Lu, Albert

    2008-05-01

    This work is devoted to the hydrothermal deposition of nanostructured (NiZn) Fe2O4 films on PCB substrates and their structural, morphological and electro-magnetic characterisation. Ferrite films were prepared by the hydrothermal treatment of iron, nickel and zinc nitrate solutions in the presence of reduced iron powder and urea at a temperature of 150 degrees C for 2 hrs. The resulting films with a black appearance are homogeneous without visible pores. The film formed is polycrystalline with a spinel structure and a thickness of about 1.5 microm. Characterisation of the films by a variety of techniques showed that their magnetic and electrical properties are comparable to those of films prepared by other methods reported in the literature.

  8. Comparison between ZnO nanowires grown by chemical vapor deposition and hydrothermal synthesis

    Science.gov (United States)

    Podrezova, L. V.; Porro, S.; Cauda, V.; Fontana, M.; Cicero, G.

    2013-11-01

    Vertically aligned zinc oxide nanowires (NWs) were synthesized by two different techniques: chemical vapor deposition (CVD) and hydrothermal synthesis. To compare the effects of different growth conditions, both F-doped SnO2 (FTO) coated-glass and silicon wafers were used as substrates. Before NWs growth, all the substrates were covered with a ZnO seed layer film obtained with the same procedure, which acts as nucleation site for the subsequent growth of the nanowires both during CVD and hydrothermal synthesis. We studied the influence of the two synthesis techniques and the growth duration on the final morphology, orientation, and density of the ZnO NWs using electron microscopy and X-ray diffraction, while the NWs optical quality was addressed by UV-Vis spectroscopy. By discussing advantages and disadvantages of both synthesis methods, we finally show that the application purpose often drives the choice of the NWs growth process and the substrate to be used.

  9. Retrograde Evolution of the Hemlo Gold Deposit, Ontario: Fractional Crystallization of a Sulfide Melt and Remobilization of Ore-Related Metals

    Science.gov (United States)

    Heiligmann, M.; Clark, J. R.; Williams-Jones, A. E.

    2003-12-01

    The Hemlo gold deposit is a greenstone-hosted, lode-gold system in north-central Ontario, Canada. The main stage of gold mineralization occurred prior to peak, amphibolite-facies metamorphism, and is characterized by disseminated Au-Mo in potassically altered, barite- and pyrite-rich schists. Locally extensive remobilization of this ore occurred at or immediately after peak metamorphism ( ˜630° C, 5-6 kb), and is represented by minerals such as stibnite, realgar, orpiment, zinkenite and cinnabar, which are unstable at high temperature. Volumetrically minor gold was subsequently precipitated in calc-silicate zones at ˜400° C. Minerals reflecting early remobilization occur either at grain boundaries or as solid inclusions along healed fractures devoid of fluid inclusions. Planes of solid inclusions, many of which are polyphase, radiate locally from the boundaries of large polyphase sulfide aggregates. Inclusions containing both liquid and sulfides are observed mainly at intersections of planes of solid-only and liquid-vapor inclusions. Solid inclusions are characterized by complex assemblages in the system As-Sb-Pb-S, that reflect contrasting conditions of fS2 and fO2. The low thermal stability of many of these minerals, the absence of liquid in the solid inclusion trails, the excessive hydrothermal solubility of stibnite above 300° C, and the evidence of contrasting fS2 and fO2 rule out hydrothermal processes as the cause of this remobilization. We therefore propose that the latter was the result of formation of an As-Sb-Pb-S melt, at or near peak metamorphic conditions, containing minor proportions of Au, Hg, Ag, Cu, Tl and Te, and support this hypothesis with results of preliminary experiments showing that realgar-stibnite-cinnabar-bearing solids homogenize to liquid at ˜435° C. The melt is envisaged to have formed as a result of exsolution of elements such as As, Sb and Au from arsenian pyrite during metamorphic recrystallization, melting of primary

  10. Understanding Cu release into environment from Kure massive sulfide ore deposits, Kastamonu, NW Turkey

    Science.gov (United States)

    Demirel, Cansu; Sonmez, Seref; Balci, Nurgul

    2014-05-01

    Covering a wide range on the earth's crust, oxidation of metal sulfide minerals have vital environmental impacts on the aquatic environment, causing one of the major environmental problems known as acid mine drainage (AMD). Located in the Kastamonu province of the Western Black Sea region, Kure district is one of the major copper mining sites in Turkey. Mining activities in the area heads back to ancient times, such that operation is thought to be started with the Roman Empire. Currently, only the underground mining tunnels of Bakibaba and Asikoy are being operated. Thus, mining heaps and ores of those pyritic deposits have been exposed to the oxidative conditions for so long. As a result of weathering processes of past and recent heaps of the Kure volcanic massive sulfide deposits in addition to the main ore mineral (chalcopyrite), significant amount of metals, especially Cu, are being released into the environment creating undesirable environmental conditions. In order to elucidate Cu release mechanisms from Kure pyritic ore deposits and mining wastes, field and laboratory approaches were used. Surface water and sediment samples from the streams around the mining and waste sites were collected. Groundwater samples from the active underground mining site were also collected. Physical parameters (pH, Eh, T°C, and EC) of water samples were determined in situ and in the laboratory using probes (WTW pH 3110, WTW Multi 9310 and CRISON CM 35). Metal and ion concentrations of the water samples were analysed using ICP-MS and DR 2800 spectrophotometer, respectively. High Cu, Co, Zn and Fe concentrations were determined in the water samples with pH values ranging from 2.9- 4. Cu concentrions ranges from 345 ppm to 36 ppm in the water samples. Consistent with the water samples, high Cu, Fe, Zn and Co were also determined in the sediment samples. Laboratory chalcopyrite oxidation experiments under the conditions representing the field site were set up as biological and

  11. Atomic Layer Deposition of Aluminum Sulfide: Growth Mechanism and Electrochemical Evaluation in Lithium-Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Xiangbo [Department; Cao, Yanqiang [Energy; Libera, Joseph A. [Energy; Elam, Jeffrey W. [Energy

    2017-10-17

    This study describes the synthesis of aluminum sulfide (AlSx) thin films by atomic layer deposition (ALD) using tris(dimethylamido)aluminum and hydrogen sulfide. We employed a suite of in situ measurement techniques to explore the ALD AlSx growth mechanism, including quartz crystal microbalance, quadrupole mass spectrometry, and Fourier transform infrared spectroscopy. A variety of ex situ characterization techniques were used to determine the growth characteristics, morphology, elemental composition, and crystallinity of the resultant AlSx films. This study revealed that the AlSx growth was self-limiting in the temperature range 100-250 degrees C, and the growth per cycle decreased linearly with increasing temperature from similar to 0.45 angstrom/cycle at 100 degrees C to similar to 0.1 angstrom/cycle at 250 degrees C. The AlSx films were amorphous in this temperature range. We conducted electrochemical testing to evaluate the ALD AlSx as a potential anode material for lithium-ion batteries (LIBs). The ALD AlSx exhibited reliable cyclability over 60 discharge-charge cycles with a sustainable discharge capacity of 640 mAh/g at a current density of 100 mA/g in the voltage window of 0.6-3.5

  12. Growth mechanisms of zinc oxide and zinc sulfide films by mist chemical vapor deposition

    Science.gov (United States)

    Uno, Kazuyuki; Yamasaki, Yuichiro; Tanaka, Ichiro

    2017-01-01

    The growth mechanisms of zinc oxide and zinc sulfide films by mist chemical vapor deposition (mist-CVD) were experimentally investigated from the viewpoint of mist behaviors and chemical reactions. The proper growth model, either vaporization or the Leidenfrost model, was studied by supplying two kinds of mists with different kinds of sources, such as H2 16O and H2 18O for ZnO growth and ZnCl2 and thiourea for ZnS growth. Moreover, the origin of the oxygen atoms of ZnO was investigated using a quantitative analysis. The role of chloro complex of zinc in the growth of ZnS from aqueous solutions was also examined by systematic studies.

  13. Comparing Carbonate-Depositing Hydrothermal Systems Along the Mid-Atlantic Ridge at Lost City Hydrothermal Field and Along the Rio Grande rift in the Southwestern US: Geochemistry, Geomicrobiology and Mineralogy

    Science.gov (United States)

    Cron, B. R.; Crossey, L.; Hall, J.; Takacs-Vesbach, C.; Dahm, K.; Northup, D.; Karlstrom, K.

    2008-12-01

    Both continental and marine rift settings are characterized by hydrothermal vents (smokers) that include important components of mantle-derived "endogenic" fluids. These fluids ascend along extensional faults and provide unique biologic settings. We hypothesize that deep crustal processes support near-surface metabolic strategies by delivering chemically reduced constituents to partially oxidized surface environments. Lost City hydrothermal field, a marine vent system located 15 km west of the Mid-Atlantic ridge, exhibits a range of temperatures (40 to 75°C), pH (9-9.8), and mineral compositions (carbonate rather than sulfide-dominated) that were originally thought to be non-existent in marine vent systems. Travertine depositing CO2 springs within the Rio Grande rift, NM exhibit striking similarities in many respects to vents in Lost City. Previous research has already determined the importance of methanogenic and sulfur metabolizing microorganisms in carbonate structures at Lost City. Phylogenetic analysis of 16S rRNA genes from a terrestrial CO2 spring was performed. In addition, cells from bacteria and fungi were also cultured with oligotrophic media. Both archaeal phylotypes from the terrestrial spring grouped within Marine Group I of the Crenarchaeota, a clade dominated by sequences from hydrothermal marine vents, including some from Lost City. We will report comparative analyses of sequences from Lost City and both cultured and environmental clone libraries from the terrestrial spring using UniFrac. Geochemical modeling of data (water and gas chemistry from both locations) is used to rank the energy available for dozens of metabolic reactions. SEM and microprobe data are presented to compare mineral compositions. Our results will be discussed in respect to the tectonic setting, microbial community distributions, and the geochemical composition and textural properties of the carbonates that are precipitated in each of these systems.

  14. Development of Vertical Cable Seismic System for Hydrothermal Deposit Survey (2) - Feasibility Study

    Science.gov (United States)

    Asakawa, E.; Murakami, F.; Sekino, Y.; Okamoto, T.; Mikada, H.; Takekawa, J.; Shimura, T.

    2010-12-01

    In 2009, Ministry of Education, Culture, Sports, Science and Technology(MEXT) started the survey system development for Hydrothermal deposit. We proposed the Vertical Cable Seismic (VCS), the reflection seismic survey with vertical cable above seabottom. VCS has the following advantages for hydrothermal deposit survey. . (1) VCS is an effective high-resolution 3D seismic survey within limited area. (2) It achieves high-resolution image because the sensors are closely located to the target. (3) It avoids the coupling problems between sensor and seabottom that cause serious damage of seismic data quality. (4) Various types of marine source are applicable with VCS such as sea-surface source (air gun, water gun etc.) , deep-towed or ocean bottom sources. (5) Autonomous recording system. Our first experiment of 2D/3D VCS surveys has been carried out in Lake Biwa, JAPAN. in November 2009. The 2D VCS data processing follows the walk-away VSP, including wave field separation and depth migration. The result gives clearer image than the conventional surface seismic. Prestack depth migration is applied to 3D data to obtain good quality 3D depth volume. Uncertainty of the source/receiver poisons in water causes the serious problem of the imaging. We used several transducer/transponder to estimate these positions. The VCS seismic records themselves can also provide sensor position using the first break of each trace and we calibrate the positions. We are currently developing the autonomous recording VCS system and planning the trial experiment in actual ocean to establish the way of deployment/recovery and the examine the position through the current flow in November, 2010. The second VCS survey will planned over the actual hydrothermal deposit with deep-towed source in February, 2011.

  15. Genesis of massive sulfide deposits in the Verkhneural'sk ore district, the South Urals, Russia: Evidence for magmatic contribution of metals and fluids

    Science.gov (United States)

    Karpukhina, V. S.; Naumov, V. B.; Vikent'ev, I. V.

    2013-03-01

    Melt inclusions and aqueous fluid inclusions in quartz phenocrysts from host felsic volcanics, as well as fluid inclusions in minerals of ores and wall rocks were studied at the Cu-Zn massive sulfide deposits in the Verkhneural'sk ore district, the South Urals. The high-temperature (850-1210°C) magmatic melts of volcanic rocks are normal in alkalinity and correspond to rhyolites of the tholeiitic series. The groups of predominant K-Na-type (K2O/Na2O = 0.3-1.0), less abundant Na-type (K2O/Na2O = 0.15-0.3), and K-type (K2O/Na2O = 1.9-9.3) rhyolites are distinguished. The average concentrations (wt %) of volatile components in the melts are as follows: 2.9 H2O (up to 6.5), 0.13 Cl (up to 0.28), and 0.09 F (up to 0.42). When quartz was crystallizing, the melt was heterogeneous, contained magnetite crystals and sulfide globules (pyrrhotite, pentlandite, chalcopyrite, bornite). High-density aqueous fluid inclusions, which were identified for the first time in quartz phenocrysts from felsic volcanics of the South Urals, provide evidence for real participation of magmatic water in hydrothermal ore formation. The fluids were homogenized at 124-245°C in the liquid phase; the salinity of the aqueous solution is 1.2-6.2 wt % NaCl equiv. The calculated fluid pressure is very high: 7.0-8.7 kbar at 850°C and 5.1-6.8 kbar at 700°C. The LA-ICP-MS analysis of melt and aqueous fluid inclusions in quartz phenocrysts shows a high saturation of primary magmatic fluid and melt with metals. This indicates ore potential of island-arc volcanic complexes spatially associated with massive sulfide deposits. The systematic study of fluid inclusions in minerals of ores and wall rocks at five massive sulfide deposits of the Verkhneural'sk district furnished evidence that ore-forming fluids had temperature of 375-115°C, pressure up to 1.0-0.5 kbar, chloride composition, and salinity of 0.8-11.2 (occasionally up to 22.8) wt % NaCl equiv. The H and O isotopic compositions of sericite from host

  16. Distribution of Ag in Cu-sulfides in Kupferschiefer deposit, SW Poland

    Science.gov (United States)

    Kozub, Gabriela A.

    2014-05-01

    The Cu-Ag Kupferschiefer deposit located at the Fore-Sudetic Monocline (SW Poland) is a world class deposit of stratabound type. The Cu-Ag mineralization in the deposit occurs in the Permian sedimentary rocks (Rotliegend and Zechstein) in three lithological types of ore: the dolomite, the black shale and the sandstone. Silver, next to copper, is the most important element in the Kupferschiefer deposit (Salamon 1979; Piestrzyński 2007; Pieczonka 2011). Although occurrence of the Ag-minerals such as native silver, silver amalgams, stromeyerite, jalpaite and mckinstryite, silver is mainly present in the deposit due to isomorphic substitutions in Cu-minerals such as chalcocite, bornite, tennantite, covellite and chalcopyrite. The aim of the study was to define distribution of silver in Cu-minerals and correlate occurrence of Ag-enriched Cu-sulfides with native silver and silver amalgams. Identification of minerals and textural observation were performed using field emission scanning electron microscope. Analyzes of chemical composition of Cu-sulfides were performed utilizing electron microprobe. Silver concentration in Cu sulfides ranges from 0.1 to 10.4 wt.% in chalcocite, 0.2-15.8 wt.% in bornite, 0.1-2.9 wt.% in tennantite, 0.05-0.3 wt.% in chalcopyrite and ca. 0.4 wt.% in covellite. In general, distribution of silver in Cu-minerals is irregular, as indicated by high variations of Ag concentration in each mineral. Content of Ag in Cu-sulphides, in samples where native silver and silver amalgams are not found, is lower than in samples, where native silver and silver amalgams are noted. The chemical analyzes of Ag-bearing Cu-minerals indicate decrease of Cu content in minerals with high Ag concentration. In such case, decrease of Fe content is also noted in bornite. Lack of micro-inclusions of the native silver or silver amalgams in the Cu-minerals indicates that presence of Ag is mainly related to the isomorphic substitutions. This is in agreement with previous

  17. Crustal contamination and sulfide immiscibility history of the Permian Huangshannan magmatic Ni-Cu sulfide deposit, East Tianshan, NW China

    Science.gov (United States)

    Mao, Ya-Jing; Qin, Ke-Zhang; Tang, Dong-Mei; Feng, Hong-Ye; Xue, Sheng-Chao

    2016-11-01

    The Huangshannan mafic-ultramafic intrusion is a Permian Ni-Cu sulfide-bearing intrusion in the southern margin of the Central Asian Orogenic Belt. The intrusion consists of an ultramafic unit, which is composed of lherzolite and olivine websterite, and a mafic unit, which is composed of olivine gabbronorite, gabbronorite and leuco-gabbronorite. This intrusion was formed by two separate pulses of magma: a more primitive magma for the early ultramafic unit and a more evolved magma for the late mafic unit. U-Pb isotope geochronology of zircon from the mafic unit yields an age of 278 ± 2 Ma. According to its olivine and Cr-rich spinel compositions, the estimated parental magma of lherzolite for the Huangshannan intrusion has 12.4 wt.% MgO, indicating picritic affinity. Fractional crystallization modeling results and the presence of rounded sulfide inclusions in an olivine crystal (Fo 86.7) indicate that sulfide immiscibility was achieved at the beginning of olivine fractionation. Co-magmatic zircon crystals from gabbronorite have a δ18O value close to 6.5‰, which is 1.2‰ higher than the typical mantle value and suggests significant crustal contamination (∼20%). The positive εHf(t) values of co-magmatic zircon (which vary from +9.2 to +15.3) and positive whole rock εNd(t) values (which vary from +4.7 to +7.8) also indicate that the parental magma was derived from a depleted mantle source and contaminated by 5-20% juvenile arc crust and then by ∼5% upper crustal materials. However, modeling results of sulfur content at sulfide saturation reveal that such a large amount of crustal contamination is not sufficient to trigger sulfide saturation in the parental magma, which strongly suggests that external sulfur addition, probably during contamination, has played a critical role in causing sulfide immiscibility. Furthermore, the arc magmatism geochemical signatures of the Huangshannan intrusion, such as significant Nb and Ta depletion relative to La and low Ca

  18. Disseminated sulphides in basalts from the northern central Indian ridge: Implications on late-stage hydrothermal activity

    Digital Repository Service at National Institute of Oceanography (India)

    Banerjee, R.; Ray, D.

    , Plüger W, Garbe-Schönberg D, Zimmer M (1998) Formation and decay of a modern massive sulfide deposit in the Indian Ocean. Min Deposita 33:302–309 Hannington MD, Scott SD (1988) Mineralogy and geochemistry of a hydrothermal silica-sulfide-sulfate spire...

  19. [The enrichment characteristic and mechanism of gold-silver minerals in submarine hydrothermal sulfides from the ultra-slow-spreading SWIR].

    Science.gov (United States)

    Wang, Yan; Sun, Xiao-ming; Wu, Zhong-wei; Deng, Xi-guang; Dai, Ying-zhi; Lin, Zhi-yong

    2014-12-01

    In the present study, content and occurrence of Au, Ag in three submarine hydrothermal sulfide samples from the ultra-slow-spreading Southwest Indian Ridge (SWIR) were studied by using inductively coupled plasma-atomic emission spectrometry (ICP-AES), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results of ICP-AES show that all of the samples have signs of Au-Ag enrichment. By SEM/EDS, we discovered a mass of gold-silver minerals in the samples. In S27-4, gold occurs as irregular-shaped native gold and electrum grains in sulfides or between crystal particles. However, we discovered lots of Au-independent silver minerals except parts of electrum in S35-22. EDS results of silver minerals indicate that silver minerals closely related with halogen element, inferring that silver minerals may be silver halides. Electrum in S35-22 can be absorbed at the surface or crystal edge of pyrite besides occurring in or between sulfides as S27-4, supposed to be related to surface defect in pyrite. Electrum is the only Au-Ag mineral discovered in S35-17. These electrum gains occur as inclusion gold, absorbed gold or fissure gold. In addition, there are different Au-Ag mole ratios of electrum in three samples, indicating distinct hydrothermal conditions. In the base of research before, we consider that AgCl2(-) is the dominant complex of silver in ore-forming fluid of S27-4, however, gold is transported as AuCl2(-) transforming to AuHS(0), indicating that hydrothermal fluids decreased from high-moderate to moderate-low temperature and conductive cooling played an important role in this process. Similar enrichment mechanism happened in S35-22, but silver halides discovered in S35-22 suggest a higher temperature and chloride in the early stage. However, The enrichment of electrums in black smoke sample (S35-17) relates to mixing of hydrothermal fluids and seawater.

  20. Identifying the Prospective Area of Sulfide Groundwater within the Area of Palvantash Oil and Gas Deposit

    Directory of Open Access Journals (Sweden)

    M. R. Zhurayev

    2014-03-01

    Full Text Available This paper describes the methodology of prospecting for sulfide groundwater in the area of Palvantash oil fields. In result of study allowed determining the favorable conditions for the sulfide waters formation, and mapping the areas of different sulfide water concentration. The relatively permeable areas were established and the water borehole positions were recommended.

  1. P-type thin films transistors with solution-deposited lead sulfide films as semiconductor

    Energy Technology Data Exchange (ETDEWEB)

    Carrillo-Castillo, A.; Salas-Villasenor, A.; Mejia, I. [Department of Materials Science and Engineering, The University of Texas at Dallas. 800 West Campbell Rd, Richardson, TX 75083 (United States); Aguirre-Tostado, S. [Centro de Investigacion en Materiales Avanzados, S. C. Alianza Norte 202, Parque de Investigacion e Innovacion Tecnologica, Apodaca, Nuevo Leon, C.P. 666000 (Mexico); Gnade, B.E. [Department of Materials Science and Engineering, University of Texas at Dallas. 800 West Campbell Rd, Richardson, TX 75083 (United States); Quevedo-Lopez, M.A., E-mail: mxq071000@utdallas.edu [Department of Materials Science and Engineering, University of Texas at Dallas. 800 West Campbell Rd, Richardson, TX 75083 (United States)

    2012-01-31

    In this paper we demonstrate p-type thin film transistors fabricated with lead sulfide (PbS) as semiconductor deposited by chemical bath deposition methods. Crystallinity and morphology of the resulting PbS films were characterized using X-ray diffraction, atomic force microscopy and scanning electron microscopy. Devices were fabricated using photolithographic processes in a bottom gate configuration with Au as source and drain top contacts. Field effect mobility for as-fabricated devices was {approx} 0.09 cm{sup 2} V{sup -1} s{sup -1} whereas the mobility for devices annealed at 150 Degree-Sign C/h in forming gas increased up to {approx} 0.14 cm{sup 2} V{sup -1} s{sup -1}. Besides the thermal annealing, the entire fabrications process was maintained below 100 Degree-Sign C. The electrical performance of the PbS-thin film transistors was studied before and after the 150 Degree-Sign C anneal as well as a function of the PbS active layer thicknesses. - Highlights: Black-Right-Pointing-Pointer Thin film transistors with PbS as semiconductor deposited by chemical bath deposition. Black-Right-Pointing-Pointer Photolithography-based thin film transistors with PbS films at low temperatures. Black-Right-Pointing-Pointer Electron mobility for anneal-PbS devices of {approx} 0.14 cm{sup 2} V{sup -1} s{sup -1}. Black-Right-Pointing-Pointer Highest mobility reported in thin film transistors with PbS as the semiconductor.

  2. Indium sulfide thin films as window layer in chemically deposited solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Lugo-Loredo, S. [Universidad Autónoma de Nuevo León, UANL, Fac. de Ciencias Químicas, Av. Universidad S/N Ciudad Universitaria San Nicolás de Los Garza Nuevo León, C.P. 66451 (Mexico); Peña-Méndez, Y., E-mail: yolapm@gmail.com [Universidad Autónoma de Nuevo León, UANL, Fac. de Ciencias Químicas, Av. Universidad S/N Ciudad Universitaria San Nicolás de Los Garza Nuevo León, C.P. 66451 (Mexico); Calixto-Rodriguez, M. [Universidad Tecnológica Emiliano Zapata del Estado de Morelos, Av. Universidad Tecnológica No. 1, C.P. 62760 Emiliano Zapata, Morelos (Mexico); Messina-Fernández, S. [Universidad Autónoma de Nayarit, Ciudad de la Cultura “Amado Nervo” S/N, C.P. 63190 Tepic, Nayarit (Mexico); Alvarez-Gallegos, A. [Universidad Autónoma del Estado de Morelos, Centro de Investigación en Ingeniería y Ciencias Aplicadas, Av. Universidad 1001, C.P. 62209, Cuernavaca Morelos (Mexico); Vázquez-Dimas, A.; Hernández-García, T. [Universidad Autónoma de Nuevo León, UANL, Fac. de Ciencias Químicas, Av. Universidad S/N Ciudad Universitaria San Nicolás de Los Garza Nuevo León, C.P. 66451 (Mexico)

    2014-01-01

    Indium sulfide (In{sub 2}S{sub 3}) thin films have been synthesized by chemical bath deposition technique onto glass substrates using In(NO{sub 3}){sub 3} as indium precursor and thioacetamide as sulfur source. X-ray diffraction studies have shown that the crystalline state of the as-prepared and the annealed films is β-In{sub 2}S{sub 3}. Optical band gap values between 2.27 and 2.41 eV were obtained for these films. The In{sub 2}S{sub 3} thin films are photosensitive with an electrical conductivity value in the range of 10{sup −3}–10{sup −7} (Ω cm){sup −1}, depending on the film preparation conditions. We have demonstrated that the In{sub 2}S{sub 3} thin films obtained in this work are suitable candidates to be used as window layer in thin film solar cells. These films were integrated in SnO{sub 2}:F/In{sub 2}S{sub 3}/Sb{sub 2}S{sub 3}/PbS/C–Ag solar cell structures, which showed an open circuit voltage of 630 mV and a short circuit current density of 0.6 mA/cm{sup 2}. - Highlights: • In{sub 2}S{sub 3} thin films were deposited using the Chemical Bath Deposition technique. • A direct energy band gap between 2.41 to 2.27 eV was evaluated for the In{sub 2}S{sub 3} films. • We made chemically deposited solar cells using the In{sub 2}S{sub 3} thin films.

  3. Structural and optical properties of tin (II) sulfide thin films deposited using organophosphorus precursor (Ph3PS)

    Science.gov (United States)

    Assili, Kawther; Alouani, Khaled; Vilanova, Xavier

    2017-02-01

    Tin sulfide (SnS) thin films have been deposited onto glass substrates using triphenylphosphine sulfide (Ph3PS) as a sulfur precursor in a chemical vapor deposition reactor in a temperature range of 250 °C-400 °C. The influence of the sulphidisation temperature in the crystal structure, surface morphology, chemical composition and optical properties has been investigated. X-ray diffraction, energy dispersive analysis of x-rays, and Raman spectroscopy showed that pure SnS thin films have been successfully obtained at 250 °C. All the deposited films were polycrystalline and showed orthorhombic structure, with a preferential orientation according to the direction . The optical measurements showed that the films deposited exhibited a direct allowed transition and have a relatively high absorption coefficient. The presence of mixed tin sulfide phases granted by the variation of the sulphidisation temperature has affected the optical properties of the deposited films. The refractive index (n) and extinction coefficient (k), has low values compared to conventional semiconductor materials. The grown films can be considered as a good light absorbing material and a promising candidate for application in optoelectronic devices.

  4. Sulfur, sulfides, oxides and organic matter aggregated in submarine hydrothermal plumes at 9°50‧N East Pacific Rise

    Science.gov (United States)

    Breier, J. A.; Toner, B. M.; Fakra, S. C.; Marcus, M. A.; White, S. N.; Thurnherr, A. M.; German, C. R.

    2012-07-01

    Deep-sea hydrothermal plume particles are known to sequester seawater trace elements and influence ocean-scale biogeochemical budgets. The relative importance of biotic versus abiotic oxidation-reduction and other particle-forming reaction, however, and the mechanisms of seawater trace element sequestration remain unknown. Suspended particulate material was collected from a non-buoyant hydrothermal plume by in situ filtration at 9°50‧N East Pacific Rise during a 3-day, 24 sample, time-series. Twenty-three samples were digested for total elemental analysis. One representative sample was selected for particle-by-particle geochemical analyses including elemental composition by X-ray fluorescence, speciation of Fe, S, and C by 1s X-ray absorption near edge structure spectroscopy, and X-ray diffraction. Consistent with past studies, positive linear correlations were observed for P, V, As, and Cr with Fe in the bulk chemistry. Arsenic was associated with both Fe oxyhydroxides and sulfides but not uniformly distributed among either mineral type. Particle aggregation was common. Aggregates were composed of minerals embedded in an organic matrix; the minerals ranged from 10 μm in diameter. The speciation of major mineral forming elements (Fe, Mn, S) was complex. Over 20 different minerals were observed, nine of which were either unpredicted by thermodynamic modeling or had no close match in the thermodynamic database. Sulfur-bearing phases consisted of polysulfides (S6, S8), and metal sulfides (Fe, Cu, Zn, Mn). Four dominant species, Fe oxyhydroxide, Fe monosulfide, pyrrhotite, and pyrite, accounted for >80% of the Fe present. Particulate Mn was prevalent in both oxidized and reduced minerals. The organic matrix was: (1) always associated with minerals, (2) composed of biomolecules, and (3) rich in S. Possible sources of this S-rich organic matter include entrained near vent biomass and in situ production by S-oxidizing microorganisms. These results indicate that

  5. Challenges for rescuing drill core from volcanogenic massive sulfide deposits in northern Wisconsin

    Science.gov (United States)

    Stanley, V.; Schoephoester, P.; Lodge, R. W. D.

    2016-12-01

    Providing adequate physical care for unique lithologies can be a challenge for rock core repositories. The purpose of a repository is to preserve its collections such that they will be available and useful for current and future research. Preservation requires both documentation and physical care, including the state of the facility housing the collections, as specimens can be endangered by environmental factors. Digital documentation is a crucial first step in rescuing at-risk samples as it allows the collection to be monitored through time. Exploratory drill core from the Flambeau copper-gold mine in Ladysmith, WI was donated to the Wisconsin Geological and Natural History Survey (WGNHS). The collection includes over 4.7 km of irreplaceable core from 50 sites. The ore body is situated in the Ladysmith-Rhinelander Volcanic Complex, an Early Proterozoic greenstone belt that hosts at least 13 volcanogenic massive sulfide deposits (DeMatties, 1996), including Flambeau. Mineral assemblages include up to 50% sulfide minerals, mainly pyrite and marcasite (May and Dinkowitz, 1996). These lithologies present a unique preservation challenge - storage conditions must be temperature and humidity controlled to prevent pyrite oxidation (Newman 1998), which chemically and physically degrades the samples as well as labels, containers, and shelving. Once initiated, pyrite oxidation cannot be stopped or reversed, but may be stabilized (Howie, 1992). Although protecting these materials is a vital part of the WGNHS mission, climate-control modifications to the facility are cost-prohibitive. In order to rescue the samples, we documented the collection's present state. We developed and implemented a new database schema including IGSNs to improve metadata records, track samples, and link data. Although preservation of the physical samples remains a challenge, digital workflows and data management improvements will allow WGNHS to monitor the condition of these samples while also

  6. Zinc, copper, and lead in mid-ocean ridge basalts and the source rock control on Zn/Pb in ocean-ridge hydrothermal deposits

    Science.gov (United States)

    Doe, B.R.

    1994-01-01

    The contents of Zn, Cu, and Pb in mid-ocean ridge basalts (MORB) and the MORB source-rock control on Zn/Pb in ocean-ridge hydrothermal deposits are examined. The values of Zn, Cu, and Pb for submarine mid-ocean ridge basalts (MORB) are, respectively (in ppm): average MORB-75, 75, and 0.7; West Valley, Juan de Fuca Ridge (JFR)-87, 64, and 0.5; southern JFR-120 and 0.5; and 21??N, East Pacific Rise (EPR)-73, 78, and 0.5. Values of Zn/Pb range from about 100-240 and Cu/ Pb from 100-156. In this study, Zn is found to correlate positively with TiO2 + FeO (mean square of weighted deviates, MSWD, of 1.6 for JFR basalt), and inversely with Mg number (MSWD of 3.5). Therefore, contrary to statements in the literature that Zn should be compatible in MORB, Zn is a mildly incompatible element and must be enriched in the glass phase relative to olivine as Zn does not fit into the other major phenocryst phase, plagioclase. In the source of MORB, Zn likely is most enriched in oxides: spinel, magnetite, and titanomagnetite. Copper generally does not correlate well with other elements in most MORB data examined. When differentiation is dominated by olivine, Cu has a tendency to behave incompatibly (e.g., at Mg numbers > 70), but, overall, Cu shows some tendency towards being a compatible element, particularly along the Mid-Atlantic Ridge, a behavior presumably due to separation of sulfides in which Cu (but not Zn) is markedly enriched. Copper thus may be in dispersed sulfides in the source of MORB. Ocean ridges provide important data on source-rock controls for sulfide deposits because, in sediment-starved ridges, much is known about the possible source rocks and mineralization is presently occurring. In contrast to Zn/Pb ~5 in continental hot Cl-rich brines, Zn/Pb in the hottest sediment-starved ridge black smoker hydrothermal fluids at 21 ??N, EPR is about 110, similar to local MORB (145), but Cu/Pb is closer to 30, possibly due to subsurface deposition of Cu. At the JFR, the best

  7. Evidence of magmatic degassing in Archean komatiites: Insights from the Wannaway nickel-sulfide deposit, Western Australia

    Science.gov (United States)

    Caruso, Stefano; Fiorentini, Marco L.; Moroni, Marilena; Martin, Laure A. J.

    2017-12-01

    Magmatic degassing from komatiite lava flows potentially influenced the geochemical evolution of the Archean atmosphere and hydrosphere. We argue that the escape of SO2-rich volatiles from komatiites impacted on the mineralogical, geochemical and isotopic composition of associated nickel-sulfide mineralization leaving behind detectable and measurable footprints that can be best observed where the polarity of the magmatic sequence is clearly recognizable. Here we focus on the ore-bearing sequence of the Archean komatiite-hosted N01 nickel-sulfide orebody at Wannaway, Yilgarn Craton, Western Australia. This deposit displays a volcanic sequence with a well-defined succession of stratigraphically-correlated facies comprising a massive sulfide horizon at the base of the channelized komatiite flow, overlain by matrix and disseminated sulfide mineralization. Pyrrhotite is the dominant sulfide phase in the lower part of the ore profile. The amount of troilite gradually increases from the base of the matrix ore over several meters up-sequence, eventually becoming dominant at the expense of pyrrhotite. In the upper portion of the mineralized sequence troilite is associated with accessory Mn sulfide alabandite (MnS), which is usually reported in reduced terrestrial and extra-terrestrial environments. Such mineralogical and volcanological features are consistent with upwards decreasing in fS2 and fO2 away from the basal contact of the komatiite flow. After evaluating the possible role of metamorphism, the pyrrhotite-troilite-alabandite assemblage and the progressive up-sequence decrease of the pyrrhotite/troilite ratio across the upper part of the mineralized sequence are interpreted as magmatic and indicative of progressive loss of sulfur with concomitant establishment of reducing conditions within the sulfide melt ponding at the base of the komatiite lava. In this context, the investigation of spatially constrained sulfur isotopic signatures allows to isolate the multiple

  8. Novel Microbial Assemblages Dominate Weathered Sulfide-Bearing Rock from Copper-Nickel Deposits in the Duluth Complex, Minnesota, USA.

    Science.gov (United States)

    Jones, Daniel S; Lapakko, Kim A; Wenz, Zachary J; Olson, Michael C; Roepke, Elizabeth W; Sadowsky, Michael J; Novak, Paige J; Bailey, Jake V

    2017-08-15

    The Duluth Complex in northeastern Minnesota hosts economically significant deposits of copper, nickel, and platinum group elements (PGEs). The primary sulfide mineralogy of these deposits includes the minerals pyrrhotite, chalcopyrite, pentlandite, and cubanite, and weathering experiments show that most sulfide-bearing rock from the Duluth Complex generates moderately acidic leachate (pH 4 to 6). Microorganisms are important catalysts for metal sulfide oxidation and could influence the quality of water from mines in the Duluth Complex. Nevertheless, compared with that of extremely acidic environments, much less is known about the microbial ecology of moderately acidic sulfide-bearing mine waste, and so existing information may have little relevance to those microorganisms catalyzing oxidation reactions in the Duluth Complex. Here, we characterized the microbial communities in decade-long weathering experiments (kinetic tests) conducted on crushed rock and tailings from the Duluth Complex. Analyses of 16S rRNA genes and transcripts showed that differences among microbial communities correspond to pH, rock type, and experimental treatment. Moreover, microbial communities from the weathered Duluth Complex rock were dominated by taxa that are not typically associated with acidic mine waste. The most abundant operational taxonomic units (OTUs) were from the genera Meiothermus and Sulfuriferula, as well as from diverse clades of uncultivated Chloroflexi, Acidobacteria, and Betaproteobacteria Specific taxa, including putative sulfur-oxidizing Sulfuriferula spp., appeared to be primarily associated with Duluth Complex rock, but not pyrite-bearing rocks subjected to the same experimental treatment. We discuss the implications of these results for the microbial ecology of moderately acidic mine waste with low sulfide content, as well as for kinetic testing of mine waste.IMPORTANCE Economic sulfide mineral deposits in the Duluth Complex may represent the largest undeveloped

  9. Fluid inclusion studies of the polymetallic hydrothermal ore deposits in bolivia

    Science.gov (United States)

    Sugaki, A.; Kojima, S.; Shimada, N.

    1988-01-01

    Homogenization temperature and salinity were determined for fluid inclusions in mostly quartz and partly sphalerite, cassiterite, and barite from the 28 tin-polymetallic ore deposits in Bolivia. Generally, the homogenization temperatures and salinities of these fluid inclusions are comparatively high for ore deposits formed by cassiterite mineralization, such as Morococala and Avicaya in the Oruro district, frequently indicating a temperature higher than 300°C and salinity higher than 20 equiv. wt% NaCl. Particularly, it is quite possible that tin deposits associated with the W-Bi and tourmaline mineralizations such as Viloco and Caracoles have been produced by such high-temperature hypersaline fluid ranging up to 500°C and 56 equiv. wt% NaCl, similar to the porphyry copper type. This feature reveals that the hydrothermal fluid related to the Sn-W-Bi mineralization may be of magmatic origin. Homogenization temperatures for the Pb-Zn deposits with no tin minerals are low, mostly ranging 170° 300°C. At the Avicaya-Bolivar mining area in the Oruro district as well as at the Tasna and Chocaya-Animas mining areas in the Quechisla district temperature gradients consistent with the zonal distributions of ore minerals were confirmed.

  10. A comprehensive study on atomic layer deposition of molybdenum sulfide for electrochemical hydrogen evolution

    Science.gov (United States)

    Kwon, Do Hyun; Jin, Zhenyu; Shin, Seokhee; Lee, Wook-Seong; Min, Yo-Sep

    2016-03-01

    Atomic layer deposition (ALD) has emerged as an efficient method to design and prepare catalysts with atomic precision. Here, we report a comprehensive study on ALD of molybdenum sulfide (MoSx) for an electrocatalytic hydrogen evolution reaction. By using molybdenum hexacarbonyl and dimethyldisulfide as the precursors of Mo and S, respectively, the MoSx catalysts are grown at 100 °C on porous carbon fiber papers (CFPs). The ALD process results in the growth of particle-like MoSx on the CFP due to the lack of adsorption sites, and its crystallographic structure is a mixture of amorphous and nano-crystalline phases. In order to unveil the intrinsic activity of the ALD-MoSx, the exchange current densities, Tafel slopes, and turnover frequencies of the catalysts grown under various ALD conditions have been investigated by considering the fractional surface coverage of MoSx on the CFP and catalytically-active surface area. In addition, the ALD-MoSx/CFP catalysts exhibit excellent catalytic stability due to the strong adhesion of MoSx on the CFP and the mixed phase.Atomic layer deposition (ALD) has emerged as an efficient method to design and prepare catalysts with atomic precision. Here, we report a comprehensive study on ALD of molybdenum sulfide (MoSx) for an electrocatalytic hydrogen evolution reaction. By using molybdenum hexacarbonyl and dimethyldisulfide as the precursors of Mo and S, respectively, the MoSx catalysts are grown at 100 °C on porous carbon fiber papers (CFPs). The ALD process results in the growth of particle-like MoSx on the CFP due to the lack of adsorption sites, and its crystallographic structure is a mixture of amorphous and nano-crystalline phases. In order to unveil the intrinsic activity of the ALD-MoSx, the exchange current densities, Tafel slopes, and turnover frequencies of the catalysts grown under various ALD conditions have been investigated by considering the fractional surface coverage of MoSx on the CFP and catalytically

  11. Surface modification of cadmium sulfide thin film honey comb nanostructures: Effect of in situ tin doping using chemical bath deposition

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, K.C., E-mail: wilsonphy@gmail.com [Department of Physics, Govt. Polytechnic College Kothamangalam, Chelad P O, Ernakulam, Kerala 686681 (India); Department of Physics, B. S. Abdur Rahman University, Vandaloor, Chennai, Tamilnadu 600048 (India); Basheer Ahamed, M. [Department of Physics, B. S. Abdur Rahman University, Vandaloor, Chennai, Tamilnadu 600048 (India)

    2016-01-15

    Graphical abstract: - Highlights: • Novel honey comb like cadmium sulfide thin film nanostructures prepared using chemical bath deposition on glass substrates. • Honey comb nanostructure found in two layers: an ultra thin film at bottom and well inter connected with walls of < 25 nm thick on top; hence maximum surface area possible for CdS nanostructure. • Shell size of the nanostructures and energy band gaps were controlled also an enhanced persistent conductivity observed on Sn doping. - Abstract: Even though nanostructures possess large surface to volume ratio compared to their thin film counterpart, the complicated procedure that demands for the deposition on a substrate kept them back foot in device fabrication techniques. In this work, a honey comb like cadmium sulfide (CdS) thin films nanostructure are deposited on glass substrates using simple chemical bath deposition technique at 65 °C. Energy band gaps, film thickness and shell size of the honey comb nanostructures are successfully controlled using tin (Sn) doping and number of shells per unit area is found to be maximum for 5% Sn doped (in the reaction mixture) sample. X-ray diffraction and optical absorption analysis showed that cadmium sulfide and cadmium hydroxide coexist in the samples. TEM measurements showed that CdS nanostructures are embedded in cadmium hydroxide just like “plum pudding”. Persistent photoconductivity measurements of the samples are also carried out. The decay constants found to be increased with increases in Sn doping.

  12. Fluid Evolution During Mineralization of Atashkuh Fluorite-Barite (±Sulfide Deposit, South of Delijan

    Directory of Open Access Journals (Sweden)

    Seyed Javad Moghaddasi

    2016-07-01

    Full Text Available Introduction More than 30 fluorite occurrences with approximately 1.35 million tons of reserves have been recognized in Iran (Ghorbani, 2013. The Atashkuh fluorite-barite (±sulfide deposit is one of four occurrences located south of the city of Delijan in Markazi province, about 80 km SE of Arak city. The Atashkuh deposit occurs between the central Iran structural zone on the north and the Sanandaj-Sirjan structural zone on the south. The geology of the area is dominated by folded and faulted Jurassic carbonates and shales (Thiele et al., 1968. The lower Jurassic shale and calcareous sandstone of the Shemshak Formation and the Middle to Upper Jurassic dolomite of the Badamu Formation are the main host rocks for the fluorite veins. In this study, 40 samples from fluorite veins and host rocks were collected, from which 25 thin sections and 8 doubly-polished thin sections were prepared. Micro-thermometric studies were conducted on primary fluid inclusions using the Linkam THM600 heating-freezing stage. In addition, 10 samples were analyzed by XRD. Results Fluid inclusion data indicate that the Atashkuh fluorite-barite (±sulfides veins were deposited as a result of mixing a primary multi-component Na-K(-Mg-Ca high-salinity brine (SH type inclusions with less saline calcium-rich connate water (LVHH type inclusions and pressure reduction of ore bearing fluids. Fluid inclusions containing halite in high-salinity brine, and hydrohalite in connate water show suggest a high-salinity brine and connate water before mixing. The main mineralization stage was followed by circulation of low temperature meteoric water, responsible for the late stage mineralization. The micro-thermometry results suggest that the main fluorite mineralization occurred at 250 °C and 150 Mpa pressure. Dolomitization and silicification are the main alteration types associated with the Atashkuh mineralization. The occurrence of chlorite, talc, illite and dolomitized host rock all

  13. Intermediate sulfidation epithermal mineralization of No. 4 anomaly of Golojeh deposit (N. Zanjan based on mineralography, alteration and ore fluid geochemistry features

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    Behzad Mehrab

    2014-04-01

    Full Text Available The base (Cu–Pb–Zn and precious metals (Ag±Au mineralization at the No. 4 anomaly of Golojeh deposit occurred in volcanic and sub–volcanic Eocene–Oligocene host rocks, in the central part of the Tarom–Hashtjin zone. Basic to intermediate volcanic, volcaniclastic and sub–volcanic rocks are dominated in the area and include andesite, basaltic andesite, trachy-andesite, dacite and tuff with affinity to sub–alkaline to high–potassic calc–alkaline series. The mineralization in the area with average grade of Au (0.15 ppm, Ag (0.24%, Cu (0.6%, Zn (4% and Pb (6% occurred in two major NW–SE trending quartz–sulfide veins (A and B with crustiform, breccia, vein–veinlet and open-space filling structure and texture. The sulfide content varies from 5 to 60% and is dominated by galena, sphalerite, chalcopyrite and pyrite. SEM studies indicated presence of Ag (0.47 to 0.66 wt.% and Cd (0.33 to 0.72 wt.% in galena and Fe (0.23 wt.% in sphalerite. Hydrothermal alteration of phyllic (quartz–sericite–pyrite, argillic (quartz–illite/muscovite and silicification are related to mineralization. Correlation coefficient of metal pairs of Cd–Zn (0.86, Cd–Pb (0.82, Pb–Ag (0.80, Au–Ag (0.75, Pb–Zn (0.70 and Cd–Bi (0.74 was recorded in the quartz–sulfide ore–bearing veins. Microthermometric studies on two phases liquid–vapor fluid inclusions in ore–bearing veins, shows homogenization temperature to liquid (Thlv→l in the range of 223 to 287°C and salinity of 6.5 to 17 wt.% NaCl eq. (quartz-hosted and homogenization temperature ranging from 175 to 244°C and salinity from 1.5 to 12 wt.% NaCl eq. (sphaerite-hosted. First ice–melting temperature (Tmf ranges of fluid inclusion in sphalerite-hosted of quartz–sulfide ore–bearing veins were recorded between −23 and −18°C in NaCl–H2O system. Vein–breccia and crustified structure and texture, presence of illite/muscovite alteration assemblage accompanied by high

  14. Stable Te isotope fractionation in tellurium-bearing minerals from precious metal hydrothermal ore deposits

    Science.gov (United States)

    Fornadel, Andrew P.; Spry, Paul G.; Haghnegahdar, Mojhgan A.; Schauble, Edwin A.; Jackson, Simon E.; Mills, Stuart J.

    2017-04-01

    The tellurium isotope compositions of naturally-occurring tellurides, native tellurium, and tellurites were measured by multicollector-inductively coupled plasma-mass spectrometry (MC-ICP-MS) and compared to theoretical values for equilibrium mass-dependent isotopic fractionation of representative Te-bearing species estimated with first-principles thermodynamic calculations. Calculated fractionation models suggest that 130/125Te fractionations as large as 4‰ occur at 100 °C between coexisting tellurates (Te VI) and tellurides (Te -II) or or native tellurium Te(0), and smaller, typically ore-forming systems. Our data suggest that these sorts of reactions during mineralization may account for a ∼3‰ range of δ130/125Te values. Based on the data ranges for Te minerals from various ore deposits, the underpinning geologic processes responsible for mineralization seem to have primary control on the magnitude of fractionation, with tellurides in epithermal gold deposits showing a narrower range of isotope values than those in orogenic gold and volcanogenic massive sulfide deposits.

  15. High and Low Temperature Gold Mineralizations in the Fe–Cu–Zn Sulfide Deposits of Corchia Ophiolite, Northern Italian Apennine

    OpenAIRE

    Zaccarini Federica; Giorgio Garuti

    2013-01-01

    Gold has been found in the Cyprus-type volcanogenic massive sulfide ore (VMS) deposits of Corchia ophiolite (Parma province, Italy) in the Cantiere Donnini, Speranza and Pozzo mining sites. At Cantiere Donnini and Speranza, the mineralization occurs at the contact between pillow lava and sedimentary rocks. The Pozzo mineralization is hosted by a serpentinite. Concentrations of gold up to 3070 ppb have been reported for the Cantiere Donnini and up to 6295 ppb in the Pozzo mine. According to th...

  16. Correlation between compositions of ore and host rocks in volcanogenic massive sulfide deposits of the Southern Urals

    Science.gov (United States)

    Seravkin, I. B.

    2013-05-01

    The geology and typification of volcanogenic massive sulfide (VMS) deposits of the Southern Urals are considered. The mineralogical-geochemical types of these deposits correlate with the composition of the underlying igneous rocks: Ni-Co-Cu deposits correlatedwith serpentinites (Ivanovka type); (Co)-Cu deposits, with basalts (Dombarovka type); Cu-Zn deposits, with basalt-rhyolite and basalt-andesite-rhyolite complexes (Ural type); and Au-Ba-Pb-Zn-Cu deposits, with basalt-andesite-rhyolite complexes with predominance of andesitic and felsic volcanics (Baimak type). The Ural-type deposits are subdivided into three subtypes: I, underlain by basalts (Zn-Cu deposits); II, hosted in felsic volcanic rocks of bimodal complexes (Cu-Zn deposits); and III, hosted in felsic volcanic rocks of continuously differentiated complexes (Zn-Cu deposits with Ba, Pb, and As). The above types and subtypes bearing local names are compared with global types of VMS deposits (MAR, Cyprus, Noranda, and Kuroko), to which they are close but not identical.

  17. Strata-bound Fe-Co-Cu-Au-Bi-Y-REE deposits of the Idaho Cobalt Belt: Multistage hydrothermal mineralization in a magmatic-related iron oxide copper-gold system

    Science.gov (United States)

    Slack, John F.

    2012-01-01

    Mineralogical and geochemical studies of strata-bound Fe-Co-Cu-Au-Bi-Y-rare-earth element (REE) deposits of the Idaho cobalt belt in east-central Idaho provide evidence of multistage epigenetic mineralization by magmatic-hydrothermal processes in an iron oxide copper-gold (IOCG) system. Deposits of the Idaho cobalt belt comprise three types: (1) strata-bound sulfide lenses in the Blackbird district, which are cobaltite and, less commonly, chalcopyrite rich with locally abundant gold, native bismuth, bismuthinite, xenotime, allanite, monazite, and the Be-rich silicate gadolinite-(Y), with sparse uraninite, stannite, and Bi tellurides, in a gangue of quartz, chlorite, biotite, muscovite, garnet, tourmaline, chloritoid, and/or siderite, with locally abundant fluorapatite or magnetite; (2) discordant tourmalinized breccias in the Blackbird district that in places have concentrations of cobaltite, chalcopyrite, gold, and xenotime; and (3) strata-bound magnetite-rich lenses in the Iron Creek area, which contain cobaltiferous pyrite and locally sparse chalcopyrite or xenotime. Most sulfide-rich deposits in the Blackbird district are enclosed by strata-bound lenses composed mainly of Cl-rich Fe biotite; some deposits have quartz-rich envelopes.Whole-rock analyses of 48 Co- and/or Cu-rich samples show high concentrations of Au (up to 26.8 ppm), Bi (up to 9.16 wt %), Y (up to 0.83 wt %), ∑REEs (up to 2.56 wt %), Ni (up to 6,780 ppm), and Be (up to 1,180 ppm), with locally elevated U (up to 124 ppm) and Sn (up to 133 ppm); Zn and Pb contents are uniformly low (≤821 and ≤61 ppm, respectively). Varimax factor analysis of bulk compositions of these samples reveals geochemically distinct element groupings that reflect statistical associations of monazite, allanite, and xenotime; biotite and gold; detrital minerals; chalcopyrite and sparse stannite; quartz; and cobaltite with sparse selenides and tellurides. Significantly, Cu is statistically separate from Co and As

  18. Iron oxide deposits associated with the ectosymbiotic bacteria in the hydrothermal vent shrimp Rimicaris exoculata

    Science.gov (United States)

    Corbari, L.; Cambon-Bonavita, M.-A.; Long, G. J.; Grandjean, F.; Zbinden, M.; Gaill, F.; Compère, P.

    2008-04-01

    The Rimicaris exoculata shrimp is considered a primary consumer that dominates the fauna of most Mid-Atlantic Ridge (MAR) hydrothermal ecosystems. These shrimps harbour in their gill chambers an important ectosymbiotic community of chemoautotrophic bacteria associated with iron oxide deposits. The structure and elemental composition of the minerals associated with these bacteria have been investigated by using X-ray microanalyses, light microscopy, and transmission, environmental scanning and scanning transmission electron microscopy. The nature of the iron oxides in shrimps obtained from the Rainbow vent field at 36°14.0' N, has also been determined by Mössbauer spectroscopy. This multidisciplinary approach has revealed that the three step-levels of mineral crust found in the Rimicaris exoculata shrimps consist of heavy concretions formed by nanoparticles of two-line ferrihydrite intermixed with minor inorganic SiO2, (Ca,Mg)SO4, and (Ca,Mg)3(PO4)2 minerals that may stabilise the ferrihydrite form of iron oxides. Morphological observations on the bacteria have revealed their close interactions with these minerals and, thus, indicate the biogenic origin of the iron oxide deposits. The evolution of the bacterial density in the three mineral crust levels is related to the amount of the iron deposits and it is proposed that the lower crust level is the most likely region for the location of the iron-oxidizing bacteria.

  19. Annealing study and thermal investigation on bismuth sulfide thin films prepared by chemical bath deposition in basic medium

    Science.gov (United States)

    Dachraoui, O.; Merino, J. M.; Mami, A.; León, M.; Caballero, R.; Maghraoui-Meherzi, H.

    2018-02-01

    Bismuth sulfide thin films were prepared by chemical bath deposition using thiourea as sulfide ion source in basic medium. First, the effects of both the deposition parameters on film growth as well as the annealing effect under argon and sulfur atmosphere on as-deposited thin films were studied. The parameters were found to be influential using the Doehlert matrix experimental design methodology. Ranges for a maximum surface mass of films (3 mg cm-2) were determined. A well-crystallized major phase of bismuth sulfide with stoichiometric composition was achieved at 190 °C for 3 h. The prepared thin films were characterized using grazing incidence X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray analysis. Second, the bandgap energy value was found to be 1.5 eV. Finally, the thermal properties have been studied for the first time by means of the electropyroelectric (EPE) technique. Indeed, the thermal conductivity varied in the range of 1.20-0.60 W m-1 K-1, while the thermal diffusivity values increased in terms of the annealing effect ranging from 1.8 to 3.5 10-7 m2 s-1.

  20. Molybdenum isotopes in modern marine hydrothermal Fe/Mn deposits: Implications for Archean and Paleoproterozoic Mo cycles

    Science.gov (United States)

    Goto, K. T.; Hein, J. R.; Shimoda, G.; Aoki, S.; Ishikawa, A.; Suzuki, K.; Gordon, G. W.; Anbar, A. D.

    2016-12-01

    Molybdenum isotope (δ98/95Mo) variations recorded in Archean and Paleoproterozoic Fe/Mn-rich sediments have been used to constrain ocean redox conditions at the time of deposition (Canfield et al., 2013 PNAS; Planavsky et al., 2014 Nat. Geo.; Kurzweil et al., 2015 GCA). However, except for hydrogenous Fe-Mn crusts (Siebert et al., 2003), δ98/95Mo variation of modern Fe and Mn oxide deposits has been poorly investigated. Marine hydrothermal systems are thought to be the major source of Fe and Mn in Archean and Paleoproterozoic Fe- and Mn-rich sediments. Hence, to accurately interpret Mo isotope data of those ancient sedimentary rocks, it is important to evaluate the possible influence of hydrothermally derived Mo on δ98/95Mo of modern Fe- and Mn-rich sediments. In this study, we analyzed Mo isotopic compositions of one hydrothermal Fe oxide and 15 Mn oxides from five different hydrothermal systems in the modern ocean. The Fe oxide is composed mainly of goethite, and has a δ98/95Mo of 0.7‰, which is 1.4‰ lighter than that of present-day seawater. The observed offset is similar to isotope fractionation observed during adsorption experiments of Mo on goethite (Δ98/95Mogoethite-solution = -1.4 ± 0.5%; Goldberg et al., 2009 GCA). The 15 hydrothermal Mn oxides show large variations in δ98/95Mo ranging from -1.7 to 0.5‰. However, most of the values are similar to those of modern hydrogenous Fe-Mn crusts (Siebert et al., 2003 EPSL), and fall within the range of estimated δ98/95Mo of Mn oxides precipitated from present-day seawater using the isotope offset reported from adsorption experiments (Δ98/95Mo = -2.7 ± 0.3‰; Wasylenki et al., 2008 GCA). These findings indicate that seawater is the dominant source of Mo for modern hydrothermal Fe and Mn deposits. However, the observed large variation indicates that the contribution Mo from local hydrothermal systems is not negligible. The oceanic Mo inventory during the Archean and Paleoproterozoic is thought to be

  1. Siderite deposits in northern Italy: Early Permian to Early Triassic hydrothermalism in the Southern Alps

    Science.gov (United States)

    Martin, Silvana; Toffolo, Luca; Moroni, Marilena; Montorfano, Carlo; Secco, Luciano; Agnini, Claudia; Nimis, Paolo; Tumiati, Simone

    2017-07-01

    We present a minero-petrographic, geochemical and geochronological study of siderite orebodies from different localities of the Southern Alps (northern Italy). Siderite occurs as veins cutting the Variscan basement and the overlying Lower Permian volcano-sedimentary cover (Collio Fm.), and as both veins and conformable stratabound orebodies in the Upper Permian (Verrucano Lombardo and Bellerophon Fms.) and Lower Triassic (Servino and Werfen Fms.) sedimentary sequences of the Lombardian and the Venetian Alps. All types of deposits show similar major- and rare-earth (REE)-element patterns, suggesting a common iron-mineralizing event. The compositions of coexisting siderite, Fe-rich dolomite and calcite suggest formation from hydrothermal fluids at relatively high temperature conditions (≥ 250 °C). Geochemical modelling, supported by REE analyses and by literature and new δ13C and δ18O isotopic data, suggests that fluids responsible for the formation of siderite in the Variscan basement and in the overlying Lower Permian cover were derived from dominant fresh water, which leached Fe and C from volcanic rocks (mainly rhyolites/rhyodacites) and organic carbon-bearing continental sediments. On the basis of U-Th-Pb microchemical dating of uraninite associated with siderite in the Val Vedello and Novazza deposits (Lombardian Alps), the onset of hydrothermalism is constrained to 275 ± 13 Ma (Early-Mid Permian), i.e., it was virtually contemporaneous to the plutonism and the volcanic-sedimentary cycle reported in the same area (Orobic Basin). The youngest iron-mineralizing event is represented by siderite veins and conformable orebodies hosted in Lower Triassic shallow-marine carbonatic successions. In this case, the siderite-forming fluids contained a seawater component, interacted with the underlying Permian successions and eventually replaced the marine carbonates at temperatures of ≥ 250 °C. The absence of siderite in younger rocks suggests an Early Triassic

  2. Liquid immiscibility between arsenide and sulfide melts: evidence from a LA-ICP-MS study in magmatic deposits at Serranía de Ronda (Spain)

    Science.gov (United States)

    Piña, R.; Gervilla, F.; Barnes, S.-J.; Ortega, L.; Lunar, R.

    2015-03-01

    The chromite-Ni arsenide (Cr-Ni-As) and sulfide-graphite (S-G) deposits from the Serranía de Ronda (Málaga, South Spain) contain an arsenide assemblage (nickeline, maucherite and nickeliferous löllingite) that has been interpreted to represent an arsenide melt and a sulfide-graphite assemblage (pyrrhotite, pentlandite, chalcopyrite and graphite) that has been interpreted to represent a sulfide melt, both of which have been interpreted to have segregated as immiscible liquids from an arsenic-rich sulfide melt. We have determined the platinum-group element (PGE), Au, Ag, Se, Sb, Bi and Te contents of the arsenide and sulfide assemblages using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to establish their partitioning behaviour during the immiscibility of an arsenide melt from a sulfide melt. Previous experimental work has shown that PGE partition more strongly into arsenide melts than into sulfide melts and our results fit with this observation. Arsenide minerals are enriched in all PGE, but especially in elements with the strongest affinity for the arsenide melt, including Ir, Rh and Pt. In contrast and also in agreement with previous studies, Se and Ag partition preferentially into the sulfide assemblage. The PGE-depleted nature of sulfides in the S-G deposits along with the discordant morphologies of the bodies suggest that these sulfides are not mantle sulfides, but that they represent the crystallization product of a PGE-depleted sulfide melt due to the sequestering of PGE by an arsenide melt.

  3. Hydrothermal synthesis of graphene flake embedded nanosheet-like molybdenum sulfide hybrids as counter electrode catalysts for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jeng-Yu, E-mail: jylin@ttu.edu.tw [Department of Chemical Engineering, Tatung University, No. 40, Sec. 3, ChungShan North Rd., Taipei City 104, Taiwan (China); Yue, Gentian [Department of Chemical Engineering, Tatung University, No. 40, Sec. 3, ChungShan North Rd., Taipei City 104, Taiwan (China); Institute of Materials Physical Chemistry, Huaqiao University, Quanzhou, Fujian 362021 (China); Tai, Sheng-Yen [Department of Chemical Engineering, Tatung University, No. 40, Sec. 3, ChungShan North Rd., Taipei City 104, Taiwan (China); Xiao, Yaoming [Department of Chemical Engineering, Tatung University, No. 40, Sec. 3, ChungShan North Rd., Taipei City 104, Taiwan (China); Institute of Molecular Science, Key Laboratory of Chemical Biology and Molecular Engineering of Education Ministry, Shanxi University, Taiyuan 030006 (China); Cheng, Ho-Ming; Wang, Fu-Ming [Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, No. 43, Sec. 4, Keelung Rd., Taipei City 106, Taiwan (China); Wu, Jihuai [Institute of Materials Physical Chemistry, Huaqiao University, Quanzhou, Fujian 362021 (China)

    2013-12-16

    In this study, graphene flake (GF) was successfully embedded into a nanosheet-like molybdenum sulfide (MoS{sub 2}) matrix via an in situ hydrothermal route, and the resultant hybrid was employed as a counter electrode (CE) for Pt-free dye-sensitized solar cells (DSCs). It is confirmed from scanning electron microscopy, X-ray diffraction, Raman spectroscopy and transmission electron microscopy that GFs are successfully incorporated in the nanosheet-like MoS{sub 2} matrix and thus result in its surface evolution. The extensive electrochemical analyses reveal that the remarkably enhanced electrocatalytic activity can be demonstrated when GFs are incorporated in the MoS{sub 2} matrix. After the optimization, the nanosheet-like MoS{sub 2}/GF hybrid with 1.5 wt.% GF shows the best electrocatalytic activity. The DSC assembled with the novel nanosheet-like MoS{sub 2}/GF hybrid CE exhibits a high photovoltaic conversion efficiency of 6.07% under standard illumination, up to 95% of the level obtained using conventional Pt CE (6.41%). - Highlights: • Nanosheet-like MoS{sub 2}/graphene flake hybrid was prepared by a hydrothermal route. • The surface morphology of MoS{sub 2} changed with the incorporation of graphene flake. • The hybrid with 1.5 wt.% graphene flake showed the superior catalytic activity. • The cell efficiency of DSC with the hybrid CE reached 95% of that using Pt CE.

  4. The mass balance calculation of hydrothermal alteration in Sarcheshmeh porphyry copper deposit

    Directory of Open Access Journals (Sweden)

    Mohammad Maanijou

    2013-10-01

    Full Text Available Sarcheshmeh porphyry copper deposit is located 65 km southwest of Rafsanjan in Kerman province. The Sarcheshmeh deposit belongs to the southeastern part of Urumieh-Dokhtar magmatic assemblage (i.e., Dehaj-Sarduyeh zone. Intrusion of Sarcheshmeh granodiorite stock in faulted and thrusted early-Tertiary volcano-sedimentary deposits, led to mineralization in Miocene. In this research, the mass changes and element mobilities during hydrothermal process of potassic alteration were studied relative to fresh rock from the deeper parts of the plutonic body, phyllic relative to potassic, argillic relative to phyllic and propylitic alteration relative to fresh andesites surrounding the deposit. In the potassic zone, enrichment in Fe2O3 and K2O is so clear, because of increasing Fe coming from biotite alteration and presence of K-feldspar, respectively. Copper and molybdenum enrichments resulted from presence of chalcopyrite, bornite and molybdenite mineralization in this zone. Enrichment of SiO2 and depletion of CaO, MgO, Na2O and K2O in the phyllic zone resulted from leaching of sodium, calcium and magnesium from the aluminosilicate rocks and alteration of K-feldspar to sericite and quartz. In the argillic zone, Al2O3, CaO, MgO, Na2O and MnO have also been enriched in which increasing Al2O3 may be from kaolinite and illite formation. Also, enrichment in SiO2, Al2O3 and CaO in propylitic alteration zone can be attributed to the formation of chlorite, epidote and calcite as indicative minerals of this zone.

  5. The Genesis of tectonically and hydrothermally controlled industry mineral deposits: A geochemical and structural study

    Science.gov (United States)

    Wölfler, Anke; Prochaska, Walter; Henjes-Kunst, Friedhelm; Fritz, Harald

    2010-05-01

    The study aims to investigate the role of hydrothermal fluids in the formation of talc and magnesite deposits. These deposits occur in manifold geological and tectonical settings such as stockworks and veins within ultramafite hostrocks and monomineralic lenses within marine platform sediments. Along shear zones talc mineralizations may occur as a result of tectonical and hydrothermal activity. To understand the role of the fluids for the genesis of the mineralization, deposits in different geological and tectonical settings are investigated: Talc mineralization within in magnesite in low-grade palaeozoic nappe complexes (Gemerska Poloma, Slovakia): The magnesite body lies within the Gemer unit of the Inner Carpathians consisting of Middle Triassic metacarbonates and Upper Triassic pelagic limestones and radiolarites. The talc mineralization is bound to crosscutting veins. Two metamorphic events can be distinguished, one during Variscan orogeny and one related to the Alpine orogeny leading to the formation of talc along faults in an Mg carbonate body (Radvanec et al, 2004).The origin of the fluids as well as the tectonic events leading to the mineralization is still widely unknown. Talc mineralization in shearzones within Palaeozoic meta sedimentary rocks (Sa Matta, Sardinia): Variscan granitoids intruded Palaeozoic meta sedimentary rocks and were overprinted be NE striking tectonic structures that host talc mineralizations. The origin of Mg and fluids leading to the mineralization is still not answered satisfactorily (Grillo and Prochaska, 2007) and thus a tectonic model for the genesis of the talc deposit is missing. Talc mineralization within UHP pre-Alpine continental crust (Val Chisone, Italy): The talc deposit forms part of the Dora-Maira Massif. Geologicaly the massif derived from a Variscan basement that includes post-Variscan intrusions. The talc mineralization occurs as a sheetlike, conformable body. A possible tectonic emplacement of talc along shear

  6. Iron oxide deposits associated with the ectosymbiotic bacteria in the hydrothermal vent shrimp Rimicaris exoculata

    Directory of Open Access Journals (Sweden)

    P. Compère

    2008-09-01

    Full Text Available The Rimicaris exoculata shrimp is considered as a primary consumer that dominates the fauna of most Mid-Atlantic Ridge (MAR hydrothermal ecosystems. These shrimps harbour in their gill chambers an important ectosymbiotic community of chemoautotrophic bacteria associated with iron oxide deposits. The structure and elemental composition of the mineral concretions associated with these bacteria have been investigated by using LM, ESEM, TEM STEM and EDX microanalyses. The nature of the iron oxides in shrimps obtained from the Rainbow vent field has also been determined by Mössbauer spectroscopy. This multidisciplinary approach has revealed that the three layers of mineral crust in the Rimicaris exoculata shrimps consist of large concretions formed by aggregated nanoparticles of two-line ferrihydrite and include other minor elements as Si, Ca, Mg, S and P, probably present as silicates cations, sulphates or phosphates respectively that may contribute to stabilise the ferrihydrite form of iron oxides. TEM-observations on the bacteria have revealed their close interactions with these minerals. Abiotic and biotic precipitation could occur within the gill chamber of Rimicaris exoculata, suggesting the biologically-mediated formation of the iron oxide deposits. The difference of the bacterial density in the three-mineral crust layers could be correlated to the importance of the iron oxide concretions and suggest that the first mineral particles precipitates on the lower layer which could be considered as the most likely location of iron-oxidizing bacteria.

  7. Mineralogic sources of metals in leachates from the weathering of sedex, massive sulfide, and vein deposit mining wastes

    Science.gov (United States)

    Diehl, S.F.; Hageman, P.L.; Seal, R.R.; Piatak, N.M.; Lowers, H.

    2011-01-01

    Weathered mine waste consists of oxidized primary minerals and chemically unstable secondary phases that can be sources of readily soluble metals and acid rock drainage. Elevated concentrations of metals such as Cd, Cu, Fe, Mn, Ni, Pb, and Zn are observed in deionized water-based leachate solutions derived from complex sedex and Cu-Pb-Zn mine wastes. Leachate (USGS FLT) from the Elizabeth mine, a massive sulfide deposit, has a pH of 3.4 and high concentrations of Al (16700 ug/L), Cu (440 ug/L), and Zn (8620 ug/L). Leachate from the sedex Faro mine has a pH of 3.5 and high concentrations of Al (2040 ug/L), Cu (1930 ug/L), Pb (2080 ug/L), and Zn (52900 ug/L). In contrast, higher-pH leachates produced from tailings of polymetallic vein deposits have order of magnitude lower metal concentrations. These data indicate that highly soluble secondary mineral phases exist at the surface of waste material where the samples were collected. Sulfide minerals from all sites exhibit differential degrees of weathering, from dissolution etched grain rims, to rinds of secondary minerals, to skeletal remnants. These microscale mineral-dissolution textures enhance weathering and metal teachability of waste material. Besides the formation of secondary minerals, sulfide grains from dried tailings samples may be coated by amorphous Fe-Al-Si minerals that also adsorb metals such as Cu, Ni, and Zn.

  8. Geodynamic conditions of formation of massive sulfide deposits in the Magnitogorsk Megazone, Southern Urals, and prospection criteria

    Science.gov (United States)

    Seravkin, I. B.; Kosarev, A. M.; Puchkov, V. N.

    2017-05-01

    The zoned composition changes of the massive sulfide deposits in the major massive sulfide zone of the Southern Urals such as the Magnitogorsk Megasynclinorium are considered. The zoning is expressed as the trend of Ni-Co-Cu → Zn-Cu → Cu-Zn → Au-Ba-Pb-Cu-Zn. This trend is related to two basic factors: (1) the subduction process with the slab's eastward subsidence preconditioned the formation (from the west to the east) of the following massive sulfide zones: accretionary prism, frontal island arc, developed island arc, inter-arc spreading zone, split back arc, and back-arc spreading; (2) the longitudinal zoning of the massive sulfide paleovolcanic belts related to changes in the thickness of the crust's basaltic layer and an inclination of the subducting plate in transverse blocks of the belt. The first factor affects the general paleovolcanic and metallogenic latitudinal zoning of the studied region, while the second factor defines the local meridional zoning. The composition of ore-bearing solutions is dependent on the formation depth of the subduction fluids, magma differentiation type, and the ratio of deep fluids to solutions of near-surface convective cells. The combination of the geodynamic factors expressed in the composition of ore-bearing volcanic complexes and the specific geological settings defines the massive sulfide mineralization composition and productivity criteria. The most productive structures include the frontal island-arc and inter-arc spreading zones and within them, the central-type volcanic edifices whose basalts are referred to as the island-arc tholeiite series and are characterized by the minimum TiO2 and Zr content and low La/Yb ratios.

  9. High and Low Temperature Gold Mineralizations in the Fe–Cu–Zn Sulfide Deposits of Corchia Ophiolite, Northern Italian Apennine

    Directory of Open Access Journals (Sweden)

    Zaccarini Federica

    2013-03-01

    Full Text Available Gold has been found in the Cyprus-type volcanogenic massive sulfide ore (VMS deposits of Corchia ophiolite (Parma province, Italy in the Cantiere Donnini, Speranza and Pozzo mining sites. At Cantiere Donnini and Speranza, the mineralization occurs at the contact between pillow lava and sedimentary rocks. The Pozzo mineralization is hosted by a serpentinite. Concentrations of gold up to 3070 ppb have been reported for the Cantiere Donnini and up to 6295 ppb in the Pozzo mine. According to the field relationships, gold composition, mineralogical assemblage and sulfur isotope data, we can conclude that two different types of gold mineralization have been recognized in the Corchia ophiolite: (1 formed at low temperature in submarine environment (Cantiere Donnini and Speranza and (2 formed at high temperature in the oceanic mantle (Pozzo by segregation of an immiscible sulfide liquid.

  10. S/Se ratio of pyrite from eastern Australian VHMS deposits: implication of magmatic input into volcanogenic hydrothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Huston, D.L. [Geological Survey of Canada, Ottawa, ON (Canada); Sie, S.H.; Suter, G.F. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience; Cooke, D.R. [Tasmania Univ., Sandy Bay, TAS (Australia)

    1993-12-31

    The proton microprobe was used to determine the concentrations of over twenty trace elements in pyrite grains from four volcanic-hosted massive sulphide (VHMS) deposits in eastern Australia. Of the elements determined, Se has the most potential in resolving important problems in the genesis of this class of ore deposits. This paper summarises analytical conditions, describes the distribution of Se in pyrite in VHMS deposits as determined in this and other studies, discusses the speciation of Se in hydrothermal fluids, and presents a genetic model on the relative contribution of magmatic versus sea water Se (and S) in VHMS systems. 2 refs., 1 fig.

  11. Nanostructured Multilayer Composite Films of Manganese Dioxide/Nickel/Copper Sulfide Deposited on Polyethylene Terephthalate Supporting Substrate

    Directory of Open Access Journals (Sweden)

    Awangku Nabil Syafiq Bin Awangku Metosen

    2015-01-01

    Full Text Available Nanostructured multilayer manganese dioxide/nickel/copper sulfide (MnO2/Ni/CuS composite films were successfully deposited onto supporting polyethylene terephthalate (PET substrate through the sequential deposition of CuS, Ni, and MnO2 thin films by chemical bath deposition, electrodeposition, and horizontal submersion deposition techniques, respectively. Deposition of each thin-film layer was optimized by varying deposition parameters and conditions associated with specific deposition technique. Both CuS and Ni thin films were optimized for their electrical conductivity whereas MnO2 thin film was optimized for its microstructure and charge capacity. The electrochemical properties of nanostructured multilayer MnO2/Ni/CuS composite films were evaluated by cyclic voltammetry as electrode materials of an electrochemical capacitor prototype in a dual-planar device configuration. Cyclic voltammogram in mild Na2SO4 aqueous electrolyte exhibited a featureless and almost rectangular shape which was indicative of the ideal capacitive behavior and high cycling reversibility of the electrochemical capacitor prototype. Nanostructured multilayer MnO2/Ni/CuS composite films on supporting polyethylene terephthalate (PET substrate could potentially be utilized as electrode materials for the fabrication of high performance electrochemical capacitors.

  12. Deposition of cobalt and nickel sulfide thin films from thio- and alkylthio-urea complexes as precursors via the aerosol assisted chemical vapour deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Mgabi, L.P.; Dladla, B.S. [Department of Chemistry, University of Zululand, Private bag X1001 KwaDlangezwa, 3880 (South Africa); Malik, M.A. [School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Garje, Shivram S. [Department of Chemistry, University of Mumbai, Vidyanagari, Santacruz (East), Mumbai 400098 (India); Akhtar, J. [Nanoscience and Materials Synthesis Lab, Department of Physics, COMSATS, Institute of Information Technology (CIIT), Chak shahzad, Islamabad (Pakistan); Revaprasadu, N., E-mail: RevaprasaduN@unizulu.ac.za [Department of Chemistry, University of Zululand, Private bag X1001 KwaDlangezwa, 3880 (South Africa)

    2014-08-01

    We report the synthesis of Co(II) and Ni(II) thiourea and alkylthiourea complexes by reacting the metal salts (CoCl{sub 2} and NiCl{sub 2}) with the thiourea, phenylthiourea and dicyclohexylthiourea ligands in a 1:2 ratio. The complexes, [CoCl{sub 2}(CS(NH{sub 2}){sub 2}){sub 2}] (I), [CoCl{sub 2}(CSNHC{sub 6}H{sub 5}NH{sub 2}){sub 2} (II) and [CoCI{sub 2}(SC(NHC{sub 6}H{sub 11}){sub 2}){sub 2}] (III), [NiCl{sub 2}(CS(NH{sub 2}){sub 2}){sub 2}] (IV), [NiCl{sub 2}(CSNHC{sub 6}H{sub 5}NH{sub 2}){sub 2}] (V) and [NiCl{sub 2}(SC(NHC{sub 6}H{sub 11}){sub 2}){sub 2}] (VI) were characterized by C, H, N analysis and Fourier transform infrared spectroscopy. Thermogravimetric analysis shows that all complexes undergo a two step decomposition process except for [NiCl{sub 2}(CSNHC{sub 6}H{sub 5}NH{sub 2}){sub 2}] (V) which decomposes in a single step. The complexes were used as single-source precursors for the deposition of cobalt sulfide and nickel sulfide thin films by aerosol assisted chemical vapor deposition at temperatures between 350 an 500 °C. The crystallinity of the films was determined by X-ray diffraction and their morphology was determined by scanning electron microscopy. The morphology of the cobalt sulfide thin films varies from randomly oriented platelets, to granulated spheres and cubes as the precursor and deposition conditions are changed. For nickel sulfide, the [NiCl{sub 2}(CS(NH{sub 2}){sub 2}){sub 2}] (IV) complex gave rods whereas the [NiCl{sub 2}(CSNHC{sub 6}H{sub 5}NH{sub 2}){sub 2}] (V) produced spherical particles. - Highlights: • We report the synthesis of Co(II) and Ni(II) thiourea and alkylthiourea complexes. • C, H, N analysis and Fourier transform infrared spectroscopy characterization • NiS and CoS thin films deposited by aerosol assisted chemical vapor deposition • X-ray diffraction characterization of the phase of the films • Film morphology determined by scanning electron microscopy.

  13. Peralkaline- and calc-alkaline-hosted volcanogenic massive sulfide deposits of the Bonnifield District, East-Central Alaska

    Science.gov (United States)

    Dusel-Bacon, Cynthia; Foley, Nora K.; Slack, John E.; Koenig, Alan E.; Oscarson, Robert L.

    2012-01-01

    Volcanogenic massive sulfide (VMS) Zn-Pb-Cu-Ag-Au deposits of the Bonnifield mining district formed during Late Devonian-Early Mississippian magmatism along the western edge of Laurentia. The largest deposits, Dry Creek and WTF, have a combined resource of 5.7 million tonnes at 10% Zn, 4% Pb, 0.3% Cu, 300 grams per tonne (g/t) Ag, and 1.6 g/t Au. These polymetallic deposits are hosted in high field strength element (HFSE)- and rare-earth element (REE)-rich peralkaline (pantelleritic) metarhyolite, and interlayered pyritic argillite and mudstone of the Mystic Creek Member of the Totatlanika Schist Formation. Mystic Creek metarhyolite and alkali basalt (Chute Creek Member) constitute a bimodal pair that formed in an extensional environment. A synvolcanic peralkaline quartz porphyry containing veins of fluorite, sphalerite, pyrite, and quartz intrudes the central footwall at Dry Creek. The Anderson Mountain deposit, located ~32 km to the southwest, occurs within calc-alkaline felsic to intermediate-composition metavolcanic rocks and associated graphitic argillite of the Wood River assemblage. Felsic metavolcanic rocks there have only slightly elevated HFSEs and REEs. The association of abundant graphitic and siliceous argillite with the felsic volcanic rocks together with low Cu contents in the Bonnifield deposits suggests classification as a siliciclastic-felsic type of VMS deposit. Bonnifield massive sulfides and host rocks were metamorphosed and deformed under greenschist-facies conditions in the Mesozoic. Primary depositional textures, generally uncommon, consist of framboids, framboidal aggregates, and spongy masses of pyrite. Sphalerite, the predominant base metal sulfide, encloses early pyrite framboids. Galena and chalcopyrite accompanied early pyrite formation but primarily formed late in the paragenetic sequence. Silver-rich tetrahedrite is a minor late phase at the Dry Creek deposit. Gold and Ag are present in low to moderate amounts in pyrite from all of

  14. Atomic Layer Deposition of Ultrathin Nickel Sulfide Films and Preliminary Assessment of Their Performance as Hydrogen Evolution Catalysts.

    Science.gov (United States)

    Çimen, Yasemin; Peters, Aaron W; Avila, Jason R; Hoffeditz, William L; Goswami, Subhadip; Farha, Omar K; Hupp, Joseph T

    2016-11-22

    Transition metal sulfides show great promise for applications ranging from catalysis to electrocatalysis to photovoltaics due to their high stability and conductivity. Nickel sulfide, particularly known for its ability to electrochemically reduce protons to hydrogen gas nearly as efficiently as expensive noble metals, can be challenging to produce with certain surface site compositions or morphologies, e.g., conformal thin films. To this end, we employed atomic layer deposition (ALD), a preeminent method to fabricate uniform and conformal films, to construct thin films of nickel sulfide (NiSx) using bis(N,N'-di-tert-butylacetamidinato)nickel(II) (Ni(amd)2) vapor and hydrogen sulfide gas. Effects of experimental conditions such as pulse and purge times and temperature on the growth of NiSx were investigated. These revealed a wide temperature range, 125-225 °C, over which self-limiting NiSx growth can be observed. In situ quartz crystal microbalance (QCM) studies revealed conventional linear growth behavior for NiSx films, with a growth rate of 9.3 ng/cm2 per cycle being obtained. The ALD-synthesized films were characterized using X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) methods. To assess the electrocatalyitic activity of NiSx for evolution of molecular hydrogen, films were grown on conductive-glass supports. Overpotentials at a current density of 10 mA/cm2 were recorded in both acidic and pH 7 phosphate buffer aqueous reaction media and found to be 440 and 576 mV, respectively, with very low NiSx loading. These results hint at the promise of ALD-grown NiSx materials as water-compatible electrocatalysts.

  15. Hydrothermal dolomitization of basinal deposits controlled by a synsedimentary fault system in Triassic extensional setting, Hungary

    Science.gov (United States)

    Hips, Kinga; Haas, János; Győri, Orsolya

    2016-06-01

    Dolomitization of relatively thick carbonate successions occurs via an effective fluid circulation mechanism, since the replacement process requires a large amount of Mg-rich fluid interacting with the CaCO3 precursor. In the western end of the Neotethys, fault-controlled extensional basins developed during the Late Triassic spreading stage. In the Buda Hills and Danube-East blocks, distinct parts of silica and organic matter-rich slope and basinal deposits are dolomitized. Petrographic, geochemical, and fluid inclusion data distinguished two dolomite types: (1) finely to medium crystalline and (2) medium to coarsely crystalline. They commonly co-occur and show a gradual transition. Both exhibit breccia fabric under microscope. Dolomite texture reveals that the breccia fabric is not inherited from the precursor carbonates but was formed during the dolomitization process and under the influence of repeated seismic shocks. Dolomitization within the slope and basinal succession as well as within the breccia zones of the underlying basement block is interpreted as being related to fluid originated from the detachment zone and channelled along synsedimentary normal faults. The proposed conceptual model of dolomitization suggests that pervasive dolomitization occurred not only within and near the fault zones. Permeable beds have channelled the fluid towards the basin centre where the fluid was capable of partial dolomitization. The fluid inclusion data, compared with vitrinite reflectance and maturation data of organic matter, suggest that the ascending fluid was likely hydrothermal which cooled down via mixing with marine-derived pore fluid. Thermal gradient is considered as a potential driving force for fluid flow.

  16. Effects and quantification of acid runoff from sulfide-bearing rock deposited during construction of Highway E18, Norway

    Science.gov (United States)

    Hindar, Atle; Nordstrom, D. Kirk

    2015-01-01

    The Highway E18 between the cities of Grimstad and Kristiansand, southern Norway, constructed in the period 2006–2009, cuts through sulfide-bearing rock. The geology of this area is dominated by slowly-weathering gneiss and granites, and oxidation of fresh rock surfaces can result in acidification of surface water. Sulfide-containing rock waste from excavations during construction work was therefore deposited in three waste rock deposits off-site. The deposits consist of 630,000–2,360,000 metric tons of waste rock material. Shell sand and limestone gravel were added in layers in adequate amounts to mitigate initial acid runoff in one of the deposits. The shell sand addition was not adequate in the two others. The pH in the effluents from these two was reduced from 4.9–6.5 to 4.0–4.6, and Al concentrations increased from below 0.4 mg/L to 10–20 mg/L. Stream concentrations of trace metals increased by a factor of 25–400, highest for Ni, and then in decreasing order for Co, Mn, Cd, Zn and Cu. Concentrations of As, Cr and Fe remained unchanged. Ratios of Co/Ni and Cd/Zn indicate that the metal sources for these pair of metals are sphalerite and pyrite, respectively. Based on surveys and established critical limits for Al, surface waters downstream became toxic to fish and invertebrates. The sulfur release rates were remarkably stable in the monitoring period at all three sites. Annual sulfur release was 0.1–0.4% of the total amount of sulfur in the deposit, indicating release periods of 250–800 years. Precipitates of Al-hydroxysulfates, well-known from mining sites, were found at the base of the deposits, in streams and also along the ocean shore-line. The effects of added neutralization agents in the deposits and in treatment areas downstream gradually decreased, as indicated by reduced stream pH over time. Active measures are needed to avoid harmful ecological effects in the future.

  17. Tracing sources of crustal contamination using multiple S and Fe isotopes in the Hart komatiite-associated Ni-Cu-PGE sulfide deposit, Abitibi greenstone belt, Ontario, Canada

    Science.gov (United States)

    Hiebert, R. S.; Bekker, A.; Houlé, M. G.; Wing, B. A.; Rouxel, O. J.

    2016-10-01

    Assimilation by mafic to ultramafic magmas of sulfur-bearing country rocks is considered an important contributing factor to reach sulfide saturation and form magmatic Ni-Cu-platinum group element (PGE) sulfide deposits. Sulfur-bearing sedimentary rocks in the Archean are generally characterized by mass-independent fractionation of sulfur isotopes that is a result of atmospheric photochemical reactions, which produces isotopically distinct pools of sulfur. Likewise, low-temperature processing of iron, through biological and abiotic redox cycling, produces a range of Fe isotope values in Archean sedimentary rocks that is distinct from the range of the mantle and magmatic Fe isotope values. Both of these signals can be used to identify potential country rock assimilants and their contribution to magmatic sulfide deposits. We use multiple S and Fe isotopes to characterize the composition of the potential iron and sulfur sources for the sulfide liquids that formed the Hart deposit in the Shaw Dome area within the Abitibi greenstone belt in Ontario (Canada). The Hart deposit is composed of two zones with komatiite-associated Ni-Cu-PGE mineralization; the main zone consists of a massive sulfide deposit at the base of the basal flow in the komatiite sequence, whereas the eastern extension consists of a semi-massive sulfide zone located 12 to 25 m above the base of the second flow in the komatiite sequence. Low δ56Fe values and non-zero δ34S and Δ33S values of the komatiitic rocks and associated mineralization at the Hart deposit is best explained by mixing and isotope exchange with crustal materials, such as exhalite and graphitic argillite, rather than intrinsic fractionation within the komatiite. This approach allows tracing the extent of crustal contamination away from the deposit and the degree of mixing between the sulfide and komatiite melts. The exhalite and graphitic argillite were the dominant contaminants for the main zone of mineralization and the eastern

  18. Hydrothermal fluids circulation and travertine deposition in an active tectonic setting: Insights from the Kamara geothermal area (western Anatolia, Turkey)

    Science.gov (United States)

    Brogi, Andrea; Alçiçek, M. Cihat; Yalçıner, Cahit Çağlar; Capezzuoli, Enrico; Liotta, Domenico; Meccheri, Marco; Rimondi, Valentina; Ruggieri, Giovanni; Gandin, Anna; Boschi, Chiara; Büyüksaraç, Aydin; Alçiçek, Hülya; Bülbül, Ali; Baykara, Mehmet Oruç; Shen, Chuan-Chou

    2016-06-01

    Coexistence of thermal springs, travertine deposits and tectonic activity is a recurring feature for most geothermal areas. Although such a certainty, their relationships are debated mainly addressing on the role of the tectonic activity in triggering and controlling fluids flow and travertine deposition. In this paper, we present the results of an integrated study carried out in a geothermal area located in western Anatolia (Turkey), nearby the well-known Pamukkale area (Denizli Basin). Our study focused on the relationships among hydrothermal fluids circulation, travertine deposition and tectonic activity, with particular emphasis on the role of faults in controlling fluids upwelling, thermal springs location and deposition of travertine masses. New field mapping and structural/kinematics analyses allowed us to recognize two main faults systems (NW- and NE-trending), framed in the Neogene-Quaternary extensional tectonic evolution of western Anatolia. A geo-radar (GPR) prospection was also provided in a key-area, permitting us to reconstruct a buried fault zone and its relationships with the development of a fissure-ridge travertine deposit (Kamara fissure-ridge). The integration among structural and geophysical studies, fluids inclusion, geochemical, isotopic data and 230 Th/238 U radiometric age determination on travertine deposits, depict the characteristics of the geothermal fluids and their pathway, up to the surface. Hydrological and seismological data have been also taken in account to investigate the relation between local seismicity and fluid upwelling. As a main conclusion we found strict relationships among tectonic activity, earthquakes occurrence, and variation of the physical/chemical features of the hydrothermal fluids, presently exploited at depth, or flowing out in thermal springs. In the same way, we underline the tectonic role in controlling the travertine deposition, making travertine (mainly banded travertine) a useful proxy to reconstruct the

  19. Volcanogenic massive sulfide deposits of the world: Database and grade and tonnage models

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Information on VMS deposits from around the world. It also presents new grade and tonnage models for three subtypes of VMS deposits and a text file allowing...

  20. Cd isotope fractionation during sulfide mineral weathering in the Fule Zn-Pb-Cd deposit, Yunnan Province, Southwest China.

    Science.gov (United States)

    Zhu, Chuanwei; Wen, Hanjie; Zhang, Yuxu; Yin, Runsheng; Cloquet, Christophe

    2017-11-03

    Zinc (Zn)-Lead (Pb) deposits are generally rich in cadmium (Cd), and the weathering of sulfide minerals in such deposits results in large releases of Cd into the environment. From an environmental and public health standpoint, understanding Cd sources and cycling is critical to identifying potential hazards to humans. In this study, the Cd isotope compositions (expressed as δ114/110Cd) of secondary minerals such as anglesite (-0.57±0.03‰; 2S.D.), granular smithsonite (0.04±0.14‰; 2S.D.), layered smithsonite (0.15±0.40‰; 2S.D.), hydrozincite (0.26±0.01‰; 2S.D.) and clay minerals (-0.01±0.06‰; 2S.D.) from the Fule Zn-Pb-Cd deposit, Southwest China, are investigated to better understand the Cd sources and cycling in this area. Combined with our previous study (Zhu et al., 2017), the work herein elucidates the patterns of Cd isotopic fractionation during the formation processes of such secondary minerals and traces the weathering of these minerals into the ecosystem. The δ114/110Cd values of secondary minerals exhibit the following decreasing trend: hydrozincite>large granular smithsonite>small granular smithsonite>anglesite. Although different amounts of Cd were lost during the formation of equally sized samples, no or minor variations in Cd isotopic composition were observed. However, significant isotopic differences were observed between different size fractions. These results demonstrate that the particle size of secondary minerals and weathering products of sulfide significantly influence Cd isotope composition and fractionation during natural weathering. This systematic fractionation provides an initial foundation for the use of Cd isotopes as environmental tracers in ecosystems and in the global Cd isotope budget. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. The Sanfengshan copper deposit and early Carboniferous volcanogenic massive sulfide mineralization in the Beishan orogenic belt, Northwestern China

    Science.gov (United States)

    Wang, Jialin; Gu, Xuexiang; Zhang, Yongmei; Zhou, Chao; He, Ge; Liu, Ruiping

    2018-03-01

    The Sanfengshan copper deposit, located in the Beishan orogenic belt, Northwestern China, is hosted in the lower member of the Hongliuyuan Formation, an early Carboniferous metavolcanic-sedimentary sequence. Mineralization occurs as stratiform, stratiform-like and lenticular orebodies, and comprises of laminated, brecciated, banded, massive, and disseminated ores. The mineralogy is dominated by pyrite, chalcopyrite and sphalerite. Fe-Mn chert is widely distributed and generally occurs as massive, laminated, bands or lenses, which are consistent with the orebody. Alteration at Sanfengshan displays a clear concentric zoning pattern and the footwall alteration is more intense and somewhat thicker than the hanging-wall alteration. Systematic geochemical investigation on the volcanic rocks in this area shows that the basalts of the Hongliuyuan Formation (HLY) are predominantly tholeiites with nearly flat rare earth element (REE) pattern, insignificant negative anomalies of high field strength elements (HFSEs), and low Ti/V and Th/Nb ratios. They were most likely derived from partial melting of depleted asthenospheric mantle and formed in a fore-arc setting during initiation of the southward subduction of the Paleo-Asian Ocean. The basalts of the Maotoushan Formation (MTS) display a calc-alkaline nature and are enriched in large ion lithophile elements (LILEs) and depleted in HFSEs, suggesting an active continental margin setting. Sulfur isotope (δ34S) values of the sulfide and sulfate minerals vary between 0‰ and 5.4‰, which are consistent with sulfur derivation from leaching of the host volcanic rocks, although a direct magmatic contribution cannot be ruled out. The Re-Os isotope data of pyrite yield an isochron age of 353 ± 35 Ma, consistent with the age of the host HLY basalts. Thus, a syngenetic (volcanogenic massive sulfide) model is proposed and it is concluded that the Sanfengshan copper deposit is a typical Cyprus-type VMS deposit that formed in an early

  2. Characterization of a Subsurface Biosphere in a Massive Sulfide Deposit At Rio Tinto, Spain: Implications For Extant Life On Mars

    Science.gov (United States)

    Stoker, C. R.; Stevens, T.; Amils, R.; Gomez-Elvira, J.; Rodriguez, N.; Gomez, F.; Gonzalez-Toril, E.; Aguilera, A.; Fernandez-Remolar, D.; Dunagan, S.

    2005-01-01

    The recent discovery of abundant sulfate minerals, particularly Jarosite by the Opportunity Rover at Sinus Merdiani on Mars has been interpreted as evidence for an acidic lake or sea on ancient Mars [1,2], since the mineral Jarosite is soluble in liquid water at pH above 4. The most likely mechanism to produce sufficient protons to acidify a large body of liquid water is near surface oxidation of pyrite rich deposits [3]. The acidic waters of the Rio Tinto, and the associated deposits of Hematite, Goethite, and Jarosite have been recognized as an important chemical analog to the Sinus Merdiani site on Mars [4]. The Rio Tinto is a river in southern Spain that flows 100 km from its source in the Iberian pyrite belt, one of the Earth's largest Volcanically Hosted Massive Sulfide (VHMS) provinces, into the Atlantic ocean. The river originates in artesian springs emanating from ground water that is acidified by the interaction with subsurface pyrite ore deposits. The Mars Analog Rio Tinto Experiment (MARTE) has been investigating the hypothesis that a subsurface biosphere exists at Rio Tinto living within the VHMS deposit living on chemical energy derived from sulfur and iron minerals. Reduced iron and sulfur might provide electron donors for microbial metabolism while in situ oxidized iron or oxidants entrained in recharge water might provide electron acceptors.

  3. Characterization of a Subsurface Biosphere in a Massive Sulfide Deposits at Rio Tinto, Spain: Implications for Extant Life on Mars

    Science.gov (United States)

    Stoker, C. R.; Stevens, T.; Amils, R.; Gomez-Elvira, J.; Rodriquez, N.; Gomez, F.; Gonzalez-Toril, E.; Aguilera, A.; Fernandez-Remolar, D.; Dunagan, S.

    2005-01-01

    The recent discovery of abundant sulfate minerals, particularly Jarosite by the Opportunity Rover at Sinus Merdiani on Mars has been interpreted as evidence for an acidic lake or sea on ancient Mars [1,2], since the mineral Jarosite is soluble in liquid water at pH above 4. The most likely mechanism to produce sufficient protons to acidify a large body of liquid water is near surface oxidation of pyrite rich deposits [3]. The acidic waters of the Rio Tinto, and the associated deposits of Hematite, Goethite, and Jarosite have been recognized as an important chemical analog to the Sinus Merdiani site on Mars [4]. The Rio Tinto is a river in southern Spain that flows 100 km from its source in the Iberian pyrite belt, one of the Earth s largest Volcanically Hosted Massive Sulfide (VHMS) provinces, into the Atlantic ocean. The river originates in artesian springs emanating from ground water that is acidified by the interaction with subsurface pyrite ore deposits. The Mars Analog Rio Tinto Experiment (MARTE) has been investigating the hypothesis that a subsurface biosphere exists at Rio Tinto living within the VHMS deposit living on chemical energy derived from sulfur and iron minerals. Reduced iron and sulfur might provide electron donors for microbial metabolism while in situ oxidized iron or oxidants entrained in recharge water might provide electron acceptors.

  4. Multiple sulphur and lead sources recorded in hydrothermal exhalites associated with the Lemarchant volcanogenic massive sulphide deposit, central Newfoundland, Canada

    Science.gov (United States)

    Lode, Stefanie; Piercey, Stephen J.; Layne, Graham D.; Piercey, Glenn; Cloutier, Jonathan

    2017-01-01

    Metalliferous sedimentary rocks (mudstones, exhalites) associated with the Cambrian precious metal-bearing Lemarchant Zn-Pb-Cu-Au-Ag-Ba volcanogenic massive sulphide (VMS) deposit, Tally Pond volcanic belt, precipitated both before and after VMS mineralization. Sulphur and Pb isotopic studies of sulphides within the Lemarchant exhalites provide insight into the sources of S and Pb in the exhalites as a function of paragenesis and evolution of the deposit and subsequent post-depositional modification. In situ S isotope microanalyses of polymetallic sulphides (euhedral and framboidal pyrite, anhedral chalcopyrite, pyrrhotite, galena and euhedral arsenopyrite) by secondary ion mass spectrometry (SIMS) yielded δ34S values ranging from -38.8 to +14.4 ‰, with an average of ˜ -12.8 ‰. The δ34S systematics indicate sulphur was predominantly biogenically derived via microbial/biogenic sulphate reduction of seawater sulphate, microbial sulphide oxidation and microbial disproportionation of intermediate S compounds. These biogenic processes are coupled and occur within layers of microbial mats consisting of different bacterial/archaeal species, i.e., sulphate reducers, sulphide oxidizers and those that disproportionate sulphur compounds. Inorganic processes or sources (i.e., thermochemical sulphate reduction of seawater sulphate, leached or direct igneous sulphur) also contributed to the S budget in the hydrothermal exhalites and are more pronounced in exhalites that are immediately associated with massive sulphides. Galena Pb isotopic compositions by SIMS microanalysis suggest derivation of Pb from underlying crustal basement (felsic volcanic rocks of Sandy Brook Group), whereas less radiogenic Pb derived from juvenile sources leached from mafic volcanic rocks of the Sandy Brook Group and/or Tally Pond group. This requires that the hydrothermal fluids interacted with juvenile and evolved crust during hydrothermal circulation, which is consistent with the existing

  5. Sedimentary carbonate-hosted giant Bayan Obo REE-Fe-Nb ore deposit of Inner Mongolia, China; a cornerstone example for giant polymetallic ore deposits of hydrothermal origin

    Science.gov (United States)

    Chao, E.C.T.; Back, J.M.; Minkin, J.A.; Tatsumoto, M.; Junwen, Wang; Conrad, J.E.; McKee, E.H.; Zonglin, Hou; Qingrun, Meng; Shengguang, Huang

    1997-01-01

    Detailed, integrative field and laboratory studies of the textures, structures, chemical characteristics, and isotopically determined ages and signatures of mineralization of the Bayan Obo deposit provided evidence for the origin and characteristics favorable for its formation and parameters necessary for defining giant polymetallic deposits of hydrothermal origin. Bayan Obo is an epigenetic, metasomatic, hydrothermal rare earth element (REE)-Fe-Nb ore deposit that is hosted in the metasedimentary H8 dolostone marble of the Middle Proterozoic Bayan Obo Group. The metasedimentary sequence was deposited on the northern continental slope of the North China craton. The mine area is about 100 km south of the suture marking Caledonian subduction of the Mongolian oceanic plate from the north beneath the North China craton. The mineralogy of the deposit is very complex, consisting of more than 120 different minerals, some of which are epigenetic minerals introduced by hydrothermal solutions, and some of which are primary and secondary metamorphic minerals. The major REE minerals are monazite and bastnaesite, whereas magnetite and hematite are the dominant Fe-ore minerals, and columbite is the most abundant Nb mineral. Dolomite, alkali amphibole, fluorite, barite, aegirine augite, apatite, phlogopite, albite, and microcline are the most widespread gangue minerals. Three general types of ores occur at Bayan Obo: disseminated, banded, and massive ores. Broad zoning of these ore types occurs in the Main and East Orebodies. Disseminated ores are in the outermost zone, banded ores are in the intermediate zone, and massive ores are in the cores of the orebodies. On the basis of field relations, host rocks, textures, structures, and mineral assemblages, many varieties of these three types of ores have been recognized and mapped. Isotopic dating of monazite, bastnaesite, aeschynite, and metamorphic and metasomatic alkali amphiboles associated with the deposit provides constraints

  6. Hydrothermal alteration and permeability changes in granitic intrusions related to Sn-W deposits : case study of Panasqueira (Portugal)

    Science.gov (United States)

    Launay, Gaetan; Sizaret, Stanislas; Guillou-Frottier, Laurent; Gloaguen, Eric; Melleton, Jérémie; Pichavant, Michel; Champallier, Rémi; Pinto, Filipe

    2017-04-01

    The Panasqueira Sn-W deposit occurs as a dense network of flat wolframite and cassiterite-bearing quartz veins concentrated in the vicinity of a hidden greisen cupola, and to a lesser extent as disseminated cassiterites in the greisen. Previous studies (Thadeu 1951; 1979) have suggested that the Panasqueira deposit is genetically related to magmatic activity for which the most part is unexposed, and being only represented by the greisen cupola. Hydrothermal fluid circulation during the final stages of granite crystallisation has probably led to the greisenisation of the cupola followed by the deposition of the mineralization in the veins system. Mineral replacement reactions that occurred during the greisenisation could affect rock properties (porosity, density and permeability) which control fluid circulation in the granite. This study aims to investigate effects of greisenisation reactions on the dynamic (time varying) permeability that ultimately leads to fluid circulation in the greisen cupola. To do so, petrological study and experimental determinations of hydrodynamic features (porosity and permeability) for different granite alteration levels and petrographic types (unaltered granite to greisen) are combined and then integrated in coupled numerical models of fluid circulation around the granitic intrusion. Greisen occurs in the apical part of the granitic body and results in the pervasive alteration of the granite along the granite-schist contact. This greisen consists mainly of quartz and muscovite formed by the replacement of feldspars and bleaching of biotites of the initial granite. Otherwise, greisen is generally vuggy which suggests a porosity increase of the granite during hydrothermal alteration processes. This porosity increase has a positive effect on the permeability of the granitic system. Indeed, experimental measurements of permeability with the Paterson press indicate that the initial granite is impermeable (10-20 m2) whereas the greisen is

  7. On the origin of life in the Zinc world: 1. Photosynthesizing, porous edifices built of hydrothermally precipitated zinc sulfide as cradles of life on Earth

    Directory of Open Access Journals (Sweden)

    Mulkidjanian Armen Y

    2009-08-01

    Full Text Available Abstract Background The complexity of the problem of the origin of life has spawned a large number of possible evolutionary scenarios. Their number, however, can be dramatically reduced by the simultaneous consideration of various bioenergetic, physical, and geological constraints. Results This work puts forward an evolutionary scenario that satisfies the known constraints by proposing that life on Earth emerged, powered by UV-rich solar radiation, at photosynthetically active porous edifices made of precipitated zinc sulfide (ZnS similar to those found around modern deep-sea hydrothermal vents. Under the high pressure of the primeval, carbon dioxide-dominated atmosphere ZnS could precipitate at the surface of the first continents, within reach of solar light. It is suggested that the ZnS surfaces (1 used the solar radiation to drive carbon dioxide reduction, yielding the building blocks for the first biopolymers, (2 served as templates for the synthesis of longer biopolymers from simpler building blocks, and (3 prevented the first biopolymers from photo-dissociation, by absorbing from them the excess radiation. In addition, the UV light may have favoured the selective enrichment of photostable, RNA-like polymers. Falsification tests of this hypothesis are described in the accompanying article (A.Y. Mulkidjanian, M.Y. Galperin, Biology Direct 2009, 4:27. Conclusion The suggested "Zn world" scenario identifies the geological conditions under which photosynthesizing ZnS edifices of hydrothermal origin could emerge and persist on primordial Earth, includes a mechanism of the transient storage and utilization of solar light for the production of diverse organic compounds, and identifies the driving forces and selective factors that could have promoted the transition from the first simple, photostable polymers to more complex living organisms. Reviewers This paper was reviewed by Arcady Mushegian, Simon Silver (nominated by Arcady Mushegian, Antoine

  8. Pressure-temperature condition and hydrothermal-magmatic fluid evolution of the Cu-Mo Senj deposit, Central Alborz: fluid inclusion evidence

    Directory of Open Access Journals (Sweden)

    Ebrahim Tale Fazel

    2017-02-01

    Full Text Available Introduction The Senj deposit has significant potential for different types of mineralization, particularly porphyry-like Cu deposits, associated with subduction-related Eocene–Oligocene calc-alkaline porphyritic volcano-plutonic rocks. The study of fluid inclusions in hydrothermal ore deposits aims to identify and characterize the pressure, temperature, volume and fluid composition, (PTX conditions of fluids under which they were trapped (Heinrich et al., 1999; Ulrich and Heinrich, 2001; Redmond et al., 2004. Different characteristics of the deposit such as porphyrtic nature, alteration assemblage and the quartz-sulfide veins of the stockwork were poorly known. In this approach on the basis of alterations, vein cutting relationship and field distribution of fluid inclusions, the physical and chemical evolution of the hydrothermal system forming the porphyry Cu-Mo (±Au-Ag deposit in Senj is reconstructed. Materials and Methods Over 1000 m of drill core was logged at a scale of 1:1000 by Pichab Kavosh Co. and samples containing various vein and alteration types from different depths were collected for laboratory analyses. A total of 14 samples collected from the altered and least altered igneous rocks in the Senj deposit were analyzed for their major oxide concentrations by X-ray fluorescence in the SGS Mineral Services (Toronto, Canada. The detection limit for major oxide analysis is 0.01%. Trace and rare earth elements (REE were analyzed using inductively coupled plasma-mass spectrometery (ICP-MS, in the commercial laboratory of SGS Mineral Services. The analytical error for most elements is less than 2%. The detection limit for trace elements and REEs analysis is 0.01 to 0.1 ppm. Fluid inclusion microthermometry was conducted using a Linkam THMS600 heating–freezing stage (-190 °C to +600 °C mounted on a ZEISS Axioplan2 microscope in the fluid inclusion laboratory of the Iranian Mineral Processing Research Center (Karaj, Iran. Results

  9. Hydrothermal fluids, argon isotopes and mineralization ages of the Fankou Pb-Zn deposit in south China: Insights from sphalerite 40Ar/39Ar progressive crushing

    Science.gov (United States)

    Jiang, Ying-De; Qiu, Hua-Ning; Xu, Yi-Gang

    2012-05-01

    Hydrothermal fluid geochemistry and mineralization timing are two important factors in the genesis of a hydrothermal deposit. 40Ar/39Ar analyses of fluid inclusions not only provide time constraints for the mineralization but also help to clarify the K-Ca-Cl-Ar characteristics for the ore-forming fluids. In this study, six sphalerite samples collected from the Fankou lead-zinc sulfide deposit are investigated by 40Ar/39Ar in vacuo crushing. Gases liberated from the early and late crushing steps exhibit distinct Ar isotopic compositions and 40Ar/39Ar apparent ages. Argon released in the early steps has much higher 40Ar and 38ArCl and lower 37ArCa contents than those in the late steps. The significant excess Ar (40ArE) extracted in the early crushing steps shows a strong correlation with 38ArCl with very high 40ArE/38ArCl ratios. In contrast, those of the late steps mainly consist of atmospheric Ar and K-correlated radiogenic Ar with a constant 40ArR/39ArK ratio and the atmospheric initial 40Ar/36Ar ratio. As a result, all samples yield similar declining age spectra: the fore segments with anomalously old apparent ages decline quickly in the early crushing steps and the rear ones are flat with concordant apparent ages in the late crushing steps. The data points of the early steps define linear correlations in plots of 40ArNA/39ArK vs. 38ArCl/39ArK and 38ArCl/40ArNA vs. 39ArK/40ArNA (NA for non-atmospheric) and most yield ages of 240-230 Ma. On the other hand, the data of the late steps always construct well-defined isochrons in the plots of 36ArA/40ArNA vs. 39ArK/40ArNA with consistent ages of ˜300 Ma. We interpret that gases released in the early steps were from the secondary fluid inclusions (SFIs) due to their distribution characteristics along cracks leading to be easily extracted, and those released in the later steps represented the contribution of the primary fluid inclusions (PFIs). The initial 40Ar/36Ar ratios of SFIs, much higher than the modern

  10. Sulfide and silicate melt inclusions in the D. João de Castro Volcanic Seamount, a hydrothermally active area on the Terceira Rift, Azores

    Science.gov (United States)

    Marques, A. F. A.; Scott, S. D.; Madureira, P.; Rosa, C. J. P.; Lourenço, N.; Conceição, P.; TerRiftic Team

    2012-04-01

    phases that suggest exsolution from a higher temperature solid solution phase (Fe-Ni-Cu-S). Oxides rim some of the globules. Samples with no visible sulfide globules in the groundmass contain, apart from Fe-Ti oxides, coarse-grained Fe-oxides. Preliminary observations indicate that immiscible sulfide phases were present at different stages of magma evolution. This may have implications for metal mobility during pre- syn and post eruptive degassing (e.g., DJC and HIR), or even active hydrothermalism (DJC). Moreover, geochemical and textural similarities found between samples from the DJC volcanic high and HIR deep basin have implications for the understanding of the TR melting processes. [1] Lourenço, N et al, (1998) Mar.Geophys.Res. 20:141-56 [2] Vogt PR and Jung WY (2004) EPSL 218:77-90 Acknowledgments The authors thank Y. Liu, M. Gorton, C. Bray and G. Kretschmann (U of Toronto) for the technical and analytical support. EMAM (Estrutura de Missão para os Assuntos do Mar) the ROV Luso team and all the crew that participated in the cruises are gratefully acknowledged. A.F.A. Marques' research is funded by the PTDC/MAR/111306/2009 TerRiftic Project (funded by the FCT), and CREMINER/LA UI101-POSC (Co-financiado FEDER). Steve's Scott's research is funded by the Natural Sciences and Engineering Research Council of Canada (NSERC).

  11. Metal-rich Scales in the Reykjanes Geothermal System, SW Iceland: Sulfide Minerals in a Seawater-dominated Hydrothermal Environment

    Science.gov (United States)

    Hardardottir, Vigdis

    Downhole sampling of unboiled liquid at 1350 and 1500 m depth in the seawater-dominated Reykjanes high-temperature geothermal system in Iceland shows that metal concentrations measured at surface are minimum values due to mineral precipitation in the wells; by analogy of similar tectonic setting, host rocks and fluid composition, the metal concentrations measured in many black smoker vents at the seafloor are also minima. Fluids in the Reykjanes geothermal system react with mid-ocean ridge basalt at temperatures as high as 346°C and contain Fe 9-140 ppm, Cu 14-17 ppm, Zn 5-27 ppm, Pb 120-290 ppb, 1-6 ppb Au, and 28-107 ppb Ag. Fluids discharged at surface from the same wells have orders of magnitude lower metal concentrations due to precipitation caused by boiling and vapor loss during depressurization. Upstream of the orifice plate at high pressure (40 bar, 252°C) the precipitates consist mainly of sphalerite and chalcopyrite with a trace of galena and bornite. At the orifice plate of old wells, the pressure decreased sharply to 11 bar (188°C), resulting in abundant deposition of amorphous silica together with minor sphalerite and traces of chalcopyrite. In new wells the pressure at the orifice plate decreases to 22 bar (220°C); this pressure decrease and concomitant boiling causes deposition of fine-grained bornite-digenite solid solution together with sphalerite and galena on the fluid flow control valve. In high-pressure wells (average wellhead pressure 45-35 bar) most metals (mainly as sphalerite) are deposited downstream of the orifice plate, with up to 950 ppm Au and 2.5 wt.% Ag. Bulk concentrations in the scales vary between 15-60 wt.% upstream and downstream of the orifice plate and diminish from there. Iron increases up well from 8 to ˜20 wt.% and decreases downstream of the orifice plate from 6 to 2 wt.% at the separation station; Cu downhole is ˜3 wt.% but increases to 25 wt.% on the fluid flow control valve and then decreases; Pb downhole 100s

  12. The distribution of platinum group elements (PGE) and other chalcophile elements among sulfides from the Creighton Ni-Cu-PGE sulfide deposit, Sudbury, Canada, and the origin of palladium in pentlandite

    Science.gov (United States)

    Dare, Sarah A. S.; Barnes, Sarah-Jane; Prichard, Hazel M.

    2010-12-01

    Concentrations of platinum group elements (PGE), Ag, As, Au, Bi, Cd, Co, Mo, Pb, Re, Sb, Se, Sn, Te, and Zn, have been determined in base metal sulfide (BMS) minerals from the western branch (402 Trough orebodies) of the Creighton Ni-Cu-PGE sulfide deposit, Sudbury, Canada. The sulfide assemblage is dominated by pyrrhotite, with minor pentlandite, chalcopyrite, and pyrite, and they represent monosulfide solid solution (MSS) cumulates. The aim of this study was to establish the distribution of the PGE among the BMS and platinum group minerals (PGM) in order to understand better the petrogenesis of the deposit. Mass balance calculations show that the BMS host all of the Co and Se, a significant proportion (40-90%) of Os, Pd, Ru, Cd, Sn, and Zn, but very little (electrum (Au-Ag alloy), hessite (Ag2Te), michenerite (PdBiTe), and rhenium sulfides. The enrichment of Os, Ru, Ni, and Co in pyrrhotite, pentlandite, and pyrite and Ag, Au, Cd, Sn, Te, and Zn in chalcopyrite can be explained by fractional crystallization of MSS from a sulfide liquid followed by exsolution of the sulfides. The early crystallization of the PGE sulfarsenides from the sulfide melt depleted the MSS in Ir and Rh. The bulk of Pd in pentlandite cannot be explained by sulfide fractionation alone because Pd should have partitioned into the residual Cu-rich liquid and be in chalcopyrite or in PGM around chalcopyrite. The variation of Pd among different pentlandite textures provides evidence that Pd diffuses into pentlandite during its exsolution from MSS. The source of Pd was from the small quantity of Pd that partitioned originally into the MSS and a larger quantity of Pd in the nearby Cu-rich portion (intermediate solid solution and/or Pd-bearing PGM). The source of Pd became depleted during the diffusion process, thus later-forming pentlandite (rims of coarse-granular, veinlets, and exsolution flames) contains less Pd than early-forming pentlandite (cores of coarse-granular).

  13. The Nokomis Cu-Ni-PGE Deposit, Duluth Complex: A sulfide-bearing, crystal-laden magmatic slurry

    Science.gov (United States)

    Peterson, D. M.

    2009-12-01

    deposit. A fundamental aspect of the ever-developing ore deposit model is an understanding of the initial conditions of the magmatic system - its crystallinity, sulfur capacity, geochemistry, and geometry - and how the sulfur saturated SKI magma lived, worked, and died. Such understanding includes the realization that the magma was a crystal-liquid (silicate and sulfide liquids) slurry and the identification of magma channelways and sub-channels and their associated thermal anomalies. In addition, the SKI magmas locally melted the footwall granitoid rocks, and such melts have been incorporated into the sulfide-bearing troctolitic melts of the SKI. In the end, hard work (>16,000 outcrops mapped, ~20,000 geochemical analyses completed, and >155,000 meters of core drilled) and intellectual geologic thought has been used to identify one of the world’s largest resources of Cu-Ni-PGEs.

  14. Zinc Sulfide Buffer Layer for CIGS Solar Cells Prepared by Chemical Bath Deposition

    Directory of Open Access Journals (Sweden)

    Rui-Wei You

    2016-11-01

    Full Text Available In this study, ZnS thin films were successfully synthesized by chemical bath deposition (CBD with starting materials of NH2-NH2, SC(NH22, and ZnSO4‧7H2O. ZnS thin films were deposited with different time on glass substrates by CBD at 80oC and pH=9. Based on X-ray diffraction (XRD patterns, it is found that the ZnS thin films exhibit cubic polycrystalline phase. It was found that the optimum deposition time is 90 min for preparing ZnS thin film that is suitable as buffer layer for CuIn1-xGaxSe2 solar cells. The thin film deposited for 90 min has high transmittance up to 80% in the spectra range from 350 nm to 800 nm, and the optical band gap is about 3.59 eV.

  15. Sulfide mineral paragenesis at the Hugo Dummett porphyry Cu-Au deposit, Oyu Tolgoi, South Mongolia

    Science.gov (United States)

    Sanjaa, M.; Fujimaki, H.

    2008-12-01

    Mineralogical studies of ore minerals have been conducted for the Hugo Dummett porphyry copper deposit. The Hugo Dummett porphyry copper gold deposit is located in the South Gobi region, Mongolia and currently being explored. This deposit divided into the Cu-rich South Hugo Dummett and the Cu-Au-rich North Hugo Dummett deposits. The Hugo Dummett deposits contain 1.08% copper (1.16 billion tonnes in total) and 0.23 g/t gold. Copper-gold mineralizations at this deposit are centered on a high-grade copper (typically > 2.5%) and gold (0.5-2 g/t) zone of intense quartz stockwork veining. The high grade copper and gold zone is mainly within the Late Devonian quartz monzodiorite intrusions and augite basalt, also locally occurs in dacitic rocks. Intense quartz veining forms a lens up to 100 m wide hosted by augite basalt and partly by quartz monzodiorite. Although many explorations have been carried out, but only a few scientific works were done in the Oyu Tolgoi mining area. Therefore the nature of copper-gold mineralization and orgin of the deposit is not fully understood. North Hugo Dummett and South Hugo Dummett porphyry copper-gold deposits are characterized by three mineralized stages based on our study: (1) early stage (2) middle stage and (3) late stage. The main copper- gold mineralization occurs in the early and middle stages, which is related to the quartz monzodiorite and dacitic rocks. Pyrite, chalcopyrite and bornite were continuously crystallized from early to late stage. The early stage of pyrite, chalcopyrite, bornite, molybdenite and sphalerite were replaced by middle stage of minerals. The middle stage minerals are sphalerite, tennantite, tetrahedrite, chalcocite, covellite, eugenite, galena, electrum, and gold, those are dominantly occur in the quartz monzodiorite. Additional pyrite, bornite and chalcopyrite were also deposited during this stage. In the late stage, pyrite, chalcopyrite and bornite are dominantly occurs as veins, veinlets and fracture

  16. Detailed paragenesis and Li-mica compositions as recorders of the magmatic-hydrothermal evolution of the Maoping W-Sn deposit (Jiangxi, China)

    Science.gov (United States)

    Legros, Hélène; Marignac, Christian; Mercadier, Julien; Cuney, Michel; Richard, Antonin; Wang, Ru-Cheng; Charles, Nicolas; Lespinasse, Marc-Yves

    2016-11-01

    Li-micas have been used as indicators of the evolution of granites. However, hydrothermal Li-micas are less documented. World-class W-Sn deposits associated with Early Yanshanian granites (South Jiangxi, China) show magmatic and hydrothermal Li-micas which could help unravelling the magmatic-hydrothermal evolution of rare metal deposits. Six types of Li-micas have been identified in the vein system of the Maoping W-Sn deposit through detailed petrography and EPMA and LA-ICP-MS analyses, by chronological order: (i) late-magmatic Li-micas in feldspar veins, associated with late crystallization of a peraluminous melt; (ii) hydrothermal Fe-Li micas (Fe-Li mica veins and selvages); (iii) hydrothermal Fe-Li micas in W-Sn veins; (iv) Fe-Li micas in later banded quartz veins; (v) Li-muscovite in the final stages; and finally (vi) micas associated with alteration at each stage. Based on oscillatory variations and trends in major elements composition, the chemical variations in Li-micas from the successive stages and in hydrothermal micas that crystallized in the veins are interpreted to reflect mixing between at least three fluids of possible magmatic, meteoric and metamorphic origins. The crystallization of zircons and REE minerals, combined with variations of major and trace element concentrations in the Li-micas, notably an enrichment of rare metals (W-Sn-Ta-Nb) in the Li-micas, implies emplacement of a hidden peralkaline REE-rich magma during the crystallization of the banded quartz veins, a source which was different to the pre-existing peraluminous granites. The possible involvement of both peraluminous and peralkaline intrusives suggests the existence of polyphase magmatic-hydrothermal systems in the Maoping deposit, during the Yanshanian event (190-80 Ma).

  17. Multielement statistical evidence for uraniferous hydrothermal activity in sandstones overlying the Phoenix uranium deposit, Athabasca Basin, Canada

    Science.gov (United States)

    Chen, Shishi; Hattori, Keiko; Grunsky, Eric C.

    2017-07-01

    The Phoenix U deposit, with indicated resources of 70.2 M lb U3O8, occurs along the unconformity between the Proterozoic Athabasca Group sandstones and the crystalline basement rocks. Principal component analysis (PCA) is applied to the compositions of sandstones overlying the deposit. Among PCs, PC1 accounts for the largest variability of U and shows a positive association of U with rare earth elements (REEs) + Y + Cu + B + Na + Mg + Ni + Be. The evidence suggests that U was dispersed into sandstones together with these elements during the uraniferous hydrothermal activity. Uranium shows an inverse association with Zr, Hf, Th, Fe, and Ti. Since they are common in detrital heavy minerals, such heavy minerals are not the major host of U. The elements positively associated with U are high in concentrations above the deposit, forming a "chimney-like" or "hump-like" distribution in a vertical section. Their enrichment patterns are explained by the ascent of basement fluids through faults to sandstones and the circulation of basinal fluids around the deposit. The Pb isotope compositions of whole rocks are similar to expected values calculated from the concentrations of U, Th, and Pb except for sandstones close to the deposit. The data suggest that in situ decay of U and Th is responsible for the Pb isotope compositions of most sandstones and that highly radiogenic Pb dispersed from the deposit to the proximal sandstones long after the mineralization. This secondary dispersion is captured in PC8, which has low eigenvalue. The data suggests that the secondary dispersion has minor effect on the overall lithogeochemistry of sandstones.

  18. Fluid inclusion evidence for the physicochemical conditions of sulfide deposition in the Olympias carbonate-hosted Pb-Zn(Au, Ag) sulfide ore deposit, E. Chalkidiki peninsula, N. Greece

    Science.gov (United States)

    Kilias, S. P.; Kalogeropoulos, S. I.; Konnerup-Madsen, J.

    1996-07-01

    The Olympias Pb-Zn(Au, Ag) sulfide ore deposit, E. Chalkidiki, N. Greece, is hosted by marbles of the polymetamorphic Kerdilia Formation of Paleozoic or older age. The geologic environment of the ore also comprises biotite-hornblende gneisses and amphibolites intruded by Tertiary pegmatite-aplite dikes, lamprophyre dikes, the 30-Ma Stratoni granodiorite, and porphyritic stocks. Only limited parts of the deposit display shear folding and brecciation; most of it is undeformed. Microthermometry of fluid inclusions in gangue syn-ore quartz indicates three types of primary and pseudosecondary inclusions: (1) H2O-rich, 1 18 wt. % NaCl equivalent, inclusions, inclusions found only in undeformed ore. Type 2 inclusions are differentiated into two sub-types: (2a) relatively constant CO2 content in the narrow range of 8 15 mol % and homogenization to the liquid phase; (2b) variable CO2 content between 18 and 50 mol % and homogenization to the vapor phase. Type 1 and 2b inclusions are consistent with trapping of two fluids by unmixing of a high-temperature, saline, aqueous, CO2-bearing fluid of possible magmatic origin, probably trapped in type 2a inclusions. Fluid unmixing and concomitant ore mineralization took place at temperatures of 350±30 °C and fluctuating pressures of less than 500 bar, for both undeformed and deformed ores. The wide salinity range of type 1 inclusions probably represents a complex effect of salinity increase, due to fluid unmixing and volatile loss, and dilution, due to mixing with low-salinity meteoric waters. High solute enrichment of the residual liquid, due to extreme volatile loss during unmixing, may account for high salinity type 3 inclusions. The Olympias fluid inclusion salinity-temperature gradients bear similarities to analogous gradients related to Pb-Zn ores formed in “granite”-hosted, low- T distal skarn, skarn-free carbonate-replacement and epithermal environments.

  19. Fluid inclusion and sulfur isotope studies in probable modern analogue Kuroko-type ores from the JADE hydrothermal field (Central Okinawa Trough, Japan)

    OpenAIRE

    Volker Lüders; B. Pracejus; Halbach, P.

    2001-01-01

    Fluid inclusions and sulfur isotopic compositions were studied in sulfides and barites from the JADE active hydrothermal field in the Central Okinawa Trough. The mineral assemblages in the JADE field strongly resemble ancient Kuroko-type deposits. The formation of massive sulfide mineralization is related to alteration of felsic volcanic rocks by deep penetrating heated seawater. Fluid inclusions in sphalerite from stockwork mineralization show homogenization temperatures that range between 2...

  20. Synthesis of nanostructured and microstructured ZnO and Zn(OH)2 on activated carbon cloth by hydrothermal and microwave-assisted chemical bath deposition methods

    Science.gov (United States)

    Mosayebi, Elham; Azizian, Saeid; Hajian, Ali

    2015-05-01

    Nanostructured and microstructured ZnO and Zn(OH)2 loaded on activated carbon cloth were synthesized by microwave-assisted chemical bath deposition and hydrothermal methods. By hydrothermal method the deposited sample on carbon fiber is pure ZnO with dandelion-like nanostructures. By microwave-assisted chemical bath method the structure and composition of deposited sample depends on solution pH. At pH = 9.8 the deposited sample on carbon fiber is pure ZnO with flower-like microstructure; but at pH = 10.8 the sample is a mixture of ZnO and Zn(OH)2 with flower-like and rhombic microstructures, respectively. The mechanism of crystal grow by microwave-assisted chemical bath method was investigated by SEM method at both pH.

  1. Variation of Mo isotopes from molybdenite in high-temperature hydrothermal ore deposits

    Science.gov (United States)

    Mathur, Ryan; Brantley, S.; Anbar, A.; Munizaga, F.; Maksaev, V.; Newberry, R.; Vervoort, J.; Hart, G.

    2010-01-01

    Measurable molybdenum isotope fractionation in molybdenites from different ore deposits through time provides insights into ore genesis and a new technique to identify open-system behavior of Re-Os in molybdenites. Molybdenite samples from six porphyry copper deposits, one epithermal polymetallic vein deposit, four skarns, and three Fe-oxide Cu-Au deposits were analyzed. The δ97Mo‰ (where [InlineEquation not available: see fulltext.]) for all samples varied from 1.34 ± 0.09‰ to -0.26 ± 0.04‰. This is the largest molybdenum isotopic variation in molybdenite from high-temperature ore deposits recorded to date. δ97Mo‰ of molybdenite varies as a function of the deposit type and the rhenium and osmium concentrations of the samples. Isotope values for Mo also vary within the individual deposits. In general, molybdenites from porphyry copper deposits have the lightest values averaging 0.07 ± 0.23‰ (1 σ). Molybdenites from the other deposit types average 0.49 ± 0.26‰ (1 σ). The variations could be related to the fractionation of Mo into different mineral phases during the ore-forming processes. A comparison of the Mo isotope ratios and the Re-Os ages obtained from the same aliquot may possess a geochronological evaluation tool. Samples that yielded robust ages have different Mo isotopic compositions in comparison to samples that yielded geologically unreasonable ages. Another observed relationship between the Re-Os and Mo isotope data reveals a weak correspondence between Re concentration and Mo isotope composition. Molybdenites with higher concentrations of Re correspond to lighter Mo isotope values.

  2. Paleomagnetism of the Red Dog Zn-Pb massive sulfide deposit in northern Alaska

    Science.gov (United States)

    Lewchuk, Michael T.; Leach, D.L.; Kelley, K.D.; Symons, David T. A.

    2004-01-01

    Paleomagnetic methods have isolated two ancient magnetizations in and around the Paleozoic shale-hosted Red Dog ore deposit in northern Alaska. A high-latitude, westerly magnetization carried by magnetite, termed characteristic remanent magnetization A, was found in rocks that have barite and/or substantial quartz replacement of barite. An intermediate- to low-latitude, southerly magnetization (characteristic remanent magnetization B) is carried by pyrrhotite and was found in rocks dominated by galena and sphalerite. The ages the two components are constrained by their relationship with geochemistry, radiometric age dating, and hypotheses for the Mesozoic tectonic history of the Brooks Range. Characteristic remanent magnetization A fails the fold test so it must postdate the end of Brookian orogenesis (??? 150 Ma). It is always found with replacement quartz that has a radiometric date (white mica from a vug, 39Ar/40Ar) of 126 Ma. The paleolatitude for characteristic remanent magnetization B is too shallow to be Mesozoic or younger, regardless of the model for the tectonic origin of northern Alaska, and must predate Brookian orogenesis. Geologic mapping suggests that most of the ore is syngenetic, formed at 330 to 340 Ma, and a radiometric date (Re-Os on pyrite) yields an age of 338 Ma. Since characteristic remanent magnetization B predates deformation, is found in mineralized rocks and is carried by pyrrhotite, it was probably acquired during the mineralizing process as well. The combined radiometric ages and paleomagnetic data sets can be best interpreted by assuming that northern Alaska was part of an accreted terrane that was translated northward by about 30?? into its current location relative to the rest of North America and then rotated counterclockwise by 50?? to 70??. This tectonic interpretation yields plausible magnetization ages for both characteristic remanent magnetization A and B. Geologic evidence, isotopic ages, and paleomagnetic data indicate

  3. Finding Massive Sulfides at Mid-Ocean Ridges

    Science.gov (United States)

    Barckhausen, Udo; Dressel, Ingo; Ehrhardt, Axel; Heyde, Ingo; Schwarz-Schampera, Ulrich; Schreckenberger, Bernd; Schwalenberg, Katrin

    2017-04-01

    The formation of Polymetallic Massive Sulfides is connected to hydrothermal activity concentrated in small areas close to mid-ocean ridges. Other geological settings of hydrothermal activity exist of course (like backarcs), but these are typically not located in The Area and therefore not under the regime of the International Seabed Authority (ISA). The ISA grants license areas for mineral exploration of up to 100 blocks of 10 km x 10 km size. The areas in which Polymetallic Massive Sulfides are exposed on the seafloor are tiny compared to the size of the license areas (typically in the order of 100-200m in diameter), and until recently were in most cases detected only be chance. For localizing and investigating Polymetallic Massive Sulfide deposits, geophysical methods are used at a wide range of scales. Ship-mounted overview surveys include multibeam bathymetry, magnetic and gravity measurements and are supplemented with high density sea surface investigations, and deep tow surveys close to the seafloor. Once a Massive Sulfide deposit has been surmised, ROV based video observations and measurements directly at the seafloor are used to confirm the deposit. It turns out that hydrothermal vent sites ("Black Smokers") near mid-ocean ridges are far more common than previously thought, however, due to their small size and location in rugged terrain in the deep sea they are not easy to find. Even though we have no full understanding yet of the geologic and tectonic settings in which long lasting hydrothermal systems can develop, the hydrothermal vent fields known so far seem to have some characteristics in common which can be used to define promising areas on the basis of the bathymetric overview maps. At a dense line spacing of 2.5 km, distinct magnetic anomalies can be observed in surface towed data which are connected to known hydrothermal vent fields. This means that similar magnetic anomalies observed in other places are potential sites of recent or former

  4. Relevance of Pitted Material and Impact Melt to Early Martian Hydrothermalism and Habitability; Ries Ejecta Deposits as a Martian Analogue

    Science.gov (United States)

    Caudill, C. M.; Greenberger, R. N.; Tornabene, L. L.; Osinski, G. R.; Flemming, R. L.; Ehlmann, B. L.

    2017-10-01

    Hydrothermal features are investigated at the Ries impact structure as potentially analogous to crater-related pitted material in Martian ancient terrains, which may reveal shallow sub-surface hydrothermal environments and prime exploration targets.

  5. Environmental geochemistry of shale-hosted Ag-Pb-Zn massive sulfide deposits in northwest Alaska: Natural background concentrations of metals in water from mineralized areas

    Science.gov (United States)

    Kelley, K.D.; Taylor, C.D.

    1997-01-01

    Red Dog, Lik and Drenchwater are shale-hosted stratiform Ag-Pb-Zn massive sulfide deposits in the northwestern Brooks Range. Natural background concentrations of metals in waters from the undisturbed (unmined) Drenchwater prospect and Lik deposit were compared to pre-mining baseline studies conducted at Red Dog. The primary factors affecting water chemistry are the extent of exposure of the deposits, the grade of mineralization, the presence of carbonate reeks in the section, and the proportion of Fe-sulfide in the ore. Surface water samples from the Drenchwater prospect, which has pyrite-dominant mineralization exposed in outcrop, have pH values as low as 2.8 and high dissolved concentrations of metals including as much as 95 mg 1-1 Al, 270 mg 1-1 Fe, 8 ??1-1 Cd, 10 ??1-1 Pb, and 2600 ??1-1 Zn, with As up to 26 ??g1-1. Surface waters from the Red Dog deposit prior to mining were also acidic and metal-rich, however, dissolved metal concentrations in Red Dog waters were many times greater. The higher metal concentrations in Red Dog waters reflect the high Zn grades and the abundant sphalerite, pyrite, and galena that were present in outcrop prior to mining. In contrast, despite significant mineralization at the Lik deposit, carbonate rocks in the section buffer the system, resulting in less acidic, mostly near-neutral pH values with low concentrations of most metals except Zn.

  6. Structural, optical and electrical properties of copper antimony sulfide thin films grown by a citrate-assisted single chemical bath deposition

    Science.gov (United States)

    Loranca-Ramos, F. E.; Diliegros-Godines, C. J.; Silva González, R.; Pal, Mou

    2018-01-01

    Copper antimony sulfide (CAS) has been proposed as low toxicity and earth abundant absorber materials for thin film photovoltaics due to their suitable optical band gap, high absorption coefficient and p-type electrical conductivity. The present work reports the formation of copper antimony sulfide by chemical bath deposition using sodium citrate as a complexing agent. We show that by tuning the annealing condition, one can obtain either chalcostibite or tetrahedrite phase. However, the main challenge was co-deposition of copper and antimony as ternary sulfides from a single chemical bath due to the distinct chemical behavior of these metals. The as-deposited films were subjected to several trials of thermal treatment using different temperatures and time to find the optimized annealing condition. The films were characterized by different techniques including Raman spectroscopy, X-ray diffraction (XRD), profilometer, scanning electron microscopy (SEM), UV-vis spectrophotometer, and Hall Effect measurements. The results show that the formation of chalcostibite and tetrahedrite phases is highly sensitive to annealing conditions. The electrical properties obtained for the chalcostibite films varied as the annealing temperature increases from 280 to 350 °C: hole concentration (n) = 1017-1018 cm-3, resistivity (ρ) = 1.74-2.14 Ωcm and carrier mobility (μ) = 4.7-9.26 cm2/Vseg. While for the tetrahedrite films, the electrical properties were n = 5 × 1019 cm-3, μ = 18.24 cm2/Vseg, and ρ = 5.8 × 10-3 Ωcm. A possible mechanism for the formation of ternary copper antimony sulfide has also been proposed.

  7. Mapping hydrothermal alteration using aircraft VNIR scanners at the Rosemont porphyry copper deposit. [Visible-Near Infrared

    Science.gov (United States)

    Sadowski, R. M.; Abrams, M. J.

    1983-01-01

    Two Visible-Near Infrared (VNIR) scanners, the NS-001 and the M2S, were flown over the Rosemont porphyry copper deposit as part of the NASA/JPL/GEOSAT test site program. This program was established to determine the feasibility and limitations of mapping hydrothermal alteration with multispectral scanners. Data from the NS-001 at 0.83 and 2.2 microns were used to identify Fe(3+) and OH enriched outcrops. These areas were then correlated with three alteration assemblages. The first correlation, hematite-epidote, was the most obvious and appeared as a strong ferric iron signature associated with hematite stained Cretaceous arkoses and andesites. The second correlation, qtz-sericite, showed a combined ferric-hydroxyl signature for a phyllicly altered quartz monzonite. The third correlation, skarn, was identified only after a review of calc-silicate mineral VNIR spectra. Altered limestones that outcrop west of the deposit have a similar ferric iron-hydroxyl signature as the quartz-sericite altered quartz monzonite. This skarn signature has been interpreted to indicate the presence of andradite, hydro-grossularite and idocrase. Data from the second scanner, M2S, was used to search for variation in ferric iron mineral type. Resulting imagery data indicated that hematite was the dominant ferric iron mineral present in the Rosemont area.

  8. Hydrothermal zebra dolomite in the Great Basin, Nevada--attributes and relation to Paleozoic stratigraphy, tectonics, and ore deposits

    Science.gov (United States)

    Diehl, S.F.; Hofstra, A.H.; Koenig, A.E.; Emsbo, P.; Christiansen, W.; Johnson, Chad

    2010-01-01

    In other parts of the world, previous workers have shown that sparry dolomite in carbonate rocks may be produced by the generation and movement of hot basinal brines in response to arid paleoclimates and tectonism, and that some of these brines served as the transport medium for metals fixed in Mississippi Valley-type (MVT) and sedimentary exhalative (Sedex) deposits of Zn, Pb, Ag, Au, or barite. Numerous occurrences of hydrothermal zebra dolomite (HZD), comprised of alternating layers of dark replacement and light void-filling sparry or saddle dolomite, are present in Paleozoic platform and slope carbonate rocks on the eastern side of the Great Basin physiographic province. Locally, it is associated with mineral deposits of barite, Ag-Pb-Zn, and Au. In this paper the spatial distribution of HZD occurrences, their stratigraphic position, morphological characteristics, textures and zoning, and chemical and stable isotopic compositions were determined to improve understanding of their age, origin, and relation to dolostone, ore deposits, and the tectonic evolution of the Great Basin. In northern and central Nevada, HZD is coeval and cogenetic with Late Devonian and Early Mississippian Sedex Au, Zn, and barite deposits and may be related to Late Ordovician Sedex barite deposits. In southern Nevada and southwest California, it is cogenetic with small MVT Ag-Pb-Zn deposits in rocks as young as Early Mississippian. Over Paleozoic time, the Great Basin was at equatorial paleolatitudes with episodes of arid paleoclimates. Several occurrences of HZD are crosscut by Mesozoic or Cenozoic intrusions, and some host younger pluton-related polymetallic replacement and Carlin-type gold deposits. The distribution of HZD in space (carbonate platform, margin, and slope) and stratigraphy (Late Neoproterozoic Ediacaran-Mississippian) roughly parallels that of dolostone and both are prevalent in Devonian strata. Stratabound HZD is best developed in Ediacaran and Cambrian units, whereas

  9. Tin-polymetallic sulfide deposits in the eastern part of the Dachang tin field (South China) and the role of black shales in their origin

    Science.gov (United States)

    Pašava, Jan; Kříbek, Bohdan; Dobeš, Petr; Vavřín, Ivan; Žák, Karel; Delian, Fan; Tao, Zhang; Boiron, Marie-Christine

    2003-01-01

    The Dafulou and Huile vein and stratabound cassiterite-sulfide deposits and sheeted ore veins at the Kangma cassiterite-sulfide deposit are located in the eastern part of the Dachang tin field. These deposits are hosted in a sedimentary sequence containing significant concentrations of organic matter in the form of Lower Devonian calcareous black shales and hornfels. These rocks together with the younger intrusion of Longxianggai granite (91±2 Ma) actively participated in the formation of Sn-polymetallic deposits. The following three major stages have been distinguished in stratiform and vein-type orebodies at Dafulou, Huile and Kangma: stage I (cassiterite, pyrrhotite, arsenopyrite, tourmaline, carbonate), stage II - main sulfide stage (quartz, cassiterite, arsenopyrite, pyrrhotite, sphalerite, stannite, pyrite, carbonates) and stage III (native Bi, galena, electrum, sulfosalts). Stage IV (post-ore), recognized at Huile is represented by barren carbonates and zeolites. Whole rock geochemistry has revealed that at Dafulou, Bi and Cu correlate strongly with S, whereas V and Pb correlate well with Corg (organic carbon). The similar distribution patterns of selected elements in average slightly mineralized low-Ca black shales indicate a fluid composition similar for all deposits studied. Studies of graphitization of the organic matter in black shales adjacent to orebodies indicate that d(002) and FWHM (full width in half maximum)/peak height values gradually decrease in the following sequence: Dafulou deposit → Kangma deposit → Huile deposit. The pyrolysate of wall rocks at the Dafulou deposit is relatively enriched in asphaltenes and maltenes (55.6-72.0% of the pyrolysate) comparable with pyrolysate obtained from more distal black shales (19.2-28.5%). Typical GC-MS spectra of pyrolysate from distal black shales are dominated by alkanes in the n-C15 to n-C25 range, aromatic molecules being represented mostly by alkyl-naphthalenes. In contrast, only traces of

  10. Magmatic-hydrothermal fluid evolution of the Dalli porphyry Cu-Au deposit; using Amphibole and Plagioclas mineral chemistry

    Directory of Open Access Journals (Sweden)

    Houshang Pourkaseb

    2017-07-01

    Full Text Available Introduction The formation of porphyry copper deposits is attributed to the shallow emplacement, and subsequent cooling of the hydrothermal system of porphyritic intrusive rocks (Titley and Bean, 1981. These deposits have usually been developed along the chain of subduction-related volcanic and calc-alkalin batholiths (Sillitoe, 2010. Nevertheless, it is now confirmed that porphyry copper systems can also form in collisional and post collisional settings (Zarasvandi et al., 2015b. Detailed studies on the geochemical features of ore-hosting porphyry Cu-Mo-Au intrusions indicate that they are generally adakitic, water and sulfur- riched, and oxidized (Wang et al., 2014. For example, high oxygen fugacity of magma has decisive role in transmission of copper and gold to the porphyry systems as revealed in (Wang et al., 2014. In this regard, the present work deals with the mineral chemistry of amphibole and plagioclase in the Dalli porphyry Cu-Au deposit. The data is used to achieve the physical and chemical conditions of magma and its impact on mineralization. Moreover, the results of previous studies on the hydrothermal system of the Dalli deposit such as Raman laser spectroscopy and fluid inclusion studies are included for determination of the evolution from magmatic to hydrothermal conditions. Materials and methods In order to correctly characterize the physical and chemical conditions affecting the trend of mineralization, 20 least altered and fractured samples of diorite and quartz-diorite intrusions were chosen from boreholes. Subsequently, 20 thin-polished sections were prepared in the Shahid Chamran University of Ahvaz. Finally, mineral chemistry of amphibole and plagioclase were determined using electron micro probe analyses (EMPA in the central lab of the Leoben University. Results Amphibole that is one of the the main rock-forming minerals can form in a wide variety of igneous and metamorphic rocks. Accordingly, amphibole chemistry can be

  11. Deposition of very thin uniform indium sulfide layers over metallic nano-rods by the Spray-Ion Layer Gas Reaction method

    Energy Technology Data Exchange (ETDEWEB)

    Genduso, G. [Dipartimento di Ingegneria Chimica, Gestionale, Informatica, Meccanica, Università di Palermo, Viale delle Scienze, 90100 Palermo (Italy); Institut for Heterogeneous Material Systems, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Inguanta, R.; Sunseri, C.; Piazza, S. [Dipartimento di Ingegneria Chimica, Gestionale, Informatica, Meccanica, Università di Palermo, Viale delle Scienze, 90100 Palermo (Italy); Kelch, C.; Sáez-Araoz, R. [Institut for Heterogeneous Material Systems, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Zykov, A. [Institut for Heterogeneous Material Systems, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); present address: Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15,12489 Berlin (Germany); Fischer, Ch.-H., E-mail: fischer@helmholtz-berlin.de [Institut for Heterogeneous Material Systems, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); second affiliation: Free University Berlin, Chemistry Institute, Takustr. 3, D-14195 Berlin (Germany)

    2013-12-02

    Very thin and uniform layers of indium sulfide were deposited on nickel nano-rods using the sequential and cyclical Spray-ILGAR® (Ion Layer Gas Reaction) technique. Substrates were fabricated by electrodeposition of Ni within the pores of polycarbonate membranes and subsequent chemical dissolution of the template. With respect to the depositions on flat substrates, experimental conditions were modified and optimized for the present geometry. Our results show that nano-rods up to a length of 10 μm were covered uniformly along their full length and with an almost constant film growth rate, thus allowing a good control of the coating thickness; the effect of the deposition temperature was also investigated. However, for high numbers of process steps, i.e. thickness, the films became uneven and crusty, especially at higher temperature, mainly owing to the simultaneous side reaction of the metallic Ni forming nickel sulfide at the surface of the rods. However, such a problem occurs only in the case of reactive nano-rod materials, such as less noble metals. It could be strongly reduced by doubling the spray step duration and thereby sealing the metallic surface before the process step of the sulfurization. Thus, quite smooth, about 100 nm thick coatings could be obtained. - Highlights: • Ni nano-rod substrates were grown within polycarbonate membranes. • We can coat nano-rods uniformly by the Ion Layer Gas Reaction method. • As a model we deposited up to about 100 nm In{sub 2}S{sub 3} on Ni nanorods (250 nm × 10 μm). • Element mapping at insulated rods showed homogenous coating over the full length. • Parameter optimization reduced effectively the Ni sulfide formation.

  12. Physicochemical conditions of deposition and origin of carbonate-hosted base metal sulfide mineralization, Thermes ore-field, Rhodope Massif, northeastern Greece

    Science.gov (United States)

    Kalogeropoulos, S. I.; Kilias, S. P.; Arvanitidis, N. D.

    1996-07-01

    Vein and stratabound base metal sulfide mineralization of the Thermes ore-field, Rhodope Massif, NE Greece, is hosted in marbles. The Thermes area is a structurally complex, E W-trending zone consisting of felsic gneisses alternating with amphibolites, amphibole-biotite, and biotite gneisses, and marbles. These rocks have undergone amphibolite facies metamorphism (5 7 kbar, 580 ° 620 °C), in Upper Cretaceous to Eocene times, and were subsequently retrograded to greenschist facies metamorphism of Miocene age. Granitoids of Oligocene age, and volcanic rocks of Eocene-Oligocene age, crosscut the metamorphic rocks. Two major base metal sulfide ore varieties occur in the Thermes ore-field. The first comprises brecciated vein Pb-Zn mineralization, related to NNW- and NNE-trending faults. The second comprises stratabound (manto) polymetallic, and Pb-Zn replacement ores with associated veins. On the basis of ore geochemistry, as well as field and textural evidence, these two ore varieties form part of a vein associated skarn-replacement base metal sulfide ore system. Based on fluid inclusion data in quartz, together with the iron content of sphalerites and existing lead and sulfur isotope data, it is suggested that after the cessation of the regional amphibolite facies metamorphism circulating evolved meteoric waters, probably with magmatic fluid contributions, deposited sulfide ores at temperatures of 200 ° 400 °C, and pressures of less than 300 bar. Ore was deposited as a result of increase in pH of the mineralizing fluids due to fluid-rock interaction, and adiabatic cooling and/or simple cooling accompanying fluid boiling. Thermochemical considerations indicate a pH increase from about 4 to 7 and a decrease in f S2 and f O2.

  13. Trace elements in magnetite from massive iron oxide-apatite deposits indicate a combined formation by igneous and magmatic-hydrothermal processes

    Science.gov (United States)

    Knipping, Jaayke L.; Bilenker, Laura D.; Simon, Adam C.; Reich, Martin; Barra, Fernando; Deditius, Artur P.; Wälle, Markus; Heinrich, Christoph A.; Holtz, François; Munizaga, Rodrigo

    2015-12-01

    Iron oxide-apatite (IOA) deposits are an important source of iron and other elements (e.g., REE, P, U, Ag and Co) vital to modern society. However, their formation, including the namesake Kiruna-type IOA deposit (Sweden), remains controversial. Working hypotheses include a purely magmatic origin involving separation of an Fe-, P-rich, volatile-rich oxide melt from a Si-rich silicate melt, and precipitation of magnetite from an aqueous ore fluid, which is either of magmatic-hydrothermal or non-magmatic surface or metamorphic origin. In this study, we focus on the geochemistry of magnetite from the Cretaceous Kiruna-type Los Colorados IOA deposit (∼350 Mt Fe) located in the northern Chilean Iron Belt. Los Colorados has experienced minimal hydrothermal alteration that commonly obscures primary features in IOA deposits. Laser ablation-inductively coupled plasma-mass spectroscopy (LA-ICP-MS) transects and electron probe micro-analyzer (EPMA) wavelength-dispersive X-ray (WDX) spectrometry mapping demonstrate distinct chemical zoning in magnetite grains, wherein cores are enriched in Ti, Al, Mn and Mg. The concentrations of these trace elements in magnetite cores are consistent with igneous magnetite crystallized from a silicate melt, whereas magnetite rims show a pronounced depletion in these elements, consistent with magnetite grown from an Fe-rich magmatic-hydrothermal aqueous fluid. Further, magnetite grains contain polycrystalline inclusions that re-homogenize at magmatic temperatures (>850 °C). Smaller inclusions (500 ppm) concentrations.

  14. Structural studies of TiO2/wood coatings prepared by hydrothermal deposition of rutile particles from TiCl4 aqueous solutions on spruce (Picea Abies) wood

    Science.gov (United States)

    Pori, Pavel; Vilčnik, Aljaž; Petrič, Marko; Sever Škapin, Andrijana; Mihelčič, Mohor; Šurca Vuk, Angela; Novak, Urban; Orel, Boris

    2016-05-01

    A low temperature approach was developed for the deposition of rutile TiO2 particles on a wood surface by hydrolysis of TiCl4 in aqueous solutions acidified with HCl, and crystallization at 75 and 90 °C (1 h). Prior to hydrothermal treatment, Picea Abies wood was first soaked in a 0.5 mmol/l aqueous solution containing anionic surfactant sodium dodecyl sulphate (SDS, Sigma Aldrich) for 2 h at 80 °C. The crystal structure of the hydrothermally made rutile particles was determined with XRD, while the morphology of the deposited TiO2 particles and their distribution in the wood were examined with SEM and EDX measurements. The penetration and amount of deposited rutile particles could be modified by changing the deposition conditions. Thicker layers were obtained from more concentrated aqueous TiCl4 solutions with and without added HCl, and with longer deposition times and higher temperatures of the hydrothermal treatment. The interaction of TiO2 particles with hemicellulose and lignin in wood was established from infrared attenuated total reflection (FT-IR ATR) and Raman spectra measurements, from which the spectra of wood were subtracted. Analysis of the subtraction spectra showed the presence of titania particles on the wood surface, revealing also the establishment of TiO2-wood coordinative bonds of titanium ions with hemicellulose and lignin. The red frequency shift of the OH stretching modes suggested interaction of the TiO2 particles with water molecules of wood. TiO2 deposited on wood treated with SDS became hydrophobic (water contact angles (WCA) of 150°), contrasting the properties of untreated wood with a deposited TiO2 particle coating, which remained hydrophilic.

  15. New data on the hydrothermal alterations in the Plavica deposit (Eastern Macedonia)

    OpenAIRE

    Spasovski, Orce; Mircovski, Vojo

    2008-01-01

    The data presented in the paper were obtained based on analyses carried out on samples collected from various depths along the entire length of drill-hole no. 4. The drill-hole was the last one made in the area of the Plavica deposit by the Rio Tinto Company. The samples analyzed point out the presence of subvolcanic to volcanic rocks, presumably dacites and dacite- andesites, that can be distinguished based on the presence of primary quartz. An exception is sample no. 6 which, most p...

  16. The chemistry of hydrothermal magnetite: a review

    Science.gov (United States)

    Nadoll, Patrick; Angerer, Thomas; Mauk, Jeffrey L.; French, David; Walshe, John

    2014-01-01

    Magnetite (Fe3O4) is a well-recognized petrogenetic indicator and is a common accessory mineral in many ore deposits and their host rocks. Recent years have seen an increased interest in the use of hydrothermal magnetite for provenance studies and as a pathfinder for mineral exploration. A number of studies have investigated how specific formation conditions are reflected in the composition of the respective magnetite. Two fundamental questions underlie these efforts — (i) How can the composition of igneous and, more importantly, hydrothermal magnetite be used to discriminate mineralized areas from barren host rocks, and (ii) how can this assist exploration geologists to target ore deposits at greater and greater distances from the main mineralization? Similar to igneous magnetite, the most important factors that govern compositional variations in hydrothermal magnetite are (A) temperature, (B) fluid composition — element availability, (C) oxygen and sulfur fugacity, (D) silicate and sulfide activity, (E) host rock buffering, (F) re-equilibration processes, and (G) intrinsic crystallographic controls such as ionic radius and charge balance. We discuss how specific formation conditions are reflected in the composition of magnetite and review studies that investigate the chemistry of hydrothermal and igneous magnetite from various mineral deposits and their host rocks. Furthermore, we discuss the redox-related alteration of magnetite (martitization and mushketovitization) and mineral inclusions in magnetite and their effect on chemical analyses. Our database includes published and previously unpublished magnetite minor and trace element data for magnetite from (1) banded iron formations (BIF) and related high-grade iron ore deposits in Western Australia, India, and Brazil, (2) Ag–Pb–Zn veins of the Coeur d'Alene district, United States, (3) porphyry Cu–(Au)–(Mo) deposits and associated (4) calcic and magnesian skarn deposits in the southwestern United

  17. Physico-chemistry and geochemistry of Balengou clay deposit (West Cameroon) with inference to an argillic hydrothermal alteration

    Science.gov (United States)

    Tassongwa, Bernard; Eba, François; Njoya, Dayirou; Tchakounté, Jacqueline Numbem; Jeudong, Narcisse; Nkoumbou, Charles; Njopwouo, Daniel

    2017-09-01

    Field description and sampling along two pits, granulometry, Atterberg limits, mineralogical (XRD, FTIR, DSC & TGA) and geochemical analyses of the Balengou clays help to determine their characteristics and the genesis of the deposit. The mineralogical composition is comprised of halloysite-kaolinite, quartz, montmorillonite, hematite, anatase, feldspar, zircon, chromite, and apatite. Gibbsite and illite occur at the shallow and deep depth, respectively. Dikes of sand-poor clays contain also cristobalite and tridymite. Pairs of elements Rb-Ba, Rb-Sr, Nb-Ta, Ta-Zr, TiO2-Zr display good positive correlations (R2 > 0.85). REE patterns are highly fractionated (LaN up to 3312, LaN/YbN: 19-10) and are marked by deep Ce and Eu negative anomalies. Immobile element canonical ratios indicate that the protoliths were commendite/pantelerite, rhyolite and dacite, or their plutonic equivalents. Mineralogical and geochemical features lead to the suggestion that the clays derived from an advanced argillic hydrothermal alteration.

  18. Caledonian formation of gold-bearing sulfide depositions in Early Proterozoic gabbroids in the northern Ladoga region

    Science.gov (United States)

    Baltybaev, Sh. K.; Ovchinnikova, G. V.; Glebovitskii, V. A.; Alekseev, I. A.; Vasil'eva, I. M.; Risvanova, N. G.

    2017-09-01

    We have studied Pb isotopic systems of K-feldspar, pyrite, and pyrrhotine from gabbroids and ore of the Velimyaki Early Proterozoic massif in the northern Ladoga region in the southeastern part of the Fennoscandian Shield. The isochronous Pb-Pb age of sulfides has been determined as ˜450 Ma, which corresponds to intersection of the regression line with the lead accumulation curve with μ = 10.4-10.8; the model Pb age of sulfides is close to isochronous under the condition that the composition of lead evolved from a geochemical reservoir with an age of 1.9 Ga. The isotopic parameters of the lead in sulfides and K-feldspar indicate their formation in upper crust conditions (μ = 238U/204Pb > 10). From the obtained data, it follows that the isotopic composition of lead in K-feldspar corresponds to a Proterozoic age (1890 Ma) of magmatic crystallization of the rocks in the massif, and strongly radiogenic lead sulfides testify, with the greatest probability, to the later (Caledonian) formation of sulfide ores.

  19. Cu-Ag Besshi type volcanogenic massive sulfide mineralization in the Late Cretaceous volcano- sedimentary sequence: the case of Garmabe Paein deposit, southeast of Shahrood

    Directory of Open Access Journals (Sweden)

    Majid Tashi

    2017-07-01

    Full Text Available Introduction Iran hosts numerous types of Volcanogenic massive sulfide (VMS deposits that occur within different tectonic assemblages and have formed at discrete time periods (Mousivand et al. 2008. The Sabzevar zone hosts several VMS deposits including the Nudeh Cu-Ag deposit (Maghfouri, 2012 and some deposits in the Kharturan area (Tashi et al., 2014, and the Kharturan area locates in the Sabzevar subzone of the Central East Iranian Microcontinent. The Sabzevar subzone mainly involves Mesozoic and Cenozoic rock unites. The Late Cretaceous ophiolite mellanges and volcano-sedimentary sequences have high extension in the Subzone. Based on Rossetti (Rossetti et al. 2010, the Cretaceous rock units were formed in a back-arc setting due to subduction of the Neo-Tethyan oceanic crust beneath the Iranian plate. The exposed rock units of the Kharturan area from bottom to top are dominated by Early Cretaceous, orbitolina-bearing massive limestone, dacitic-andesitic volcanics and related volcaniclastic rocks٫ chert and radiolarite and Late Cretaceous globotrunkana- bearing limestone, paleocene polygenic conglomerate consisting of the Cretaceous volcanics and limestone pebbles (equal to the Kerman conglomerate, and Pliocene weakly-cemented polygenic conglomerate horizon. The Garmabe Paein copper-silver deposit and the Asbkeshan deposit and a few occurrences, are located at 290 km southeast of Shahrood and they have occurred within the Upper Cretaceous volcano-sedimentary sequence in the Sabzevar subzone. The aim of this study is to discuss the genesis of the Garmabe Paein deposit based on geological, textural and structural, mineralogical and geochemical evidence. Materials and methods A field study and sampling was performed during the year 2013. During the field observations, 94 rock samples were collected from the study area, and 45 thin sections were prepared and studied using a polarizing microscope. Also, 5 samples for the XRD method, 21 samples for

  20. The nature of hydrothermal fluids in the Kahang porphyry copper deposit (Northeast of Isfahan) based on mineralography, fluid inclusion and stable isotopic data

    OpenAIRE

    Salimeh Sadat Komeili; Mahmoud Khalili; Hooshang Asadi Haroni; Hashem Bagheri; Farimah Ayati

    2017-01-01

    Introduction The Kahang Cu- Mo deposit is situated approximately 73 Km northeast of Isfahan. Asadi (2007) identified a geological reserve of 40 Mt (proven reserve) grading at 0.53 Cu, 0.02 Mo and estimated reserve of 120 Mt. All the rock types in the region have been subjected to hydrothermal solutions which gave rise to three different alteration facies. The dacite and rhyodacite volcanic rocks and granitic- granodioritic stocks have experienced phyllic alteration. Disseminated and stockw...

  1. Evaluation of protective effect of deposits formed by naphthenic corrosion and sulfidation on carbon steel and steel 5Cr-0.5Mo exposed in atmospheric distillation fractions

    Directory of Open Access Journals (Sweden)

    Gloria Duarte

    2017-05-01

    Full Text Available Refining of so-called opportunity crude oils with a high level of naphthenic acids and sulfur compounds has been increasing interest due to limited availability of light crude oils, however, considerable corrosive effects in the processing to high temperature on pipes and distillation towers mainly by the attack of naphthenic acids and sulfur compounds; sulfur compounds could be corrosive or can reduce the attack of naphthenic acids due to the formation of sulfides layers on the metal surface. In this work was evaluated the performance of deposits formed on the surface of carbon steel AISI SAE 1020 and 5% Cr-0.5% Mo steel exposed in crude oil fractions obtained from atmospheric distillation tower. For this, gravimetric tests were performed in dynamic autoclave using metal samples pre-treated in a crude oil fraction obtained from the atmospheric distillation tower of the Crude Distillation Unit (CDU # 1 in order to form layers of sulfides on the surface of the two materials and subsequently to expose pre-treated and non-pretreated samples in two different crude oil fractions obtained from atmospheric distillation tower of Crude Distillation Unit (CDU # 2. The evaluation showed that the samples pretreated decreased tendency to corrosion by naphthenic acids and sulfidation compared to untreated samples.

  2. Stable-isotope geochemistry of the Pierina high-sulfidation Au-Ag deposit, Peru: Influence of hydrodynamics on SO42--H2S sulfur isotopic exchange in magmatic-steam and steam-heated environments

    Science.gov (United States)

    Fifarek, R.H.; Rye, R.O.

    2005-01-01

    The Pierina high-sulfidation Au-Ag deposit formed 14.5 my ago in rhyolite ash flow tuffs that overlie porphyritic andesite and dacite lavas and are adjacent to a crosscutting and interfingering dacite flow dome complex. The distribution of alteration zones indicates that fluid flow in the lavas was largely confined to structures but was dispersed laterally in the tuffs because of a high primary and alteration-induced permeability. The lithologically controlled hydrodynamics created unusual fluid, temperature, and pH conditions that led to complete SO42--H2S isotopic equilibration during the formation of some magmatic-steam and steam-heated alunite, a phenomenon not previously recognized in similar deposits. Isotopic data for early magmatic hydrothermal and main-stage alunite (??34S=8.5??? to 31.7???; ??18 OSO4=4.9??? to 16.5???; ??18 OOH=2.2??? to 14.4???; ??D=-97??? to -39???), sulfides (??34 S=-3.0??? to 4.3???), sulfur (??34S=-1.0??? to 1.1???), and clay minerals (??18O=4.3??? to 12.5???; ??D=-126??? to -81???) are typical of high-sulfidation epithermal deposits. The data imply the following genetic elements for Pierina alteration-mineralization: (1) fluid and vapor exsolution from an I-type magma, (2) wallrock buffering and cooling of slowing rising vapors to generate a reduced (H2S/SO4???6) highly acidic condensate that mixed with meteoric water but retained a magmatic ??34S???S signature of ???1???, (3) SO2 disproportionation to HSO4- and H2S between 320 and 180 ??C, and (4) progressive neutralization of laterally migrating acid fluids to form a vuggy quartz???alunite-quartz??clay???intermediate argillic???propylitic alteration zoning. Magmatic-steam alunite has higher ??34S (8.5??? to 23.2???) and generally lower ??18OSO4 (1.0 to 11.5???), ??18OOH (-3.4 to 5.9???), and ??D (-93 to -77???) values than predicted on the basis of data from similar occurrences. These data and supporting fluid-inclusion gas chemistry imply that the rate of vapor ascent for this

  3. Compositions of hydrothermal dravitic tourmalines from some deposits in the Urals, Russia

    Science.gov (United States)

    Baksheev, I.; Kudryavtseva, O.

    2003-04-01

    We have studied compositions of tourmaline from the phlogopite schist and other alterations in the Emerald mines, propylitic- and listwaenitic-type alterations and related veins at the Berezovskoe Au and the Shabrovskoe talc deposits in the Central Urals and Syrostanskoe talc deposit in the South Urals. In the Emerald mines tourmaline associates with hornblende and different phyllosilicates, including phlogopite, paragonite, margarite and chlorite. All phyllosilicates are F-bearing. Based on calculations, however, they are characterized by different values of the Fe/(Fe+Mg) ratio (f) and F, OH, and O in the W site. Tourmaline from the earliest albite-hornblende alteration is OH dominated (0.67-0.96 apfu) with the f value ranging from 0.15 to 0.22. Tourmaline from usual phlogopite schists is OH dominated (0.44-0.80 apfu) with F and O ranging from 0.02 to 0.38 apfu and from 0 to 0.24 apfu. The f value ranges from 0.12 to 0.25. Tourmaline associated with the Fe-free phlogopite and paragonite cementing brecciated chromium spinel crystals is F or OH dominated ranging from 0 to 0.75 apfu and from 0 to 0.83 apfu, respectively. The f value is very low ranging from 0 to 0.01. Tourmaline associated with paragonite and topaz is also F or OH dominated ranging from 0 to 0.52 apfu and from 0.18 to 0.76 apfu, respectively. The f value varies from 0.24 to 0.32. Tourmaline from margarite veinlets cutted phlogopite schists is OH dominated (0.54-0.80 apfu). The f value ranges from 0.19 to 0.29. Tourmalines from the phlogopite-chlorite alteration and carbonate-muscovite-chlorite veinlets are F-poor and are characterized by different amounts of OH and O, ranging from 0.29 to 0.97 apfu and from 0 to 0.59 apfu. The f values of these tourmalines range from 0.17 to 0.29 and from 0.25 to 0.37, respectively. Based on the Moesbauer data the Fe3+/Fetotal ratio in the Emerald mines tourmalines is low and ranges from 0.04 to 0.08. All above tourmalines are Na dominated in the X site. According

  4. Hydrothermal modification of host rock geochemistry within Mo-Cu porphyry deposits in the Galway Granite, western Ireland

    Science.gov (United States)

    Tolometti, Gavin; McCarthy, Will

    2016-04-01

    Hydrothermal alteration of host rock is a process inherent to the formation of porphyry deposits and the required geochemical modification of these rocks is regularly used to indicate proximity to an economic target. The study involves examining the changes in major, minor and trace elements to understand how the quartz vein structures have influenced the chemistry within the Murvey Granite that forms part of the 380-425Ma Galway Granite Complex in western Ireland. Molybdenite mineralisation within the Galway Granite Complex occurred in close association with protracted magmatism at 423Ma, 410Ma, 407Ma, 397Ma and 383Ma and this continues to be of interest to active exploration. The aim of the project is to characterize hydrothermal alteration associated with Mo-Cu mineralisation and identify geochemical indicators that can guide future exploration work. The Murvey Granite intrudes metagabbros and gneiss that form part of the Connemara Metamorphic complex. The intrusion is composed of albite-rich pink granite, garnetiferous granite and phenocrytic orthoclase granite. Minor doleritic dykes post-date the Murvey Granite, found commonly along its margins. Field mapping shows that the granite is truncated to the east by a regional NW-SE fault and that several small subparallel structures host Mo-Cu bearing quartz veins. Petrographic observations show heavily sericitized feldspars and plagioclase and biotite which have undergone kaolinization and chloritisation. Chalcopyrite minerals are fine grained, heavily fractured found crystallized along the margins of the feldspars and 2mm pyrite crystals. Molybdenite are also seen along the margins of the feldspars, crystallized whilst the Murvey Granite cooled. Field and petrographic observations indicate that mineralisation is structurally controlled by NW-SE faults from the selected mineralization zones and conjugate NE-SW cross cutting the Murvey Granite. Both fault orientations exhibit quartz and disseminated molybdenite

  5. Strontium isotopes and rare-earth element geochemistry of hydrothermal carbonate deposits from Lake Tanganyika, East Africa

    Science.gov (United States)

    Barrat, J. A.; Boulègue, J.; Tiercelin, J. J.; Lesourd, M.

    2000-01-01

    At Cape Banza (North Tanganyika Lake), fluids and aragonite chimneys have been collected many times since the discovery of this sublacustrine field in 1987. This sampling has been investigated here for the Sr isotopic compositions and the rare-earth element features of the carbonates and a few fluid samples. The 87Sr/ 86Sr ratios of the chimneys indicate that they have precipitated from a mixture of lake water (more than 95%) and hydrothermal fluids. No zoning in the chimneys was detected with our Sr data. For the rare-earth elements, the situation is more complex. The external walls of the chimneys are rare-earth-element-poor (La ≈ 500 ppb, Yb ≈ 200 ppb, La/Yb = 2 to 3.4). Their shale normalised rare-earth element patterns suggest that they are in equilibrium with the inferred carbonate-depositing fluids. The rare-earth element concentrations of the internal walls of the chimneys are significantly light rare earth elements (LREE)-enriched with La contents sometimes up to 5 ppm. We suggest that they contain more vent-fluid rare-earth elements than the external wall samples, possibly adsorbed on the surface of growing crystals or simply hosted by impurities. It was not possible to constrain the nature of these phases, but the variations of the compositions of the internal wall materials of the active chimneys with time, as well as data obtained on an inactive chimney indicate that this rare-earth element excess is mobile. Partition coefficients were calculated between the external wall aragonite and carbonate-depositing fluid. The results are strikingly similar to the values obtained by Sholkovitz and Shen (1995) on coral aragonite, and suggest that there is no significant biologic effect on the incorporation of rare-earth elements into coral aragonite and that the various carbonate complexes involved Me(CO 3+) complexes are the main LREE carriers in seawater (Cantrell and Byrne, 1987) instead of Me(CO 3) 2- in Banza fluids) have the same behaviour during

  6. Temporal evolution of the giant Salobo IOCG deposit, Carajás Province (Brazil): constraints from paragenesis of hydrothermal alteration and U-Pb geochronology

    Science.gov (United States)

    deMelo, Gustavo H. C.; Monteiro, Lena V. S.; Xavier, Roberto P.; Moreto, Carolina P. N.; Santiago, Erika S. B.; Dufrane, S. Andrew; Aires, Benevides; Santos, Antonio F. F.

    2017-06-01

    The giant Salobo copper-gold deposit is located in the Carajás Province, Amazon Craton. Detailed drill core description, petrographical studies, and U-Pb SHRIMP IIe and LA-ICP-MS geochronology unravel its evolution regarding the host rocks, hydrothermal alteration and mineralization. Within the Cinzento Shear Zone, the deposit is hosted by orthogneisses of the Mesoarchean Xingu Complex (2950 ± 25 and 2857 ± 6.7 Ma) and of the Neoarchean Igarapé Gelado suite (2763 ± 4.4 Ma), which are crosscut by the Old Salobo granite. Remnants of the Igarapé Salobo metavolcanic-sedimentary sequence are represented by a quartz mylonite with detrital zircon populations (ca. 3.1-3.0, 2.95, 2.86, and 2.74 Ga). High-temperature calcic-sodic hydrothermal alteration (hastingsite-actinolite) was followed by silicification, iron-enrichment (almandine-grunerite-magnetite), tourmaline formation, potassic alteration with biotite, copper-gold ore formation, and later Fe-rich hydrated silicate alteration. Myrmekitic bornite-chalcocite and magnetite comprise the bulk of copper-gold ore. All these alteration assemblages have been overprinted by post-ore hematite-bearing potassic and propylitic alteration, which is also recognized in the Old Salobo granite. In the central zone of the deposit the mylonitized Igarapé Gelado suite rocks yield an age of 2701 ± 30 Ma. Zircon ages of 2547 ± 5.3 and 2535 ± 8.4 Ma were obtained for the Old Salobo granite and for the high-grade copper ore, respectively. A U-Pb LA-ICP-MS monazite age (2452 ± 14 Ma) from the copper-gold ore indicates hydrothermal activity and overprinting in the Siderian. Therefore, a protracted tectono-thermal event due to the reactivation of the Cinzento Shear Zone is proposed for the evolution of the Salobo deposit.

  7. Superficial characterization by XP S of silver nanoparticles and their hydrothermal deposit over zircaloy; Caracterizacion superficial por XPS de nanoparticulas de plata y su deposito hidrotermal sobre zircaloy

    Energy Technology Data Exchange (ETDEWEB)

    Contreras R, A.; Gutierrez W, C.; Martinez M, I.; Medina A, A. L., E-mail: aida.contreras@inin.gob.mx [ININ, Departamento de Tecnologia de Materiales, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2012-10-15

    The analysis technique of X-ray photoelectron spectroscopy (XP S) is sensitive exclusively to the first layers of the solids surface, which allows obtaining information about the chemical, physical and electronic properties of them. The combustible elements of the boiling water nuclear reactors (BWR) are formed by zircaloy pipes that contain in their interior pellets or uranium dioxide. In this work is studied the zircaloy surface, oxidized zircaloy under similar conditions to those of a reactor BWR type and oxidized zircaloy with a hydrothermal deposit of silver nanoparticles and zinc. The silver deposit is a proposal of the Materials Technology Department of the Instituto Nacional de Investigaciones Nucleares (ININ) in Mexico, which has the same objective that the noble metals deposit (Pt, Pd, and Rh) that is practiced in some of the reactors BWR, in order to mitigating the speed of crack growth for IGSCC in stainless steels 304 Ss. (Author)

  8. Tin sulfide (SnS) nanostructured films deposited by continuous spray pyrolysis (CoSP) technique for dye-sensitized solar cells applications

    Energy Technology Data Exchange (ETDEWEB)

    Alam, Firoz; Dutta, Viresh, E-mail: vdutta@ces.iitd.ac.in

    2015-12-15

    Highlights: • Single phase, perfectly stoichiometric tin sulfide (SnS) films have been deposited by continuous spray pyrolysis technique. • Structural and morphological investigations show the orthorhombic SnS with nanoflakes. • SnS film shows excellent electrochemical stability. • SnS films have been used as a counter electrode (CE) in an I{sub 3}{sup −}/I{sup −} based dye-sensitized solar cells. - Abstract: Tin sulfide (SnS) nanostructured films have been deposited on transparent conducting glass substrate using continuous spray pyrolysis (CoSP) technique using aqueous spray solution of tin chloride and thiourea. Structural, morphological and optical properties of as-synthesized SnS nanostructured films showed the formation of (1 0 1) oriented orthorhombic SnS with nanoflakes having a direct band gap of 1.40 eV. X-ray photoelectron spectroscopy (XPS) analysis confirms the formation of pure SnS with Sn in +2 oxidation state. The SnS nanostructured film has also been characterized using Brunauer–Emmett–Teller (BET) technique to determine the surface area and pore volume which are found to be 11.4 m{sup 2}/g and 0.02 cm{sup 2}/g, respectively. The film has been used as a counter electrode (CE) in a triiodide/iodide (I{sub 3}{sup −}/I{sup −}) based dye-sensitized solar cells (DSSCs). The DSSCs of 0.25 cm{sup 2} area with SnS nanostructured CE exhibits a lower power conversion efficiency (2.0 ± 0.06%) than that for the cell with standard platinum (Pt) CE (4.5 ± 0.13%). However, the usefulness of the CoSP technique for deposition of nanostructures SnS CE film has been established in the present study.

  9. Homogenization Temperature Measurements in Hydrothermal Diamond-Anvil Cell for Melt and Fluid Inclusions from the Jiajika Pegmatite Deposit, China

    Science.gov (United States)

    Li, J.; Chou, I.; Yuan, S.; Burruss, R. C.

    2009-12-01

    We measured the total homogenization temperatures (Th) of volatile-rich melt and fluid inclusions under elevated external pressures in a hydrothermal diamond-anvil cell (HDAC) to understand fluid evolution in the Jiajika pegmatite deposit in China, the largest spodumene deposit in Asia. Three types of inclusions were investigated: 1. CH4-H2O (~10 vol. %) bearing aluminosilicate melt inclusions hosted in quartz from granite; 2. CO2-NaCl-H2O (~80 vol. %) inclusions with daughter minerals mainly hosted in spodumene from pegmatite dikes; and 3. CO2-NaCl-H2O inclusions mainly hosted in quartz from pegmatite dikes. During normal microthermometric measurements at atmospheric pressure, most of these inclusions decrepitated at ~300°C. Therefore, we extended the method of Schmidt et al. (1998, Am. Mineral. 83, 995) and Darling and Bassett (2002, Am. Mineral., 87, 67) to melt inclusions in HDAC and conducted long-duration experiments with type 1 and 2 inclusions at one kbar Ar pressure in cold-seal pressure vessels (CSPV) as described by Thomas et al. (2006, Chapter 9 in Mineralogical Association of Canada Short Course, 36, 189). Results in both HDAC and CSPV experiments showed that Th's of type 1 and 2 inclusions were between 600 and 700 °C and between 500 and 700 °C, respectively. In HDAC experiments for type 1 inclusions, daughter minerals melted and coexisted with the fluid phase before total homogenization; however, in type 2 inclusions, daughter minerals dissolved completely in the CO2-NaCl-H2O solution at Th. Results obtained for type 3 inclusions showed that the CO2-rich and CO2-poor inclusions homogenized to liquid CO2 and aqueous phases at 260 - 570 and 240 - 350°C, respectively. Also, Th’s decrease linearly as the external pressure increases; the reduction of Th was ~1.5 °C/kbar, which is similar to ~1.2 °C/kbar reported by Darling and Bassett (ibid.) for the same type of natural fluid inclusions, but is much less than ~4.6 °C/kbar reported by Schmidt et

  10. Selenium Sulfide

    Science.gov (United States)

    Selenium sulfide, an anti-infective agent, relieves itching and flaking of the scalp and removes the dry, ... Selenium sulfide comes in a lotion and is usually applied as a shampoo. As a shampoo, selenium ...

  11. The hydrothermal exploration system on the 'Qianlong2' AUV

    Science.gov (United States)

    Tao, W.; Tao, C.; Jinhui, Z.; Cai, L.; Guoyin, Z.

    2016-12-01

    ABSTRACT: Qianlong2, is a fully Autonomous Underwater Vehicle (AUV) designed for submarine resources research, especially for polymetallic sulphides, and the survey depths of is up to 4500 m. Qianlong2 had successfully explored hydrothermal vent field on the Southwest Indian Ridge (SWIR), and collected conductance, temperature and depth (CTD), turbidity, and Oxidation-Reduction Potential (ORP) data. It also had mapped precise topography by high resolution side scan sonar (HRBSSS) during every dive; and obtained photographs of sulfide deposits during some dives. Here, we detailedly described the implementation of investigation, data administration, and fast mapping of hydrothermal exploration system by Qianlong2. Giving a description of how to remove the platform magnetic interference by using magnetic data during Qianlong2 spin. Based on comprehensive hydrochemical anomalies, we get a rapid method for finding the localization of hydrothermal vents. Taking one dive as an example, we systemically showed the process about how to analyse hydrothermal survey data and acquire the location results of hydrothermal vents. Considering that this method is effective and can be used in other deep-submergence assets such as human occupied vehicles (HOVs) and remotely operated vehicles (ROVs) during further studies. Finally, we discussed how to promote and optimize the installation and application of those sensors and how to improve Qianlong2's autonomy of investigation.

  12. Ground Penetrating Radar Investigation of Sinter Deposits at Old Faithful Geyser and Immediately Adjacent Hydrothermal Features, Yellowstone National Park, Wyoming, USA

    Science.gov (United States)

    Foley, D.; Lynne, B. Y.; Jaworowski, C.; Heasler, H.; Smith, G.; Smith, I.

    2015-12-01

    Ground Penetrating Radar (GPR) was used to evaluate the characteristics of the shallow subsurface siliceous sinter deposits around Old Faithful Geyser. Zones of fractures, areas of subsurface alteration and pre-eruption hydrologic changes at Old Faithful Geyser and surrounding hydrothermal mounds were observed. Despite being viewed directly by about 3,000,000 people a year, shallow subsurface geologic and hydrologic conditions on and near Old Faithful Geyser are poorly characterized. GPR transects of 5754 ft (1754m) show strong horizontal to sub-horizontal reflections, which are interpreted as 2.5 to 4.5 meters of sinter. Some discontinuities in reflections are interpreted as fractures in the sinter, some of which line up with known hydrothermal features and some of which have little to no surface expression. Zones with moderate and weak amplitude reflections are interpreted as sinter that has been hydrothermally altered. Temporal changes from stronger to weaker reflections are correlated with the eruption cycle of Old Faithful Geyser, and are interpreted as post-eruption draining of shallow fractures, followed by pre-eruption fracture filling with liquid or vapor thermal fluids.

  13. Pd-BISMUTHOTELLURIDES and Other Tellurides from Some Cu-Ni-PGE Deposits, Eastern Desert, Egypt

    Science.gov (United States)

    Helmy, H. M.

    2003-04-01

    Pd-bismuthotellurides and other tellurides are described from three Cu-Ni-PGE deposits in the Eastern Desert, Egypt: Abu Swayl, Genina Gharbia, Gabbro Akarem. The deposits are hosted in Late Precambrian mafic-ultramafic rocks and have different geologic histories. The Abu Swayel deposit occurs in conformable, lens-like mafic-ultramafic rocks in metasediments. Mineralization and host rocks are metamorphosed (amphibolite facies; 550-650ºC, 4-5 kbar) and syn-metamorphically sheared. Metamorphism and associated fluid regimes resulted in remobilization and transport of Cu-sulfides and PGE, and development of hydrosilicates. Michenerite, merenskyite, Pd-Bi-melonite, (NiPdBi)Te2, melonite, hessite, altaite and joséite-B occur as inclusions in mobilized sulfides and along cracks in garnet and plagioclase. The Genina Gharbia and Gabbro Akarem deposits are hosted in concentrically zoned, Alaskan-type, complexes; neither is metamorphosed. At Genina Gharbia, ore forms either disseminations in peridotite or massive patches in hornblende-pyroxenite in the vicinity of metasediments. Important petrographic features are a dominance of hornblende, biotite and chlorapatite and alteration of plagioclase to epidote. Disseminated and network sulfide ores are dominated by po, pn, cp and minor py; accessories are cobaltite, molybdenite and valleriite. Sulfide textures and host rock petrography suggest a prolonged late-magmatic hydrothermal event. Michenerite, merenskyite, Pd-Bi-melonite, altaite, hessite, tsumoite and native-Te are mainly present at sulfide-silicate contacts. The Gabbro Akarem deposit is hosted in dunite pipes where net-textured and massive sulfides are associated with spinel and Cr-magnetite. Michenerite, merenskyite, Pd-Bi-melonite and hessite occur mainly as inclusions in sulfides. Typical magmatic textures indicate the limited role of late- and post-magmatic hydrothermal processes. Different geological history of the different deposits enables examination of the

  14. A Two-Step Absorber Deposition Approach To Overcome Shunt Losses in Thin-Film Solar Cells: Using Tin Sulfide as a Proof-of-Concept Material System

    Energy Technology Data Exchange (ETDEWEB)

    Steinmann, Vera; Chakraborty, Rupak; Rekemeyer, Paul H.; Hartman, Katy; Brandt, Riley E.; Polizzotti, Alex; Yang, Chuanxi; Moriarty, Tom; Gradečak, Silvija; Gordon, Roy G.; Buonassisi, Tonio

    2016-08-31

    As novel absorber materials are developed and screened for their photovoltaic (PV) properties, the challenge remains to reproducibly test promising candidates for high-performing PV devices. Many early-stage devices are prone to device shunting due to pinholes in the absorber layer, producing 'false-negative' results. Here, we demonstrate a device engineering solution toward a robust device architecture, using a two-step absorber deposition approach. We use tin sulfide (SnS) as a test absorber material. The SnS bulk is processed at high temperature (400 degrees C) to stimulate grain growth, followed by a much thinner, low-temperature (200 degrees C) absorber deposition. At a lower process temperature, the thin absorber overlayer contains significantly smaller, densely packed grains, which are likely to provide a continuous coating and fill pinholes in the underlying absorber bulk. We compare this two-step approach to the more standard approach of using a semi-insulating buffer layer directly on top of the annealed absorber bulk, and we demonstrate a more than 3.5x superior shunt resistance Rsh with smaller standard error ..sigma..Rsh. Electron-beam-induced current (EBIC) measurements indicate a lower density of pinholes in the SnS absorber bulk when using the two-step absorber deposition approach. We correlate those findings to improvements in the device performance and device performance reproducibility.

  15. A Two-Step Absorber Deposition Approach To Overcome Shunt Losses in Thin-Film Solar Cells: Using Tin Sulfide as a Proof-of-Concept Material System.

    Science.gov (United States)

    Steinmann, Vera; Chakraborty, Rupak; Rekemeyer, Paul H; Hartman, Katy; Brandt, Riley E; Polizzotti, Alex; Yang, Chuanxi; Moriarty, Tom; Gradečak, Silvija; Gordon, Roy G; Buonassisi, Tonio

    2016-08-31

    As novel absorber materials are developed and screened for their photovoltaic (PV) properties, the challenge remains to reproducibly test promising candidates for high-performing PV devices. Many early-stage devices are prone to device shunting due to pinholes in the absorber layer, producing "false-negative" results. Here, we demonstrate a device engineering solution toward a robust device architecture, using a two-step absorber deposition approach. We use tin sulfide (SnS) as a test absorber material. The SnS bulk is processed at high temperature (400 °C) to stimulate grain growth, followed by a much thinner, low-temperature (200 °C) absorber deposition. At a lower process temperature, the thin absorber overlayer contains significantly smaller, densely packed grains, which are likely to provide a continuous coating and fill pinholes in the underlying absorber bulk. We compare this two-step approach to the more standard approach of using a semi-insulating buffer layer directly on top of the annealed absorber bulk, and we demonstrate a more than 3.5× superior shunt resistance Rsh with smaller standard error σRsh. Electron-beam-induced current (EBIC) measurements indicate a lower density of pinholes in the SnS absorber bulk when using the two-step absorber deposition approach. We correlate those findings to improvements in the device performance and device performance reproducibility.

  16. Correlating Cu-sulfide and Au mineralization in the Ertsberg-Grasberg District using LA-ICP-MS and HRXCT

    Science.gov (United States)

    Wright, K. A.; Miller, N. R.; Ketcham, R. A.; Kyle, R.

    2016-12-01

    The Ertsberg-Grasberg district in Papua, Indonesia, hosts to two of the largest intrusion-related Cu-Au deposits in the world: the Ertsberg East Skarn system and the Grasberg Intrusive Complex. Cu mineralization within the Grasberg porphyry and Ertsberg skarn systems primarily consists of bornite and chalcopyrite, with minor digenite and idiate. Native Au is commonly found in association with Cu mineralization where Au occurs as inclusions within or immediately proximal to primary Cu-sulfide minerals. At hydrothermal-ore forming temperatures, approximately 400° to 700° C, bornite and chalcopyrite can host up to 1800 ppm Au within the Cu-sulfide lattice. Upon retrograde cooling of the hydrothermal system, the ability of bornite and chalcopyrite to host Au decreases significantly to about 10 ppm, indicating that the Au could be expulsed from the sulfide lattice. Given the close association of native Au and Cu-sulfide concentrations, it is possible that native gold grains form as the Au emerges from the Cu-sulfides. Constraining the genetic and spatio-temporal relationship between Cu-sulfide and Au mineralization within these deposits is of significant interest with regard to the geometallurgical processing of the ore, and to future exploration. This study seeks to evaluate this relationship using High Resolution X-ray Computed Tomography (HRXCT) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). Previous HRXCT studies on Ertsberg-Grasberg ore samples have identified numerous occurrences of native Au grains at the edges of Cu-sulfide masses. HRXCT data are used here to construct 3D Voronoi regions of potential Au "diffusional drainage" from within the Cu-sulfides, where the expectation is a positive correlation between Au grain size and modified Voronoi polyhedron volume, defined as the volume of sulfide closer to that grain than any other via a connected path through sulfide. LA-ICP-MS data are used to determine variations in Au contents

  17. Oxygen, carbon and sulphur isotope studies in the Keban Pb-Zn deposits, eastern Turkey: An approach on the origin of hydrothermal fluids

    Science.gov (United States)

    Kalender, Leyla

    2011-03-01

    Pb-Zn deposits are widespread and common in various parts of the Taurus Belt. Most of the deposits are of pyrometasomatic and hydrothermal origin. The Keban Pb-Zn deposits are located along the intrusive contact between the Paleozoic - Lower Triassic Keban Metamorphic Formation and the syenite porphyry of the Upper Cretaceous Keban igneous rocks. Various studies have already been carried out; using fluid inclusion studies on fluorite, calcite and quartz on the pyrite-chalcopyrite bearing Keban ore deposits. This study focuses on the interpretation of stable isotope compositions in connexion with fluid inclusion data. Sulphur isotope values (δ 34S) of pyrite are within the range of -0.59 to +0.17‰ V-CDT ( n = 10). Thus, the source of sulphur is considered to be magmatic, as evidenced by associated igneous rocks and δ 34S values around zero"0". Oxygen isotope values δ 18O of quartz vary between +10.5 and +19.9‰ (SMOW). However, δ 18O and δ 13C values of calcite related to re-crystallized limestone (Keban Metamorphic Formation) reach up to +27.3‰ (SMOW) and +1.6‰ (PDB), respectively. The δ 34S, δ 13C and δ 18O values demonstrate that skarn-type Pb-Zn deposits formed within syeno-monzonitic rocks and calc-schist contacts could have developed at low temperatures, by mixing metamorphic and meteoric waters in the final stages of magmatism.

  18. Hydrothermal treatment for the marked structural and optical quality improvement of ZnO nanowire arrays deposited on lightweight flexible substrates

    Science.gov (United States)

    Lupan, Oleg; Pauporté, Thierry

    2010-08-01

    ZnO nanowire arrays (NWs) have attracted great interest as the building blocks for emerging applications in new flexible and elastic electronic and optoelectronic devices (e.g. smart cards, light emitting diodes (LEDs), displays, etc.) with higher functionality. Since flexible plastic substrates (FPS) are important, soft post-growth treatments compatible with FPS must be found to significantly improve the properties of NWs deposited on it. We present an innovative low-temperature hydrothermal treatment in an autoclave to improve the structural and optical properties of ZnO NWs grown by electrochemical deposition at low temperature (80 °C) on transparent flexible polymer -based indium-tin-oxide (ITO) coated substrates. The layer characterizations by scanning electron microscopy (SEM) and X-ray diffraction (XRD) showed the improvement of the wire surface smoothness and of their structural quality. The observed higher excitonic photoluminescence at 381 nm and the stronger optical phonon modes in the Raman spectra demonstrated the superior performance of the post-growth hydrothermal treatment compared to a conventional annealing at the same temperature. The presented results pave the way for the realization of new highly efficient ZnO-based optoelectronic devices on flexible plastic substrates or elastic foils.

  19. STUDY OF HYDROGEN SULFIDE REMOVAL FROM GROUNDWATER

    OpenAIRE

    T. Lupascu; M. Ciobanu; V. Botan; T. Gromovoy; S. Cibotaru

    2013-01-01

    The process of the hydrogen sulfide removal from the underground water of the Hancesti town has been investigated. By oxygen bubbling through the water containing hydrogen sulfide, from the Hancesti well tube, sulfur is deposited in the porous structure of studied catalysts, which decreases their catalytic activity. Concomitantly, the process of adsorption / oxidation of hydrogen sulfide to sulfate take place. The kinetic research of the hydrogen sulfide removal from the Hancesti underground ...

  20. Re-Os sulfide (chalcopyrite, pyrite and molybdenite) systematics and fluid inclusion study of the Duobaoshan porphyry Cu (Mo) deposit, Heilongjiang Province, China

    Science.gov (United States)

    Liu, Jun; Wu, Guang; Li, Yuan; Zhu, Mingtian; Zhong, Wei

    2012-04-01

    The Duobaoshan porphyry deposit, located in the northwestern part of the Lesser Hinggan Range, is one of the biggest porphyry Cu (Mo) deposits in the Central Asian orogenic belt in China. The Duobaoshan porphyry deposit occurs in granodiorite and volcanic rocks of the Middle Ordovician Duobaoshan Formation. Six types of veins have been identified in three ore-forming stages as follows: a quartz-potassic feldspar vein in the early ore-forming stage, an early stage quartz-molybdenite vein, late stage quartz-molybdenite and quartz-chalcopyrite-pyrite veins in the middle ore-forming stage, and quartz-pyrite and calcite-quartz veins in the late ore-forming stage. The following four types of fluid inclusions are distinguished from various quartz veins: two-phase aqueous, pure gas phase, CO2-bearing and daughter mineral-bearing inclusions. The ore-forming fluid for the early ore-forming stage belongs to the H2O-CO2-NaCl system, which is characterized by high temperatures (>550 °C), intermediate salinities (16.2-18.1 wt% NaCl eqv.) and high CO2 content. The ore-forming fluid from the middle ore-forming stage evolved to the H2O-CO2-NaCl system, which is characterized by intermediate to high temperatures (230-450 °C) and high/low salinities (0.8 to >65.3 wt% NaCl eqv.) and is also rich in CO2 and metals. The ore-forming fluid finally reached cool temperatures (110-200 °C), low salinities (3.9-8.4 wt% NaCl eqv.) and was CO2-poor. Intensive fluid immiscibility or boiling occurred when the ore-forming fluid with temperatures of 230-450 °C and pressures of 10-41 MPa ascended to 4.1 km, inducing the escape of CO2, depressing the solubility of fluid, and depositing abundant metal sulfides. The total Re and Os concentrations of chalcopyrite and pyrite range from 0.15 to 2.95 μg/g and 0.74 to 15.01 ng/g, respectively. Analyses of seven chalcopyrite and pyrite samples yielded isochron ages of 482-486 Ma, and the model age of one molybdenite sample is 485.6 ± 3.7 Ma. The

  1. Hydrothermal titanite from the Chengchao iron skarn deposit: temporal constraints on iron mineralization, and its potential as a reference material for titanite U-Pb dating

    Science.gov (United States)

    Hu, Hao; Li, Jian-Wei; McFarlane, Christopher R. M.

    2017-09-01

    Uranium-lead isotopes and trace elements of titanite from the Chengchao iron skarn deposit (Daye district, Eastern China), located along the contact zones between Triassic marine carbonates and an early Cretaceous intrusive complex consisting of granite and quartz diorite, were analyzed using laser ablation inductively coupled plasma mass spectrometry to provide temporal constraints on iron mineralization and to evaluate its potential as a reference material for titanite U-Pb geochronology. Titanite grains from mineralized endoskarn have simple growth zoning patterns, exhibit intergrowth with magnetite, diopside, K-feldspar, albite and actinolite, and typically contain abundant primary two-phase fluid inclusions. These paragenetic and textural features suggest that these titanite grains are of hydrothermal origin. Hydrothermal titanite is distinct from the magmatic variety from the ore-related granitic intrusion in that it contains unusually high concentrations of U (up to 2995 ppm), low levels of Th (12.5-453 ppm), and virtually no common Pb. The REE concentrations are much lower, as are the Th/U and Lu/Hf ratios. The hydrothermal titanite grains yield reproducible uncorrected U-Pb ages ranging from 129.7 ± 0.7 to 132.1 ± 2.7 Ma (2σ), with a weighted mean of 131.2 ± 0.2 Ma [mean standard weighted deviation (MSWD) = 1.7] that is interpreted as the timing of iron skarn mineralization. This age closely corresponds to the zircon U-Pb age of 130.9 ± 0.7 Ma (MSWD = 0.7) determined for the quartz diorite, and the U-Pb ages for zircon and titanite (130.1 ± 1.0 Ma and 131.3 ± 0.3 Ma) in the granite, confirming a close temporal and likely genetic relationship between granitic magmatism and iron mineralization. Different hydrothermal titanite grains have virtually identical uncorrected U-Pb ratios suggestive of negligible common Pb in the mineral. The homogeneous textures and U-Pb characteristics of Chengchao hydrothermal titanite suggest that the mineral might be a

  2. Host-rock controlled epigenetic, hydrothermal metasomatic origin of the Bayan Obo REEFe-Nb ore deposit, Inner Mongolia, P.R.C.

    Science.gov (United States)

    Chao, E.C.T.; Back, J.M.; Minkin, J.A.; Yinchen, R.

    1992-01-01

    Bayan Obo, a complex rare earth element (REE)FeNb ore deposit, located in Inner Mongolia, P.R.C. is the world's largest known REE deposit. The deposit is chiefly in a marble unit (H8), but extends into an overlying unit of black shale, slate and schist unit (H9), both of which are in the upper part of the Middle Proterozoic Bayan Obo Group. Based on sedimentary structures, the presence of detrital quartz and algal fossil remains, and the 16-km long geographic extent, the H8 marble is a sedimentary deposit, and not a carbonatite of magmatic origin, as proposed by some previous investigators. The unit was weakly regionally metamorphosed (most probably the lower part of the green schist facies) into marble and quartzite prior to mineralization. Tectonically, the deposit is located on the northern flank of the Sino-Korean craton. Many hypotheses have been proposed for the origin of the Bayan Obo deposit; the studies reported here support an epigenetic, hydrothermal, metasomatic origin. Such an origin is supported by field and laboratory textural evidence; 232Th/208Pb internal isochron mineral ages of selected monazite and bastnaesite samples; 40Ar/39Ar incremental heating minimum mineral ages of selected alkali amphiboles; chemical compositions of different generations of both REE ore minerals and alkali amphiboles; and evidence of host-rock influence on the various types of Bayan Obo ores. The internal isochron ages of the REE minerals indicate Caledonian ages for various episodes of REE and Fe mineralization. No evidence was found to indicate a genetic relation between the extensive biotite granitic rocks of Hercynian age in the mine region and the Bayan Obo are deposit, as suggested by previous workers. ?? 1992.

  3. Electrochemical deposition of molybdenum sulfide thin films on conductive plastic substrates as platinum-free flexible counter electrodes for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Chao-Kuang; Hsieh, Chien-Kuo, E-mail: jack_hsieh@mail.mcut.edu.tw

    2015-06-01

    In this study, pulsed electrochemical deposition (pulsed ECD) was used to deposit molybdenum sulfide (MoS{sub x}) thin films on indium tin oxide/polyethylene naphthalate (ITO/PEN) substrates as flexible counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). The surface morphologies and elemental distributions of the prepared MoS{sub x} thin films were examined using field-emission scanning electron microscope (FE-SEM) equipped with energy-dispersive X-ray spectroscopy. The chemical states and crystallinities of the prepared MoS{sub x} thin films were examined by X-ray photoelectron spectroscopy and X-ray diffraction, respectively. The optical transmission (T (%)) properties of the prepared MoS{sub x} samples were determined by ultraviolet–visible spectrophotometry. Cyclic voltammetry (CV) and Tafel-polarization measurements were performed to analyze the electrochemical properties and catalytic activities of the thin films for redox reactions. The FE-SEM results showed that the MoS{sub x} thin films were deposited uniformly on the ITO/PEN flexible substrates via the pulsed ECD method. The CV and Tafel-polarization curve measurements demonstrated that the deposited MoS{sub x} thin films exhibited excellent performances for the reduction of triiodide ions. The photoelectric conversion efficiency (PCE) of the DSSC produced with the pulsed ECD MoS{sub x} thin-film CE was examined by a solar simulator. In combination with a dye-sensitized TiO{sub 2} working electrode and an iodine-based electrolyte, the DSSC with the MoS{sub x} flexible CE showed a PCE of 4.39% under an illumination of AM 1.5 (100 mW cm{sup −2}). Thus, we report that the MoS{sub x} thin films are active catalysts for triiodide reduction. The MoS{sub x} thin films are prepared at room temperature and atmospheric pressure and in a simple and rapid manner. This is an important practical contribution to the production of flexible low-cost thin-film CEs based on plastic substrates. The MoS{sub x

  4. Characterization and modeling of illite crystal particles and growth mechanisms in a zoned hydrothermal deposit, Lake City, Colorado

    Science.gov (United States)

    Bove, D.J.; Eberl, D.D.; McCarty, D.K.; Meeker, G.P.

    2002-01-01

    Mean thickness measurements and crystal-thickness distributions (CTDs) of illite particles vary systematically with changes in hydrothermal alteration type, fracture density, and attendant mineralization in a large acid-sulfate/Mo-porphyry hydrothermal system at Red Mountain, near Lake City, Colorado. The hydrothermal illites characterize an extensive zone of quartz-sericite-pyrite alteration beneath two deeply rooted bodies of magmatic-related, quartz-alunite altered rock. Nineteen illites from a 3000 ft vertical drill hole were analyzed by XRD using the PVP-10 intercalation method and the computer program MudMaster (Bertaut-Warren-Averbach technique). Mean crystallite thicknesses, as determined from 001 reflections, range from 5-7 nanometers (nm) at depths from 0-1700 ft, then sharply increase to 10-16 nm at depths between 1800-2100 ft, and decrease again to 4-5 nm below this level. The interval of largest particle thickness correlates strongly with the zone of most intense quartz-sericite-pyrite alteration (QSP) and attendant high-density stockwork fracturing, and with the highest concentrations of Mo within the drill core. CTD shapes for the illite particles fall into two main categories: asymptotic and lognormal. The shapes of the CTDs are dependent on conditions of illite formation. The asymptotic CTDs correspond to a nucleation and growth mechanism, whereas surface-controlled growth was the dominant mechanism for the lognormal CTDs. Lognormal CTDs coincide with major through-going fractures or stockwork zones, whereas asymptotic CTDs are present in wallrock distal to these intense fracture zones. The increase in illite particle size and the associated zone of intense QSP alteration and stockwork veining was related by proximity to the dacitic magma(s), which supplied both reactants and heat to the hydrothermal system. However, no changes in illite polytype, which in other studies reflect temperature transitions, were observed within this interval.

  5. Diagnostic Genesis Features of Au-Ag Selenide-Telluride Mineralization of Western Java Deposits

    Directory of Open Access Journals (Sweden)

    Euis Tintin Yuningsih

    2016-01-01

    Full Text Available DOI: 10.17014/ijog.3.1.67-76The ore mineralogy of the westernmost part of West Java such as Pongkor, Cibaliung, Cikidang, Cikotok, and Cirotan are characterized by the dominance of silver-arsenic-antimony sulfosalt with silver selenides and rarely tellurides over the argentite, whereas the eastern part of West Java including Arinem and Cineam deposits are dominated by silver-gold tellurides. Mineralogy of Se-type deposits at Pongkor, Cikidang, Cibaliung, Cisungsang, and Cirotan and Te-type deposits at Arinem and Cineam shows their different geochemical characteristics. Mineralogical and geochemical differences can be explained by variation of physico-chemical conditions that existed during gold-silver deposition by applying the phase relation among sulfide, telluride, and selenide mineral association in the deposits. The relative values of ƒSe2(g, ƒTe(g, and ƒS2(g control the actual presence of selenide or telluride minerals within the West Java deposits, which also depend on their concentrations in the hydrothermal fluid. Even though the concentration of selenium in the hydrothermal fluid of Te-type deposits might have been similar or even higher than that in the Se-type, early substitution of selenium in the sulfide minerals prevents its concentration in the hydrothermal fluid to the levels for precipitating selenide minerals. Therefore, early sulfide mineral deposition from reduction fluids will not increase the ƒSe2(g/ƒS2(g ratio to form selenide minerals in Te-type deposits of Arinem and Cineam, other than selenium-bearing sulfide mineral such as Se-bearing galena or Se-bearing pyrargyrite-proustite.

  6. Depositional environments inferred from variations of calcium carbonate, organic carbon, and sulfide sulfur: a core from southeastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Paropkari, A; Iyer, S.D.; Chauhan, O; PrakashBabu, C.

    The variations in CaCO3 and organic carbon and their inter-relationship in a core from the southeastern Arabian Sea (water depth 2,212 m) have been used to demarcate the Holocene/Pleistocene boundary; an increased terrigenous deposition during Late...

  7. Geochemistry, Paragenesis, and Wall-Rock Alteration of the Qatruyeh Iron Deposits, Southwest of Iran: Implications for a Hydrothermal-Metasomatic Genetic Model

    Directory of Open Access Journals (Sweden)

    Sina Asadi

    2014-01-01

    Full Text Available The Qatruyeh iron deposits, located on the eastern border of the NW-SE trending Sanandaj-Sirjan metamorphic zone, southwest of Iran, are hosted by a late Proterozoic to early Paleozoic sequence dominated by metamorphosed carbonate rocks. The magnetite ores occurred as layered to massive bodies, with lesser amounts of disseminated magnetite and hematite-bearing veins. Textural evidences, along with geochemical analyses of the high field strengths (HFSEs, large ion lithophiles (LILEs, and rare earth elements (REEs, indicate that the main mineralization stage occurred as low-grade layered magnetite ores due to high-temperature hydrothermal fluids accompanied by Na-Ca alteration. Most of the main ore-stage minerals precipitated from an aqueous-carbonic fluid (3.5–15 wt.% NaCl equiv. at temperatures ranging between 300° and 410°C during fluid mixing process, CO2 effervescence, cooling, and increasing of pH. Low-temperature hydrothermal activity subsequently produced hematite ores associated with propylitic alteration. The metacarbonate host rocks are LILE-depleted and HFSE-enriched due to metasomatic alteration.

  8. Stable light isotope biogeochemistry of hydrothermal systems.

    Science.gov (United States)

    Des Marais, D J

    1996-01-01

    The stable isotopic composition of the elements O, H, S and C in minerals and other chemical species can indicate the existence, extent, conditions and the processes (including biological activity) of hydrothermal systems. Hydrothermal alteration of the 18O/16O and D/H values of minerals can be used to detect fossil systems and delineate their areal extent. Water-rock interactions create isotopic signatures which indicate fluid composition, temperature, water-rock ratios, etc. The 18O/16O values of silica and carbonate deposits tend to increase with declining temperature and thus help to map thermal gradients. Measurements of D/H values can help to decipher the origin(s) of hydrothermal fluids. The 34S/32S and 13C/12C values of fluids and minerals reflect the origin of the S and C as well as oxygen fugacities and key redox processes. For example, a wide range of 34S/32S values which are consistent with equilibration below 100 degrees C between sulfide and sulfate can be attributed to sulfur metabolizing bacteria. Depending on its magnitude, the difference in the 13C/12C value of CO2 and carbonates versus organic carbon might be attributed either to equilibrium at hydrothermal temperatures or, if the difference exceeds 1% (10/1000), to organic biosynthesis. Along the thermal gradients of thermal spring outflows, the 13C/12C value of carbonates and 13C-depleted microbial organic carbon increases, principally due to the outgassing of relatively 13C-depleted CO2.

  9. Relationships between microbial communities and environmental parameters at sites impacted by mining of volcanogenic massive sulfide deposits, Prince William Sound, Alaska

    Science.gov (United States)

    Foster, A.L.; Munk, L.; Koski, R.A.; Shanks, Wayne C.; Stillings, L.L.

    2008-01-01

    The relations among geochemical parameters and sediment microbial communities were examined at three shoreline sites in the Prince William Sound, Alaska, which display varying degrees of impact by acid-rock drainage (ARD) associated with historic mining of volcanogenic massive sulfide deposits. Microbial communities were examined using total fatty acid methyl esters (FAMEs), a class of compounds derived from lipids produced by eukaryotes and prokaryotes (bacteria and Archaea); standard extraction techniques detect FAMEs from both living (viable) and dead (non-viable) biomass, but do not detect Archaeal FAMEs. Biomass and diversity (as estimated by FAMEs) varied strongly as a function of position in the tidal zone, not by study site; subtidal muds, Fe oxyhydroxide undergoing biogenic reductive dissolution, and peat-rich intertidal sediment had the highest values. These estimates were lowest in acid-generating, intertidal zone sediment; if valid, the estimates suggest that only one or two bacterial species predominate in these communities, and/or that Archeal species are important members of the microbial community in this sediment. All samples were dominated by bacterial FAMEs (median value >90%). Samples with the highest absolute abundance of eukaryotic FAMEs were biogenic Fe oxyhydroxides from shallow freshwater pools (fungi) and subtidal muds (diatoms). Eukaryotic FAMEs were practically absent from low-pH, sulfide-rich intertidal zone sediments. The relative abundance of general microbial functional groups such as aerobes/anaerobes and gram(+)/gram(-) was not estimated due to severe inconsistency among the results obtained using several metrics reported in the literature. Principal component analyses (PCAs) were performed to investigate the relationship among samples as separate functions of water, sediment, and FAMEs data. PCAs based on water chemistry and FAMEs data resulted in similar relations among samples, whereas the PCA based on sediment chemistry

  10. Formation of hydrothermal deposits at Kings Triple Junction, northern Lau back-arc basin, SW Pacific: The geochemical perspectives

    Digital Repository Service at National Institute of Oceanography (India)

    Paropkari, A.L.; Ray, D.; Balaram, V.; Prakash, L.S.; Mirza, I.H.; Satyanarayana, M.; Rao, T.G.; Kaisary, S.

    with earlier petrological investigations at KTJ which also revealed prominent impregnation of SSZ mantle (Hawkins, 1995). High Ba to Nb ratios (a proxy for total subduction inputs; Paerce and Stern, 2006,) in the pedestal slab (Ba/Nb=10 3 -10 5 , Table 2....P., Peterson, N., Roggenthen, W., Schrader, E.L., Srivastava, R.K., 18 Warren, N., 1979. Galapagos hydrothermal mounds: stratigraphy and chemistry revealed by deep-sea drilling. Science 204, 613-616. Paerce J. A., Stern R. J., 2006. Origin of Back...

  11. Extended photo-response of ZnO/CdS core/shell nanorods fabricated by hydrothermal reaction and pulsed laser deposition.

    Science.gov (United States)

    Yang, Qin; Li, Yanli; Hu, Zhigao; Duan, Zhihua; Liang, Peipei; Sun, Jian; Xu, Ning; Wu, Jiada

    2014-04-07

    Heterogenous nanostructures shaped with CdS covered ZnO (ZnO/CdS) core/shell nanorods (NRs) are fabricated on indium-tin-oxide by pulsed laser deposition of CdS on hydrothermally grown ZnO NRs and characterized through morphology examination, structure characterization, photoluminescence and optical absorption measurements. Both the ZnO cores and the CdS shells are hexagonal wurtzite in structure. Compared with bare ZnO NRs, the fabricated ZnO/CdS core/shell NRs present an extended photo-response and have optical properties corresponding to the two excitonic band-gaps of ZnO and CdS as well as the effective band-gap formed between the conduction band minimum of ZnO and the valence band maximum of CdS.

  12. STUDY OF HYDROGEN SULFIDE REMOVAL FROM GROUNDWATER

    Directory of Open Access Journals (Sweden)

    T. Lupascu

    2013-06-01

    Full Text Available The process of the hydrogen sulfide removal from the underground water of the Hancesti town has been investigated. By oxygen bubbling through the water containing hydrogen sulfide, from the Hancesti well tube, sulfur is deposited in the porous structure of studied catalysts, which decreases their catalytic activity. Concomitantly, the process of adsorption / oxidation of hydrogen sulfide to sulfate take place. The kinetic research of the hydrogen sulfide removal from the Hancesti underground water, after its treatment by hydrogen peroxide, proves greater efficiency than in the case of modified carbonic adsorbents. As a result of used treatment, hydrogen sulfide is completely oxidized to sulfates

  13. Reactive Hydrothermal Flow Model for Mid-Oceanic Ridges

    Science.gov (United States)

    Starger, J. L.; Garven, G.; Tivey, M. K.

    2016-12-01

    A two-dimensional finite-element code known as RST2D [1] is being used to study the geothermal energy, geohydrology, and geochemistry of fluid convection in seafloor hydrothermal systems such as the Juan de Fuca Ridge, East Pacific Rise, and TAG hydrothermal fields. Relative to black smoker vents and other discharge features, submarine recharge zones are understudied. We are attempting to model both the recharge and discharge limbs of these flow fields as a coupled system by mathematically and physically linking the fluid dynamics, heat flow, and geochemical reactions. Numerical simulations have been made to quantify likely flow rates and relevant geochemical water-rock reactions including mineral precipitation and dissolution using a fully-coupled reactive flow modeling approach. In particular, the reactive flow model is being used to predict the formation, likely spatial-temporal distribution, and preservation of anhydrite in the hydrothermal recharge zone and its feedback influence on permeability, fluid flow, and heat transport in the discharge zone. We are focusing on the geochemical effects and controls of on- and off-ridge geology and geometry, permeability-porosity, vent width and geometry, and thermal boundary conditions on the predicted size and extent of the recharge and discharge zones, and whether hydrothermal recharge is focused along extensional faults or diffused across broad areas of the seafloor. Hydrothermal flow systems of this type are known to represent modern analogs for ancient systems such as those being studied for understanding the origin of life on the planet, but also as modern analogs for the formation of volcanogenic massive sulfide ore deposits. Reactive flow modeling provides a useful tool for developing a better understanding of the physiobiochemistry of these episodic flow systems, and could potentially guide exploration for modern and ancient ore deposits. [1] Raffensperger, J.P.,1996, Advances in Porous Media 3, 185 - 305.

  14. Hydrothermal Biogeochemistry

    Science.gov (United States)

    Shock, E.; Havig, J.; Windman, T.; Meyer-Dombard, D.; Michaud, A.; Hartnett, H.

    2006-12-01

    Life in hot spring ecosystems is confronted with diverse challenges, and the responses to those challenges have dynamic biogeochemical consequences over narrow spatial and temporal scales. Within meters along hot spring outflow channels at Yellowstone, temperatures drop from boiling, and the near-boiling conditions of hot chemolithotrophic communities, to those that permit photosynthesis and on down to conditions where nematodes and insects graze on the edges of photosynthetic mats. Many major and trace element concentrations change only mildly in the water that flows through the entire ecosystem, while concentrations of other dissolved constituents (oxygen, sulfide, ammonia, total organic carbon) increase or decrease dramatically. Concentrations of metals and micronutrients range from toxic to inadequate for enzyme synthesis depending on the choice of hot spring. Precipitation of minerals may provide continuous growth of microbial niches, while dissolution and turbulent flow sweeps them away. Consequently, microbial communities change at the meter scale, and even more abruptly at the photosynthetic fringe. Isotopic compositions of carbon and nitrogen in microbial biomass reflect dramatic and continuous changes in metabolic strategies throughout the system. Chemical energy sources that support chemolithotrophic communities can persist at abundant or useless levels, or change dramatically owing to microbial activity. The rate of temporal change depends on the selection of hot spring systems for study. Some have changed little since our studies began in 1999. Others have shifted by two or more units in pH over several years, with corresponding changes in other chemical constituents. Some go through daily or seasonal desiccation cycles, and still others exhibit pulses of changing temperature (up to 40°C) within minutes. Taken together, hydrothermal ecosystems provide highly manageable opportunities for testing how biogeochemical processes respond to the scale of

  15. Cu and Fe Isotope Variation in Candelaria Sulfides: Tracing to Origin of Fluid Components in a Stratiform Ore Deposit

    Science.gov (United States)

    Graham, S.; Griffin, W.; Pearson, N.; Jackson, S.; O'Reilly, S.; Rutherford, R.

    2004-05-01

    We have used LA-MC-ICPMS to determine Cu and Fe isotope ratios in chalcopyrite and pyrite from a stratigraphic section through the stratiform Candelaria Cu-Au deposit. Chalcopyrite ɛ 65Cu range from -11 to +6 (n = 85), many of which are 65Cu depleted when compared to chalcopyrite from igneous porphyry systems. However, chalcopyrite from the Candelaria open-pit have ɛ 65Cu overlapping porphyry systems, suggesting an igneous source for the Cu in the massive ore. Very low ɛ 65Cu in sequences above the Candelaria open-pit may reflect the vapor transport of Cu, or fluid mixing. Chalcopyrite ɛ 57Fe range from -22 to +4 (n = 102), but the majority cluster between -22 and -8, and are indistinguishable from those in porphyry deposits. In contrast, the ɛ 57Fe of pyrite (n = 111) show a bi-modal distribution, with ɛ 57Fe ranging between -25 to -10 and -2 to +15. The high ɛ 57Fe are indistinguishable from igneous porphyry pyrite (ɛ 57Fe = 0 to +12) and provide unambiguous evidence for the involvement of an igneous component in Candelaria ore genesis. However, the low ɛ 57Fe pyrites also suggest the involvement of another Fe source. Three samples, from the west, central and eastern zones of the Candelaria open-pit show evidence for interaction between the igneous and, presumably, crustal fluids. Chalcopyrite and pyrite from the western-most sample, near a shear zone, have Cu and Fe isotope variations similar to those observed in igneous porphyry deposits. In contrast, chalcopyrite and pyrite from the eastern-most sample, near a major fault, have an igneous-like ɛ 65Cu, but the chalcopyrite and pyrite ɛ 57Fe are unlike that observed in porphyry systems. The Cu and Fe isotope variations of the central sample are intermediate between the western and eastern samples. These variations undoubtedly result from mixing between Fe from an igneous fluid from the shear zone and Fe from a crustal fluid from the fault zone.

  16. The origin and hydrothermal mobilization of carbonaceous matter associated with Paleoproterozoic orogenic-type gold deposits of West Africa

    Czech Academy of Sciences Publication Activity Database

    Kříbek, B.; Sýkorová, Ivana; Machovič, V.; Knésl, I.; Laufek, F.; Zachariáš, J.

    2015-01-01

    Roč. 270, November 01 (2015), s. 300-317 ISSN 0301-9268 Institutional support: RVO:67985891 Keywords : carbonaceous matter * gold deposits * graphite Subject RIV: DB - Geology ; Mineralogy Impact factor: 4.037, year: 2015

  17. The Hydrothermal Chemistry of Gold, Arsenic, Antimony, Mercury and Silver

    Energy Technology Data Exchange (ETDEWEB)

    Bessinger, Brad; Apps, John A.

    2003-03-23

    A comprehensive thermodynamic database based on the Helgeson-Kirkham-Flowers (HKF) equation of state was developed for metal complexes in hydrothermal systems. Because this equation of state has been shown to accurately predict standard partial molal thermodynamic properties of aqueous species at elevated temperatures and pressures, this study provides the necessary foundation for future exploration into transport and depositional processes in polymetallic ore deposits. The HKF equation of state parameters for gold, arsenic, antimony, mercury, and silver sulfide and hydroxide complexes were derived from experimental equilibrium constants using nonlinear regression calculations. In order to ensure that the resulting parameters were internally consistent, those experiments utilizing incompatible thermodynamic data were re-speciated prior to regression. Because new experimental studies were used to revise the HKF parameters for H2S0 and HS-1, those metal complexes for which HKF parameters had been previously derived were also updated. It was found that predicted thermodynamic properties of metal complexes are consistent with linear correlations between standard partial molal thermodynamic properties. This result allowed assessment of several complexes for which experimental data necessary to perform regression calculations was limited. Oxygen fugacity-temperature diagrams were calculated to illustrate how thermodynamic data improves our understanding of depositional processes. Predicted thermodynamic properties were used to investigate metal transport in Carlin-type gold deposits. Assuming a linear relationship between temperature and pressure, metals are predicted to predominantly be transported as sulfide complexes at a total aqueous sulfur concentration of 0.05 m. Also, the presence of arsenic and antimony mineral phases in the deposits are shown to restrict mineralization within a limited range of chemical conditions. Finally, at a lesser aqueous sulfur

  18. SHRIMP U–Pb and REE data pertaining to the origins of xenotime in Belt Supergroup rocks: evidence for ages of deposition, hydrothermal alteration, and metamorphism

    Science.gov (United States)

    Aleinikoff, John N.; Lund, Karen; Fanning, C. Mark

    2015-01-01

    The Belt–Purcell Supergroup, northern Idaho, western Montana, and southern British Columbia, is a thick succession of Mesoproterozoic sedimentary rocks with an age range of about 1470–1400 Ma. Stratigraphic layers within several sedimentary units were sampled to apply the new technique of U–Pb dating of xenotime that sometimes forms as rims on detrital zircon during burial diagenesis; xenotime also can form epitaxial overgrowths on zircon during hydrothermal and metamorphic events. Belt Supergroup units sampled are the Prichard and Revett Formations in the lower Belt, and the McNamara and Garnet Range Formations and Pilcher Quartzite in the upper Belt. Additionally, all samples that yielded xenotime were also processed for detrital zircon to provide maximum age constraints for the time of deposition and information about provenances; the sample of Prichard Formation yielded monazite that was also analyzed. Ten xenotime overgrowths from the Prichard Formation yielded a U–Pb age of 1458 ± 4 Ma. However, because scanning electron microscope – backscattered electrons (SEM–BSE) imagery suggests complications due to possible analysis of multiple age zones, we prefer a slightly older age of 1462 ± 6 Ma derived from the three oldest samples, within error of a previous U–Pb zircon age on the syn-sedimentary Plains sill. We interpret the Prichard xenotime as diagenetic in origin. Monazite from the Prichard Formation, originally thought to be detrital, yielded Cretaceous metamorphic ages. Xenotime from the McNamara and Garnet Range Formations and Pilcher Quartzite formed at about 1160– 1050 Ma, several hundred million years after deposition, and probably also experienced Early Cretaceous growth. These xenotime overgrowths are interpreted as metamorphic–diagenetic in origin (i.e., derived during greenschist facies metamorphism elsewhere in the basin, but deposited in sub-greenschist facies rocks). Several xenotime grains are older detrital grains of igneous

  19. Effect of sulfurization time on the properties of copper zinc tin sulfide thin films grown by electrochemical deposition

    Science.gov (United States)

    Aldalbahi, Ali; Mkawi, E. M.; Ibrahim, K.; Farrukh, M. A.

    2016-01-01

    We report growth of quaternary Cu2 ZnSnS4 (CZTS) thin films prepared by the electrochemical deposition from salt precursors containing Cu (II), Zn (II) and Sn (IV) metals. The influence of different sulfurization times t (t = 75, 90, 105, and 120 min) on the structural, compositional, morphological, and optical properties, as well as on the electrical properties is studied. The films sulfurized 2 hours showed a prominent kesterite phase with a nearly stoichiometric composition. Samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and Raman and UV-VIS-NIR spectrometer at different stages of work. X-ray diffraction and Raman spectroscopy analyses confirmed the formation of phase-pure CZTS films. (FESEM) shows that compact and dense morphology and enhanced photo-sensitivity. STEM - EDS elemental map of CZTS cross-section confirms homogeneous distribution. From optical study, energy gap was enlarged with a changed sulfurization times in the range of 1.37–1.47 eV. PMID:27600023

  20. Effect of sulfurization time on the properties of copper zinc tin sulfide thin films grown by electrochemical deposition.

    Science.gov (United States)

    Aldalbahi, Ali; Mkawi, E M; Ibrahim, K; Farrukh, M A

    2016-09-07

    We report growth of quaternary Cu2 ZnSnS4 (CZTS) thin films prepared by the electrochemical deposition from salt precursors containing Cu (II), Zn (II) and Sn (IV) metals. The influence of different sulfurization times t (t = 75, 90, 105, and 120 min) on the structural, compositional, morphological, and optical properties, as well as on the electrical properties is studied. The films sulfurized 2 hours showed a prominent kesterite phase with a nearly stoichiometric composition. Samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and Raman and UV-VIS-NIR spectrometer at different stages of work. X-ray diffraction and Raman spectroscopy analyses confirmed the formation of phase-pure CZTS films. (FESEM) shows that compact and dense morphology and enhanced photo-sensitivity. STEM - EDS elemental map of CZTS cross-section confirms homogeneous distribution. From optical study, energy gap was enlarged with a changed sulfurization times in the range of 1.37-1.47 eV.

  1. Magnetization distribution of hydrothermal deposits from three component magnetometer survey using ROV in the Lau Basin, the southwestern Pacific

    Science.gov (United States)

    Kim, C.; Choi, S.; Park, C.

    2013-12-01

    Deep sea three component magnetic surveys, using ROV (Remotely Operated Vehicle), were conducted at Apr., 2011 and Jan., 2012 in TA25 and TA26 seamounts, the Lau Basin, the southwestern Pacific. At 2011, the survey area was only the western slope of the caldera of TA25 using IBRV(Ice Breaker Research Vessel) ARAON of KIOST (Korea Institute of Ocean Science & Technology) and ROV of Oceaneering Co. And, at Jan. 2012, the magnetic survey was conducted in the western (site A) and eastern (site B) slopes of the caldera of TA25 and the summit area of TA26 using German R/V SONNE and ROV of ROPOS Co. The 2011 and 2012 three component magnetic survey lines were the 13 N-S lines and the 29 N-S lines (TA25-East : 12 lines, TA25-West : 11 lines, TA26 : 6 lines) with about 100 m spacing, respectively. Also, we conducted the 8 figure circle rotation survey of ROV for magnetic calibration at 2011 and 2012. For the magnetic survey, the magnetometer sensor was attached with the line frame of ROV and the data logger and motion sensor in ROV. The three component magnetometer measure the X (North), Y (East) and Z (Vertical) vector components of a magnetic field. A motion sensor (Octans) provided us the data of pitch, roll, yaw for the correction of the magnetic data to the motion of ROV. In the survey, ROV followed the tracks of the plan at 50 m above seafloor. The data of the magnetometer and motion sensors and the USBL(Ultra Short Base Line) data of the position of ROV were recorded on a notebook through the optical cable of ROV. Hydrothermal fluids over Curie temperature can quickly alter or replace the iron-rich magnetic minerals, reducing the magnetic remanence of the crustal rocks, in some cases to near 0 A/m magnetization. Low magnetization zones occur in the south-western and northern parts of TA25 site A and the south-south-western, north-western and central parts of TA25 site B. TA26 has low magnetization zones in the central part. The low magnetization zones of the survey

  2. Fingerprinting the Hydrothermal Fluid Characteristics from LA-ICP-MS Trace Element Geochemistry of Garnet in the Yongping Cu Deposit, SE China

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    Yu Zhang

    2017-10-01

    Full Text Available The large Yongping Cu deposit is situated in the eastern Qin-Hang Metallogenic Belt, Southeast China and on the southern side of the Yangtze—Cathaysia suture zone, and is characterized by large stratiform orebodies. Garnet represents the main non-metallic mineral at Yongping, and shows variations in color from dark red to green to light brown with distance from the Shizitou porphyritic biotite granite stock. An in situ elemental analysis using EPMA and LA-ICP-MS and fluid inclusions microthermometric measurement on the Yongping garnet were conducted to constrain the hydrothermal and physicochemical mineralization conditions and the ore origin. The Yongping garnet ranges from nearly pure to impure andradite, is characterized by low concentrations of MnO (0.11–0.71 wt % with a wide range of Y/Ho (2.1–494.9 and does not exhibit any melting inclusions or fluid-melt inclusions, indicating that they are likely to be resulted from hydrothermal replacements. The Yongping garnet is rich in LREEs, Cs, Th, U and Pb; relatively depleted in HREEs, Rb, Sr and Ba; but exhibits distinct Eu anomalies (δEu of the dark red, green and light brown garnet range 2.12–20.54, 0.74–1.70 and 0.52–0.85, respectively with the homogenization temperatures and salinities of the fluid inclusions principally ranging from 387–477 °C and 7.8–16.0 wt % NaCl equivalent, respectively. The distinct trace elements and microthermometric characteristics reveal that the garnet was formed in a physicochemical conditions of medium-high temperature, 44–64 MPa pressures, mildly acidic pH levels, and unstable oxygen fugacity, and indicate that they were primarily formed by infiltration metasomatism, quite fitting with the scenario that the preferential entrance of magmatic-hydrothermal fluids derived from the Shizitou stock into the relatively low-pressure fracture zones between the limestone and quartz sandstone in the Yejiawan Formation, and further led to the formation

  3. The effect of ZnO nanorod growth duration by hydrothermal deposition method to the photovoltaic properties

    Science.gov (United States)

    Ali, Engku Abd Ghapur Engku; Rezali, Roslinda

    2012-11-01

    In this study, the effect of time in hydrothermal method to the growth of ZnO nanorods at low temperature was investigated. The substrate is prepared through three stages which are the seeding stage, the growth stage and the dye sensitized stage. The morphology of the ZnO growth was measured using the Scanning Electron Microscope (SEM). Efficiency was verified by the growth duration of 2, 4 and 8 hours. The current and voltage of the thin films were measured by using two point probes under dark and different light intensity of 10, 20, 50 and 100 Wm-2. The efficiency under light intensity was increased with increasing growth duration. Growth duration of 8 hours combined with Bis(2,2'-bipyridine)-4,4'-dicarboxybipyridine-ruthenium di(N-succinimidyl ester) bis(hexafluorophosphate) and 1-butyl-2,3-dimethylimidazolium chloride thin films on indium tin oxide (ITO) thin films are suitable to increase the efficiency of the device under 100 W/m2 intensity of light which is 1.2 7%.

  4. Integrating Data of ASTER and Landsat-8 OLI (AO for Hydrothermal Alteration Mineral Mapping in Duolong Porphyry Cu-Au Deposit, Tibetan Plateau, China

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    Tingbin Zhang

    2016-10-01

    Full Text Available One of the most important characteristics of porphyry copper deposits (PCDs is the type and distribution pattern of alteration zones which can be used for screening and recognizing these deposits. Hydrothermal alteration minerals with diagnostic spectral absorption properties in the visible and near-infrared (VNIR through the shortwave infrared (SWIR regions can be identified by multispectral and hyperspectral remote sensing data. Six Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER bands in SWIR have been shown to be effective in the mapping of Al-OH, Fe-OH, Mg-OH group minerals. The five VNIR bands of Landsat-8 (L8 Operational Land Imager (OLI are useful for discriminating ferric iron alteration minerals. In the absence of complete hyperspectral coverage area, an opportunity, however, exists to integrate ASTER and L8-OLI (AO to compensate each other’s shortcomings in covering area for mineral mapping. This study examines the potential of AO data in mineral mapping in an arid area of the Duolong porphyry Cu-Au deposit(Tibetan Plateau in China by using spectral analysis techniques. Results show the following conclusions: (1 Combination of ASTER and L8-OLI data (AO has more mineral information content than either alone; (2 The Duolong PCD alteration zones of phyllic, argillic and propylitic zones are mapped using ASTER SWIR bands and the iron-bearing mineral information is best mapped using AO VNIR bands; (3 The multispectral integration data of AO can provide a compensatory data of ASTER VNIR bands for iron-bearing mineral mapping in the arid and semi-arid areas.

  5. Calcite veining and feeding conduits in a hydrothermal system: Insights from a natural section across the Pleistocene Gölemezli travertine depositional system (western Anatolia, Turkey)

    Science.gov (United States)

    Capezzuoli, Enrico; Ruggieri, Giovanni; Rimondi, Valentina; Brogi, Andrea; Liotta, Domenico; Alçiçek, Mehmet Cihat; Alçiçek, Hülya; Bülbül, Ali; Gandin, Anna; Meccheri, Marco; Shen, Chuan-Chou; Baykara, Mehmet Oruç

    2018-02-01

    Linking the architecture of structural conduits with the hydrothermal fluids migrating from the reservoir up to the surface is a key-factor in geothermal research. A contribution to this achievement derives from the study of spring-related travertine deposits, but although travertine depositional systems occur widely, their feeding conduits are only rarely exposed. The integrated study carried out in the geothermal Gölemezli area, nearby the well-known Pamukkale area (Denizli Basin, western Anatolia, Turkey), focused on onyx-like calcite veins (banded travertine) and bedded travertine well exposed in a natural cross-section allowing the reconstruction of the shallower part of a geothermal system. The onyx-like veins represent the thickest vein network (> 150 m) so far known. New field mapping and structural/kinematic analyses allowed to document a partially dismantled travertine complex (bedded travertine) formed by proximal fissure ridges and distal terraced/pools depositional systems. The banded calcite veins, WNW-trending and up to 12 m thick, developed within a > 200 m thick damaged rock volume produced by parallel fault zones. Th/U dating indicates a long lasting (middle-late Pleistocene) fluids circulation in a palaeo-geothermal system that, due to its location and chemical characteristics, can be considered the analogue of the nearby, still active, Pamukkale system. The isotopic characteristics of the calcite veins together with data from fluid inclusions analyses, allow the reconstruction of some properties (i.e. temperature, salinity and isotopic composition) and processes (i.e. temperature variation and intensity of degassing) that characterized the parent fluids and the relation between degassing intensity and specific microfabric of calcite crystals (elongated/microsparite-micrite bands), controlled by changes/fluctuations of the physico-chemical fluid characteristics.

  6. Hydrothermal fluoride and chloride complexation of indium: an EXAFS study

    Science.gov (United States)

    Loges, Anselm; Testemale, Denis; Huotari, Simo; Honkanen, Ari-Pekka; Potapkin, Vasily; Wagner, Thomas

    2017-04-01

    Indium (In) is one of the geochemically lesser studied ore metals, and the factors that control the hydrothermal transport and deposition are largely unknown. It has no ore deposits of its own and is commonly mined as a by-product of Zn ores, and there are very few minerals that contain In as an essential structural component. Recently, industrial application of In in touch screen devices has drastically increased demand, which is projected to exceed supply from the current sources in the near future. Since the most relevant In sources are hydrothermal sphalerite ores and to a lesser extent hydrothermal greisen-type deposits in evolved granitic plutons, the aqueous geochemistry of In is of particular interest for understanding its ore forming processes. As a first step towards a comprehensive model for hydrothermal In solubility and speciation, we have studied In speciation in fluoride and chloride bearing solutions at 30-400˚ C and 500 bar using X-Ray Absorption Spectroscopy (XAS) measurements. The experiments were conducted in a unique hydrothermal autoclave setup at beamline BM30B-FAME at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. Our results show that the complexation of In changes dramatically between 30 and 400˚ C. Below ca. 200˚ C, fluoride complexes are the most stable ones, but they break down at higher temperatures. Chloride complexes on the other hand become increasingly stable with increasing temperature. This behavior has interesting consequences for natural ore forming systems. In Cl-rich systems (e.g. massive sulfide ores formed in sea floor environments), cooling can be an effective precipitating mechanism. In F-rich systems, fluoride complexation can extend In mobility to low temperatures and In will only precipitate when F is effectively removed from the fluid, e.g. by mixing with a Ca-rich fluid and precipitation of fluorite (CaF2) as is commonly observed in skarn or greisen-type deposits. Due to In complexing with

  7. Bismoclite (BiOCl in the San Francisco de los Andes Bi–Cu–Au Deposit, Argentina. First Occurrence of a Bismuth Oxychloride in a Magmatic–Hydrothermal Breccia Pipe and Its Usefulness as an Indicator Phase in Mineral Exploration

    Directory of Open Access Journals (Sweden)

    Francisco J. Testa

    2016-06-01

    Full Text Available The rare bismuth oxychloride, bismoclite (BiOCl, has been identified in the weathered tourmaline–cemented, magmatic–hydrothermal breccia complex at the San Francisco de los Andes Bi–Cu–Au deposit, Argentina. A wide variety of supergene minerals were detected in the oxidized zone, but only preisingerite (Bi3(AsO42O(OH is intimately associated with bismoclite. Bismuth arsenate is present either as minor accessory phases or as traces in bismoclite-rich samples. This is the first documented occurrence of bismoclite in a porphyry-related, and magmatic–hydrothermal breccia pipe deposit. Bismoclite is interpreted to have formed by weathering of hypogene bismuthinite (Bi2S3, which originally occurred with arsenopyrite to cement the breccias. These appear to have reacted with O2- and HCl-bearing meteoric waters to produce pockets of supergene bismoclite–preisingerite assemblages. Bismoclite samples have been characterized by means of X-ray diffractometry (XRD, geochemistry, petrography, scanning electron microscopy (SEM, differential thermal analysis–thermogravimetry analysis (DTA–TGA and infrared analysis (IR providing useful insights and updated information regarding this rare bismuth oxychloride and associated arsenate mineral. The San Francisco de los Andes breccia complex shows similar geometry, morphology and internal organization as those found in traditional magmatic–hydrothermal breccias associated with Cu–Mo porphyry deposits. Bismoclite and preisingerite form due to the presence of hypogene Bi-bearing minerals followed by appropriate supergene conditions. These hypogene minerals commonly occur only as trace phases, or are entirely absent, in porphyry and related magmatic–hydrothermal breccia deposits. The scarcity of hypogene Bi–mineral phases in porphyry and related magmatic–hydrothermal breccia deposits is the main reason why bismoclite has not previously been reported in these types of deposits. The detection of

  8. Age constraints on the hydrothermal history of the Prominent Hill iron oxide copper-gold deposit, South Australia

    Science.gov (United States)

    Bowden, Bryan; Fraser, Geoff; Davidson, Garry J.; Meffre, Sebastien; Skirrow, Roger; Bull, Stuart; Thompson, Jay

    2017-08-01

    The Mesoproterozoic Prominent Hill iron-oxide copper-gold deposit lies on the fault-bound southern edge of the Mt Woods Domain, Gawler Craton, South Australia. Chalcocite-bornite-chalcopyrite ores occur in a hematitic breccia complex that has similarities to the Olympic Dam deposit, but were emplaced in a shallow water clastic-carbonate package overlying a thick andesite-dacite pile. The sequence has been overturned against the major, steep, east-west, Hangingwall Fault, beyond which lies the clastic to potentially evaporitic Blue Duck Metasediments. Immediately north of the deposit, these metasediments have been intruded by dacite porphyry and granitoid and metasomatised to form magnetite-calc-silicate skarn ± pyrite-chalcopyrite. The hematitic breccia complex is strongly sericitised and silicified, has a large sericite ± chlorite halo, and was intruded by dykes during and after sericitisation. This paper evaluates the age of sericite formation in the mineralised breccias and provides constraints on the timing of granitoid intrusion and skarn formation in the terrain adjoining the mineralisation. The breccia complex contains fragments of granitoid and porphyry that are found here to be part of the Gawler Range Volcanics/Hiltaba Suite magmatic event at 1600-1570 Ma. This indicates that some breccia formation post-dated granitoid intrusion. Monazite and apatite in Fe-P-REE-albite metasomatised granitoid, paragenetically linked with magnetite skarn formation north of the Hangingwall Fault, grew soon after granitoid intrusion, although the apatite experienced U-Pb-LREE loss during later fluid-mineral interaction; this accounts for its calculated age of 1544 ± 39 Ma. To the south of the fault, within the breccia, 40Ar-39Ar ages yield a minimum age of sericitisation (+Cu+Fe+REE) of dykes and volcanics of ˜1575 Ma, firmly placing Prominent Hill ore formation as part of the Gawler Range Volcanics/Hiltaba Suite magmatic event within the Olympic Cu-Au province of the

  9. Homogenization Experiments of Crystal-Rich Inclusions in Spodumene from Jiajika Lithium Deposit, China, under Elevated External Pressures in a Hydrothermal Diamond-Anvil Cell

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    Jiankang Li

    2017-01-01

    Full Text Available Extensive studies of the crystal-rich inclusions (CIs hosted in minerals in pegmatite have resulted in substantially different models for the formation mechanism of the pegmatite. In order to evaluate these previously proposed formation mechanisms, the total homogenization processes of CIs hosted in spodumene from the Jiajika pegmatite deposit in Sichuan, China, were observed in situ under external H2O pressures in a new type of hydrothermal diamond-anvil cell (HDAC. The CIs in a spodumene chip were loaded in the sample chamber of HDAC with water, such that the CIs were under preset external H2O pressures during heating to avoid possible decrepitation. Our in situ observations showed that the crystals within the CIs were dissolved in carbonic-rich aqueous fluid during heating and that cristobalite was usually the first mineral being dissolved, followed by zabuyelite and silicate minerals until their total dissolution at temperatures between 500 and 720°C. These observations indicated that the minerals within the CIs were daughter minerals crystallized from an entrapped carbonate- and silica-rich aqueous solution and therefore provided useful information for evaluating the formation models of granitic pegmatites.

  10. In situ deposition of graphene nanosheets on wood surface by one-pot hydrothermal method for enhanced UV-resistant ability

    Science.gov (United States)

    Wan, Caichao; Jiao, Yue; Li, Jian

    2015-08-01

    Graphene nanosheets were successfully in situ deposited on the surface of the wood matrix via a mild fast one-pot hydrothermal method, and the resulting hybrid graphene/wood (GW) were characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Raman spectroscopy, and thermogravimetric analysis (TGA). According to the results, the wood matrix was evenly coated by dense uninterrupted multilayer graphene membrane structure, which was formed by layer-by-layer self-assembly of graphene nanosheets. Meanwhile, the graphene coating also induced significant improvement in the thermal stability of GW in comparison with that of the original wood (OW). Accelerated weathering tests were employed to measure and determine the UV-resistant ability of OW and GW. After about six hundred hours of experiments, the surface color change of GW was much less than that of OW; besides, the Fourier transform infrared spectroscopy (FTIR) analysis also proved the less significant changes in surface chemical compositions of GW. The results both indicated that the graphene coating effectively protected wood surface from UV damage. Therefore, this class of GW composite might be expected to be served as high-performance wooden building material for outdoor or some particular harsh environments like strong UV radiation regions use.

  11. Hydrothermal minerals

    Digital Repository Service at National Institute of Oceanography (India)

    Nath, B.N.

    , radon etc. to locate active venting site 4. Seabed sampling for rocks and minerals looking for indications of hydrothermal mineralization 5. TV and still Photographic surveys with real- time imaging on board 6. Submersible/ROVs for direct... thriving in this unique environments. However, the study of hydrothermal systems is still relatively young, and there are many fundamental questions that remain to be addressed in the forthcoming years. Suggested reading 1. Seafloor hydrothermal...

  12. Petrology and Geochemistry of Hydrothermally Altered Volcanic Rocks in the Iheya North Hydrothermal Field, Middle Okinawa Trough

    Science.gov (United States)

    Yamasaki, T.

    2015-12-01

    The Iheya North hydrothermal field is located in the middle Okinawa Trough, a young and actively spreading back-arc basin extending behind the Ryukyu arc-trench system in the southeastern margin of the East China Sea. In this hydrothermal field, two scientific drilling expeditions (IODP Exp 331 and SIP CK14-04) were conducted using a deep-sea drilling vessel "Chikyu," and samples from a total of 27 holes were taken. Through these expeditions, Kuroko-type volcanogenic massive sulfide deposits (VMS), hydrothermally altered volcanic rocks, and pumiceous and pelagic sediments were recovered. The recovered core provided important information about the relationship between hydrothermal activity, alteration, and ore mineralization. Whole-rock major element composition and trace element (TE) patterns of pumices were very similar to those of rhyolites in the middle Okinawa Trough (RMO). However, pumices were relatively enriched in chalcophile elements Sr and Nb, which suggest incipient mineralization. Volcanic rock generally demonstrated strong silicification and was greenish pale gray in color. Regardless of severe alteration, some rock displayed major element composition broadly similar to the RMO. Alteration was evidenced by an increase in the content of SiO2 and MgO, and decrease in Al2O3, Na2O, and K2O content. The most striking geochemical feature of altered volcanic rock was the discordance between texture and the degree of modification of TEs. Some samples showed decussate texture occupied by petal-like quartz with severe silicification, but no prominent disturbance of concentration and patterns of TEs were observed. In contrast, samples with well-preserved igneous porphyritic texture showed very low TE content and modification of TE patterns. These results suggest that the modification of texture and composition of TEs, as well as silicification, do not occur by a uniform process, but several processes. This may reflect the differences in temperature and the

  13. Lithium isotope traces magmatic fluid in a seafloor hydrothermal system.

    Science.gov (United States)

    Yang, Dan; Hou, Zengqian; Zhao, Yue; Hou, Kejun; Yang, Zhiming; Tian, Shihong; Fu, Qiang

    2015-09-08

    Lithium isotopic compositions of fluid inclusions and hosted gangue quartz from a giant volcanogenic massive sulfide deposit in China provide robust evidence for inputting of magmatic fluids into a Triassic submarine hydrothermal system. The δ(7)Li results vary from +4.5‰ to +13.8‰ for fluid inclusions and from +6.7‰ to +21.0‰ for the hosted gangue quartz(9 gangue quartz samples containing primary fluid inclusions). These data confirm the temperature-dependent Li isotopic fractionation between hydrothermal quartz and fluid (i.e., Δδ(7)Liquartz-fluid = -8.9382 × (1000/T) + 22.22(R(2) = 0.98; 175 °C-340 °C)), which suggests that the fluid inclusions are in equilibrium with their hosted quartz, thus allowing to determine the composition of the fluids by using δ(7)Liquartz data. Accordingly, we estimate that the ore-forming fluids have a δ(7)Li range from -0.7‰ to +18.4‰ at temperatures of 175-340 °C. This δ(7)Li range, together with Li-O modeling , suggest that magmatic fluid played a significant role in the ore formation. This study demonstrates that Li isotope can be effectively used to trace magmatic fluids in a seafloor hydrothermal system and has the potential to monitor fluid mixing and ore-forming process.

  14. Evolution of ore deposits on terrestrial planets

    Science.gov (United States)

    Burns, R. G.

    1991-01-01

    Ore deposits on terrestrial planets materialized after core formation, mantle evolution, crustal development, interactions of surface rocks with the hydrosphere and atmosphere, and, where life exists on a planet, the involvement of biological activity. Core formation removed most of the siderophilic and chalcophilic elements, leaving mantles depleted in many of the strategic and noble metals relative to their chondritic abundances. Basaltic magma derived from partial melting of the mantle transported to the surface several metals contained in immiscible silicate and sulfide melts. Magmatic ore deposits were formed during cooling, fractional crystallization and density stratification from the basaltic melts. Such ore deposits found in earth's Archean rocks were probably generated during early histories of all terrestrial planets and may be the only types of igneous ores on Mars. Where plate tectonic activity was prevalent on a terrestrial planet, temporal evolution of ore deposits took place. Repetitive episodes of subduction modified the chemical compositions of the crust and upper mantles, leading to porphyry copper and molybdenum ores in calc-alkaline igneous rocks and granite-hosted tin and tungsten deposits. Such plate tectonic-induced mineralization in relatively young igneous rocks on earth may also have produced hydrothermal ore deposits on Venus in addition to the massive sulfide and cumulate chromite ores associated with Venusian mafic igneous rock. Sedimentary ore deposits resulting from mechanical and chemical weathering in reducing atmospheres in Archean earth included placer deposits (e.g., uraninite, gold, pyrite ores). Chromite, ilmenite, and other dense unreactive minerals could also be present on channel floors and in valley networks on Mars, while banded iron formations might underlie the Martian northern plains regions. As oxygen evolved in earth's atmosphere, so too did oxide ores. By analogy, gossans above sulfide ores probably occur on Mars

  15. Sulfur and oxygen isotopic study of Paleozoic sediment-hosted Zn-Pb(-Ag-Au-Ba-F) deposits and associated hydrothermal alteration zones in the Nome Complex, Seward Peninsula, Alaska

    Science.gov (United States)

    Shanks, W.C. Pat; Slack, John F.; Till, Alison B.; Thurston, Roland; Gemery-Hill, Pamela

    2014-01-01

    Results of sulfur and oxygen isotope studies of sedimentary exhalative (SEDEX) Zn-Pb(-Ag-Au-Ba-F) deposits hosted in metamorphosed Paleozoic clastic and carbonate rocks of the Nome Complex, Seward Peninsula, Alaska, are consistent with data for similar deposits worldwide. Stable isotopic studies of the Nome Complex are challenging because the rocks have undergone Mesozoic blueschist- and greenschist-facies metamorphism and deformation at temperatures estimated from 390–490 °C. Studies of sulfur and oxygen isotopes in other areas suggest that, in the absence of chemical and mineralogical evidence for metasomatism, the principal effect of metamorphism is re-equilibration between individual minerals at the temperature of metamorphism, which commonly leads to a narrowing of the overall range of isotope values for a suite of rocks, but generally does not significantly modify the average whole rock value for that suite. Sulfur isotope studies of the stratabound and locally stratiform sulfide lenses at the Aurora Creek-Christophosen deposit, which is of possible Late Devonian-early Carboniferous age, show a large range of δ34Ssulfide values from -9.7 to 39.4‰, suggesting multiple sulfur sources and possibly complex processes of sulfide formation that may include bacterial sulfate reduction, thermochemical sulfate reduction, and Rayleigh distillation. Low δ34S values probably represent bacterial sulfide minerals remobilized from the host metasedimentary rocks either during the original seafloor mineralization or are related to a Cretaceous mineralizing event that produced Au-vein and base-metal replacement deposits; the latter process is supported by Pb isotope data. The Wheeler North deposit is similar to Aurora Creek-Christophosen but does not have negative δ34S values. It also probably formed in an euxinic sub-basin.

  16. Supergene destruction of a hydrothermal replacement alunite deposit at Big Rock Candy Mountain, Utah: Mineralogy, spectroscopic remote sensing, stable-isotope, and argon-age evidences

    Science.gov (United States)

    Cunningham, C.G.; Rye, R.O.; Rockwell, B.W.; Kunk, M.J.; Councell, T.B.

    2005-01-01

    Big Rock Candy Mountain is a prominent center of variegated altered volcanic rocks in west-central Utah. It consists of the eroded remnants of a hypogene alunite deposit that, at ???21 Ma, replaced intermediate-composition lava flows. The alunite formed in steam-heated conditions above the upwelling limb of a convection cell that was one of at least six spaced at 3- to 4-km intervals around the margin of a monzonite stock. Big Rock Candy Mountain is horizontally zoned outward from an alunite core to respective kaolinite, dickite, and propylite envelopes. The altered rocks are also vertically zoned from a lower pyrite-propylite assemblage upward through assemblages successively dominated by hypogene alunite, jarosite, and hematite, to a flooded silica cap. This hydrothermal assemblage is undergoing natural destruction in a steep canyon downcut by the Sevier River in Marysvale Canyon. Integrated geological, mineralogical, spectroscopic remote sensing using AVIRIS data, Ar radiometric, and stable isotopic studies trace the hypogene origin and supergene destruction of the deposit and permit distinction of primary (hydrothermal) and secondary (weathering) processes. This destruction has led to the formation of widespread supergene gypsum in cross-cutting fractures and as surficial crusts, and to natrojarosite, that gives the mountain its buff coloration along ridges facing the canyon. A small spring, Lemonade Spring, with a pH of 2.6 and containing Ca, Mg, Si, Al, Fe, Mn, Cl, and SO4, also occurs near the bottom of the canyon. The 40Ar/39 Ar age (21.32??0.07 Ma) of the alunite is similar to that for other replacement alunites at Marysvale. However, the age spectrum contains evidence of a 6.6-Ma thermal event that can be related to the tectonic activity responsible for the uplift that led to the downcutting of Big Rock Candy Mountain by the Sevier River. This ???6.6 Ma event also is present in the age spectrum of supergene natrojarosite forming today, and probably dates

  17. A comparative mineralogical study of Te-rich magmatic-hydrothermal systems in northeastern Greece

    Science.gov (United States)

    Voudouris, P.

    2006-07-01

    Several magmatic-hydrothermal systems in northeastern Greece (western Thrace and Limnos Island) are highly enriched in tellurides which, in addition to native gold and electrum, represent major carriers of precious metals in the ore. Deposition near the porphyry-epithermal transition for several systems is indicated by field relations and by the presence of key minerals (Pb- and Ag-rich tellurides, Bi-sulfosalts and Bi-tellurides/tellurosulfides). Hessite, stützite, sylvanite, petzite, coloradoite, altaite, unnamed Ag-sulfotelluride, native tellurium and electrum are abundant in intermediate sulfidation quartz-carbonate veins together with zincian tetrahedrite-group minerals, chalcopyrite and galena. The presence of hessite, goldfieldite, native gold and enargite or famatinite suggests deposition at a high sulfidation state. The main stage of telluride deposition took place at ˜275 °C at log fTe2 values of -8.5 to -7.1 and log fS2 values of -10.8 to -9.0, based on the Fe-content in sphalerite and the sulfide-telluride mineralogy. The close spatial association of telluride mineralization with intrusive centers of intermediate composition, the base metal enrichment and the trace element signature involving Au, Ag, Te, Bi, Sn and Mo suggest that ore-forming components were introduced at the porphyry-epithermal transition. Potential sources of tellurium are the high-K calc-alkaline (western Thrace) to shoshonitic (Limnos) intrusive rocks.

  18. Compositional variations of zirconolite from the Evate apatite deposit (Mozambique) as an indicator of magmatic-hydrothermal conditions during post-orogenic collapse of Gondwana

    Science.gov (United States)

    Hurai, Vratislav; Huraiová, Monika; Gajdošová, Michaela; Konečný, Patrik; Slobodník, Marek; Siegfried, Pete R.

    2017-11-01

    substitution trends of the REE-zirconolite overlaps that genetically linked with carbonatites, syenites and mafic igneous rocks, whereas the U,Th-zirconolite is reminiscent of hydrothermal-metasomatic deposits. The predominance of trivalent iron in zirconolite most likely reflects strongly oxidizing parental fluids that percolated during episodic Late Ordovician to Late Cambrian rifting of Gondwana.

  19. Hydrothermal processes above the Yellowstone magma chamber: Large hydrothermal systems and large hydrothermal explosions

    Science.gov (United States)

    Morgan, L.A.; Shanks, W.C. Pat; Pierce, K.L.

    2009-01-01

    Hydrothermal explosions are violent and dramatic events resulting in the rapid ejection of boiling water, steam, mud, and rock fragments from source craters that range from a few meters up to more than 2 km in diameter; associated breccia can be emplaced as much as 3 to 4 km from the largest craters. Hydrothermal explosions occur where shallow interconnected reservoirs of steam- and liquid-saturated fluids with temperatures at or near the boiling curve underlie thermal fields. Sudden reduction in confi ning pressure causes fluids to fl ash to steam, resulting in signifi cant expansion, rock fragmentation, and debris ejection. In Yellowstone, hydrothermal explosions are a potentially signifi cant hazard for visitors and facilities and can damage or even destroy thermal features. The breccia deposits and associated craters formed from hydrothermal explosions are mapped as mostly Holocene (the Mary Bay deposit is older) units throughout Yellowstone National Park (YNP) and are spatially related to within the 0.64-Ma Yellowstone caldera and along the active Norris-Mammoth tectonic corridor. In Yellowstone, at least 20 large (>100 m in diameter) hydrothermal explosion craters have been identifi ed; the scale of the individual associated events dwarfs similar features in geothermal areas elsewhere in the world. Large hydrothermal explosions in Yellowstone have occurred over the past 16 ka averaging ??1 every 700 yr; similar events are likely in the future. Our studies of large hydrothermal explosion events indicate: (1) none are directly associated with eruptive volcanic or shallow intrusive events; (2) several historical explosions have been triggered by seismic events; (3) lithic clasts and comingled matrix material that form hydrothermal explosion deposits are extensively altered, indicating that explosions occur in areas subjected to intense hydrothermal processes; (4) many lithic clasts contained in explosion breccia deposits preserve evidence of repeated fracturing

  20. Diffuse flow hydrothermal manganese mineralization along the active Mariana and southern Izu-Bonin arc system, western Pacific

    Science.gov (United States)

    Hein, J.R.; Schulz, M.S.; Dunham, R.E.; Stern, R.J.; Bloomer, S.H.

    2008-01-01

    Abundant ferromanganese oxides were collected along 1200 km of the active Izu-Bonin-Mariana arc system. Chemical compositions and mineralogy show that samples were collected from two deposit types: Fe-Mn crusts of mixed hydrogenetic/hydrothermal origin and hydrothermal Mn oxide deposits; this paper addresses only the second type. Mn oxides cement volcaniclastic and biogenic sandstone and breccia layers (Mn sandstone) and form discrete dense stratabound layers along bedding planes and within beds (stratabound Mn). The Mn oxide was deposited within coarse-grained sediments from diffuse flow systems where precipitation occurred below the seafloor. Deposits were exposed at the seabed by faulting, mass wasting, and erosion. Scanning electron microscopy and microprobe analyses indicate the presence of both amorphous and crystalline 10 ?? and 7 ?? manganate minerals, the fundamental chemical difference being high water contents in the amorphous Mn oxides. Alternation of amorphous and crystalline laminae occurs in many samples, which likely resulted from initial rapid precipitation of amorphous Mn oxides from waxing pulses of hydrothermal fluids followed by precipitation of slow forming crystallites during waning stages. The chemical composition is characteristic of a hydrothermal origin including strong fractionation between Fe (mean 0.9 wt %) and Mn (mean 48 wt %) for the stratabound Mn, generally low trace metal contents, and very low rare earth element and platinum group element contents. However, Mo, Cd, Zn, Cu, Ni, and Co occur in high concentrations in some samples and may be good indicator elements for proximity to the heat source or to massive sulfide deposits. For the Mn sandstones, Fe (mean-8.4%) and Mn (12.4%) are not significantly fractionated because of high Fe contents in the volcaniclastic material. However, the proportion of hydrothermal Fe (nondetrital Fe) to total Fe is remarkably constant (49-58%) for all the sample groups, regardless of the degree of

  1. Faulting and off-axis submarine massive sulfide accumulation at slow spreading mid-ocean ridges: A numerical modeling perspective

    Science.gov (United States)

    Andersen, C.; Theissen-Krah, S.; Hannington, M.; Rüpke, L.; Petersen, S.

    2017-06-01

    The potential of mining seafloor massive sulfide deposits for metals such as Cu, Zn, and Au is currently debated. One key challenge is to predict where the largest deposits worth mining might form, which in turn requires understanding the pattern of subseafloor hydrothermal mass and energy transport. Numerical models of heat and fluid flow are applied to illustrate the important role of fault zone properties (permeability and width) in controlling mass accumulation at hydrothermal vents at slow spreading ridges. We combine modeled mass-flow rates, vent temperatures, and vent field dimensions with the known fluid chemistry at the fault-controlled Logatchev 1 hydrothermal field of the Mid-Atlantic Ridge. We predict that the 135 kilotons of SMS at this site (estimated by other studies) can have accumulated with a minimum depositional efficiency of 5% in the known duration of hydrothermal venting (58,200 year age of the deposit). In general, the most productive faults must provide an efficient fluid pathway while at the same time limit cooling due to mixing with entrained cold seawater. This balance is best met by faults that are just wide and permeable enough to control a hydrothermal plume rising through the oceanic crust. Model runs with increased basal heat input, mimicking a heat flow contribution from along-axis, lead to higher mass fluxes and vent temperatures, capable of significantly higher SMS accumulation rates. Nonsteady state conditions, such as the influence of a cooling magmatic intrusion beneath the fault zone, also can temporarily increase the mass flux while sustaining high vent temperatures.

  2. Ore deposits and epithermal evidences associated with intra-magmatic faults at Aïn El Araâr-Oued Belif ring structure (NW of Tunisia)

    Science.gov (United States)

    Aissa, Wiem Ben; Aissa, Lassaâd Ben; Amara, Abdesslem Ben Haj; Tlig, Said; Alouani, Rabah

    2017-03-01

    Hydrothermal ore deposits at Aïn El Araâr-Oued Belif location are classified as epithermal deposits type. The ore bodies are hosted by upper Turonian (8-9 M.y) volcanic rhyodacitic complex. Polymetallic sulfide orebodies are mainly concentrated within intra-magmatic faults. Petrographic, XRD, and TEM-STEM investigations revealed that ore minerals are essentially, arsenopyrite, pyrite, chalcopyrite, pyrrhotite, hematite, goethite and magnetite with Au, Ag and Pt trace metals. Gangue minerals are mainly adularia, quartz, sericite, alunite, tridymite, chlorite, phlogopite and smectite. Epithermal alteration is well zoned with four successive characteristic zones: (1) zone of quartz-adularia-sericite and rare alunite; (2) zone of kaolinite and plagioclase albitization; (3) intermediate zone of illite-sericite; (4) sapropelic alteration type zone of chlorite-smectite and rare illite. This can be interpreted as a telescoping of two different acidity epithermal phases; low sulfidation (adularia-sericite) and high sulfidation (quartz-alunite), separated in time or due to a gradual increase of fluids acidity and oxicity within the same mineralization phase. Brecciated macroscopic facies with fragments hosting quartz-adularia-sericite minerals (low-sulfidation phase) without alunite, support the last hypothesis. Geodynamic context and mineral alteration patterns are closely similar to those of Maria Josefa gold mine at SE of Spain which exhibit a volcanic-hosted epithermal ore deposit in a similar vein system, within rhyolitic ignimbrites, altered to an argillic assemblage (illite-sericite abundant and subordinate kaolinite) that grades outwards into propylitic alteration (Sanger-von Oepen et al. (1990)). Mineralogical and lithologic study undertaken in the volcanic host rock at Aïn El Araâr-Oued Belif reveals a typical epithermal low-sulfidation and high-sulfidation ore deposits with dominance of low-sulfidation. Host rocks in these systems range from silicic to

  3. A search for sulfide-bearing areas using LANDSAT-1 data and digital image-processing techniques. [in Pakistan

    Science.gov (United States)

    Schmidt, R. G.; Clark, B. B.; Bernstein, R.

    1975-01-01

    Two experiments were conducted using LANDSAT-1 multispectral scanner data to identify ground features that are indicators of sulfide-bearing rock. A nearby known sulfide deposit was used as a control. In the first experiment, false-color composites were examined visually to locate possible favorable areas; in the second, favorable areas were classified by digital-computer processing. The results of the experiment show that outcrops of hydrothermally altered and mineralized rock can be identified from LANDSAT-1 data under favorable conditions. The empirical method of digital-computer classification of the multispectral scanner data was relatively unrefined and rapid. The five mineralized prospecting sites identified are in locations that the geologist would not have selected as favorable on the basis of geologic knowledge or photogeologic interpretation at the time of the investigation.

  4. Metalliferous sediment and a silica-hematite deposit within the Blanco fracture zone, Northeast Pacific

    Science.gov (United States)

    Hein, J.R.; Clague, D.A.; Koski, R.A.; Embley, R.W.; Dunham, R.E.

    2008-01-01

    - and precious-metal-bearing, silica-Fe-oxide-barite deposit. Such deposits are commonly spatially and temporally associated with volcanogenic massive sulfide (VMS) ores. A plot of data for pathfinder elements shows a large hot spot at the northwestern margin of the field, which may mark a region where moderate to high temperature sulfide deposits are forming at depth; further exploration of the hydrothermal field to the northwest is warranted.

  5. Platinum Metals in Magmatic Sulfide Ores

    Science.gov (United States)

    Naldrett, A. J.; Duke, J. M.

    1980-06-01

    Platinum-group elements (PGE) are mined predominantly from deposits that have formed by the segregation of molten iron-nickel-copper sulfides from silicate magmas. The absolute concentrations of PGE in sulfides from different deposits vary over a range of five orders of magnitude, whereas those of other chalcophile elements vary by factors of only 2 to 100. However, the relative proportions of the different PGE in a given deposit are systematically related to the nature of the parent magma. The absolute and relative concentrations of PGE in magmatic sulfides are explained in terms of the degree of partial melting of mantle peridotite required to produce the parent magma and the processes of batch equilibration and fractional segregation of sulfides. The Republic of South Africa and the U.S.S.R. together possess more than 97 percent of the world PGE reserves, but significant undeveloped resources occur in North America. The Stillwater complex in Montana is perhaps the most important example.

  6. Useful Ingredients Recovery from Sewage Sludge by using Hydrothermal Reaction

    Science.gov (United States)

    Suzuki, Koichi; Moriyama, Mika; Yamasaki, Yuki; Takahashi, Yui; Inoue, Chihiro

    2006-05-01

    Hydrothermal treatment of sludge from a sewage treatment plant was conducted to obtain useful ingredients for culture of specific microbes which can reduce polysulfide ion into sulfide ion and/or hydrogen sulfide. Several additives such as acid, base, and oxidizer were added to the hydrothermal reaction of excess sludge to promote the production of useful materials. After hydrothermal treatment, reaction solution and precipitation were qualitatively and quantitatively analyzed and estimated the availability as nutrition in cultural medium. From the results of product analysis, most of organic solid in sewage was basically decomposed by hydrothermal hydrolysis and transformed into oily or water-soluble compounds. Bacterial culture of sulfate-reducing bacteria (SRB) showed the good results in multiplication with medium which was obtained from hydrothermal treatment of sewage sludge with magnesium or calcium hydroxide and hydrogen peroxide.

  7. Evaluation of protective effect of deposits formed by naphthenic corrosion and sulfidation on carbon steel and steel 5Cr-0.5Mo exposed in atmospheric distillation fractions

    OpenAIRE

    Gloria Duarte; Edwin Morantes; Edwin Bohórquez; Dario Peña; Miguel Mateus

    2017-01-01

    Refining of so-called opportunity crude oils with a high level of naphthenic acids and sulfur compounds has been increasing interest due to limited availability of light crude oils, however, considerable corrosive effects in the processing to high temperature on pipes and distillation towers mainly by the attack of naphthenic acids and sulfur compounds; sulfur compounds could be corrosive or can reduce the attack of naphthenic acids due to the formation of sulfides layers on the metal surface...

  8. Mineralogy and fluid inclusion studies in kalchoye Copper- gold deposit, East of Esfahan

    Directory of Open Access Journals (Sweden)

    Rezvan Mehvary

    2009-09-01

    Full Text Available Kalchoye Copper-gold deposit is located about 110 kilometers east of Esfahan province and within the Eocene volcano sedimentary rocks. Sandy tuff and andesite lava are important members of this complex.The form of mineralization in area is vein and veinlet and quartz as the main gangue phase. The main ore minerals are chalcopyrite, chalcocite, galena and weathered minerals such as goethite, iron oxides, malachite and azurite. Studies in area indicate that ore mineralization Kalchoye is low sulfide, quartz type of hydrothermal ore deposits and results of thermometry studies on quartz minerals low- medium fluid with low potential mineralization is responsible for mineralization in this area.

  9. Metal endowment reflected in chemical composition of silicates and sulfides of mineralized porphyry copper systems, Urumieh-Dokhtar magmatic arc, Iran

    Science.gov (United States)

    Zarasvandi, Alireza; Rezaei, Mohsen; Raith, Johann G.; Pourkaseb, Houshang; Asadi, Sina; Saed, Madineh; Lentz, David R.

    2018-02-01

    The present work attempts to discriminate between the geochemical features of magmatic-hydrothermal systems involved in the early stages of mineralization in high grade versus low grade porphyry copper systems, using chemical compositions of silicate and sulfide minerals (i.e., plagioclase, biotite, pyrite and chalcopyrite). The data indicate that magmatic plagioclase in all of the porphyry copper systems studied here has high An% and Al content with a significant trend of evolution toward AlAl3SiO8 and □Si4O8 endmembers, providing insight into the high melt water contents of the parental magmas. Comparably, excess Al and An% in the high grade deposits appears to be higher than that of selected low grade deposits, representing a direct link between the amounts of exsolving hydrothermal fluids and the potential of metal endowment in porphyry copper deposits (PCDs). Also, higher Al contents accompanied by elevated An% are linked to the increasing intensity of disruptive alteration (phyllic) in feldspars from the high grade deposits. As calculated from biotite compositions, chloride contents are higher in the exsolving hydrothermal fluids that contributed to the early mineralization stages of highly mineralized porphyry systems. However, as evidenced by scattered and elevated log (fH2O)/(fHF) and log (fH2O)/(fHCl) values, chloride contents recorded in biotite could be influenced by post potassic fluids. Geothermometry of biotite associated with the onset of sulfide mineralization indicates that there is a trend of increasing temperature from high grade to low grade porphyry systems. Significantly, this is coupled with a sharp change in copper content of pyrite assemblages precipitated at the early stages of mineralization such that Cu decreased with increasing temperature. Based on EMPA and detailed WDS elemental mapping, trace elements do not exhibit complex compositional zoning or solid solution in the sulfide structure. Nevertheless, significant amounts of Cu and

  10. Preparation of highly photocatalytic active CdS/TiO{sub 2} nanocomposites by combining chemical bath deposition and microwave-assisted hydrothermal synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Li, Li, E-mail: qqhrll@163.com [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Key Laboratory of Composite Modified Material of Colleges in Heilongjiang Province, Qiqihar 161006 (China); Wang, Lili [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Hu, Tianyu [College of Environment and Resources, Jilin University, Changchun 130024 (China); Zhang, Wenzhi; Zhang, Xiuli; Chen, Xi [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China)

    2014-10-15

    CdS/TiO{sub 2} nanocomposites were prepared from Cd and Ti (1:1 M ratio) using cetyltrimethylammonium bromide by a two-step chemical bath deposition (CBD) and microwave-assisted hydrothermal synthesis (MAHS) method. A series of nanocomposites with different morphologies and activities were prepared by varying the reaction time in the MAHS (2, 4, and 6 h). The crystal structure, morphology, and surface physicochemical properties of the nanocomposites were characterized by X-ray diffraction, UV–visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and N{sub 2} adsorption–desorption measurements. The results show that the CdS/TiO{sub 2} nanocomposites were composed of anatase TiO{sub 2} and hexagonal CdS phases with strong absorption in the visible region. The surface morphologies changed slightly with increasing microwave irradiation time, while the Brunauer–Emmett–Teller surface area increased remarkably. The photocatalytic degradation of methyl orange (MO) was investigated under UV light and simulated sunlight irradiation. The photocatalytic activity of the CdS/TiO{sub 2} (6 h) composites prepared by the MAHS method was higher than those of CdS, P25, and other CdS/TiO{sub 2} nanocomposites. The CdS/TiO{sub 2} (6 h) nanocomposites significantly affected the UV and microwave-assisted photocatalytic degradation of different dyes. To elucidate the photocatalytic reaction mechanism for the CdS/TiO{sub 2} nanocomposites, controlled experiments were performed by adding different radical scavengers. - Graphical abstract: CdS/TiO{sub 2} nanocomposites were prepared using CTAB by CBD combined with MAHS method. In addition, with increasing microwave irradiation time, the morphology of CdS/TiO{sub 2} changed from popcorn-like to wedge-like structure. - Highlights: • The CdS/TiO{sub 2} was prepared by CBD combined with MAHS two-step method under CTAB. • The morphologies of as-samples were different with the time of

  11. Sulfide minerals as new Sm-Nd geochronometers for ore genesis dating of mafic-ultramafic layered intrusions

    Science.gov (United States)

    Serov, Pavel; Ekimova, Nadezhda; Bayanova, Tamara

    2014-05-01

    The main method of dating the ore process was the Re-Os method of sulfides (Luck, Allegre, 1983; Walker et. al., 1991). However, studies of Re-Os systematics of sulfide minerals do not always give the correct ages and showing the disturbances of the Re-Os systematics. At the same time, Sm-Nd age of sulfides in good agreement with the U-Pb dating on zircon and baddeleyite and suggests that the Sm-Nd system of sulfides is more resistant to secondary alteration processes. Our studies have shown that along with rock-forming, ore minerals (sulfides) can be used to determine the ore genesis time of industrially important geological sites, since exactly with the sulfides the industry Pt-Pd mineralization is closely connected. The Sm-Nd investigations steadily employ new minerals-geochronometers. Of these, sulfides of PGE-bearing layered intrusions are quite important in terms of dating the process of ore origin. Studying the REE distribution in the sulfides of MOR hydrothermal sources has shown possible REE presence in the sulfide lattice (Rimskaya-Korsakova et. al., 2003). These are difficult to carry out because the concentrations of Sm and Nd isotopes in sulfides are much lower than chondrites (Rimskaya-Korsakova et. al., 2003). For the first time in Russia with sulfide and rock-forming minerals and WR in Sm-Nd method have been dated impregnated and brecciform ores of the following objects: Pilguyarvi Cu-Ni deposits, Pechenga (1965±87 Ma); impregnated (2433±83 Ma) and redeposited (1903±24 Ma) ores of Ahmavaara intrusion (Finland); ore gabbronorites of Penikat PGE-bearing layered intrusion (2426±38 Ma (Ekimova et.al., 2011); Pt-Pd gabbro-pegmatite ores (2476± 41 Ma, which agrees with the U-Pb zircon age - 2470±9 Ma (Bayanova, 2004) and gabbronorites (2483±86 Ma) of PGE Kievei deposit and Fedorova Tundra metagabbroids (2494±54 Ma); Monchetundra gabbronorites - 2489±49 Ma. In (Kong et. al., 2000) sulfides from two metamorphosed chondrites studied by instrumental

  12. A review of silver-rich mineral deposits and their metallogeny

    Science.gov (United States)

    Graybeal, Frederick T.; Vikre, Peter

    2010-01-01

    . Gold is absent at economic levels. The magmatic-hydrothermal silver-rich deposits are epigenetic and related to cordilleran igneous and volcanic suites. Six magmatic-hydrothermal districts each contain more than 31,000 t Ag (1,000 Moz) with grades of veins >600 g/t Ag. Mineralization occurs as veins, massive sulfides in carbonate rocks, and disseminated deposits including porphyry silver deposits, a proposed exploration model. Most deposits are epithermal with low-sulfidation alteration assemblages. Deposits are often telescoped and well-zoned. All large and high-grade magmatic-hydrothermal deposits appear confined to regions of relatively thick continental crust above Cenozoic consuming plate margins on the eastern side of the Pacific Rim. Silver in these deposits may be partly derived by hydrothermal leaching of rocks under or adjacent to the deposits.Specific metal associations in SEDEX and lithogene deposits may reflect confinement of fluid flow to and derivation of metals from specific source rock types. Variable metal associations in VMS and magmatichydrothermal deposits may reflect derivation of metals from a more diverse suite of rocks by convecting hydrothermal systems and processes related to the generation of magma. The discovery rate for silver-rich deposits has accelerated during the past decade, with new deposit types, metal associations, and exploration models being identified that provide numerous exploration and research opportunities.

  13. Cobalt—Styles of deposits and the search for primary deposits

    Science.gov (United States)

    Hitzman, Murray W.; Bookstrom, Arthur A.; Slack, John F.; Zientek, Michael L.

    2017-11-30

    Cobalt (Co) is a potentially critical mineral. The vast majority of cobalt is a byproduct of copper and (or) nickel production. Cobalt is increasingly used in magnets and rechargeable batteries. More than 50 percent of primary cobalt production is from the Central African Copperbelt. The Central African Copperbelt is the only sedimentary rock-hosted stratiform copper district that contains significant cobalt. Its presence may indicate significant mafic-ultramafic rocks in the local basement. The balance of primary cobalt production is from magmatic nickel-copper and nickel laterite deposits. Cobalt is present in several carbonate-hosted lead-zinc and copper districts. It is also variably present in Besshi-type volcanogenic massive sulfide and siliciclastic sedimentary rock-hosted deposits in back arc and rift environments associated with mafic-ultramafic rocks. Metasedimentary cobalt-copper-gold deposits (such as Blackbird, Idaho), iron oxide-copper-gold deposits, and the five-element vein deposits (such as Cobalt, Ontario) contain different amounts of cobalt. None of these deposit types show direct links to mafic-ultramafic rocks; the deposits may result from crustal-scale hydrothermal systems capable of leaching and transporting cobalt from great depths. Hydrothermal deposits associated with ultramafic rocks, typified by the Bou Azzer district of Morocco, represent another type of primary cobalt deposit.In the United States, exploration for cobalt deposits may focus on magmatic nickel-copper deposits in the Archean and Proterozoic rocks of the Midwest and the east coast (Pennsylvania) and younger mafic rocks in southeastern and southern Alaska; also, possibly basement rocks in southeastern Missouri. Other potential exploration targets include—The Belt-Purcell basin of British Columbia (Canada), Idaho, Montana, and Washington for different styles of sedimentary rock-hosted cobalt deposits;Besshi-type VMS deposits, such as the Greens Creek (Alaska) deposit and

  14. Ore genesis dating: implication of Sm-Nd method using sulfide minerals for mafic-ultramafic layered intrusions of Fennoscandian Shield

    Science.gov (United States)

    Serov, Pavel; Bayanova, Tamara; Steshenko, Ekaterina; Ekimova, Nadezhda

    2015-04-01

    The main method of dating the ore process was the Re-Os method of sulfides (Luck, Allegre, 1983; Walker et. al., 1991). However, studies of Re-Os systematics of sulfide minerals do not always give the correct ages and showing the disturbances of the Re-Os systematics. At the same time, Sm-Nd age of sulfides in good agreement with the U-Pb dating on zircon and baddeleyite and suggests that the Sm-Nd system of sulfides is more resistant to secondary alteration processes. Our studies have shown that along with rock-forming, ore minerals (sulfides) can be used to determine the ore genesis time of industrially important geological sites, since exactly with the sulfides the industry Pt-Pd mineralization is closely connected. In to Sm-Nd measurements steadily introduce new minerals-geochronometers (i.e. titanite, burbancite, eudialite etc.). Of these, sulfides of PGE-bearing layered intrusions are quite important in terms of dating the process of ore origin. Studying the REE distribution in the sulfides of MOR hydrothermal sources has shown possible REE presence in the sulfide lattice (Rimskaya-Korsakova et. al., 2003). These are difficult to carry out because the concentrations of Sm and Nd isotopes in sulfides are much lower than those in chondrites (Rimskaya-Korsakova et. al., 2003). In (Kong et. al., 2000) sulfides from two metamorphosed chondrites were studied by instrumental neutron activation analysis (INAA) and ion probe. As shown, the level of REE in the sulfide phase determined by the ion probe is quite similar to that obtained by INAA. Although the concentrations of REE in the enstatite and the Fe, Si, Cr-rich inclusions are comparable to those in sulfide, estimates based on mass balance calculations show that the silicate inclusions would not noticeably contribute to the REE budget in sulfides (Kong et. al., 2000). For the first time in Russian geochemistry laboratories using sulfide and rock-forming minerals and WR in Sm-Nd method have been dated impregnated

  15. Microearthquakes at the active Trans-Atlantic Geotraverse (TAG) hydrothermal mound, Mid-Atlantic Ridge, 26°08'N

    Science.gov (United States)

    Pontbriand, C.; Reves-Sohn, R. A.

    2010-12-01

    A small 200 m aperture network of five ocean bottom seismometers around the periphery the active TAG hydrothermal mound on the Mid-Atlantic Ridge (26°08’N) detected microearthquake events that may be associated with the subsurface hydraulics of the massive hydrothermal deposit. Seismic data were sampled at 100 Hz for a period of eight months spanning June, 2003 to February, 2004, during which time 24,191 locatable events were detected. Microearthquake hypocenters are concentrated within a 300 m radius of the sulfide mound in the top 250 m of crust, and exhibit a conical shape with the deepest events beneath the mound center. Event rates are steady at 180 events per day at the beginning of the study period and decline slightly to 116 events per day after whale calls elevate background noise levels about 2/3 of the way through the deployment. The mean local magnitude of events is -1.2 with a range of -2.9≦ML≦0.3. We suggest that events may be largely due to hydraulic fracturing of clogged flow conduits in the mineral deposit, which provides the possibility of using the microearthquake data to constrain subsurface flow parameters and the permeability structure of the active TAG deposit. Figure: A bathymetric map of the TAG area depicts a small aperture network of 5 ocean bottom seismometers (white triangles) around the periphery of the active TAG hydrothermal mound. High resolution bathymetry is from Roman and Singh, 2005.

  16. Phanerozoic Rifting Phases And Mineral Deposits

    Science.gov (United States)

    Hassaan, Mahmoud

    2016-04-01

    connected with NW,WNW and N-S faults genetically related to volcano-hydrothermal activity associated the Red Sea rifting. At Sherm EL-Sheikh hydrothermal manganese deposit occurs in Oligocene clastics within fault zone. Four iron-manganese-barite mineralization in Esh-Elmellaha plateau are controlled by faults trending NW,NE and nearly E-W intersecting Miocene carbonate rocks. Barite exists disseminated in the ores and as a vein in NW fault. In Shalatee - Halaib district 24 manganese deposits and barite veins with sulphide patches occur within Miocene carbonates distributed along two NW fault planes,trending 240°and 310° and occur in granite and basalt . Uranium -lead-zinc sulfide mineralization occur in Late Proterozoic granite, Late Cretaceous sandstones, and chiefly in Miocene clastic-carbonate-evaporate rocks. The occurrences of uranium- lead-zinc and iron-manganese-barite mineralization have the characteristic features of hypogene cavity filling and replacement deposits correlated with Miocene- Recent Aden volcanic rocks rifting. In western Saudi Arabia barite-lead-zinc mineralization occurs at Lat. 25° 45' and 25° 50'N hosted by Tertiary sediments in limestone nearby basaltic flows and NE-SW fault system. The mineralized hot brines in the Red Sea deeps considered by the author a part of this province. The author considers the constant rifting phases of Pangea and then progressive fragmentation of Western Gondwana during the Late Carboniferous-Lias, Late Jurassic-Early Aptian, Late Aptian - Albian and Late Eocene-Early Miocene and Oligocene-Miocene, responsible for formation of the mineral deposits constituting the M provinces. During these events, rifting, magmatism and hydrothermal activities took place in different peri-continental margins.

  17. The connection between iron ore formations and "mud-shrimp" colonizations around sunken wood debris and hydrothermal sediments in a Lower Cretaceous continental rift basin, Mecsek Mts., Hungary

    Science.gov (United States)

    Jáger, Viktor; Molnár, Ferenc; Buchs, David; Koděra, Peter

    2012-09-01

    In the Early Cretaceous, the continental rift basin of the Mecsek Mts. (Hungary), was situated on the southern edge of the European plate. The opening of the North Atlantic Ocean created a dilatational regime that expanded to the southern edge of the European plate, where several extensional basins and submarine volcanoes were formed during the Early Cretaceous epoch. Permanent seaquake activity caused high swell events during which a large amount of terrestrial wood fragments entered into submarine canyons from rivers or suspended woods which had sunk into the deep seafloor. These fragments created extended wood-fall deposits which contributed large-scale flourishing of numerous burrowing thalassinid crustaceans. Twelve different thalassinid coprolite ichnospecies can be found in the Berriasian-Hauterivian volcano-sedimentary formations. According to the seladonitic crustacean burrows which associated with framboidal pyrite containing Zoophycos and Chondrites ichnofossils (i.e. a "fodinichnia" trace fossil association), the bottom water was aerobic and the pore water was anaerobic; in the latter sulfate reduction occurred. The preservation of wood fragments around thalassinid burrows can be explained by rapid sedimentation related to turbidity currents. Due to the low temperature hydrothermal circulations of seawater, large amounts of iron were released from intrusive, pillowed basaltic sills; these sills intruded into soft, water-saturated sediments containing large amounts of thalassinid excrement. In the coprolites can be found idiomorphic mineral particles originating from the basalts, and coprolites can often be found in peperitic interpillow sediments. This indicates that the life-activity of the decapoda crustaceans in many Lower Cretaceous occurrences initially preceded the first magmatic eruptions. The paroxysm of the rift volcanism took place during the Valanginian age, when some submarine volcanoes emerged above sea level, reaching a maximum height of

  18. Numerical Modeling of Multiphase Fluid Flow in Ore-Forming Hydrothermal Systems

    Science.gov (United States)

    Weis, P.; Driesner, T.; Coumou, D.; Heinrich, C. A.

    2007-12-01

    Two coexisting fluid phases - a variably saline liquid and a vapor phase - are ubiquitous in ore-forming and other hydrothermal systems. Understanding the dynamics of phase separation and the distinct physical and chemical evolution of the two fluids probably plays a key role in generating different ore deposit types, e.g. porphyry type, high and low sulfidation Cu-Mo-Au deposits. To this end, processes within hydrothermal systems have been studied with a refined numerical model describing fluid flow in transient porous media (CSP~5.0). The model is formulated on a mass, energy and momentum conserving finite-element-finite-volume (FEFV) scheme and is capable of simulating multiphase flow of NaCl-H20 fluids. Fluid properties are computed from an improved equation of state (SOWAT~2.0). It covers conditions with temperatures of up to 1000 degrees~C, pressures of up to 500 MPa, and fluid salinities of 0~to 100%~NaCl. In particular, the new set-up allows for a more accurate description of fluid phase separation during boiling of hydrothermal fluids into a vapor and a brine phase. The geometric flexibility of the FEFV-meshes allows for investigations of a large variety of geological settings, ranging from ore-forming processes in magmatic hydrothermal system to the dynamics of black smokers at mid-ocean ridges. Simulations demonstrated that hydrothermal convection patterns above cooling plutons are primarily controlled by the system-scale permeability structure. In porphyry systems, high fluid pressures develop in a stock rising from the magma chamber which can lead to rock failure and, eventually, an increase in permeability due to hydrofracturing. Comparisons of the thermal evolution as inferred from modeling studies with data from fluid inclusion studies of the Pb-Zn deposits of Madan, Bulgaria are in a strikingly good agreement. This indicates that cross-comparisons of field observations, analytical data and numerical simulations will become a powerful tool towards a

  19. Examining Metasomatism in Low fO2 Environments: Exploring Sulfidation Reactions in Various Planetary Bodies

    Science.gov (United States)

    Srinivasan, P.; Shearer, C. K.; McCubbin, F. M.; Bell, A. S.; Agee, C. B.

    2016-01-01

    Hydrothermal systems are common on Earth in a variety of tectonic environments and at different temperature and pressure conditions. These systems are commonly dominated by H2O, and they are responsible for element transport and the production of ore deposits. Unlike the Earth (fO2FMQ), many other planetary bodies (e.g., Moon and asteroids) have fO2 environments that are more reduced (IW+/-2), and H2O is not the important solvent responsible for element transport. One example of a texture that could result from element transport and metasomatism, which appears to occur on numerous planetary bodies, is sulfide-silicate intergrowths. These subsolidus assemblages are interpreted to form as a result of sulfidation reactions from a S-rich fluid phase. The composition of fluids may vary within and among parent bodies and could be sourced from magmatic (e.g. Moon) or impact processes (e.g. HED meteorites and Moon). For example, it has been previously demonstrated on the Moon that the interaction of olivine with a hydrogen- and sulfur-bearing vapor phase altered primary mineral assemblages, producing sulfides (e.g. troilite) and orthopyroxene. Formation of these types of "sulfidation" assemblages can be illustrated with the following reaction: Fe2SiO4(ol) + 1/2 S(2 system) = FeS(troi)+ FeSiO3(opx) + 1/2 O2 system. The products of this reaction, as seen in lunar rocks, is a vermicular or "worm-like" texture of intergrown orthopyroxene and troilite. Regardless of the provenance of the S-bearing fluid, the minerals in these various planetary environments reacted in the same manner to produce orthopyroxene and troilite. Although similar textures have been identified in a variety of parent bodies, a comparative study on the compositions and the origins of these sulfide-silicate assemblages has yet to be undertaken. The intent of this study is to examine and compare sulfide-silicate intergrowths from various planetary bodies to explore their petrogenesis and examine the nature

  20. Identification of Zn-Bearing Micas and Clays from the Cristal and Mina Grande Zinc Deposits (Bongará Province, Amazonas Region, Northern Peru

    Directory of Open Access Journals (Sweden)

    Giuseppe Arfè

    2017-11-01

    Full Text Available Zn-bearing phyllosilicates are common minerals in nonsulfide Zn deposits, but they seldom represent the prevailing economic species. However, even though the presence of Zn-bearing clays is considered as a disadvantage in mineral processing, their characteristics can give crucial information on the genesis of the oxidized mineralization. This research has been carried out on the Mina Grande and Cristal Zn-sulfide/nonsulfide deposits, which occur in the Bongará district (Northern Peru. In both of the deposits, Zn-bearing micas and clays occur as an accessory to the ore minerals. The XRD analyses and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS investigations revealed that the Zn-bearing micas that are occurring in both deposits mostly consist of I/S mixed layers of detrital origin, which have been partly altered or overprinted by sauconite during the supergene alteration of sulfides. Sporadic hendricksite was also identified in the Cristal nonsulfide mineral assemblage, whereas at Mina Grande, the fraipontite-zaccagnaite (3R-polytype association was detected. The identified zaccagnaite polytype suggests that both fraipontite and zaccagnaite are genetically related to weathering processes. The hendricksite detected at Cristal is a product of hydrothermal alteration, which is formed during the emplacement of sulfides. The complex nature of the identified phyllosilicates may be considered as evidence of the multiple processes (hydrothermal and supergene that occurred in the Bongará district.

  1. Paleozoic and Mesozoic silica-rich seawater: Evidence from hematitic chert (jasper) deposits

    Science.gov (United States)

    Grenne, Tor; Slack, J.F.

    2003-01-01

    Laterally extensive beds of highly siliceous, hematitic chert (jasper) are associated with many volcanogenic massive sulfide (VMS) deposits of Late Cambrian to Early Cretaceous age, yet are unknown in analogous younger (including modern) settings. Textural studies suggest that VMS-related jaspers in the Ordovician Løkken ophiolite of Norway were originally deposited as Si- and Fe-rich gels that precipitated from hydrothermal plumes as colloidal silica and iron-oxyhydroxide particles. Rare earth element patterns and Ge/Si ratios of the jaspers reflect precipitation from plumes having seawater dilution factors of 103 to 104, similar to modern examples. We propose that silica in the ancient jaspers is not derived from submarine hydrothermal fluids-as suggested by previous workers-but instead was deposited from silic-rich sea-water. Flocculation and precipitation of the silica were triggered inorganically by the bridging effect of positively charged iron oxyhydroxides in the hydrothermal plume. A model involving amorphous silica (opal-A) precursors to the jaspers suggests that silica contents of Cambrian-Early Cretaceous oceans were at least 110 mg/L SiO2, compared to values of 40-60 mg/L SiO2 estimated in other studies. The evolution of ancient silica-rich to modern Fe-rich precipitates in submarine-hydrothermal plumes reflects a changeover from silica-saturated to silica-depleted seawater through Phanerozoic time, due mainly to ocean-wide emergence of diatoms in the Cretaceous.

  2. In situ ore formation experiment: Amino acids and amino sugars trapped in artificial chimneys on deep-sea hydrothermal systems at Suiyo Seamount, Izu-Bonin Arc, Pacific Ocean

    CERN Document Server

    Takano,; Marumo,; K.,; Ebashi,; T.,; Gupta,; P., L; Kawahata,; H.,; Kobayashi,; K.,; Yamagishi,; A.,; Kuwabara,; T,

    2013-01-01

    The present study reports on the bio-organic composition of a deep-sea venting hydrothermal system originating from arc volcanism; the origin of the particulates in hydrothermal fluids from the Suiyo Seamount in the southern Izu-Bonin (Ogasawara) Arc is discussed with regard to amino compounds. Chimney samples on deep-sea hydrothermal systems and core samples at Suiyo Seamount were determined for amino acids, and occasionally amino sugars. Two types of chimney samples were obtained from active hydrothermal systems by submersible vehicles: one was natural chimney (NC) on a hydrothermal natural vent; the other was artificial chimneys (AC), mainly formed by the growth and deposition of sulfide-rich particulate components in a Kuwabara-type in situ incubator (KI incubator). Total hydrolyzed amino acids (THAA) and hydrolyzed hexosamines (HA) in AC ranged from 10.7 nmol/g to 64.0 nmol/g and from 0 nmol/g to 8.1 nmol/g, respectively, while THAA in hydrothermally altered core samples ranged from 26.0 nmol/g to 107.4 ...

  3. Genetic Pd, Pt, Au, Ag, and Rh mineralogy in Noril'sk sulfide ores

    Science.gov (United States)

    Spiridonov, E. M.; Kulagov, E. A.; Serova, A. A.; Kulikova, I. M.; Korotaeva, N. N.; Sereda, E. V.; Tushentsova, I. N.; Belyakov, S. N.; Zhukov, N. N.

    2015-09-01

    The undeformed ore-bearing intrusions of the Noril'sk ore field (NOF) cut through volcanic rocks of the Late Permian-Early Triassic trap association folded in brachysynclines. Due to the nonuniform load on the roof of intrusive bodies, most sulfide melts were squeezed, up to the tops of ore-bearing intrusions; readily fusible Ni-Fe-Cu sulfide melts were almost completely squeezed. In our opinion, not only one but two stages of mineralization developed at the Noril'sk deposits: (i) syntrap magmatic and (ii) epigenetic post-trap metamorphic-hydrothermal. All platinum-group minerals (PGM) and minerals of gold are metasomatic in the Noril'sk ores. They replaced sulfide solid solutions and exsolution structures. All types of PGM and Au minerals occur in the ores, varying in composition from pyrrhotite to chalcopyrite, talnakhite, mooihoekite, and rich in galena; they are localized in the inner and outer contact zones and differ only in the quantitative proportions of ore minerals. The aureoles of PGM and Au-Ag minerals are wider than the contours of sulfide bodies and coincide with halos of fluid impact on orebodies and adjacent host rocks. The pneumatolytic PGM and Au-Ag minerals are correlated in abundance with the dimensions of sulfide bodies. Their amounts are maximal in veins of late fusible ore composed of eutectic PbS ss and iss intergrowths, as well as at their contacts. The Pd and Pt contents in eutectic sulfide ores of NOF are the world's highest. In the process of noble-metal mineral formation, the fluids supply Pd, Pt, Au, As, Sb, Sn, Bi, and a part of Te, whereas Fe, Ni, Cu, Pb, Ag, Rh, a part of Te and Pd are leached from the replaced sulfide minerals. The pneumatolytic PGM of the early stage comprises Pd and Pt intermetallic compounds enriched in Au along with Pd-Pt-Fe-Ni-Cu-Sn-Pb(As) and (Pd,Pt,Au)(Sn,Sb,Bi,Te,As) solid solutions. Pneumatolytic PGM and Au minerals of the middle stage are products of solid-phase transformation and recrystallization of

  4. Cadmium sulfide membranes

    Science.gov (United States)

    Spanhel, Lubomir; Anderson, Marc A.

    1991-10-22

    A method is described for the creation of novel q-effect cadmium sulfide membranes. The membranes are made by first creating a dilute cadmium sulfide colloid in aqueous suspension and then removing the water and excess salts therefrom. The cadmium sulfide membrane thus produced is luminescent at room temperature and may have application in laser fabrication.

  5. Hydrothermal alterations of the meta volcanic rocks associated to the gold deposits from Pontes e Lacerda region, Mato Grosso State, Brazil; Alteracao hidrotermal das metavulcanicas associadas aos depositos auriferos de Pontes e Lacerda, MT

    Energy Technology Data Exchange (ETDEWEB)

    Geraldes, M.C.; Figueiredo, B.R. [Universidade Estadual de Campinas, SP (Brazil). Inst. de Geociencias

    1997-01-01

    Geochemical changes due to hydrothermal alterations of volcanic rocks, which are associated with the gold deposits in the Pontes e Lacerda region, state of Mato Grosso, Brazil, are investigated in the present study. These rocks were analyzed for major and trace elements, including REE. Nd and Sr isotopes were used to trace the origin and tectonic environment of the magmatism. The volcanic rocks resemble ocean floor basalts in composition and their isotopic signature indicates a Sr depleted and Nd enriched source in the mantle. The hydrothermal process were responsible for enhanced concentration of K{sub 2} O, Rb, Ba and Fe{sub 2} O{sub 3} and for losses in Ca O, Sr, Mg O, and Fe O. The Zr; Y, Cr; Al{sub 2} O{sub 3} Si O{sub 2} and Ti O{sub 2} contents remained unchanged. Increasing REE contents in the altered volcanics may be due to a probable magmatic contribution to the fluids, which is also indicated by positive Ce anomalies in some altered basalts. The processes which were responsible for these geochemical changes are discussed. (author) 33 refs., 10 figs., 2 tab.

  6. Hydrothermal synthesis of fine oxide powders

    Indian Academy of Sciences (India)

    The authors describe. hydrothermal decomposition,; hydrothermal metal oxidation,; hydrothermal reaction,; hydrothermal precipitation and hydrothermal hydrolysis,; hydrothermal electrochemical,; reactive electrode submerged arc,; hydrothermal microwave,; hydrothermal sonochemical,. etc and also ideal and real powders ...

  7. Limitations in the use of archived vent mussel samples to assess genetic connectivity among seafloor massive sulfide deposits: a case study with implications for environmental management

    Directory of Open Access Journals (Sweden)

    Rachel Elizabeth Boschen

    2015-12-01

    Full Text Available Genetic connectivity studies can inform the design of mitigation strategies used in environmental management. However, the expense of developing species-specific molecular markers and collecting samples at appropriate spatial and temporal scales can be prohibitive. Using archived material and existing molecular markers may provide a cost-effective way to assess population connectivity. Genetic connectivity studies are increasingly in demand in the deep sea in response to mounting anthropogenic pressures, including seafloor massive sulfide (SMS mining. The feasibility of using archived material was assessed using the New Zealand-endemic vent mussel Gigantidas gladius, which inhabits areas licensed for the prospecting phase of SMS mining. Four molecular markers were tested, but only one (mitochondrial COI provided suitable sequences. Of 942 specimens, only 150 individuals were informative, largely due to poor tissue quality of archived samples. Seven populations spanning the distributional range of G. gladius were assessed. The results indicate that G. gladius has high levels of gene flow among sites 10s to 100s km apart and limited genetic structure. Haplotypic diversity was not equally distributed among populations, with lower diversity for the Macauley Volcano population at the northern extent of the species distribution and greater diversity within central populations. Migrant exchange was also greatest between central populations, with one population at Rumble V Seamount appearing important in terms of maintaining genetic diversity within the Kermadec Volcanic Arc region. However, interpretation of the results should be viewed with caution as small sample sizes may have limited the ability to detect genetic structure. Despite these limitations, mitigation strategies that protect areas of seabed from mining activities should consider the genetic vulnerability of the population at the northern edge of the species’ distribution and the

  8. Hydrothermal deposition and the photochromic properties of molybdenum oxide hydrate (MoO{sub 3}⋅(H{sub 2}O){sub 0.69}) films induced by D, L-malic acid

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Yi, E-mail: sysy7373@163.com; Xiao, Yilin; Yan, Peng; Yang, Yali; Hu, Fengping; Li, Zhen

    2014-03-05

    Graphical abstract: The molybdenum oxide hydrate (MoO{sub 3}⋅(H{sub 2}O){sub 0.69}) films were synthetized through a hydrothermal route with or without the D, L-malic acid as capping agent. The SEM images indicate that the films obtained without D, L-malic acid show the hexagonal prismatic structures while the films prepared with the capping agent reveal the dandelion-like hierarchical structures, and all the films have double-layer structures. Compared with the films synthetized without the D, L-malic acid, the films prepared with the capping agent show a superior photochromic properties. And the more complete the dandelion-like structures, the better performance the films possess. The best performance appeared when the film was prepared with molar ratio of D, L-malic acid and sodium molybdate at 1:5. The enhanced photochromic performances of the films may be ascribed to the dandelion-like hierarchical structures which can provide large exposed surface and ultimately, increase the amount of the photogenerated electron–hole pairs and the proton diffusion rates. -- Highlights: • Two kinds of films with novel morphologies were obtained with simple hydrothermal process. • Adding D, L-malic acid to the hydrothermal system obviously change the structure of the films. • The film with dandelion-like hierarchical structures showed better photochromic properties. -- Abstract: Two kinds of molybdenum oxide hydrate films were successfully synthesized by a simple hydrothermal deposition method. The X-ray diffraction shows that all the samples can be indexed to hexagonal structure of MoO{sub 3}·(H{sub 2}O){sub 0.69}. Scanning electron microscopy images of the products revealed that hexagonal prismatic structures were revealed on the surface of the sample prepared without capping. While the surface of ones obtained with D, L-malic acid were covered by dandelion-like hierarchical structures, which may result from the effect of hydrogen bonds, and the dandelion

  9. Mantle heat drives hydrothermal fluids responsible for carbonate-hosted base metal deposits: evidence from 3He/4He of ore fluids in the Irish Pb-Zn ore district

    Science.gov (United States)

    Davidheiser-Kroll, B.; Stuart, F. M.; Boyce, A. J.

    2014-06-01

    There is little consensus on whether carbonate-hosted base metal deposits, such as the world-class Irish Zn + Pb ore field, formed in collisional or extensional tectonic settings. Helium isotopes have been analysed in ore fluids trapped in sulphides samples from the major base metal deposits of the Irish Zn-Pb ore field in order to quantify the involvement of mantle-derived volatiles that require melting to be realised, as well as test prevailing models for the genesis of the ore fields. 3He/4He ratios range up to 0.2 R a, indicating that a small but clear mantle helium contribution is present in the mineralising fluids trapped in galena and marcasite. Sulphides from ore deposits with the highest fluid inclusion temperatures (~200 °C) also have the highest 3He/4He (>0.15 R a). Similar 3He/4He are recorded in fluids from modern continental regions that are undergoing active extension. By analogy, we consider that the hydrothermal fluids responsible for the carbonate-hosted Irish base metal mineralization circulated in thinned continental crust undergoing extension and demonstrate that enhanced mantle heat flow is ultimately responsible for driving fluid convection.

  10. Geology of the Barite Hill gold-silver deposit in the southern Carolina slate belt

    Science.gov (United States)

    Clark, S.H.B.; Gray, K.J.; Back, J.M.

    1999-01-01

    Barite Hill is a stratiform gold-silver deposit associated with base metal sulfides and barite in greenschist facies rocks. The deposit, southernmost of four recently mined gold deposits in the Carolina slate belt, is located in the Lincolnton-McCormick district of Georgia and South Carolina, which includes several known gold-silver and base metal deposits in a Kuroko-type geological setting along with deposits of kyanite and manganese. Approximately 1,835,000 g of gold was produced mainly from oxidized ores in the Main and Rainsford pits from 1990 until their closing in 1994. Ore is hosted by sericitically altered felsic metavolcanic and metasedimentary rocks of the Late Proterozoic Persimmon Fork Formation. The deposit is stratigraphically below an overturned contact between upper and lower pyroclastic units, which overlie the Lincolnton metarhyolite, an intrusive unit. Gold-silver-rich zones in the Main pit are partly coincident with lenses of siliceous barite rock, but not confined to them, and occur more commonly in pyrite-quartz-altered fragmental rock. The Main pit ore is stratigraphically overlain by a zone of base metal and barite enrichment, which is, in turn, overlain by a talc-tremolite alteration zone locally. Siliceous barite zones are absent in the Rainsford pit, and gold-silver minerals are associated with silicified rocks and chert. The Barite Hill deposit is interpreted to be the result of Kuroko-type, volcanogenic, base metal sulfide mineralization, followed by gold-silver mineralization under epithermal conditions with the following stages of evolution: (1) massive sulfides, barite, and fine-grained siliceous exhalites were deposited during Late Proterozoic to Cambrian submarine volcanism, which was related to plate convergence and subduction in a microcontinental or island-arc setting distant from the North American continental plate; (2) Au-Ag-Te and base and precious metal Te-Se-Bi minerals were deposited either during waning stages of

  11. Cordilleran vein type Pb-Zn-polymetallic deposits of the Xidamingshan district, Guangxi, SW China: Fluid inclusion and geochemical studies

    Science.gov (United States)

    Tu, Wei; Du, Yang Song; Wang, Gong Wen; Lei, Ying Ping

    2013-11-01

    There are a lot of clastic-sedimentary-rock-hosted hydrothermal vein type polymetallic deposits in the Xidamingshan district, Guangxi, SW China. Two major ones of them, the Fenghuangshan Pb-Zn-Ag-Mn deposit and the Lujing Pb-Zn deposit, have been selected for fluid inclusion and geochemical research in this paper. From fluid inclusion microthermometry, it has been found that they were deposited from fluid with low salinities at medium to low temperatures and low pressures. From hydrogen, oxygen, sulfur and carbon stable isotope studies as well as some trace element composition of sulfides, we have got the conclusion that they were formed in an intrusion-related ore-forming system, which means that they belong to Cordilleran vein type deposits.

  12. Mineralogical, chemical, and crystallographic properties of supergene jarosite-group minerals from the Xitieshan Pb-Zn sulfide deposit, northern Tibetan Plateau, China

    Science.gov (United States)

    Chen, Lei; Li, Jian-Wei; Rye, Robert O.; Benzel, William H.; Lowers, H.A.; He, Ming-Zhong

    2013-01-01

    Supergene jarosite-group minerals are widespread in weathering profiles overlying Pb-Zn sulfide ores at Xitieshan, northern Tibetan Plateau, China. They consist predominantly of K-deficient natrojarosite, with lesser amounts of K-rich natrojarosite and plumbojarosite. Electron microprobe (EMP) analyses, scanning electron microcopy (SEM) investigation, and X-ray mapping reveal that the jarosite-group minerals are characterized by spectacular oscillatory zoning composed of alternating growth bands of K-deficient and K-bearing natrojarosite (K2O >1 wt.%). Plumbojarosite, whenever present, occurs as an overgrowth in the outermost bands, and its composition can be best represented by K0.29Na0.19Pb0.31Fe2.66Al0.22(SO4)1.65(PO4)0.31(AsO4)0.04(OH)7.37. The substitution of monovalent for divalent cations at the A site of plumbojarosite is charge balanced by the substitution of five-valent for six-valent anions in XO,4/sub> at the X site. Thermogravimetric analysis (TGA) of representative samples reveal mass losses of 11.46 wt.% at 446.6 °C and 21.42 wt.% at 683.4 °C due to dehydroxylation and desulfidation, respectively. TGA data also indicate that the natrojarosite structure collapses at 446.6 °C, resulting in the formation of NaFe(SO4)2 and minor hematite. The decomposition products of NaFe(SO4) are hematite and Na,2SO4. Powder X-ray diffraction (XRD) analyses show that the jarosite-group minerals have mean unit-cell parameters of a=7.315 ä and c=016.598 ä. XRD and EMP data support the view that substitutions of Na for K in the A site and full Fe occupancy in the B site can considerably decrease the unit-cell parameter c, but only slightly increase a. The results from this study suggest that the observed oscillatory zoning of jarosite-group minerals at Xitieshan resulted mainly from substitutions of K for Na at the A site and P for S at the X site.

  13. Multistage hydrothermal silicification and Fe-Tl-As-Sb-Ge-REE enrichment in the Red Dog Zn-Pb-Ag district, northern Alaska: Geochemistry, origin, and exploration applications

    Science.gov (United States)

    Slack, J.F.; Kelley, K.D.; Anderson, V.M.; Clark, J.L.; Ayuso, R.A.

    2004-01-01

    Geochemical analyses of major, trace, and rare earth elements (REE) in more than 200 samples of variably silicified and altered wall rocks, massive and banded sulfide, silica rock, and sulfide-rich and unmineralized barite were obtained from the Main, Aqqaluk, and Anarraaq deposits in the Red Dog Zn-Pb-Ag district of northern Alaska. Detailed lithogeochemical profiles for two drill cores at Aqqaluk display an antithetic relationship between SiO2/Al2O3 and TiO2/Zr which, together with textural information, suggest preferential silicification of carbonate-bearing sediments. Data for both drill cores also show generally high Tl, Sb, As, and Ge and uniformly positive Eu anomalies (Eu/Eu* > 1.0). Similar high Tl, Sb, As, Ge, and Eu/Eu* values are present in the footwall and shallow hanging wall of Zn-Pb-Ag sulfide intervals at Anarraaq but are not as widely dispersed. Net chemical changes for altered wall rocks in the district, on the basis of average Al-normalized data relative to unaltered black shales of the host Kuna Formation, include large enrichments (>50%) of Fe, Ba, Eu, V, S, Co, Zn, Pb, Tl, As, Sb, and Ge at both Red Dog and Anarraaq, Si at Red Dog, and Sr, U, and Se at Anarraaq. Large depletions (>50%) are evident for Ca at both Red Dog and Anarraaq, for Mg, P, and Y at Red Dog, and for Na at Anarraaq. At both Red Dog and Anarraaq, wall-rock alteration removed calcite and minor dolomite during hydrothermal decarbonation reactions and introduced Si, Eu, and Ge during silicification. Sulfidation reactions deposited Fe, S, Co, Zn, Pb, Tl, As, and Sb; barite mineralization introduced Ba, S, and Sr. Light REE and U were mobilized locally. This alteration and mineralization occurred during Mississippi an hydrothermal events that predated the Middle Jurassic-Cretaceous Brookian orogeny. Early hydrothermal silicification at Red Dog took place prior to or during massive sulfide mineralization, on the basis of the dominantly planar nature of Zn-Pb veins, which suggests

  14. Hydrothermal alteration at Roosevelt Hot Springs KGRA: DDH 1976-1

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, N.L.; Parry, W.T.

    1977-09-01

    Hot waters of the Roosevelt Thermal Area, Utah, have altered granitic rocks and detritus of the Mineral Range pluton, Utah. Alteration and mineral deposition recognized in a 200' drill core from DDH 1-76 is most intense in the upper 100 feet which consists of altered alluvium and opal deposits; the lower 100 feet is weakly altered quartz monzonite. Petrographic, x-ray, and chemical methods were used to characterize systematic changes in chemistry and mineralogy. Comparison of the alteration mineral assemblages with known water chemistry and equilibrium activity diagrams suggests that a simple solution equilibrium model cannot account for the alteration. A model is proposed in which upward moving thermal water supersaturated with respect to quartz and a downward moving cool water undersaturated with respect to quartz produces the observed alteration. An estimate of the heat flow contributions from hydrothermal alteration was made by calculating reaction enthalpies for alteration reactions at each depth. The estimated heat flow varied from .02 HFU (for 200' depth, 400,000 yr duration, and no sulfur oxidation) to 67 HFU (for 5,000' depth, 1,000 yr duration, and all sulfur oxidized from sulfide). Heat flow contributions from hydrothermal alteration are comparable with those from a cooling granitic magma.

  15. Evolution of the Mothra Hydrothermal Field, Endeavour Segment of the Juan de Fuca Ridge

    Science.gov (United States)

    Glickson, D.; Kelley, D. S.; Delaney, J.

    2005-12-01

    and bounded by extensive lobate flows and disrupted terrain. At all clusters, active chimneys stand within meters of extinct chimneys, suggesting that flow in the shallow subsurface is both complex and transient. 1-2 m high mounds of sulfide talus and broken chimneys indicate that focused flow has been concentrated at the clusters for long periods, while extinct sulfide deposits between clusters and in collapse basins demonstrate that flow conduits have been rerouted and/or clogged by mineral precipitation. Two subsurface processes are responsible for hydrothermal venting at the clusters: tapping of magmatic heat near the lava drainbacks and tectonic movement along the steeply dipping, inward-facing normal faults at the western wall boundary. The interplay between these processes and fluid flow is synthesized in an evolutionary model of hydrothermal development at Mothra.

  16. The geology of the Morro Velho gold deposit in the Archean Rio das Velhas greenstone belt, Quadrilátero Ferrífero, Brazil

    Science.gov (United States)

    Vial, Diogenes Scipioni; DeWitt, Ed; Lobato, Lydia Maria; Thorman, Charles H.

    2007-01-01

    The Morro Velho gold deposit, Quadrilátero Ferrífero region, Minas Gerais, Brazil, is hosted by rocks at the base of the Archean Rio das Velhas greenstone belt. The deposit occurs within a thick carbonaceous phyllite package, containing intercalations of felsic and intermediate volcaniclastic rocks and dolomites. Considering the temporal and spatial association of the deposit with the Rio das Velhas orogeny, and location in close proximity to a major NNW-trending fault zone, it can be classified as an orogenic gold deposit. Hydrothermal activity was characterized by intense enrichment in alteration zones of carbonates, sulfides, chlorite, white mica±biotite, albite and quartz, as described in other Archean lode-type gold ores. Two types of ore occur in the deposit: dark gray quartz veins and sulfide-rich gold orebodies. The sulfide-rich orebodies range from disseminated concentrations of sulfide minerals to massive sulfide bodies. The sulfide assemblage comprises (by volume), on average, 74% pyrrhotite, 17% arsenopyrite, 8% pyrite and 1% chalcopyrite. The orebodies have a long axis parallel to the local stretching lineation, with continuity down the plunge of fold axis for at least 4.8 km. The group of rocks hosting the Morro Velho gold mineralization is locally referred to as lapa seca. These were isoclinally folded and metamorphosed prior to gold mineralization. The lapa seca and the orebodies it hosts are distributed in five main tight folds related to F1 (the best examples are the X, Main and South orebodies, in level 25), which are disrupted by NE- to E-striking shear zones. Textural features indicate that the sulfide mineralization postdated regional peak metamorphism, and that the massive sulfide ore has subsequently been neither metamorphosed nor deformed. Lead isotope ratios indicate a model age of 2.82 ± 0.05 Ga for both sulfide and gold mineralization. The lapa seca are interpreted as the results of a pre-gold alteration process and may be

  17. The arsenic removal from arsenopyrite in sulfide mineral by physicochemical extraction

    Science.gov (United States)

    Jo, Jiyu; Cho, Kanghee; Choi, Nagchoul; Park*, Cheonyoung

    2015-04-01

    The most abundant As ore mineral is arsenopyrite (FeAsS). Arsenopyrite is present in sulfide ores associated with sediment-hosted Au deposits, it tends to be the earliest-formed mineral, derived from hydrothermal solutions and formed at temperatures typically of 100(degree Celsius) or more. The aim of this study was to investigate the mineralogical phase change and arsenic removal from arsenopyrite as a penalty element in sulfide mineral contained Au by physical extraction (high frequency) and chemical leaching (thiocyanate). Arsenic removal experiments for were performed under various conditions of high frequency exposure(1~35 min), thiocyanate concentration (0.1~1.0M), HCl concentration (0.1~2.0M), copper(2) sulfate concentration (0.1~1.0M), temperature (30~60 degree Celsius). Increasing the high frequency exposure produced a positive effect on arsenic removal in arsenopyrite. The highest percentage arsenic removal of 96.67% was obtained under the following conditions by thiocyanate leaching: thiocyanate concentration = 1.0M ; HCl concentration = 2.0M ; copper(2) sulfate concentration = 1.0M ; temperature = 60(degree Celsius) This study demonstrates the adequate performance of physical extraction (high frequency) and chemical leaching (thiocyanate) for the arsenic removal from arsenopyrite as a penalty element.

  18. 40Ar/39Ar geochronological constraints on the formation of the Dayingezhuang gold deposit: New implications for timing and duration of hydrothermal activity in the Jiaodong gold province, China

    Science.gov (United States)

    Yang, Li-Qiang; Deng, J.; Goldfarb, Richard J.; Zhang, Jiahua; Gao, Bang-Fei; Wang, Zhong-Liang

    2014-01-01

    China's largest gold resource is located in the highly endowed northwestern part of the Jiaodong gold province. Most gold deposits in this area are associated with the NE- to NNE-trending shear zones on the margins of the 130–126 Ma Guojialing granite. These deposits collectively formed at ca. 120 ± 5 Ma during rapid uplift of the granite. The Dayingezhuang deposit is a large (> 120 t Au) orogenic gold deposit in the same area, but located along the eastern margin of the Late Jurassic Linglong Metamorphic Core Complex. New 40Ar/39Ar geochronology on hydrothermal sericite and muscovite from the Dayingezhuang deposit indicate the gold event is related to evolution of the core complex at 130 ± 4 Ma and is the earliest important gold event that is well-documented in the province. The Dayingezhuang deposit occurs along the Linglong detachment fault, which defines the eastern edge of the ca. 160–150 Ma Linglong granite–granodiorite massif. The anatectic rocks of the massif were rapidly uplifted, at rates of at least 1 km/m.y. from depths of 25–30 km, to form the metamorphic core complex. The detachment fault, with Precambrian metamorphic basement rocks in the hangingwall and the Linglong granitoids and migmatites in the footwall, is characterized by early mylonitization and a local brittle overprinting in the footwall. Gold is associated with quartz–sericite–pyrite–K-feldspar altered footwall cataclasites at the southernmost area of the brittle deformation along the detachment fault. Our results indicate that there were two successive, yet distinct gold-forming tectonic episodes in northwestern Jiaodong. One event first reactivated the detachment fault along the edge of the Linglong massif between 134 and 126 Ma, and then a second reactivated the shears along the margins of the Guojialing granite. Both events may relate to a component of northwest compression after a middle Early Cretaceous shift from regional NW–SE extension to a NE

  19. Geologic and tectonic setting of Deseado Massif epithermal deposits, Argentina, based on El Dorado-Monserrat

    Science.gov (United States)

    Echavarría, Leandro E.; Schalamuk, Isidoro B.; Etcheverry, Ricardo O.

    2005-09-01

    Middle-Late Jurassic bimodal volcanism, typical of a retroarc setting, developed during widespread extensional tectonism within the Deseado Massif, southern Argentina. This geologic environment led to the formation of numerous low-sulfidation epithermal deposits that are spatially and temporally related to the volcanic activity. The lack of significant high-sulfidation epithermal deposits may be because the tectonic and volcanic settings do not favor the formation of these types of deposits. El Dorado-Monserrat is a low-sulfidation epithermal prospect located near the southern boundary of the Deseado Massif. Mineralization is genetically linked to the Late Jurassic Chon Aike Formation and hosted by volcanic rocks of the middle Late Jurassic Bajo Pobre Formation. Two different mineralization areas have been identified. The Monserrat area is the most important, with veins hosted in a north-striking, left-lateral shear zone. The average thickness is 0.85 m, and the average metal content is 6.2 ppm gold and 153 ppm silver. The El Dorado area has discontinuous echelon veins within a right-lateral shear zone with low gold and silver grades. Hydrothermal alteration of the host rocks includes an inner zone of quartz-adularia and illite alteration and an outer zone of propylitic alteration. The main gangue mineral is quartz, which formed in successive pulses, plus adularia, pyrite, hematite, magnetite, and barite. Precious metals occur as zoned electrum. Ore mineral precipitation took place between 200 and 280 °C from low salinity fluids due to boiling.

  20. Distribution of REEs and yttrium among major geochemical phases of marine Fe–Mn-oxides: Comparative study between hydrogenous and hydrothermal deposits

    Digital Repository Service at National Institute of Oceanography (India)

    SuryaPrakash, L.; Ray, D.; Paropkari, A.L.; Mudholkar, A.V.; Satyanarayanan, M.; Sreenivas, B.; Chandrasekharam, D.; Kota, D.; KameshRaju, K.A.; Kaisary, S.; Balaram, V.; Gurav, T.

    deposits from Baby Bare seamount in the Northeast Pacific Ocean. Mar. Geol. 225, 145 – 156. Frank, M., O’Nions, R.K., Hein, J.R., Banakar, V.K., 1999. 60 Myr records of major elements and Pb– Nd isotopes from hydrogenous ferromanganese crusts...

  1. Efficiency improvement of InGaP/GaAs/Ge solar cells by hydrothermal-deposited ZnO nanotube structure.

    Science.gov (United States)

    Chung, Chen-Chen; Tran, Binh Tinh; Lin, Kung-Liang; Ho, Yen-Teng; Yu, Hung-Wei; Quan, Nguyen-Hong; Chang, Edward Yi

    2014-01-01

    In this paper, a zinc oxide (ZnO) nanotube, fabricated by the hydrothermal growth method on triple-junction (T-J) solar cell devices to enhance efficiency, is investigated. Compared to those of bare T-J solar cells (without antireflection (AR) coating) and solar cells with Si3N4 AR coatings, the experimental results show that the T-J solar cells, which use a ZnO nanotube as an AR coating, have the lowest reflectance in the short wavelength spectrum. The ZnO nanotube has the lowest light reflection among all experimental samples, especially in the range of 350 to 500 nm from ultraviolet (UV) to visible light. It was found that a ZnO nanotube can enhance the conversion efficiency by 4.9%, compared with a conventional T-J solar cell. The Si3N4 AR coatings also enhance the conversion efficiency by 3.2%.The results show that a cell with ZnO nanotube coating could greatly improve solar cell performances.

  2. The Lavrion Pb-Zn-Fe-Cu-Ag detachment-related district (Attica, Greece): Structural control on hydrothermal flow and element transfer-deposition

    Science.gov (United States)

    Scheffer, Christophe; Tarantola, Alexandre; Vanderhaeghe, Olivier; Voudouris, Panagiotis; Rigaudier, Thomas; Photiades, Adonis; Morin, Denis; Alloucherie, Alison

    2017-10-01

    The impact of lithological heterogeneities on deformation, fluid flow and ore deposition is discussed based on the example of the Lavrion low-angle detachment partly accommodating gravitational collapse of the Hellenides orogenic belt in Greece. The Lavrion peninsula is characterised by a multiphase Pb-Zn-Fe-Cu-Ag ore system with a probable pre-concentration before subduction followed by progressive remobilisation and deposition coeval with the development of a low-angle ductile to brittle shear zone. The mylonitic marble below the detachment shear zone is composed of white layers of pure marble alternating with blue layers containing impurities (SiO2, Al2O3, carbonaceous material). Ductile mylonitic deformation is more pervasive in the less competent impure blue marble. We propose that localised deformation in the impure marble is associated with fluid circulation and dolomitisation, which in turn causes an increase in competence of these layers. Mineralised cataclastic zones, crosscutting the mylonitic fabric, are preferentially localised in the more competent dolomitic layers. Oxygen and carbon isotopic signatures of marble invaded by carbonate replacement deposits during ductile to ductile-brittle deformation are consistent with decarbonation coeval with the invasion of magmatic fluids. Mineralised cataclastic zones reflecting brittle deformation evolve from low 13C to low 18O signatures, interpreted as local interaction with carbonaceous material that trends toward the contribution of a surface-derived fluid. These features indicate that the Lavrion area records a complex deposition history influenced by the evolution of fluid reservoirs induced by the thermal and mechanical evolution of the marble nappe stack. Ore remobilisation and deposition associated with the activity of the low-angle detachment is (i) firstly related to the intrusion of the Plaka granodiorite leading to porphyry-type and carbonate replacement mineralisation during ductile

  3. Bedded jaspers of the Ordovician Løkken ophiolite, Norway: seafloor deposition and diagenetic maturation of hydrothermal plume-derived silica-iron gels

    Science.gov (United States)

    Grenne, Tor; Slack, John F.

    2003-01-01

    Sedimentary beds of jasper (red hematitic chert) in the Ordovician Løkken ophiolite of Norway are closely associated with volcanogenic massive sulphide (VMS) deposits. The jaspers occur in the immediate hangingwall and laterally peripheral to the large Løkken (25–30 Mt) and small Høydal (0.1 Mt) VMS deposits, and are exposed discontinuously for several kilometres along strike. Massive or laminated types predominate; jasper-sulphide debris-flow deposits are also abundant near VMS deposits. The jaspers contain hematite-rich laminae showing soft-sediment deformation structures and microtextural evidence that record the presence of a colloidal precursor and an origin as gels. Early textures include: (1) straight or curved chains of hematitic filaments 3–10 µm in diameter and 20–100 µm long; (2) branching networks of 15–25 µm-thick, tubular structures surrounded by cryptocrystalline hematite and filled with quartz and euhedral hematite; (3) small (up to 10 µm) spherules composed of cryptocrystalline hematite and silica; and (4) up to 50 µm silica spherules with hematitic cores. The small filaments seem to have been deposited in varying proportions in the primary laminae, possibly together with hematitic and siliceous microspheroids. Diagenetic changes are represented by polygonal syneresis cracks, and the presence of cryptocrystalline (originally opaline) silica, chalcedony, quartz, carbonate and cryptocrystalline hematite and/or goethite forming botryoidal masses and spheroids <10 µm to 5 mm in diameter. Coarser euhedral grains of quartz, carbonate, and hematite are integral parts of these textures. Bleached, silica-rich jaspers preserve only small relics of fine-grained hematite-rich domains, and locally contain sparse pockets composed of coarse euhedral hematite±epidote.

  4. Mineralogy and geochemistry of base-metal deposits at Halilar area, NW Turkey

    Science.gov (United States)

    Kiran Yildirim, D.; Abdelnasser, A.; Doner, Z.; Kumral, M.

    2015-12-01

    This study focuses on the base-metal deposits at Halilar area (NW Turkey) by reporting new data obtained from mineralogical, petrographical and geochemical investigation of this deposit. It is to determine key features of the host rocks, mineralogical changes and alteration zones related to this mineralization. Halilar area is located about 25-30 km NE of Edremit in Balikseir district (NW Turkey). This area contains Halilar group that overlies pre-Late Triassic metamorphic rocks and Permian limestone in the surrounding areas. This Halilar group consists of Bagcagiz and Sakarkaya Formations; later intruded by Duztarla granitic rocks. The base metal deposits at study area represent locally Cu-Pb with some Zn vein type deposits. These deposits restricted to fault gouge zone directed NE-SW as well as occurred at the lower boundary of Bagcagiz and Duztarla granite. It also closely associated with intense hydrothermal alteration within brecciation, and quartz stockwork veining. The mineral assemblage includes chalcopyrite, galena, and some sphalerite, with covellite, and goethite in an abundant gangue of quartz and pyrite. Paragenetic relationships reveal three stages of mineralization; pre-ore, ore, and supergene. Wall-rock hydrothermal alteration includes pervasive silicification, sulfidation, carbonatization, and selective chloritization, sericitization and muscovitization. The geochemical studies refer to the altered samples have high CIA relative to the least altered rocks. The relationship between Na2O and K2O with the Ishikawa alteration index refers to the data plot close to chlorite/sericite. Also, based on alteration box plotting (Ishikawa alteration index vs. chlorite-carbonate-pyrite index), they mostly plotted in the field of the hydrothermal alteration close to chlorite and pyrite minerals with more hydrothermal trends; Intense sericite-chlorite ± pyrite alteration, chlorite ± sericite ± pyrite alteration, and sericite-carbonate alteration.

  5. A genetic link between magnetite mineralization and diorite intrusion at the El Romeral iron oxide-apatite deposit, northern Chile

    Science.gov (United States)

    Rojas, Paula A.; Barra, Fernando; Reich, Martin; Deditius, Artur; Simon, Adam; Uribe, Francisco; Romero, Rurik; Rojo, Mario

    2018-01-01

    El Romeral is one of the largest iron oxide-apatite (IOA) deposits in the Coastal Cordillera of northern Chile. The Cerro Principal magnetite ore body at El Romeral comprises massive magnetite intergrown with actinolite, with minor apatite, scapolite, and sulfides (pyrite ± chalcopyrite). Several generations of magnetite were identified by using a combination of optical and electron microscopy techniques. The main mineralization event is represented by zoned magnetite grains with inclusion-rich cores and inclusion-poor rims, which form the massive magnetite ore body. This main magnetite stage was followed by two late hydrothermal events that are represented by magnetite veinlets that crosscut the massive ore body and by disseminated magnetite in the andesite host rock and in the Romeral diorite. The sulfur stable isotope signature of the late hydrothermal sulfides indicates a magmatic origin for sulfur (δ34S between - 0.8 and 2.9‰), in agreement with previous δ34S data reported for other Chilean IOA and iron oxide-copper-gold deposits. New 40Ar/39Ar dating of actinolite associated with the main magnetite ore stage yielded ages of ca. 128 Ma, concordant within error with a U-Pb zircon age for the Romeral diorite (129.0 ± 0.9 Ma; mean square weighted deviation = 1.9, n = 28). The late hydrothermal magnetite-biotite mineralization is constrained at ca. 118 Ma by 40Ar/39Ar dating of secondary biotite. This potassic alteration is about 10 Ma younger than the main mineralization episode, and it may be related to post-mineralization dikes that crosscut and remobilize Fe from the main magnetite ore body. These data reveal a clear genetic association between magnetite ore formation, sulfide mineralization, and the diorite intrusion at El Romeral (at 129 Ma), followed by a late and more restricted stage of hydrothermal alteration associated with the emplacement of post-ore dikes at ca. 118 Ma. Therefore, this new evidence supports a magmatic-hydrothermal model for the

  6. Superficial characterization and zircaloy-2 electrochemistry with hydrothermal deposit of platinum; Caracterizacion superficial y electroquimica de zircaloy-2 con deposito hidrotermal de platino

    Energy Technology Data Exchange (ETDEWEB)

    Contreras R, A.; Arganis J, C. R.; Medina A, A. L. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Gris C, M. M., E-mail: aida.contreras@inin.gob.mx [Comision Federal de Electricidad, Central Nucleoelectrica Laguna Verde, Carretera Cardel-Nautla Km 42.5, Alto Lucero, Veracruz (Mexico)

    2011-11-15

    The combustible elements of the boiling water nuclear reactors (BWR) are formed by zircaloy-2 tubes that contain in their interior UO{sub 2} pellets. With the objective of mitigating the speed of crack growth by IGSCC to a minimum negative impact on the BWR operation, General Electric developed the noble metals chemical addition (NMCA), in where noble metals particles as Pt, Pd, and Rh, are deposited on the surface of the metal to catalyze the recombination of H{sub 2} and O{sub 2}. Hydrogen is also injected to have it in excess and to favor this recombination (HWC) and zinc to reduce dose. In this work was oxidized zircaloy-2 low similar conditions to the HWC, platinum was deposited starting from a solution of Na{sub 2}Pt(OH){sub 6} with 30 ppm of Pt, in refined samples and without polishing, they were characterized by scanning electron microscopy, energy dispersed spectroscopy, XPS and electrochemistry, by means of Tafel curves and cyclical polarization. On the zircaloy surface was found a ZrO{sub 2} layer that remains under the different study conditions. Under HWC conditions is the oxides formation, possibly complex oxides of zirconium, iron and tin. After the platinum deposit these oxides decrease forming the sub-oxides: Zr{sub 2}O, Zr O, Zr{sub 2}O{sub 3}. The Tafel curves indicates the reduction of the oxygen of the sample with platinum and the cyclical polarization curves show that the reactions that happen on the zircaloy electrodes are not dur to located corrosion. (Author)

  7. Mineralizing conditions and source fluid composition of base metal sulfides in the Lon District, southeastern Iceland

    Science.gov (United States)

    Kremer, C. H.; Thomas, D.; García del Real, P.; Zierenberg, R. A.; Bird, D. K.

    2014-12-01

    Hydrothermal base metal mineralization is rare in Iceland due to the scarcity of evolved magma bodies that discharge metal-rich aqueous fluids into bedrock. One exception is the Lon District of southeastern Iceland, where explosively emplaced rhyolitic breccias host base metal sulfide minerals. We performed petrographic, fluid inclusion, and stable isotope analyses on samples collected in Lon to constrain the conditions of sulfide mineral formation. Based on outcrop and hand sample observations, hot, early-stage hydrothermal fluids precipitated sulfide minerals, quartz, and epidote in rhyolitic breccia and basalt flows. Cooler late-stage fluids precipitated carbonates and quartz in rhyolitic breccia and basalt flows. The order of precipitation of the sulfides was: galena, sphalerite, then chalcopyrite. Homogenization temperatures of liquid-dominated multi-phase fluid inclusions in hydrothermal early-stage quartz coeval with chalcopyrite cluster around 303 °C and 330 °C, indicating precipitation of metallic sulfides in two main hydrothermal fluid pulses early in the period of hydrothermal activity in the Lon District. Freezing point depression analyses of fluid inclusions in quartz show that the sulfide minerals precipitated from a solution that was 4 wt. % NaCl. The 𝛿34S values of sulfides indicate that early-stage hydrothermal sulfur was derived from igneous rocks, either through leaching by non-magmatic hydrothermal fluids or by exsolution of magmatic waters. Early stage epidote 𝛿D values were on average -65.96 per mil, about 14 per mil higher than reported values in epidotes from elsewhere in southeastern Iceland. The 𝛿13C and 𝛿18O values of late-stage carbonates indicate that late stage hydrothermal fluids were meteoric in origin. Collectively, fluid inclusion and stable isotope analyses suggest that early-stage aqueous fluids derived from a mixture of magmatic waters exsolved from the proximal Geitafell intrusion and meteoric

  8. The source of hydrothermal fluids for the Sarekoubu gold deposit in the southern Altai, Xinjiang, China: Evidence from fluid inclusions and geochemistry

    Science.gov (United States)

    Xu, Jiuhua; Ding, Rufu; Xie, Yuling; Zhong, Changhua; Shan, Lihua

    2008-03-01

    The Sarekoubu gold deposit, located at the southern margin of the Altai Mountains, Xinjiang, occurs in metamorphic acid volcanic and volcaniclastic rocks of Devonian Kangbutiebao Formation. Echelon-like ore-bearing veins occur as dextrorotation, intersect ore-controlling faults at small angles. Ore-bearing minerals in the vein systems are mainly native gold, electrum, pyrite, pyrrhotite, chalcopyrite, sphalerite, galena, and native bismuth. The main gold mineralization stages are the pyrite-quartz stage (II) and the polymetallic stage (III). Native bismuth was first found in this study by electron microprobe analysis. R-type cluster analysis shows that Bi exhibits a close relationship to Au in the ore samples and wall rock samples, with a correlation coefficient of 0.75. Relatively high amounts of Bi in this area can be used as an important indicator for gold mineralization, and native bismuth may be a sign indicating gold-rich veins. Primary fluid inclusions in main gold mineralization stages are mainly pure liquid CO 2 inclusions (L CO2) under room temperatures with high densities of 0.85-1.07 g/cm 3. CO 2-H 2O inclusions (L CO2-L H2O) and aqueous inclusions (L H2O-L CO2) are subordinate. A ICP-MS study shows that the ΣREEs of fluid inclusions in vein quartz is very high which is related to CO 2-rich ore-forming fluid, and the fractionation of light REEs and heavy REEs in fluids of vein quartz is not distinct. Carbon isotope analysis on the Sarekoubu gold deposit shows that δ 13C of the CO 2 fluid inclusions ranges from -10.23‰ to -21.15‰, and the δ 13C of CH 4 in fluid inclusions varies from -32.02‰ to -34.11‰. It has been concluded that the origin of the CO 2 fluids in the Sarekoubu gold deposit may be a deep source during the late Paleozoic collisional orogeny.

  9. Mapping of Sulfur Isotopes and Trace Elements in Sulfides by LA-(MC-ICP-MS: Potential Analytical Problems, Improvements and Implications

    Directory of Open Access Journals (Sweden)

    Zhi-Yong Zhu

    2016-10-01

    Full Text Available Constraints on accurate quantitative trace element and sulfur (S isotope analysis of sulfide minerals, especially pyrite, by laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS remain imperfectly understood at the present time. Mapping of S isotope distributions within a complex sample containing several minerals requires an evaluation of the matrix effects and accuracy. Here, we apply LA-Q(quadrupole-ICP-MS and LA-MC(multiple collector-ICP-MS methods to analyze trace elements and S isotopes in sulfides. Spot analysis of S isotopes was conducted to evaluate the influence of matrix effects. The matrix effects from siderite and magnetite are deemed to be negligible in mapping analysis at the precision of this study. Both Fe and S were used as internal standard elements to normalize trace element concentrations in pyrite. Fe proved to be the better choice because the normalized counts per second ratio of trace elements with Fe is much more stable than if using S. A case study of a sulfide sample from the Chengmenshan Cu deposit, Jiangxi Province, South China, demonstrates the potential of combined S isotope and trace element mapping by LA-(MC-ICP-MS. The results suggest that this deposit underwent multi-stage ore formation. Elements, including Au and Ag, were hosted in early-stage pyrite but were re-concentrated into multi-component sulfide assemblages during a late-stage hydrothermal event, which also led to crosscutting veins containing pyrite largely devoid of trace elements, except Se. Combining in situ S isotope and trace element analysis on the same sample represents a powerful tool for understanding ore-forming processes.

  10. Isotopic and fluid-inclusion constraints on the formation of polymetallic vein deposits in the central Argentinian Patagonia

    Science.gov (United States)

    Dejonghe, Léon; Darras, Benoît; Hughes, Guillermo; Muchez, Philippe; Scoates, James S.; Weis, Dominique

    2002-03-01

    The lead isotope compositions of galena and the fluid-inclusion systematics of nine barite-bearing polymetallic (Au, Ag, Pb, Zn) deposits of the central Argentinian Patagonia (Chubut and Rio Negro provinces) have been investigated to constrain the compositions and sources of the mineralizing fluids. Most of the deposits occur as veins, with less common wall-rock disseminations and/or stockworks, and are low-sulfidation epithermal deposits hosted in Jurassic volcanic rocks. Fluid-inclusion homogenization temperatures (Th) from quartz and sphalerite from the deposits fall within the range of 100-300 °C, with the highest measured average temperatures for the most eastern deposits (Mina Angela - 298 °C; Cañadón Bagual - 343 °C). The salinities of the hydrothermal fluids at all deposits were low to moderate (≤10.4 equiv. wt% NaCl). Three groups of ore deposits can be defined on the basis of 206Pb/204Pb ratios for galena and these show a general decrease from west to east (from 18.506 to 18.000). The central Argentinian Patagonia deposits have distinctly less radiogenic lead isotope compositions than similar deposits from Peru and Chile, except for the porphyry copper deposits of central and southern Peru. Galena from the Mina Angela deposit is characterized by very low radiogenic lead isotope compositions (18.000copper systems remains an open question.

  11. Geology, mineralization, and fluid inclusion characteristics of the Kumbel oxidized W-Cu-Mo skarn and Au-W stockwork deposit in Kyrgyzstan, Tien Shan

    Science.gov (United States)

    Soloviev, Serguei G.

    2015-02-01

    The Kumbel deposit is located within a metallogenic belt of W-Mo, Cu-Mo, Au-W, and Au deposits along the Late Paleozoic active continental margin of Tien Shan. The deposit is related to a Late Carboniferous multiphase pluton, with successive intrusive phases from early olivine monzogabbro through monzonite-quartz monzonite to granodiorite and granite, with the latest monzogabbro-porphyry dikes. The deposit represents an example of a complex W-Cu-Mo-Au magmatic-hydrothermal system related to magnetite-series high-K calc-alkaline to shoshonitic igneous suite. It contains large bodies of W-Cu-Mo oxidized prograde and retrograde skarns, with abundant andradite garnet, magnetite, and especially hematite, as well as K-feldspar, molybdoscheelite, chalcopyrite, and molybdenite, with transitions to zones of intense quartz-K-feldspar (with minor andradite and hematite) veining. The skarns are cut by quartz-carbonate ± adularia ± sericite veins (locally sheeted) and stockworks bearing scheelite and minor Cu, Zn, Pb sulfides, as well as Au, Bi, Te, and As mineralization. The association of these veins with the oxidized skarns and magnetite-series intrusion is consistent with the general oxidized, intrusion-related W-Mo-Cu-Au type of deposit, with an affinity to the alkalic (silica-saturated) Cu-Au ± Mo porphyry deposits. The fluid inclusion data show the predominance of magmatic-hydrothermal aqueous chloride fluid during the formation of skarns and quartz-carbonate-scheelite-sulfide veins. The high fluid pressures (˜1,750 bars), together with their high temperature (up to 600 °C) and high salinity (˜50-60 wt% NaCl-equiv.), suggest the formation of skarns and quartz-K-feldspar-andradite-hematite veins under conditions typical of magmatic-hydrothermal transition (depth of ≥4-5 km) of intrusion-related mineralized system, possibly by exsolution of the fluids from crystallizing magma. The auriferous quartz-carbonate-scheelite-sulfide veins formed from high to moderate

  12. Characterization and origin of low-T willemite (Zn2SiO4) mineralization: the case of the Bou Arhous deposit (High Atlas, Morocco)

    Science.gov (United States)

    Choulet, Flavien; Barbanson, Luc; Buatier, Martine; Richard, James; Vennemann, Torsten; Ennaciri, Aomar; Zouhair, Mohamed

    2017-10-01

    Willemite (Zn2SiO4) usually reported in hypogene non-sulfide deposits is described as the main ore mineral in the carbonate-hosted Bou Arhous zinc deposit. This deposit is located in the High Atlas intracontinental range that formed during the Tertiary. Based on a set of microscopic observations, it was possible to establish that willemite replaces primary sphalerite. On the basis of cathodoluminescence imaging, three successive generations of willemite are distinguished, with evidence of dissolution-reprecipitation processes. Willemite is also variably enriched in Ge (up to 1000 ppm), while Ge contents lower than 100 ppm are reported in the primary sulfide minerals. Depending on the willemite generation, this substitution was positively or negatively correlated to the Zn-Pb substitution. According to the nature of zoning (sector versus oscillatory), the incorporation of Ge was either controlled by crystallographic factors or by the nature of the mineralizing fluids. Willemite is associated with other oxidation-related mineral species, like cerussite (PbCO3) but is not in isotopic equilibrium and therefore not considered to be cogenetic. Oxygen isotope compositions support the formation of willemite at temperatures below 130 °C, from mixed meteoric and deeper, hydrothermal fluids. The formation of the High Atlas Belt during the Tertiary has contributed to the exhumation of the sulfide minerals and the development of vertical conduits for percolation of meteoric water and ascending hydrothermal fluids. In addition to a local contribution of silicate minerals of the host limestone, hydrothermal fluids probably transported Si and Ge that are incorporated in willemite.

  13. Mineralogy and ore formation conditions of the Bugdaya Au-Bearing W-Mo porphyry deposit, Eastern Transbaikal Region, Russia

    Science.gov (United States)

    Kovalenker, V. A.; Kiseleva, G. D.; Krylova, T. L.; Andreeva, O. V.

    2011-04-01

    The Bugdaya Au-bearing W-Mo porphyry deposit, Eastern Transbaikal Region, Russia, is located in the central part of volcanic dome and hosted in the large Variscan granitic pluton. In its characteristics, this is a Climax-type deposit, or an Mo porphyry deposit of rhyolitic subclass. The enrichment in gold is related to the relatively widespread vein and veinlet gold-base-metal mineralization. More than 70 minerals (native metals, sulfides, sulfosalts, tellurides, oxides, molybdates, wolframates, carbonates, and sulfates) have been identified in stockwork and vein ores, including dzhalindite, greenockite, Mo-bearing stolzite, Ag and Au amalgams, stromeyerite, cervelleite, and berryite identified here for the first time. Four stages of mineral formation are recognized. The earliest preore stage in form of potassic alteration and intense silicification developed after emplacement of subvolcanic rhyolite (granite) porphyry stock. The stockwork and vein W-Mo mineralization of the quartz-molybdenite stage was the next. Sericite alteration, pyritization, and the subsequent quartz-sulfide veins and veinlets with native gold, base-metal sulfides, and various Ag-Cu-Pb-Bi-Sb sulfosalts of the gold-base-metal stage were formed after the rearrangement of regional pattern of tectonic deformation. The hydrothermal process was completed by argillic (kaolinite-smectite) assemblage of the postore stage. The fluid inclusion study (microthermometry and Raman spectroscopy) allowed us to establish that the stockwork W-Mo mineralization was formed at 550-380°C from both the highly concentrated Mg-Na chloride solution (brine) and the low-density gas with significant N2 and H2S contents. The Pb-Zn vein ore of the gold-base-metal stage enriched in Au, Ag, Bi, and other rare metals was deposited at 360-140°C from a homogeneous Na-K chloride (hydrocarbonate, sulfate) hydrothermal solution of medium salinity.

  14. Hydrothermal iron flux variability following rapid sea level changes

    National Research Council Canada - National Science Library

    Middleton, Jennifer L; Langmuir, Charles H; Mukhopadhyay, Sujoy; McManus, Jerry F; Mitrovica, Jerry X

    2016-01-01

    .... Mir sediments reveal sixfold to eightfold increases in hydrothermal iron and copper deposition during the Last Glacial Maximum, followed by a rapid decline during the sea level rise associated with deglaciation...

  15. Equilibrium nickel isotope fractionation in nickel sulfide minerals

    Science.gov (United States)

    Liu, Shanqi; Li, Yongbing; Ju, Yiwen; Liu, Jie; Liu, Jianming; Shi, Yaolin

    2018-02-01

    Nickel is an important element on Earth, and a major element in the Earth's core, and plays important roles in many geological and biological systems. As an important sink of Ni, Ni sulfides are closely concerned with Ni migration in magma systems and the genesis and evolution of magmatic sulfide deposits. Ni isotopes of Ni sulfides may be a powerful geochemical tracer in magmatic processes and evolution of magmatic sulfide deposits. However Ni isotope fractionation factors of sulfides remain poorly known, which makes the applications of Ni isotopes to geological problems associated with sulfides difficult. In this study, the first-principles methods are used to compute Ni isotope fractionation parameters of polydymite (Ni3S4), heazlewoodite (Ni3S2), millerite (NiS), godlevskite (Ni9S8) and vaesite (NiS2). The reduced partition function ratios of 60Ni/58Ni (103 lnβ60-58) for these minerals decrease in the order of polydymite > heazlewoodite > millerite > godlevskite > vaesite. Ni isotope fractionations in these Ni sulfides show an approximately linear dependence on the average Nisbnd S bond lengths, and have a significant negative correlation with the average Nisbnd Ni bond lengths. Furthermore, a change in Fe/Ni ratio can also lead to Ni isotope fractionation, and with substitution Fe for Ni, the reduced partition function ratios of 60Ni/58Ni decrease.

  16. Cavity-based secondary mineralization in volcanic tuffs of Yucca Mountain, Nevada: a new type of the polymineral vadose speleothem, or a hydrothermal deposit?

    Directory of Open Access Journals (Sweden)

    Dublyansky Yuri V.

    2005-07-01

    Full Text Available Secondary minerals (calcite, chalcedony, quartz, opal, fluorite, heulandite, strontianite residing in open cavities in the Miocenerhyolite tuffs of Yucca Mountain, Nevada have been interpreted by some researchers as "speleothemic" formations, deposited as aresult of downward infiltration of meteoric waters (DOE, 2001, Whelan et al., 2002. The major mineral of the paragenesis, calcite,shows spectacular trend of the textural and crystal morphology change: from anhedral granular occurrences, through (optionalplatelet, bladed and scepter varieties, to euhedral blocky morphologies. The trend is consistent with the overall decrease in thesupesaturation of the mineral forming solution. Stable isotope properties of calcite evolve from 13C-enriched (δ13C = +4 to +9 ‰ PDBat early stages of growth to 13C-depleted (-5 to -10 ‰ at late stages. The non-cyclic character of the isotope record and extremevariations of isotopic values argue against the meteoric origin of mineral forming fluids. The δ13C >4 ‰ PDB require isotope partitioningbetween dissolved CO2 and CH4, which is only possible in reducing anoxic environment, but not in aerated vadose zone.Fluid inclusions studied in calcite, quartz and fluorite revealed that the minerals were deposited from thermal solutions. Thetemperatures were higher at early stages of mineral growth (60 to 85oC and declined with time. Most late-stage calcites containonly all-liquid inclusions, suggesting temperatures less than ca. 35-50oC. Minerals collected close to the major fault show the highesttemperatures. Gases trapped in fluid inclusions are dominated by CO2 and CH4; Raman spectrometry results suggest the presenceof aromatic/cyclic hydrocarbon gases. The gas chemistry, thus, also indicates reduced (anoxic character of the mineral formingfluids.Secondary minerals at Yucca Mountain have likely formed during the short-term invasion(s of the deep-seated aqueous fluidsinto the vadose zone. Following the invasion

  17. Rare Earth Element Fluorocarbonate Minerals from the Olympic Dam Cu-U-Au-Ag Deposit, South Australia

    Directory of Open Access Journals (Sweden)

    Danielle S. Schmandt

    2017-10-01

    Full Text Available Olympic Dam is a world-class breccia-hosted iron-oxide copper-gold-uranium ore deposit located in the Gawler Craton, South Australia. It contains elevated concentrations of rare earth elements (REE which occur as the REE minerals bastnäsite, synchysite, florencite, monazite, and xenotime. This is the first study to focus on the mineralogy and composition of the most abundant REE mineral at Olympic Dam, bastnäsite, and subordinate synchysite. The sample suite extends across the deposit and represents different sulfide mineralization styles (chalcopyrite-bornite and bornite-chalcocite and breccias of various types, ranging from those dominated by clasts of granite, dykes, and hematite. The REE-fluorocarbonates (bastnäsite and synchysite typically occur as fine-grained (<50 μm disseminations in Cu-Fe-sulfides and gangue minerals, and also within breccia matrix. They are also locally concentrated within macroscopic REE-mineral-rich pockets at various locations across the deposit. Such coarse-grained samples formed the primary target of this study. Three general textural groups of bastnäsite are recognized: matrix (further divided into disseminated, fine-grained, and stubby types, irregular (sulfide-associated, and clast replacement. Textures are largely driven by the specific location and prevailing mineral assemblage, with morphology and grain size often controlled by the associated minerals (hematite, sulfides. Major element concentration data reveal limited compositional variation among the REE-fluorocarbonates; all are Ce-dominant. Subtle compositional differences among REE-fluorocarbonates define a spectrum from relatively La-enriched to (Ce + Nd-enriched phases. Granite-derived hydrothermal fluids were the likely source of F in the REE-fluorocarbonates, as well as some of the CO2, which may also have been contributed by associated mafic-ultramafic magmatism. However, transport of REE by Cl-ligands is the most likely scenario. Stubby bastn

  18. Paleoproterozoic high-sulfidation mineralization in the Tapajós gold province, Amazonian Craton, Brazil: geology, mineralogy, alunite argon age, and stable-isotope constraints

    Science.gov (United States)

    Juliani, Caetano; Rye, Robert O.; Nunes, Carmen M.D.; Snee, Lawrence W.; Correa, Rafael H.; Monteiro, Lena V.S.; Bettencourt, Jorge S.; Neumann, Rainer; Neto, Arnaldo A.

    2005-01-01

    The Brazilian Tapajós gold province contains the first evidence of high-sulfidation gold mineralization in the Amazonian Craton. The mineralization appears to be in large nested calderas. The Tapajós–Parima (or Ventuari–Tapajós) geological province consists of a metamorphic, igneous, and sedimentary sequence formed during a 2.10 to 1.87 Ga ocean−continent orogeny. The high-sulfidation mineralization with magmatic-hydrothermal alunite is related to hydrothermal breccias hosted in a rhyolitic volcanic ring complex that contains granitic stocks ranging in age from 1.89 to 1.87 Ga. Cone-shaped hydrothermal breccias, which flare upward, contain vuggy silica and have an overlying brecciated cap of massive silica; the deposits are located in the uppermost part of a ring-structure volcanic cone. Drill cores of one of the hydrothermal breccias contain alunite, natroalunite, pyrophyllite, andalusite, quartz, rutile, diaspore, woodhouseite–svanbergite, kaolinite, and pyrite along with inclusions of enargite–luzonite, chalcopyrite, bornite, and covellite. The siliceous core of this alteration center is surrounded by advanced argillic and argillic alteration zones that grade outward into large areas of propylitically altered rocks with sericitic alteration assemblages at depth. Several occurrences and generations of alunite are observed. Alunite is disseminated in the advanced argillic haloes that envelop massive and vuggy silica or that underlie the brecciated silica cap. Coarse-grained alunite also occurs in branching veins and locally is partly replaced by a later generation of fine-grained alunite. Silicified hydrothermal breccias associated with the alunite contain an estimated reserve of 30 tonnes of gold in rock that grades up to 4.5 g t−1 Au. Seven alunite samples gave 40Ar/39Ar ages of 1.869 to 1.846 Ga, with various degrees of apparent minor Ar loss. Stable isotopic data require a magmatic-hydrothermal origin for the alunite, typical for high-sulfidation

  19. The volcanic-sedimentary sequence of the Lousal deposit, Iberian Pyrite Belt (Portugal)

    Science.gov (United States)

    Rosa, Carlos; Rosa, Diogo; Matos, Joao; Relvas, Jorge

    2010-05-01

    dominant fragmentation mechanism. Unlike many locations of the IPB, fiamme-rich pyroclastic units were not identified at Lousal. The ore deposits occur in close proximity with this volcanic centre that may have driven hydrothermal circulation that led to ore formation. The volcanic rocks show intense chloritic alteration, indicating that the mineralizing event occurred after most of the rhyolitic units have emplaced. The massive sulfides show abundant sedimentary structures which is not typical in the massive sulfide deposits of the IPB. The Lousal 50 Mt massive sulfide deposit consists of at least 11 ore bodies and was exploited until 1988 mainly for pyrite. The ores mined averaged 0.7% Cu, 0.8%Pb e 1.4%Zn (Strauss, 1971). These relatively low base metal grades led to an evaluation of the contents and distribution of high-tech element in the ore bodies, which would improve the economic viability of mining the deposit. This evaluation is currently focusing on the distribution and mineralogy of selenium, as ores mined in the past were known to be rich in this element. This work benefits from research projects INCA (PTDC/CTE-GIN/67027/2006; Characterization of crucial mineral resources for the development of renewable energy technologies: The Iberian Pyrite Belt ores as a source of indium and other high-technology elements) and project ARCHYMEDES II (POCTI/CTA/45873/2002), both funded by the Fundação para a Ciência e Tecnologia. REFERENCES Strauss, G.K., 1970. Sobre la geologia de la provincia piritifera del Suroeste de la Peninsula Iberica y sus yacimientos, en especial sobre la mina de pirita de Lousal (Portugal): Memoria del IGME 77, 1-266. Tornos, F., 2006. Environment of formation and styles of volcanogenic massive sulfides: The Iberian Pyrite Belt. Ore Geology Reviews 28, 259-307.

  20. Metal influence on metallothionein synthesis in the hydrothermal vent mussel Bathymodiolus thermophilus

    OpenAIRE

    Hardivillier, Yann; Denis, Françoise; Demattei, Marie-Véronique; Bustamante, Paco; Laulier, Marc; Cosson, Richard,

    2006-01-01

    International audience; The present study reports on the metallothionein expression in the hydrothermal vent mussel Bathymodiolus thermophilus. Metallothioneins (MT) are proteins involved in intracellular metal regulation and conserved throughout the animal kingdom. The hydrothermal vent environment presents peculiarities (high levels of sulfides and metals, low pH, anoxia) that may have driven associated species to develop original evolutionary ways to face these extreme living conditions. M...

  1. Hydrodynamic modeling of magmatic-hydrothermal activity at submarine arc volcanoes, with implications for ore formation

    Science.gov (United States)

    Gruen, Gillian; Weis, Philipp; Driesner, Thomas; Heinrich, Christoph A.; de Ronde, Cornel E. J.

    2014-10-01

    Subduction-related magmas have higher volatile contents than mid-ocean ridge basalts, which affects the dynamics of associated submarine hydrothermal systems. Interaction of saline magmatic fluids with convecting seawater may enhance ore metal deposition near the seafloor, making active submarine arcs a preferred modern analogue for understanding ancient massive sulfide deposits. We have constructed a quantitative hydrological model for sub-seafloor fluid flow based on observations at Brothers volcano, southern Kermadec arc, New Zealand. Numerical simulations of multi-phase hydrosaline fluid flow were performed on a two-dimensional cross-section cutting through the NW Caldera and the Upper Cone sites, two regions of active venting at the Brothers volcanic edifice, with the former hosting sulfide mineralization. Our aim is to explore the flow paths of saline magmatic fluids released from a crystallizing magma body at depth and their interaction with seawater circulating through the crust. The model includes a 3 × 2km2 sized magma chamber emplaced at ∼ 2.5 km beneath the seafloor connected to the permeable cone via a ∼ 200 m wide feeder dike. During the simulation, a magmatic fluid was temporarily injected from the top of the cooling magma chamber into the overlying convection system, assuming hydrostatic conditions and a static permeability distribution. The simulations predict a succession of hydrologic regimes in the subsurface of Brothers volcano, which can explain some of the present-day hydrothermal observations. We find that sub-seafloor phase separation, inferred from observed vent fluid salinities, and the temperatures of venting at Brothers volcano can only be achieved by input of a saline magmatic fluid at depth, consistent with chemical and isotopic data. In general, our simulations show that the transport of heat, water, and salt from magmatic and seawater sources is partly decoupled. Expulsion of magmatic heat and volatiles occurs within the first

  2. Mineral equilibria and zircon, garnet and titanite U-Pb ages constraining the PTt path of granite-related hydrothermal systems at the Big Bell gold deposit, Western Australia

    Science.gov (United States)

    Mueller, Andreas G.; McNaughton, Neal J.

    2018-01-01

    The Big Bell deposit (75 t gold) is located in a narrow spur of the Meekatharra greenstone belt, Yilgarn Craton, Western Australia. Two ore bodies are located in a calcic-potassic contact alteration zone overprinting lineated granodiorite dykes and amphibolite: almandine-cummingtonite-hornblende skarn (1-3 g/t Au, 1700 g/t As, 330 g/t W) and the muscovite-microcline gneiss (3-5 g/t Au, 580 g/t Sb, 620 g/t W) of the Main Lode. Genetic models vary from pre- to post-metamorphic replacement. Hornblende-plagioclase pairs in amphibolite constrain peak metamorphic temperature to 670 ± 50 °C. In contrast, garnet-biotite thermometry provides estimates of 578 ± 50 and 608 ± 50 °C for garnet-cordierite-biotite schist bordering the skarn and enveloping the Main Lode. Garnet-cordierite and garnet-hornblende pairs extend the range of fluid temperature to 540 ± 65 °C, well below peak metamorphic temperature. At 540-600 °C, the alteration assemblage andalusite + sillimanite constrains pressure to 300-400 MPa corresponding to 11-14 km crustal depth. Published U-Pb ages indicate that metamorphism took place in the aureole of the southeast granodiorite-tonalite batholith (2740-2700 Ma), followed by gold mineralization at 2662 ± 5 Ma and by the emplacement of biotite granite and Sn-Ta-Nb granite-pegmatite dykes at 2625-2610 Ma. Amphibolite xenoliths in granite northwest of the deposit record the lowest temperature (628 ± 50 °C), suggesting it lacks a metamorphic aureole. The rare metal dykes are spatially associated with epidote-albite and andradite-diopside skarns (≤1.5 g/t Au), mined where enriched in the weathered zone. We analysed hydrothermal zircon intergrown with andradite. Concordant U-Pb ages of 2612 ± 7 and 2609 ± 10 Ma confirm the presence of a second granite-related system. The zircons display oscillatory zoning and have low Th/U ratios (0.05-0.08). Low-Th titanite from an albite granite dyke has a concordant but reset U-Pb age of 2577 ± 7 Ma.

  3. Origin of ore-forming fluids of the Haigou gold deposit in the eastern Central Asian Orogenic belt, NE China: Constraints from H-O-He-Ar isotopes

    Science.gov (United States)

    Zeng, Qingdong; He, Huaiyu; Zhu, Rixiang; Zhang, Song; Wang, Yongbin; Su, Fei

    2017-08-01

    The Haigou lode deposit contains 40 t of gold at an average grade of 3.5 g/t, and is one of the largest deposits in the Jiapigou gold belt located along the eastern segment of the northern margin of the North China Craton. The deposit comprises 15 gold-bearing quartz veins hosted in a Carboniferous monzonite-monzogranite stock. Cretaceous dikes consisting of diorite, diabase, and granodiorite porphyries are well developed in the deposit. The diorite porphyry dikes (130.4 ± 6.3 Ma) occur together with gold-bearing quartz veins in NNE- and NE-striking faults. Gold-bearing quartz veins crosscut the diorite porphyry dikes, and the veins are in turn crosscut by E-W-striking 124.6 ± 2.2 Ma granodiorite porphyry dikes. The mineralization mainly occurs as auriferous quartz veins with minor amounts of sulfide minerals, including pyrite, galena, chalcopyrite, and molybdenite. Gold occurs as either native gold or calaverite. Common gangue minerals in the deposit include quartz, sericite, and calcite. The deposit is characterized by various types of hydrothermal alteration, including silicification, sericitization, chloritization, potassic alteration, and carbonatization. Three stages of hydrothermal activity have been recognized in the deposit: (1) a barren quartz stage; (2) a polymetallic sulfide (gold) stage; (3) a calcite stage. Fluid inclusions in hydrothermal pyrites have 3He/4He ratios of 0.3 to 3.3 Ra and 40Ar/36Ar ratios of 351 to 1353, indicating mixing of fluids of mantle and crustal origin. Hydrothermal quartz yielded δ18O values of -1.3‰ to +7.2‰ and δD values of fluid inclusions in the quartz vary between -80‰ and -104‰. These stable isotope data also suggest mixing of magmatic and meteoric fluids. Noble gas and stable isotopic data suggest that the ore fluids have a predominant mantle source with a significant crustal component. Based on the spatial association of gold-bearing quartz veins with early Cretaceous intrusions, and the H-O-He-Ar isotopic

  4. Pingüino In-bearing polymetallic vein deposit, Deseado Massif, Patagonia, Argentina: characteristics of mineralization and ore-forming fluids

    Science.gov (United States)

    Jovic, Sebastián M.; Guido, Diego M.; Schalamuk, Isidoro B.; Ríos, Francisco J.; Tassinari, Colombo C. G.; Recio, Clemente

    2011-03-01

    The Pingüino deposit, located in the low sulfidation epithermal metallogenetical province of the Deseado Massif, Patagonia, Argentina, represents a distinct deposit type in the region. It evolved through two different mineralization events: an early In-bearing polymetallic event that introduced In, Zn, Pb, Ag, Cd, Au, As, Cu, Sn, W and Bi represented by complex sulfide mineralogy, and a late Ag-Au quartz-rich vein type that crosscut and overprints the early polymetallic mineralization. The indium-bearing polymetallic mineralization developed in three stages: an early Cu-Au-In-As-Sn-W-Bi stage (Ps1), a Zn-Pb-Ag-In-Cd-Sb stage (Ps2) and a late Zn-In-Cd (Ps3). Indium concentrations in the polymetallic veins show a wide range (3.4 to 1,184 ppm In). The highest indium values (up to 1,184 ppm) relate to the Ps2 mineralization stage, and are associated with Fe-rich sphalerites, although significant In enrichment (up to 159 ppm) is also present in the Ps1 paragenesis associated with Sn-minerals (ferrokesterite and cassiterite). The hydrothermal alteration associated with the polymetallic mineralization is characterized by advanced argillic alteration within the immediate vein zone, and sericitic alteration enveloping the vein zone. Fluid inclusion studies indicate homogenisation temperatures of 308.2-327°C for Ps1 and 255-312.4°C for Ps2, and low to moderate salinities (2 to 5 eq.wt.% NaCl and 4 to 9 eq.wt.% NaCl, respectively). δ34S values of sulfide minerals (+0.76‰ to +3.61‰) indicate a possible magmatic source for the sulfur in the polymetallic mineralization while Pb isotope ratios for the sulfides and magmatic rocks (206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios of 17.379 to 18.502; 15.588 to 15.730 and 38.234 to 38.756, respectively) are consistent with the possibility that the Pb reservoirs for both had the same crustal source. Spatial relationships, hydrothermal alteration styles, S and Pb isotopic data suggest a probable genetic relation between the

  5. Intermediate sulfidation type base metal mineralization at Aliabad-Khanchy, Tarom-Hashtjin metallogenic belt, NW Iran

    Science.gov (United States)

    Kouhestani, Hossein; Mokhtari, Mir Ali Asghar; Chang, Zhaoshan; Johnson, Craig A.

    2018-01-01

    The Aliabad-Khanchy epithermal base metal deposit is located in the Tarom-Hashtjin metallogenic belt (THMB) of northwest Iran. The mineralization occurs as Cu-bearing brecciated quartz veins hosted by Eocene volcanic and volcaniclastic rocks of the Karaj Formation. Ore formation can be divided into five stages, with most ore minerals, such as pyrite and chalcopyrite being formed in the early stages. The main wall-rock alteration is silicification, and chlorite, argillic and propylitic alteration. Microthermometric measurements of fluid inclusion assemblages show that the ore-forming fluids have eutectic temperatures between −30 and −52 °C, trapping temperatures of 150–290 °C, and salinities of 6.6–12.4 wt% NaCl equiv. These data demonstrate that the ore-forming fluids were medium- to high-temperature, medium- to low-salinity, and low-density H2O–NaCl–CaCl2 fluids. Calculated δ18O values indicate that ore-forming hydrothermal fluids had δ18Owater ranging from +3.6‰ to +0.8‰, confirming that the ore–fluid system evolved from dominantly magmatic to dominantly meteoric. The calculated 34SH2S values range from −8.1‰ to −5.0‰, consistent with derivation of the sulfur from either magma or possibly from local volcanic wall-rock. Combined, the fluid inclusion and stable isotope data indicate that the Aliabad-Khanchy deposit formed from magmatic-hydrothermal fluids. After rising to a depth of between 790 and 500 m, the fluid boiled and subsequent hydraulic fracturing may have led to inflow and/or mixing of early magmatic fluids with circulating groundwater causing deposition of base metals due to dilution and/or cooling. The Aliabad-Khanchy deposit is interpreted as an intermediate-sulfidation style of epithermal mineralization. Our data suggest that the mineralization at Aliabad-Khanchy and other epithermal deposits of the THMB formed by hydrothermal activity related to shallow late Eocene magmatism. The altered Eocene volcanic and

  6. Deposit model for volcanogenic uranium deposits

    Science.gov (United States)

    Breit, George N.; Hall, Susan M.

    2011-01-01

    Volcanism is a major contributor to the formation of important uranium deposits both close to centers of eruption and more distal as a result of deposition of ash with leachable uranium. Hydrothermal fluids that are driven by magmatic heat proximal to some volcanic centers directly form some deposits. These fluids leach uranium from U-bearing silicic volcanic rocks and concentrate it at sites of deposition within veins, stockworks, breccias, volcaniclastic rocks, and lacustrine caldera sediments. The volcanogenic uranium deposit model presented here summarizes attributes of those deposits and follows the focus of the International Atomic Energy Agency caldera-hosted uranium deposit model. Although inferred by some to have a volcanic component to their origin, iron oxide-copper-gold deposits with economically recoverable uranium contents are not considered in this model.

  7. The competing effects of sulfide saturation versus degassing on the behavior of the chalcophile elements during the differentiation of hydrous melts

    Science.gov (United States)

    Jenner, Frances E.; Hauri, Erik H.; Bullock, Emma S.; König, Stephan; Arculus, Richard J.; Mavrogenes, John A.; Mikkelson, Nicole; Goddard, Charlotte

    2015-05-01

    There is a lack of consensus regarding the roles of sulfide saturation versus volatile degassing on the partitioning of Cu and Ag during differentiation and eruption of convergent margin magmas. Because of their oxidized character, volatile-rich magmas from the Eastern Manus Back-arc Basin (EMBB) only reach sulfide saturation following magnetite-driven reduction of the melt: the so-called "magnetite crisis." If sulfide saturation typically precedes volatile saturation, the magnetite crisis will limit the proportion of Cu and Ag that can partition from the melt into an exsolving volatile-rich phase, which may contribute to the sporadic occurrence of magmatic-hydrothermal ore deposits at convergent margins. However, it is unclear whether the magnetite crisis is a common or rare event during differentiation of volatile-rich magmas. We report major and trace element data for submarine volcanic glasses from the Tonga arc-proximal Valu Fa Ridge (VFR; SW Pacific). Cu-Se-Ag systematics of samples erupting at the southern VFR suggest magnetite fractionation-triggered sulfide saturation. The similarity in chalcophile element systematics of the southern VFR and EMBB samples is unlikely to be coincidental, and may indicate that the magnetite crisis is a common event during differentiation of hydrous melts. However, unlike many convergent margin magmas, it is unlikely that the evolving VFR and EMBB were saturated in a S-bearing volatile phase prior to magnetite fractionation. Hence, the metal-depleting magnetite crisis may be restricted to back-arc basin magmas that do not degas volatiles prior to magnetite fractionation and potentially convergent margin magmas fractionating at high pressures in the continental crust.

  8. Spontaneous and Widespread Electricity Generation in Natural Deep-Sea Hydrothermal Fields.

    Science.gov (United States)

    Yamamoto, Masahiro; Nakamura, Ryuhei; Kasaya, Takafumi; Kumagai, Hidenori; Suzuki, Katsuhiko; Takai, Ken

    2017-05-15

    Deep-sea hydrothermal vents discharge abundant reductive energy into oxidative seawater. Herein, we demonstrated that in situ measurements of redox potentials on the surfaces of active hydrothermal mineral deposits were more negative than the surrounding seawater potential, driving electrical current generation. We also demonstrated that negative potentials in the surface of minerals were widespread in the hydrothermal fields, regardless of the proximity to hydrothermal fluid discharges. Lab experiments verified that the negative potential of the mineral surface was induced by a distant electron transfer from the hydrothermal fluid through the metallic and catalytic properties of minerals. These results indicate that electric current is spontaneously and widely generated in natural mineral deposits in deep-sea hydrothermal fields. Our discovery provides important insights into the microbial communities that are supported by extracellular electron transfer and the prebiotic chemical and metabolic evolution of the ocean hydrothermal systems. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Molybdenum isotope behaviour in groundwaters and terrestrial hydrothermal systems, Iceland

    Science.gov (United States)

    Neely, Rebecca A.; Gislason, Sigurdur R.; Ólafsson, Magnus; McCoy-West, Alex J.; Pearce, Christopher R.; Burton, Kevin W.

    2018-03-01

    Molybdenum (Mo) isotopes have proved useful in the reconstruction of paleoredox conditions. Their application generally relies upon a simplified model of ocean inputs in which rivers dominate Mo fluxes to the oceans and hydrothermal fluids are considered to be a minor contribution. To date, however, little attention has been paid to the extent of Mo isotope variation of hydrothermal waters, or to the potential effect of direct groundwater discharge to the oceans. Here we present Mo isotope data for two Icelandic groundwater systems (Mývatn and Þeistareykir) that are both influenced by hydrothermal processes. Relative to NIST 3134 = +0.25‰, the cold (Icelandic rivers. In contrast, waters that are hydrothermally influenced (>10 °C) possess isotopically heavy δ98/95MoHYDROTHERMAL values of +0.25‰ to +2.06‰ (n = 18) with the possibility that the high temperature endmembers are even heavier. Although the mechanisms driving this fractionation remain unresolved, the incongruent dissolution of the host basalt and both the dissolution and precipitation of sulfides are considered. Regardless of the processes driving these variations, the δ98Mo data presented in this study indicate that groundwater and hydrothermal waters have the potential to modify ocean budget calculations.

  10. Geochemistry of hydrothermal fluids from the PACMANUS, Northeast Pual and Vienna Woods hydrothermal fields, Manus Basin, Papua New Guinea

    Science.gov (United States)

    Reeves, Eoghan P.; Seewald, Jeffrey S.; Saccocia, Peter; Bach, Wolfgang; Craddock, Paul R.; Shanks, Wayne C.; Sylva, Sean P.; Walsh, Emily; Pichler, Thomas; Rosner, Martin

    2011-01-01

    Spreading Center. Variations in alkali and dissolved gas abundances with Cl at PACMANUS and NE Pual suggest that phase separation has affected fluid chemistry despite the low temperatures of many vents. In further contrast to Vienna Woods, substantial modification of PACMANUS/NE Pual fluids has taken place as a result of seawater ingress into the upflow zone. Consistently high measured Mg concentrations as well as trends of increasingly non-conservative SO4 behavior, decreasing endmember Ca/Cl and Sr/Cl ratios with increased Mg indicate extensive subsurface anhydrite deposition is occurring as a result of subsurface seawater entrainment. Decreased pH and endmember Fe/Mn ratios in higher Mg fluids indicate that the associated mixing/cooling gives rise to sulfide deposition and secondary acidity production. Several low temperature (< or = 80 degrees C) fluids at PACMANUS/NE Pual also show evidence for anhydrite dissolution and water-rock interaction (fixation of B) subsequent to seawater entrainment. Hence, the evolution of fluid compositions at Pual Ridge reflects the cumulative effects of water/rock interaction, admixing and reaction of fluids exsolved from silicic magma, phase separation/segregation and seawater ingress into upflow zones.

  11. Mineralogy, geochemistry and origin of Zafarabad iron deposit based on REE and trace elements of magnetite

    Directory of Open Access Journals (Sweden)

    Mehrdad Barati

    2013-10-01

    Full Text Available Zafarabad iron deposit is located northwest of Divandareh, in the northern margin of Sanandaj-Sirjan plutonic-metamorphic zone. The deposit is in lentoid to tubular shape, within a shear zone and occrrued in host rocks of calc-schist and limestone. Magnetite with massive, cataclastic and replacement textures are the main phases, while pyrite and other sulfide minerals are found. Major and trace elements are measured by ICP-MS and ICP-AES methods. Based on some ratios of trace elements in the ore samples and (Ti+V vs. Cal+Al+Mn and Ti+V vs. Ni/(Cr+Mn diagrams which are used for classification of iron deposit types, Zafarabad iron deposit fall in the range of skarn deposits. Spider diagrams show a steady decline from LREE to HREE elements with Eu (mean value of 0.06 ppm and Ce (mean value of 0.94 ppm negative anomalies. Comparing the distribution patterns of REE for the Zafarabad magnetites with those of various types of iron deposits shows that the REE pattern for Zafarabad is similar to these deposits. Analysis of calculated parameters for REE shows that the hydrothermal fluids responsible for mineralization are mainly of magmatic origin through fractionation and crystallization processes of a deep iron rich fluid phase and its emplacement within the carbonate rocks, forming iron skarn.

  12. Hydrothermal alteration, fluid inclusions and stable isotope systematics of the Alvo 118 iron oxide-copper-gold deposit, Carajás Mineral Province (Brazil): Implications for ore genesis

    Science.gov (United States)

    Torresi, Ignacio; Xavier, Roberto Perez; Bortholoto, Diego F. A.; Monteiro, Lena V. S.

    2012-03-01

    The Alvo 118 iron oxide-copper-gold (IOCG) deposit (170 Mt at 1.0 wt.% Cu, 0.3 g/t Au) lies in the southern sector of the Itacaúnas Shear Belt, Carajás Mineral Province, along a WNW-ESE-striking, 60-km-long shear zone, close to the contact of the ~2.76-Ga metavolcano-sedimentary Itacaiúnas Supergroup and the basement (~3.0 Ga Xingu Complex). The Alvo 118 deposit is hosted by mafic and felsic metavolcanic rocks and crosscutting granitoid and gabbro intrusions that have been subjected to the following hydrothermal alteration sequence towards the ore zones: (1) poorly developed sodic alteration (albite and scapolite); (2) potassic alteration (biotite or K-feldspar) accompanied by magnetite formation and silicification; (3) widespread, pervasive chlorite alteration spatially associated with quartz-carbonate-sulphide infill ore breccia and vein stockworks; and (4) local post-ore quartz-sericite alteration. The ore assemblage is dominated by chalcopyrite (~60%), bornite (~10%), hematite (~20%), magnetite (10%) and subordinate chalcocite, native gold, Au-Ag tellurides, galena, cassiterite, F-rich apatite, xenotime, monazite, britholite-(Y) and a gadolinite-group mineral. Fluid inclusion studies in quartz point to a fluid regime composed of two distinct fluid types that may have probably coexisted within the timeframe of the Cu-Au mineralizing episode: a hot (>200°C) saline (32.8‰ to 40.6 wt.% NaCl eq.) solution, represented by salt-bearing aqueous inclusions, and a lower temperature (aqueous fluid defined by two-phase (LH2O + VH2O) fluid inclusions. This trend is very similar to those defined for other IOCG systems of the Carajás Mineral Province. δ 18OH2O values in equilibrium with calcite (-1.0‰ to 7.5‰ at 277°C to 344°C) overlap the lower range for primary magmatic waters, but the more 18O-depleted values also point to the involvement of externally derived fluids, possibly of meteoric origin. Furthermore, sulphide δ 34S values (5.1‰ to 6.3

  13. Sulfidation kinetics of silver nanoparticles reacted with metal sulfides.

    Science.gov (United States)

    Thalmann, Basilius; Voegelin, Andreas; Sinnet, Brian; Morgenroth, Eberhard; Kaegi, Ralf

    2014-05-06

    Recent studies have documented that the sulfidation of silver nanoparticles (Ag-NP), possibly released to the environment from consumer products, occurs in anoxic zones of urban wastewater systems and that sulfidized Ag-NP exhibit dramatically reduced toxic effects. However, whether Ag-NP sulfidation also occurs under oxic conditions in the absence of bisulfide has not been addressed, yet. In this study we, therefore, investigated whether metal sulfides that are more resistant toward oxidation than free sulfide, could enable the sulfidation of Ag-NP under oxic conditions. We reacted citrate-stabilized Ag-NP of different sizes (10-100 nm) with freshly precipitated and crystalline CuS and ZnS in oxygenated aqueous suspensions at pH 7.5. The extent of Ag-NP sulfidation was derived from the increase in dissolved Cu(2+) or Zn(2+) over time and linked with results from X-ray absorption spectroscopy (XAS) analysis of selected samples. The sulfidation of Ag-NP followed pseudo first-order kinetics, with rate coefficients increasing with decreasing Ag-NP diameter and increasing metal sulfide concentration and depending on the type (CuS and ZnS) and crystallinity of the reacting metal sulfide. Results from analytical electron microscopy revealed the formation of complex sulfidation patterns that seemed to follow preexisting subgrain boundaries in the pristine Ag-NP. The kinetics of Ag-NP sulfidation observed in this study in combination with reported ZnS and CuS concentrations and predicted Ag-NP concentrations in wastewater and urban surface waters indicate that even under oxic conditions and in the absence of free sulfide, Ag-NP can be transformed into Ag2S within a few hours to days by reaction with metal sulfides.

  14. Mineralogic, fluid inclusion, and sulfur isotope evidence for the genesis of Sechangi lead-zinc (-copper) deposit, Eastern Iran

    Science.gov (United States)

    Malekzadeh Shafaroudi, Azadeh; Karimpour, Mohammad Hassan

    2015-07-01

    The Sechangi lead-zinc (-copper) deposit lies in the Lut block metallogenic province of Eastern Iran. This deposit consists of ore-bearing vein emplaced along fault zone and hosted by Late Eocene monzonite porphyry. Hydrothermal alteration minerals developed in the wall rock include quartz, kaolinite, illite, and calcite. Microscopic studies reveal that the vein contains galena and sphalerite with minor chalcopyrite and pyrite as hypogene minerals and cerussite, anglesite, covellite, malachite, hematite, and goethite as secondary minerals. Fluorite and quartz are the dominant gangue minerals and show a close relationship with sulfide mineralization. Calculated δ34S values for the ore fluid vary between -9.9‰ and -5.9‰. Sulfur isotopic compositions suggest that the ore-forming aqueous solutions were derived from magmatic source and mixed with isotopically light sulfur, probably leached from the volcanic and plutonic country rocks. Microthermometric study of fluid inclusions indicates homogenization temperatures of 151-352 °C. Salinities of ore-forming fluids ranged from 0.2 to 16.5 wt.% NaCl equivalent. The ore-forming fluids of the Sechangi deposit are medium- to low-temperature and salinity. Fluid mixing may have played an important role during Pb-Zn (-Cu) mineralization. The key factors allowing for metal transport and precipitation during ore formation include the sourcing of magmatic fluids with high contents of metallogenic elements and the mixing of these hydrothermal fluids with meteoric waters resulting in the formation of deposit. In terms of the genetic type of deposit, the Sechangi is classified as a volcanic-subvolcanic hydrothermal-related vein deposit.

  15. Various communications concerning sulfigran (sodium sulfide)

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt, H.; Montfort, F.; Wickert; Horn; Junkermann; Wissel, K.; Pier, M.

    1943-01-01

    Most of these communications concerned the problems experienced by Poelitz when its regular supplier of Sulfigran (sodium sulfide), the I.G. Farbenindustrie plant at Luverkusen, had to shut down for repairs and Poelitz had to get an impure form of Sulfigran mixture (a crude melt of ore) from other suppliers, including the I.G. Farbenindustrie plant at Wolfen (Bitterfeld). Various problems arose in the transition, including the fact that the mixture supplied was not ground finely enough for the coal-paste-preparing machinery at Poelitz to handle without damage. An analysis of one sample of the raw melt mixture gave 68.8% sodium sulfide, 12.0% carbon, 1.5% hydrogen, 1.6% silicon dioxide, 1.8% iron, 1.0% aluminum, 0.6% calcium, traces of magnesium and sulfate, and 15.4% water-insoluble. An analysis for another sample showed about 1.8% less sodium sulfide, 1.5% more silicon dioxide, 0.7% less iron, 0.5% less aluminum, 0.6% more calcium, etc., than the previous analysis. Finally one of the communications was a letter in which Ludwigshafen responded favorably to Poelitz's question about whether it would be advantageous to add Sulfigran directly to the first oven of a hydrogenation chamber instead of grinding it with the coal paste. Ludwigshafen said that in some experiments it had observed deposits at places where Sulfigran and coal paste encountered each other in preheater tubes. The deposits consisted of sodium sulfide and iron compounds. 3 tables.

  16. Geochemistry and geochronology of carbonate-hosted base metal deposits in the southern Brooks Range, Alaska: temporal association with VMS deposits and metallogenic implications

    Science.gov (United States)

    Kelly, Karen; Slack, John; Selby, David

    2009-01-01

    The Brooks Range contains enormous accumulations of zinc and copper, either as VMS or sediment-hosted deposits. The Ruby Creek and Omar deposits are Cu-Co stratabound deposits associated with dolomitic breccias. Numerous volcanogenic Cu-Zn (+/-Ag, Au) deposits are situated ~20 km north of the Ruby Creek deposit. The carbonate-hosted deposits consist of chalcopyrite and bornite that fill open spaces, replace the matrix of the breccias, and occur in later cross-cutting veins. Cobaltiferous pyrite, chalcocite, minor tennantite-tetrahedrite, galena, and sphalerite are also present. At Ruby Creek, phases such as carrollite, renierite, and germanite occur rarely. The deposits have undergone post-depositional metamorphism (Ruby Creek, low greenschist facies; Omar, blueschist facies). The unusual geochemical signature includes Cu-Co +/- Ag, As, Au, Bi, Ge, Hg, Sb, and U with sporadic high Re concentrations (up to 2.7 ppm). New Re-Os data were obtained for chalcopyrite, bornite, and pyrite from the Ruby Creek deposit (analyses of sulfides from Omar are in progress). The data show extremely high Re abundances (hundreds of ppb, low ppm) and contain essentially no common Os. The Re-Os data provide the first absolute ages of ore formation for the Ruby Creek deposit and demonstrate that the Re-Os systematics of pyrite, chalcopyrite, and bornite are unaffected by greenschist metamorphism. The Re-Os data show that the main phase of Cu mineralization occurred at 384 +/-4.2 Ma, which coincides with zircon U-Pb ages from igneous rocks that are spatially and genetically associated with VMS deposits. This suggests a temporal link between regional magmatism and hydrothermal mineralization.

  17. The giant Jiaodong gold province: The key to a unified model for orogenic gold deposits?

    Directory of Open Access Journals (Sweden)

    David I. Groves

    2016-05-01

    Full Text Available Although the term orogenic gold deposit has been widely accepted for all gold-only lode-gold deposits, with the exception of Carlin-type deposits and rare intrusion-related gold systems, there has been continuing debate on their genesis. Early syngenetic models and hydrothermal models dominated by meteoric fluids are now clearly unacceptable. Magmatic-hydrothermal models fail to explain the genesis of orogenic gold deposits because of the lack of consistent spatially – associated granitic intrusions and inconsistent temporal relationships. The most plausible, and widely accepted, models involve metamorphic fluids, but the source of these fluids is hotly debated. Sources within deeper segments of the supracrustal successions hosting the deposits, the underlying continental crust, and subducted oceanic lithosphere and its overlying sediment wedge all have their proponents. The orogenic gold deposits of the giant Jiaodong gold province of China, in the delaminated North China Craton, contain ca. 120 Ma gold deposits in Precambrian crust that was metamorphosed over 2000 million years prior to gold mineralization. The only realistic source of fluid and gold is a subducted oceanic slab with its overlying sulfide-rich sedimentary package, or the associated mantle wedge. This could be viewed as an exception to a general metamorphic model where orogenic gold has been derived during greenschist- to amphibolite-facies metamorphism of supracrustal rocks: basaltic rocks in the Precambrian and sedimentary rocks in the Phanerozoic. Alternatively, if a holistic view is taken, Jiaodong can be considered the key orogenic gold province for a unified model in which gold is derived from late-orogenic metamorphic devolatilization of stalled subduction slabs and oceanic sediments throughout Earth history. The latter model satisfies all geological, geochronological, isotopic and geochemical constraints but the precise mechanisms of auriferous fluid release, like many

  18. Formation stages and ore matter sources of the Devdoraki copper deposit, Kazbek volcanic center, the Greater Caucasus

    Science.gov (United States)

    Lebedev, V. A.; Chugaev, A. V.; Vashakidze, G. T.; Parfenov, A. V.

    2016-11-01

    Comprehensive petrological-mineralogical, geochronological, and isotope-geochemical studies have been carried out at the Devdoraki copper deposit situated in the Kazbek neovolcanic center, the frontier territory between Georgia and Russia. The formation history of this deposit has been deciphered on the basis of K-Ar isotopic geochronological data, and the multistage evolution of ore-magmatic system has been established. The subeconomic disseminated and less abundant stringer pyrite mineralization formed at the first stage in the Early Cretaceous back to 130-120 Ma at the retrograde stage of regional metamorphism. The second productive stage was related to intense Quaternary volcanism of the Kazbek center. The late stringer base-metal mineralization formed about 400 ka ago in connection with the activity of minor volcanoes in the eastern part of deposit. In its western part adjoining the Kazbek volcanic cone, ore formation apparently continued over the entire period of recent magmatic activity from 400 to 100 ka ago. It is quite probable that this process is currently proceeding at deep levels of the Devdoraki deposit. Pb-Pb isotope-geochemical data show that Jurassic metasedimentary rocks that host sulfide mineralization could have been a main source of matter for early pyrite. At the second stage of base-metal mineralization formation, the source of ore matter was earlier metamorphic pyrite combined with hydrothermal solutions related to Quaternary endogenic activity within the Kazbek volcanic center. Gangue mineral matter (quartz, carbonates) was supplied simultaneously from the postmagmatic hydrothermal solution and host shale.

  19. Early Archaean hydrothermal systems

    Science.gov (United States)

    de Vries, S. T.; Nijman, W.

    2003-04-01

    Although many people have written about hydrothermal systems in the early Earth, little real evidence is available. New data from the Barberton greenstone belt (South Africa) and greenstone belts of the East Pilbara (Western Australia), provide proof of the existence and nature of hydrothermal systems in the Early Archaean (around 3.4 Ga). Detailed field relationships between vein systems, host rock and overlying sediments are combined with data from fluid inclusions studies on quartz fills in the sediments. An intimate relationship between chert veins and the overlying sediments has been established (the veins are syn-sedimentary). The salinity and temperature of the fluids in the inclusions shows that these are of hydrothermal origin. Similar types of hydrothermal systems, of approximately the same age, have been found at different locations; in the Barberton greenstone belt and at various locations in the East Pilbara. The setting of these hydrothermal systems is not always identical however. Although a felsic substratum is more common, in the North Pole area (Pilbara) the hydrothermal systems rise from a basaltic substratum. In the Barberton greenstone belt, the systems are closely related to shallow intrusive (felsic) bodies. The study of these ancient hydrothermal systems forms an important framework for studies of early life on Earth. This study forms part of an international project on Earth's Earliest Sedimentary Basins, supported by the Foundation Dr. Schürmannfonds.

  20. Mineralogy and geochemistry of El Dorado epithermal gold deposit, El Sauce district, central-northern Chile

    Science.gov (United States)

    Carrillo-Rosúa, J.; Morales-Ruano, S.; Morata, D.; Boyce, A. J.; Belmar, M.; Fallick, A. E.; Fenoll Hach-Alí, P.

    2008-03-01

    The El Dorado Au-Cu deposit is located in an extensive intra-caldera zone of hydrothermal alteration affecting Upper Cretaceous andesites of the Los Elquinos Formation at La Serena (≈ 29°47'S Lat., 70°43'W Long., Chile). Quartz-sulfide veins of economic potential are hosted by N25W and N20E fault structures associated with quartz-illite alteration (+supergene kaolinite). The main ore minerals in the deposit are pyrite, chalcopyrite ± fahlore (As/(As + Sb): 0.06-0.98), with electrum, sphalerite, galena, bournonite-seligmanite (As/(As + Sb): 0.21-0.31), marcasite, pyrrhotite being accessory phases. Electrum, with an Ag content between 32 and 37 at.%, occurs interstitial to pyrite aggregates or along pyrite fractures. Pyrite commonly exhibits chemical zonation with some zones up to 1.96 at.% As. Electron probe microanalyses of pyrite indicate that As-rich zones do not exhibit detectable Au values. Fluid inclusion microthermometry shows homogenization temperatures between 130 and 352 °C and salinities between 1.6 and 6.9 wt.% NaCl eq. Isotope data for quartz, ankerite and phyllosilicates and estimated temperatures show that δ18O and δD for the hydrothermal fluids were between 3 and 10‰ and between -95 and -75‰, respectively. These results suggest the mineralizing fluids were a mixture of meteoric and magmatic waters. An epithermal intermediate-sulfidation model is proposed for the formation of the El Dorado deposit.

  1. When can Electrochemical Techniques give Reliable Corrosion Rates on Carbon Steel in Sulfide Media?

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Hemmingsen, Tor; Nielsen, Lars Vendelbo

    2005-01-01

    Effects of film formation on carbon steel in hydrogen sulfide media may corrupt corrosion rate monitoring by electrochemical techniques. Electrochemical data from hydrogen sulfide solutions, biological sulfide media and natural sulfide containing geothermal water have been collected and the process...... of film formation in sulfide solutions was followed by video. It can be shown that capacitative and diffusional effects due to porous reactive deposits tend to dominate the data resulting in unreliable corrosion rates measured by electrochemical techniques. The effect is strongly increased if biofilm...... in combination with ferrous sulfide corrosion products cover the steel surface. Corrosion rates can be overestimated by a factor of 10 to 100 with electrochemical techniques - both by linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS). Oxygen entering the system accelerates...

  2. Interactions Between Serpentinization, Hydrothermal Activity and Microbial Community at the Lost City Hydrothermal Field

    Science.gov (United States)

    Delacour, A.; Frueh-Green, G. L.; Bernasconi, S. M.; Schaeffer, P.; Frank, M.; Gutjahr, M.; Kelley, D. S.

    2008-12-01

    Seafloor investigations of slow- and ultraslow-spreading ridges have reported many occurrences of exposed mantle peridotites and gabbroic rocks on the ocean floor. Along the Mid-Atlantic Ridge, these uplifted portions of oceanic crust host high-temperature black smoker-type hydrothermal systems (e.g., Rainbow, Logatchev, Saldanha), and the more distinct low-temperature Lost City Hydrothermal Field (LCHF). Built on a southern terrace of the Atlantis Massif, the LCHF is composed of carbonate-brucite chimneys that vent alkaline and low-temperature (40-90°C) hydrothermal fluids. These fluids are related to serpentinization of mantle peridotites, which together with minor gabbroic intrusions form the basement of the LCHF. Long-lived hydrothermal activity at Lost City led to extensive seawater-rock interaction in the basement rocks, as indicated by seawater-like Sr- and mantle to unradiogenic Nd-isotope compositions of the serpentinites. These high fluid fluxes in the southern part of the massif influenced the conditions of serpentinization and have obliterated the early chemical signatures in the serpentinites, especially those of carbon and sulfur. Compared to reducing conditions commonly formed during the first stages of serpentinization, serpentinization at Lost City is characterized by relatively oxidizing conditions resulting in a predominance of magnetite, the mobilization/dissolution and oxidation of igneous sulfides to secondary pyrite, and the incorporation of seawater sulfate, all leading to high bulk-rock S-isotope compositions. The Lost City hydrothermal fluids contain high concentrations in methane, hydrogen, and low-molecular weight hydrocarbons considered as being produced abiotically. In contrast, organic compounds in the serpentinites are dominated by the occurrences of isoprenoids (pristane, phytane, and squalane), polycyclic compounds (hopanes and steranes), and higher abundances of C16 to C20 n-alkanes indicative of a marine organic input. We

  3. Hydrothermal alteration in oceanic ridge volcanics: A detailed study at the Galapagos Fossil Hydrothermal Field

    Science.gov (United States)

    Ridley, W.I.; Perfit, M.R.; Josnasson, I.R.; Smith, M.F.

    1994-01-01

    The Galapagos Fossil Hydrothermal Field is composed of altered oceanic crust and extinct hydrothermal vents within the eastern Galapagos Rift between 85??49???W and 85??55???W. The discharge zone of the hydrothermal system is revealed along scarps, thus providing an opportunity to examine the uppermost mineralized, and highly altered interior parts of the crust. Altered rocks collected in situ by the submersible ALVIN show complex concentric alteration zones. Microsamples of individual zones have been analysed for major/minor, trace elements, and strontium isotopes in order to describe the complex compositional details of the hydrothermal alteration. Interlayered chlorite-smectite and chlorite with disequilibrium compositions dominate the secondary mineralogy as replacement phases of primary glass and acicular pyroxene. Phenocrysts and matrix grains of plagioclase are unaffected during alteration. Using a modification of the Gresens' equation we demonstrate that the trivalent rare earth elements (REEs) are relatively immobile, and calculate degrees of enrichment and depletion in other elements. Strontium isotopic ratios increase as Sr concentrations decrease from least-altered cores to most-altered rims and cross-cutting veins in individual samples, and can be modeled by open system behaviour under low fluid-rock ratio (< 10) conditions following a period of lower-temperature weathering of volcanics within the rift zone. The complex patterns of element enrichment and depletion and strontium isotope variations indicate mixing between pristine seawater and ascending hot fluids to produce a compositional spectrum of fluids. The precipitation of base-metal sulfides beneath the seafloor is probably a result of fluid mixing and cooling. If, as suggested here, the discharge zone alteration occurred under relatively low fluid-rock ratios, then this shallow region must play an important role in determining the exit composition of vent fluids in marine hydrothermal systems

  4. Genesis of Pb-Zn-Cu-Ag Deposits within Permian Carboniferous-Carbonate Rocks in Madina Regency, North Sumatra

    Directory of Open Access Journals (Sweden)

    Bhakti Hamonangan Harahap

    2015-09-01

    Full Text Available DOI:10.17014/ijog.2.3.167-184Strong mineralized carbonate rock-bearing Pb-Zn-Cu-Ag-(Au ores are well exposed on the Latong River area, Madina Regency, North Sumatra Province. The ore deposit is hosted within the carbonate rocks of the Permian to Carboniferous Tapanuli Group. It is mainly accumulated in hollows replacing limestone in the forms of lensoidal, colloform, veins, veinlets, cavity filling, breccia, and dissemination. The ores dominantly consist of galena (126 000 ppm Pb and sphalerite (2347 ppm Zn. The other minerals are silver, azurite, covellite, pyrite, marcasite, and chalcopyrite. This deposit was formed by at least three phases of mineralization, i.e. pyrite and then galena replaced pyrite, sphalerite replaced galena, and pyrite. The last phase is the deposition of chalcopyrite that replaced sphalerite. The Latong sulfide ore deposits posses Pb isotope ratio of 206Pb/204Pb = 19.16 - 20.72, 207Pb/204Pb = 16.16 - 17.29, and 208Pb/204Pb = 42.92 - 40.78. The characteristic feature of the deposit indicates that it is formed by a sedimentary process rather than an igneous activity in origin. This leads to an interpretation that the Latong deposit belongs to the Sedimentary Hosted Massive Sulfide (SHMS of Mississippi Valley-Type (MVT. The presence of SHMS in the island arc such as Sumatra has become controversial. For a long time, ore deposits in the Indonesian Island Arc are always identical with the porphyry and hydrothermal processes related to arc magmatism. This paper is dealing with the geology of Latong and its base metal deposits. This work is also to interpret their genesis as well as general relationship to the regional geology and tectonic setting of Sumatra.

  5. Geological, mineralogical and geochemical characteristics of the Radzimowice Au As Cu deposit from the Kaczawa Mountains (Western Sudetes, Poland): an example of the transition of porphyry and epithermal style

    Science.gov (United States)

    Mikulski, Stanislaw Z.

    2005-03-01

    The sheeted quartz sulfide veins of the Radzimowice Au As Cu deposit in the Kaczawa Mountains are related to Upper Carboniferous post-collisional potassic magmatism of the composite Zelezniak porphyry intrusion. Multiple intrusive activity ranges from early calc-alkaline to sub-alkaline and alkaline rocks and is followed by multiple hydrothermal events. Early crustally derived dacitic magma has low mg# (electrum of two generations, and minor maldonite (Au2Bi). Fluid inclusions from various quartz generations co-genetic with base-metal sulfides and associated with carbonates, tellurides and non-refractory gold indicate fluids with moderate salinity (9 15 wt% NaCl equiv.) and a temperature and pressure drop from 350 to 190°C and 1.2 to 0.8 kbar, respectively. According to the result of the sulfur isotope fractionation geothermometer the temperature of base-metal crystallization was in the range from 322 to 289°C. Preliminary results of oxygen isotope studies of quartz from veins indicate a gradual increase in the proportion of meteoric water in the epithermal stage. The gold to silver ratio in ore samples with >3 ppm Au is about 1:5 (geometric mean). Hydrothermal alteration started with sericitization, pyritization, and kaolinitization in vein selvages followed by alkaline hydrothermal alteration of propylitic character (illitization and chloritization), albitization and carbonatization. The mineralization of the Radzimowice deposit is considered as related to alkaline magmatism and is characterized by the superposition of low-sulfidation epithermal mineralization on higher-temperature and deeper-seated mesothermal/porphyry style.

  6. Chemical properties and hydrothermal processes on the first two directly sampled deep-sea eruptions (Invited)

    Science.gov (United States)

    Butterfield, D. A.; Resing, J. A.; Roe, K. K.; Christensen, M.; Embley, R. W.; Lupton, J. E.; Chadwick, W.

    2009-12-01

    To understand the effects of deep-sea volcanic eruptions on oceanic chemistry, on the ecology of hydrothermal vent communities, on microbial communities in the sub-seafloor biosphere, and on the alteration of oceanic lithosphere requires direct observation and sampling of active eruption sites. Known mid-ocean ridge eruptions have so far been too brief to observe and sample, but a nearly continuous eruption at NW Rota-1 submarine volcano in the Mariana arc (2004-2009) and a potentially long-term eruption at West Mata volcano in the NE Lau Basin (detected Nov. 2008) have provided unprecedented access to magma degassing and rapid water-rock reaction processes that may typify active submarine arc volcanism. How closely this resembles the hydrothermal processes associated with mid-ocean ridge volcanism remains to be seen. NW Rota-1 has a significantly higher output of a free gas phase, but based on initial observations of fluid chemistry and venting types, NW Rota-1 and W Mata have much in common. Active hydrothermal venting was found within a depth horizon encompassing the top 100 meters of the summit peak on both volcanoes (520 m at Rota; 1200 m at Mata). The dominant particulate and chemical plumes originate at active volcanic vents. The hydrothermal chemistry of these volcanic vents is dominated by the condensation of magmatic sulfur dioxide gas, its dissolution into seawater, and subsequent acid attack on volcanic rock. Disproportionation of SO2 to elemental sulfur, H2S, and sulfuric acid occurs. Percolation of hot, acidic fluids through volcaniclastic deposits results in rapid uptake of iron, aluminum, and other metals into solution. Chemical compositions and models indicate that continued water/rock reaction, cooling, and sub-surface mixing with seawater result in rising pH and precipitation of sulfur, alunite, anhydrite, iron sulfides, and iron oxyhydroxides (in order of increasing pH and decreasing temperature). Venting fluids sampled directly out of the

  7. Hydrothermal liquefaction of biomass

    DEFF Research Database (Denmark)

    Toor, Saqib; Rosendahl, Lasse; Rudolf, Andreas

    2011-01-01

    This article reviews the hydrothermal liquefaction of biomass with the aim of describing the current status of the technology. Hydrothermal liquefaction is a medium-temperature, high-pressure thermochemical process, which produces a liquid product, often called bio-oil or bi-crude. During...... the hydrothermal liquefaction process, the macromolecules of the biomass are first hydrolyzed and/or degraded into smaller molecules. Many of the produced molecules are unstable and reactive and can recombine into larger ones. During this process, a substantial part of the oxygen in the biomass is removed...... by dehydration or decarboxylation. The chemical properties of bio-oil are highly dependent of the biomass substrate composition. Biomass constitutes of various components such as protein; carbohydrates, lignin and fat, and each of them produce distinct spectra of compounds during hydrothermal liquefaction...

  8. Structure, stability and geochemical role of palladium chloride complexes in hydrothermal fluids

    Science.gov (United States)

    Bazarkina, Elena F.; Pokrovski, Gleb S.; Hazemann, Jean-Louis

    2014-12-01

    In situ X-ray absorption spectroscopy (XANES and EXAFS) was applied to study palladium speciation in model (Na,Li)Cl-HCl-HNO3-HClO4-H2O solutions and to measure the solubility of PdO(s) and PdS(s) in NaCl-HCl-H2O solutions up to 450 °C and 600 bar. In HNO3 and HClO4 solutions, the square planar Pd(H2O)42+ cation with an average Pd-O distance of 2.00 ± 0.01 Å is the dominant form at 30-100 °C. At T > 100 °C, this cation undergoes hydrolysis resulting in Pd precipitation. In (Na,Li)Cl-HCl solutions Pd forms square planar PdCln(H2O)4-n2-n complexes with Pd-O and Pd-Cl distances of 2.00-2.10 and 2.26-2.31 Å, respectively. At 30-250 °C our data are consistent with a mixture of PdCl(H2O)3+, PdCl2(H2O)20(aq), PdCl3(H2O)-, and PdCl42-, but at T > 250 °C PdCl3(H2O)- and PdCl42- become dominant over a wide range of chloride concentration, from ∼0.03 to at least 9 mol/kg H2O. XANES and EXAFS analyses of these species distribution allowed derivation of the stability constant of the reaction PdCl3- + Cl- = PdCl42- from 300 to 450 °C and 600 bar. These results, coupled with in situ PdO(s) and PdS(s) solubility measurements of this study and a revision of thermodynamic data for these solid phases, allowed generation of a self-consistent thermodynamic data set of the system PdS(s)-PdO(s)-PdCl3--PdCl42-. Our data indicate that Pd can be significantly mobilized as chloride complexes only in sulfide-free oxidizing geological settings (e.g., Chudnoe deposits in Russia, Waterberg deposits in South Africa, Jacutinga-type deposits in Brazil). By contrast, at typical pH (4-8), chlorinity (<10-15 wt% NaCl) and H2S contents (0.001-0.1 wt%) of most hydrothermal fluids, the absolute concentration of Pd-Cl complexes is too low to explain Pd enrichment in volcanogenic massive sulfide, modern seafloor sulfide, and porphyry Cu-Au-Mo deposits. Complexes with S-bearing ligands, very likely other than H2S/HS-, such as S3- and other polysulfide anions, are required to account for Pd

  9. Sulfide oxidation in a biofilter

    DEFF Research Database (Denmark)

    Pedersen, Claus Lunde; Liu, Dezhao; Hansen, Michael Jørgen

    2012-01-01

    oxidizing bacteria but several fungal families including Trichocomaceae. A positive correlation was found between the presence of mold and sulfide uptake. However there have been no reports on fungi metabolizing hydrogen sulfide. We hypothesize that the mold increases the air exposed surface, enabling...... higher hydrogen sulfide uptake followed by oxidation catalyzed by iron-containing enzymes such as cytochrome c oxidase in a process uncoupled from energy conservation....

  10. Sulfide oxidation in a biofilter

    DEFF Research Database (Denmark)

    Pedersen, Claus Lunde; Dezhao, Liu; Hansen, Michael Jørgen

    oxidizing bacteria but several fungal families including Trichocomaceae. A positive correlation was found between the presence of mold and sulfide uptake. However there have been no reports on fungi metabolizing hydrogen sulfide. We hypothesize that the mold increases the air exposed surface, enabling...... higher hydrogen sulfide uptake followed by oxidation catalyzed by iron-containing enzymes such as cytochrome c oxidase in a process uncoupled from energy conservation....

  11. Gold-silver-tellurium mineral assemblages in different ore styles of the Southern Urals VHMS deposits

    Science.gov (United States)

    Maslennikov, V. V.; Zaykov, V. V.; Maslennikova, S. P.; Tesalina, S. G.; Herrington, R. J.; Buschmann, B.; Becker, K.; Petersen, S.; Orgeval, J. J.; Leistel, M.

    2003-04-01

    VMS deposits of the South Urals generally show a continuum in degradation and reworking ranging from pristine steep-sided hydrothermal sulphide mounds to deposits dominated by layered strata of clastic sulphides. Four different deposits with varying degrees of degradation in order of increased reworking: (Yaman-Kasy longrightarrow Molodezhnoe longrightarrow Alexandrinskoe longrightarrow Balta-Tau) have been ranged. The influence of sulphide mound destruction and of sea-floor alteration on mineral assemblages was investigated In the pristine Yaman-Kasy sulphide mound gold and silver occur as altaite+tellurium+hessite-stuetzite+sylvanite and later galena+native gold+pyrite assemblages in chalcopyrite+isocubanite-rich linings of former chimney conduits. Chalcopyrite-dominated conduit fragments in clastic ore facies contain native tellurium+gold intergrowths. In the weakly reworked Molodezhnoe deposit gold-silver assemblages only occur in sea-floor altered clastic sulphides on the slope of massive sulphide mounds in bornite- and tennantite-rich ores in association with Cu-Ag sulfides such as jalpaite, mckinstryite, and stromeyerite and rare Au-Ag-tellurides (petzite). The Alexandrinskoe deposit is dominated by clastic ores and here native gold and rare hessite occur together with galena in tennantite-sphalerite-dominated veins of the footwall as well as in drusy sphalerite forming conduits of vent chimneys. An assemblage of electrum+galena+tennantite was observed in secondary chalcopyrite in the outer walls of chimneys. Native gold+stromeyerite are common in bornite-rich clastic sulphides while an assemblage of Ag-sulphosalts+electrum is common in barite-rich ores. In the reworked Balta-Tau deposit Ag-sulphosalts+electrum-kustelite occur often together with tennantite+galena+barite banded ores. Gold-silver-telluride mineralisation in these VMS deposits changes with degree of reworking from Au-tellurides, and native gold+galena+pyrite in pristine sulphide mounds to

  12. Catalytic Diversity in Alkaline Hydrothermal Vent Systems on Ocean Worlds

    Science.gov (United States)

    Cameron, Ryan D.; Barge, Laura; Chin, Keith B.; Doloboff, Ivria J.; Flores, Erika; Hammer, Arden C.; Sobron, Pablo; Russell, Michael J.; Kanik, Isik

    2016-10-01

    Hydrothermal systems formed by serpentinization can create moderate-temperature, alkaline systems and it is possible that this type of vent could exist on icy worlds such as Europa which have water-rock interfaces. It has been proposed that some prebiotic chemistry responsible for the emergence of life on Earth and possibly other wet and icy worlds could occur as a result ofredox potential and pH gradients in submarine alkaline hydrothermal vents (Russell et al., 2014). Hydrothermal chimneys formed in laboratory simulations of alkaline vents under early Earth conditions have precipitate membranes that contain minerals such as iron sulfides, which are hypothesized to catalyze reduction of CO2 (Yamaguchi et al. 2014, Roldan et al. 2014) leading to further organic synthesis. This CO2 reduction process may be affected by other trace components in the chimney, e.g. nickel or organic molecules. We have conducted experiments to investigate catalytic properties of iron and iron-nickel sulfides containing organic dopants in slightly acidic ocean simulants relevant to early Earth or possibly ocean worlds. We find that the electrochemical properties of the chimney as well as the morphology/chemistry of the precipitate are affected by the concentration and type of organics present. These results imply that synthesis of organics in water-rock systems on ocean worlds may lead to hydrothermal precipitates which can incorporate these organic into the mineral matrix and may affect the role of gradients in alkaline vent systems.Therefore, further understanding on the electroactive roles of various organic species within hydrothermal chimneys will have important implications for habitability as well as prebiotic chemistry. This work is funded by NASA Astrobiology Institute JPL Icy Worlds Team and a NAI Director's Discretionary Fund award.Yamaguchi A. et al. (2014) Electrochimica Acta, 141, 311-318.Russell, M. J. et al. (2014), Astrobiology, 14, 308-43.Roldan, A. (2014) Chem. Comm. 51

  13. Mercury accumulation in hydrothermal vent mollusks from the southern Tonga Arc, southwestern Pacific Ocean.

    Science.gov (United States)

    Lee, Seyong; Kim, Se-Joo; Ju, Se-Jong; Pak, Sang-Joon; Son, Seung-Kyu; Yang, Jisook; Han, Seunghee

    2015-05-01

    We provide the mercury (Hg) and monomethylmercury (MMHg) levels of the plume water, sulfide ore, sediment, and mollusks located at the hydrothermal vent fields of the southern Tonga Arc, where active volcanism and intense seismic activity occur frequently. Our objectives were: (1) to address the potential release of Hg from hydrothermal fluids and (2) to examine the distribution of Hg and MMHg levels in hydrothermal mollusks (mussels and snails) harboring chemotrophic bacteria. While high concentrations of Hg in the sediment and Hg, As, and Sb in the sulfide ore indicates that their source is likely hydrothermal fluids, the MMHg concentration in the sediment was orders of magnitude lower than the Hg (mollusks were much higher (10-100 times) than in other hydrothermal vent environments, indicating that organisms located at the Tonga Arc are exposed to exceedingly high Hg levels. While Hg concentration was higher in the gills and digestive glands than in the mantles and residues of snails and mussels, the MMHg concentrations in the gills and digestive glands were orders of magnitude lower (0.004-0.04%) than Hg concentrations. In summary, our results suggest that the release of Hg from the hydrothermal vent fields of the Tonga Arc and subsequent bioaccumulation are substantial, but not for MMHg. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Evidence for Hesperian Impact-Induced Hydrothermalism on Mars

    Science.gov (United States)

    Marzo, Giuseppe A.; Davila, Alfonso F.; Tornabene, Livio L.; Dohm, James M.; Fairen, Alberto G.; Gross, Christoph; Kneissl, Thomas; Bishop, Janice L.; Roush, Ted L.; McKay, Chris P.

    2010-01-01

    Several hydrated silicate deposits on Mars are observed within craters and are interpreted as excavated Noachian material. Toro crater (71.8 deg E, 17.0 deg N), located on the northern edge of the Syrtis Major Volcanic Plains, shows spectral and morphologic evidence of impact-induced hydrothermal activity. Spectroscopic observations were used to identify extensive hydrated silicate deposits, including prehnite, chlorites, smectites, and opaline material, a suite of phases that frequently results from hydrothermal alteration in terrestrial craters and also expected on Mars from geochemical modeling of hydrothermal environments. When combined with altimetry and high-resolution imaging data, these deposits appear associated predominantly with the central uplift and with portions of the northern part of the crater floor. Detailed geologic mapping of these deposits reveals geomorphic features that are consistent with hydrothermal activity that followed the impact event, including vent-like and conical mound structures, and a complex network of tectonic structures caused by fluid interactions such as fractures and joints. The crater age has been calculated from the cumulative crater size-frequency distributions and is found to be Early Hesperian. The evidence presented here provides support for impact-induced hydrothermal activity in Toro crater, that extends phyllosilicate formation processes beyond the Noachian era.

  15. Hydrogen sulfide intoxication.

    Science.gov (United States)

    Guidotti, Tee L

    2015-01-01

    Hydrogen sulfide (H2S) is a hazard primarily in the oil and gas industry, agriculture, sewage and animal waste handling, construction (asphalt operations and disturbing marshy terrain), and other settings where organic material decomposes under reducing conditions, and in geothermal operations. It is an insoluble gas, heavier than air, with a very low odor threshold and high toxicity, driven by concentration more than duration of exposure. Toxicity presents in a unique, reliable, and characteristic toxidrome consisting, in ascending order of exposure, of mucosal irritation, especially of the eye ("gas eye"), olfactory paralysis (not to be confused with olfactory fatigue), sudden but reversible loss of consciousness ("knockdown"), pulmonary edema (with an unusually favorable prognosis), and death (probably with apnea contributing). The risk of chronic neurcognitive changes is controversial, with the best evidence at high exposure levels and after knockdowns, which are frequently accompanied by head injury or oxygen deprivation. Treatment cannot be initiated promptly in the prehospital phase, and currently rests primarily on supportive care, hyperbaric oxygen, and nitrite administration. The mechanism of action for sublethal neurotoxicity and knockdown is clearly not inhibition of cytochrome oxidase c, as generally assumed, although this may play a role in overwhelming exposures. High levels of endogenous sulfide are found in the brain, presumably relating to the function of hydrogen sulfide as a gaseous neurotransmitter and immunomodulator. Prevention requires control of exposure and rigorous training to stop doomed rescue attempts attempted without self-contained breathing apparatus, especially in confined spaces, and in sudden release in the oil and gas sector, which result in multiple avoidable deaths. © 2015 Elsevier B.V. All rights reserved.

  16. Hydrothermal, biogenic, and seawater components in metalliferous black shales of the Brooks Range, Alaska: Synsedimentary metal enrichment in a carbonate ramp setting

    Science.gov (United States)

    Slack, John F.; Selby, David; Dumoulin, Julie A.

    2015-01-01

    Trace element and Os isotope data for Lisburne Group metalliferous black shales of Middle Mississippian (early Chesterian) age in the Brooks Range of northern Alaska suggest that metals were sourced chiefly from local seawater (including biogenic detritus) but also from externally derived hydrothermal fluids. These black shales are interbedded with phosphorites and limestones in sequences 3 to 35 m thick; deposition occurred mainly on a carbonate ramp during intermittent upwelling under varying redox conditions, from suboxic to anoxic to sulfidic. Deposition of the black shales at ~335 Ma was broadly contemporaneous with sulfide mineralization in the Red Dog and Drenchwater Zn-Pb-Ag deposits, which formed in a distal marginal basin.Relative to the composition of average black shale, the metalliferous black shales (n = 29) display large average enrichment factors (>10) for Zn (10.1), Cd (11.0), and Ag (20.1). Small enrichments (>2–Dog and Drenchwater Zn-Pb-Ag deposits, have the highest Zn/TOC (total organic carbon), Cu/TOC, and Tl/TOC ratios for calculated marine fractions (no detrital component) of these three metals.Average authigenic (detrital-free) contents of Mo, V, U, Ni, Cu, Cd, Pb, Ge, Re, Se, As, Sb, Tl, Pd, and Au show enrichment factors of 4.3 × 103 to 1.2 × 106 relative to modern seawater. Such moderate enrichments, which are common in other metalliferous black shales, suggest wholly marine sources (seawater and biogenic material) for these metals, given similar trends for enrichment factors in organic-rich sediments of modern upwelling zones on the Namibian, Peruvian, and Chilean shelves. The largest enrichment factors for Zn and Ag are much higher (1.4 × 107 and 2.9 × 107, respectively), consistent with an appreciable hydrothermal component. Other metals such as Cu, Pb, and Tl that are concentrated in several black shale samples, and are locally abundant in the Red Dog and Drenchwater Zn-Pb-Ag deposits, may have a partly hydrothermal origin

  17. Geology and structural evolution of the Muruntau gold deposit, Kyzylkum desert, Uzbekistan

    Science.gov (United States)

    Drew, L.J.; Berger, B.R.; Kurbanov, N.K.

    1996-01-01

    The Muruntau gold deposit in the Kyzylkum desert of Uzbekistan is the largest single deposit (??? 1100 tonnes of gold) of the class of low-sulfide syndeformation/synigenous gold deposits formed in the brittle/ductile transition zone of the crust within transpressional shear zones. Hosted by the Cambrian to Ordovician Besopan Suite, the ores were deposited in pre-existing thrust-fault- and metamorphism-related permeabilities and in synmineralization dilational zones created in a large fault-related fold. The Besopan Suite is a 5,000-m-thick sequence of turbiditic siltstones, shales and sandstones. The ore is primarily localized at the base of the Besopan-3 unit, which is a 2,000-m-thick series of carbonaceous shales, siltstones, sandstones and cherts. Initial gold deposition took place within the Sangruntau-Tamdytau shear zone, which was developed along the stratigraphic contact between the Besopan-3 and Besopan-4 units. During the mineralization process, folding of the Besopan Suite and a left-step adjustment in the Sangruntau-Tamdytau shear zone were caused by two concurrent events: (1) the activation of the left-lateral Muruntau-Daugyztau shear zone that developed at nearly a 90?? angle to the preceding shear zone and (2) the intrusion of granitoid plutons. These structural events also resulted in the refocusing of hydrothermal fluid flow into new zones of permeability.

  18. Magmatic Cu-Ni sulfide mineralization of the Huangshannan mafic-untramafic intrusion, Eastern Tianshan, China

    Science.gov (United States)

    Zhao, Yun; Xue, Chunji; Zhao, Xiaobo; Yang, YongQiang; Ke, Junjun

    2015-06-01

    The Huangshannan Ni-Cu (-PGE) sulfide deposit, a new discovery from geological prospecting in Eastern Tianshan, is in a belt of magmatic Ni-Cu (-PGE) sulfide deposits along the southern margin of the Central Asian Orogenic Belt. The host intrusion of the Huangshannan deposit is composed of a layered ultramafic sequence and a massive gabbro-diorite unit. The major sulfide orebodies occur mainly within websterite and lherzolite in the layered ultramafic sequence. In-situ zircon U-Pb dating analyses yielded a crystallization age of 282.5 ± 1.4 Ma, similar to the ages of the Permian Tarim mantle plume. Samples from the Huangshannan intrusion are characterized by nearly flat rare earth elements patterns, negative Zr, Ti and Nb anomalies, arc-like Th/Yb and Nb/Yb ratios, and significantly lower rare earth element and immobile trace element contents than the Tarim basalts. These characteristics suggest that the Huangshannan intrusion was not generated from the Tarim mantle plume. The primary magma for the Huangshannan intrusion and its associated sulfide mineralization were formed from different pulses of picritic magma with different degrees of crustal contamination. The first pulse underwent an initial removal of 0.016% sulfide in the deep magma chamber. The evolved magma reached sulfide saturation again in the shallow magma chamber and formed sulfide ores in lherzolite. The second pulse of magma reached a level of 0.022% sulfide segregation at staging chamber before ascending up to the shallow magma chamber. In the shallow conduit system, this sulfide-unsaturated magma mixed with the first pulse of magma and with contamination from the country rocks, leading to the formation of sulfide ores in websterite. The third magma pulse from the deep chamber formed the unmineralized massive gabbro-diorite unit of the Huangshannan intrusion.

  19. Fluid-mediated metal transport in subduction zones and its link to arc-related giant ore deposits: Constraints from a sulfide-bearing HP vein in lawsonite eclogite (Tianshan, China)

    Science.gov (United States)

    Li, Ji-Lei; Gao, Jun; John, Timm; Klemd, Reiner; Su, Wen

    2013-11-01

    High-pressure (HP) veins in eclogites provide insight into element mobility during fluid-rock interaction in subduction zones. Here, we present a petrological-geochemical study of a sulfide-bearing HP vein and its massive lawsonite eclogite host rock from the Chinese Tianshan (ultra-)high-pressure/low-temperature metamorphic belt. The omphacite-dominated vein is enveloped by a garnet-poor, sulfide-bearing eclogite-facies reaction selvage. Lawsonite, garnet, omphacite, glaucophane and other HP minerals occur as inclusions in pyrite porphyroblasts of the selvage rock, indicating that the selvage formed prograde under eclogite-facies conditions. Relicts of wall-rock garnet (Grt_I) cores in recrystallized selvage garnet (Grt_II) close to the wall rock and the Ca distribution in Grt_II, which images the overgrown selvage matrix, indicate that the selvage formed due to dissolution-precipitation processes as a consequence of fluid-rock interaction of the wall rock eclogite with the vein-forming fluid. The peak metamorphic P-T conditions of the wall-rock eclogite are estimated at ca. 590 °C and 23 kbar. Mass-balance calculations indicate that the reaction selvage experienced: (1) a depletion of the large-ion lithophile elements (K-Rb-Ba) of up to 100% relative to their concentrations in the wall-rock eclogite; (2) a moderate depletion of the HREE and some transition metal elements including Fe, Cu, Ni, Zn, Co, Cr, and Mn (10-40%); (3) a significant enrichment of CaO (up to 50-80%), Sr (up to ˜200%), Pb (up to ˜170%) and S (up to ˜210%); (4) a slight to moderate enrichment of the LREE (10-20%) and MREE (0-40%); whereas (5) the HFSE show no significant variations.

  20. Catalytic Hydrothermal Gasification

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Douglas C.

    2015-05-31

    The term “hydrothermal” used here refers to the processing of biomass in water slurries at elevated temperature and pressure to facilitate the chemical conversion of the organic structures in biomass into useful fuels. The process is meant to provide a means for treating wet biomass materials without drying and to access ionic reaction conditions by maintaining a liquid water processing medium. Typical hydrothermal processing conditions are 523-647K of temperature and operating pressures from 4-22 MPa of pressure. The temperature is sufficient to initiate pyrolytic mechanisms in the biopolymers while the pressure is sufficient to maintain a liquid water processing phase. Hydrothermal gasification is accomplished at the upper end of the process temperature range. It can be considered an extension of the hydrothermal liquefaction mechanisms that begin at the lowest hydrothermal conditions with subsequent decomposition of biopolymer fragments formed in liquefaction to smaller molecules and eventually to gas. Typically, hydrothermal gasification requires an active catalyst to accomplish reasonable rates of gas formation from biomass.

  1. [Raman spectra characteristics of alunite in the Zijinshan gold-copper deposit].

    Science.gov (United States)

    Wang, Cui-Zhi; Xiong, Xin

    2014-02-01

    The Zijinshan gold-copper deposit is the first one of high sulfidation epithermal hydrothermal deposits. The gold bodies up, and the copper bodies down. The gold bodies mainly occur above the ground water table associated with strong silicification, and the copper bodies mainly occur below the ground water table associated with alunitization. The alunite of the Zijinshan gold-copper deposit has four types of occurrence status, that is the altered rock type, the intergrowth-with-Cu-sulphide type, the vein type and the powder type. Different types of the alunite are of different Raman spectra characteristics and fluorescence scattering background. Laser Raman spectra of inclusions in the alunite show that: (1) The characteristics of the Laser Raman spectra of the alunite are of characteristic spectral bands of alunite, just fluorescent scattering weaken gradually from the altered rock type, the intergrowth-with-Cu-sulphide type to the vein type; the alunite in the Powder type has different bands of the Laser Raman spectra relative to the former three types, the intensity of each band is weaker, and it's fluorescent scattering intensity is strongger. (2) The bands in 100-700 cm(-1) of the Laser Raman spectra can be used as "fingerprint" bands indicating the condition of the cation replacement in the molecular structure of alunite. The intensities at 161 and 234 peak change obviously in the bands of the alunite in the altered rock type, which indicating a wide replacement between K and Na; the intensities at 381 and 484 peak in the bands of the alunite in the intergrowth-with-Cu-sulphide type change significantly, indicating Al can be replaced with Cu, Ga, etc.; the larger and stable intensities of the alunite in the vein type in the bands at the peaks about 161, 234, 484, 508, etc. indicate that there are less chances with the replacement between K and Na, Al and Si; fluorescence scatorescent scattering is very strong and the intensity of each band is weaker in the

  2. Vieillissement des catalyseurs de craquage sous l'effet des conditions hydrothermiques et du dépôt de métaux Aging of Cracking Catalysts under the Effect of Hydrothermal Conditions and Metal Deposits

    Directory of Open Access Journals (Sweden)

    Marcilly C.

    2006-11-01

    Full Text Available This article is a bibliographic update on the aging of FCC catalysts under the effect of the severe hydrothermal conditions encountered in regenerators in industrial plants as well as metallic poisons, mainly nickel and vanadium, contained in feedstocks. After examining the changes or degradations undergone by catalysts, particularly by the zeolite Y they contain, and their consequences on catalytic performances, various solutions described in the literature are given, some of which are used industrially.

  3. Cierco Pb-Zn-Ag vein deposits: Isotopic and fluid inclusion evidence for formation during the mesozoic extension in the pyrenees of Spain

    Science.gov (United States)

    Johnson, C.A.; Cardellach, E.; Tritlla, J.; Hanan, B.B.

    1996-01-01

    The Cierco Pb-Zn-Ag vein deposits, located in the central Pyrenees of Spain, crosscut Paleozoic metasedimentary rocks and are in close proximity to Hercynian granodiorite dikes and plutons. Galena and sphalerite in the deposits have average ??34S values of -4.3 and -0.8 per mil (CDT), respectively. Coexisting mineral pairs give an isotopic equilibration temperature range of 89?? to 163??C which overlaps with the 112?? to 198??C range obtained from primary fluid inclusions. Coexisting quartz has a ??18O value of 19 ?? 1 per mil (VSMOW). The fluid which deposited these minerals is inferred to have had ??18OH2o and ??34SH2s values of 5 ?? 1 and -1 ?? 1 per mil, respectively. Chemical and microthermometric analyses of fluid inclusions in quartz and sphalerite indicate salinities of 3 to 29 wt percent NaCl equiv with Na+ and Ca2+ as the dominant cations in solution. The Br/Cl and I/Cl ratios differ from those characteristic of magmatic waters and pristine seawater, but show some similarity to those observed in deep ground waters in crystalline terranes, basinal brines, and evaporated seawater, Barite, which postdates the sulfides, spans isotopic ranges of 13 to 21 per mil, 10 to 15 per mil, and 0.7109 to 0.7123 for ??34S, ??18O, and 87Sr/86Sr, respectively. The three parameters are correlated providing strong evidence that the barites are products of fluid mixing. We propose that the Cierco deposits formed along an extensional fault system at the margin of a marine basin during the breakup of Pangea at some time between the Early Triassic and Early Cretaceous. Sulfide deposition corresponded to an upwelling of hydrothermal fluid from the Paleozoic basement and was limited by the amount of metals carried by the fluid. Barite deposition corresponded to the waning of upward flow and the collapse of sulfate-rich surface waters onto the retreating hydrothermal plume. Calcite precipitated late in the paragenesis as meteoric or marine waters descended into the fault system

  4. Effect of hydrothermal heat treatment on magnetic properties of copper zinc ferrite rf sputtered films

    Science.gov (United States)

    Kaur, Jasmeet; Gadipelly, Thirupathi; Singh, R.

    2016-05-01

    The hydrothermal treatment to the nano-structured films can overcome the destruction of the films. The Cu-Zn Ferrite films were fabricated by RF-sputtering on quartz substrates. Subsequently, the as deposited films were heat treated using hydrothermal process. The X-ray diffraction pattern of the as-deposited and hydrothermal treated films indicate nano-crystalline cubic spinel structure. The amorphous nature of the films is removed after hydrothermal treatment with decreased crystallite size. The field emission scanning electron micrographs showed merged columnar growth for as deposited films, which changes to well define columns after hydrothermal heating. The homogeneous cluster distribution is observed in surface view of the hydrothermal treated films. Hydrothermal treated films show merging of in-plane and out of plane magnetization plots (M(H)) whereas the M(H) plots of as deposited films show angular dependence. The strong angular dependence is observed in the FMR spectra due to the presence of a uniaxial anisotropy in the films. The ferromagnetic interactions decrease in hydrothermal heated films due to the reduced shape anisotropy and crystallite size.

  5. CTS and CZTS for solar cells made by pulsed laser deposition and pulsed electron deposition

    DEFF Research Database (Denmark)

    Ettlinger, Rebecca Bolt

    This thesis concerns the deposition of thin films for solar cells using pulsed laser deposition (PLD) and pulsed electron deposition (PED). The aim was to deposit copper tin sulfide (CTS) and zinc sulfide (ZnS) by pulsed laser deposition to learn about these materials in relation to copper zinc tin......, which make them promising alternatives to the commercially successful solar cell material copper indium gallium diselenide (CIGS). Complementing our group's work on pulsed laser deposition of CZTS, we collaborated with IMEM-CNR in Parma, Italy, to deposit CZTS by pulsed electron deposition for the first...... of using pulsed electron deposition was to make CZTS at a low processing temperature, avoiding the 570 °C annealing step used for our pulsed laser deposited solar cells. Preliminary solar cells had an efficiency of 0.2 % with a 300 °C deposition step without annealing. Further process control is needed...

  6. The Lassen hydrothermal system

    Science.gov (United States)

    Ingebritsen, Steven E.; Bergfeld, Deborah; Clor, Laura; Evans, William C.

    2016-01-01

    The active Lassen hydrothermal system includes a central vapor-dominated zone or zones beneath the Lassen highlands underlain by ~240 °C high-chloride waters that discharge at lower elevations. It is the best-exposed and largest hydrothermal system in the Cascade Range, discharging 41 ± 10 kg/s of steam (~115 MW) and 23 ± 2 kg/s of high-chloride waters (~27 MW). The Lassen system accounts for a full 1/3 of the total high-temperature hydrothermal heat discharge in the U.S. Cascades (140/400 MW). Hydrothermal heat discharge of ~140 MW can be supported by crystallization and cooling of silicic magma at a rate of ~2400 km3/Ma, and the ongoing rates of heat and magmatic CO2 discharge are broadly consistent with a petrologic model for basalt-driven magmatic evolution. The clustering of observed seismicity at ~4–5 km depth may define zones of thermal cracking where the hydrothermal system mines heat from near-plastic rock. If so, the combined areal extent of the primary heat-transfer zones is ~5 km2, the average conductive heat flux over that area is >25 W/m2, and the conductive-boundary length summit of Lassen Peak. However, there is a rich record of intermittent hydrothermal measurement over the past several decades and more-frequent measurement 2009–present. These data reveal sensitivity to climate and weather conditions, seasonal variability that owes to interaction with the shallow hydrologic system, and a transient 1.5- to twofold increase in high-chloride discharge in response to an earthquake swarm in mid-November 2014.

  7. Genome-resolved metagenomics reveals that sulfur metabolism dominates the microbial ecology of rising hydrothermal plumes

    Science.gov (United States)

    Anantharaman, K.; Breier, J. A., Jr.; Jain, S.; Reed, D. C.; Dick, G.

    2015-12-01

    Deep-sea hydrothermal plumes occur when hot fluids from hydrothermal vents replete with chemically reduced elements and compounds like sulfide, methane, hydrogen, ammonia, iron and manganese mix with cold, oxic seawater. Chemosynthetic microbes use these reduced chemicals to power primary production and are pervasive throughout the deep sea, even at sites far removed from hydrothermal vents. Although neutrally-buoyant hydrothermal plumes have been well-studied, rising hydrothermal plumes have received little attention even though they represent an important interface in the deep-sea where microbial metabolism and particle formation processes control the transformation of important elements and impact global biogeochemical cycles. In this study, we used genome-resolved metagenomic analyses and thermodynamic-bioenergetic modeling to study the microbial ecology of rising hydrothermal plumes at five different hydrothermal vents spanning a range of geochemical gradients at the Eastern Lau Spreading Center (ELSC) in the Western Pacific Ocean. Our analyses show that differences in the geochemistry of hydrothermal vents do not manifest in microbial diversity and community composition, both of which display only minor variance across ELSC hydrothermal plumes. Microbial metabolism is dominated by oxidation of reduced sulfur species and supports a diversity of bacteria, archaea and viruses that provide intriguing insights into metabolic plasticity and virus-mediated horizontal gene transfer in the microbial community. The manifestation of sulfur oxidation genes in hydrogen and methane oxidizing organisms hints at metabolic opportunism in deep-sea microbes that would enable them to respond to varying redox conditions in hydrothermal plumes. Finally, we infer that the abundance, diversity and metabolic versatility of microbes associated with sulfur oxidation impart functional redundancy that could allow it to persist in the dynamic settings of hydrothermal plumes.

  8. Thermophilic Sulfate Reduction in Hydrothermal Sediment of Lake Tanganyika, East-Africa

    DEFF Research Database (Denmark)

    ELSGAARD, L.; PRIEUR, D.; MUKWAYA, GM

    1994-01-01

    In environments with temperatures above 60 degrees C, thermophilic prokaryotes are the only metabolically active life-forms. By using the (SO42-)-S-35 tracer technique, we studied the activity of sulfate-reducing microorganisms (SRM) in hot sediment from a hydrothermal vent site in the northern...... population of SRM in the hydrothermal sediment. Thermophilic sulfate reduction had a pH optimum of about 7 and was completely inhibited at pH 8.8 to 9.2. SRM could be enriched from hydrothermal chimney and sediment samples at 60 and 75 degrees C. In lactate-grown enrichments, sulfide production occurred...... at up to 70 and 75 degrees C, with optima at 63 and 71 degrees C, respectively. Several sporulating thermophilic enrichments were morphologically similar to Desulfotomaculum spp. Dissimilatory sulfate reduction in the studied hydrothermal area of Lake Tanganyika apparently has an upper temperature limit...

  9. Hydrothermal energy development projects

    Science.gov (United States)

    Dibello, E. G.

    The development of hydrothermal energy for direct heat applications is being accelerated by twenty-two demonstration projects that are funded on a cost sharing basis by the US Department of Energy, Division of Geothermal Energy. These projects are designed to demonstrate the technical and economic feasibility of the direct use of hydrothermal resources in the United States. Engineering and economic data for the projects are summarized. The data and experience being generated by these projects will serve as an important basis for future direct heat development.

  10. The Au-Hosting Minerals and Process of Formation of the Carlin-Type Bojitian Deposit, Southwestern China

    Directory of Open Access Journals (Sweden)

    Kai Hu

    2017-01-01

    Full Text Available The recently discovered middle-sized Bojitian Carlin-type Au deposit is located in southwestern Guizhou Province, China, near the well-known Shuiyindong super-large-sized deposit. To improve the understanding on this deposit, here we investigate the minerals that host Au and the occurrence of Au in the deposit, using a combination of microscopic work and electron probe microanalysis (EPMA. Based on the results, the formation of the deposit was addressed. Results indicate that the dominant minerals that host Au include arsenian pyrite and arsenopyrite. Au in the cores of zoned pyrite exists mainly as natural nanoscale Au (Au0, while Au in the rims exists mainly as solid solution Au (Au+, but it likely also exists in the rims as natural nanoscale Au. The framboidal, coarse-grained, and banded pyrite types contain both natural nanoscale Au0 and solid solution Au+. The arsenopyrite is of hydrothermal origin, and Au within the arsenopyrite exists as gold solution Au+. The Bojitian deposit was formed from As-bearing, H2S-rich, low-to-medium-temperature fluids that migrated along faults and other channels. Au that was already present in the strata or source beds migrated with the fluids in the form of Au(HS− and ore-forming fluids were then formed in the reducing environment. The ore-forming fluids interacted with Fe-rich carbonates to form an abundance of Au-hosting arsenian sulfides.

  11. Sulfide Mineral Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Rosso, Kevin M.; Vaughan, David J.

    2006-08-01

    The past twenty years or so have seen dramatic development of the experimental and theoretical tools available to study the surfaces of solids at the molecular (?atomic resolution?) scale. On the experimental side, two areas of development well illustrate these advances. The first concerns the high intensity photon sources associated with synchrotron radiation; these have both greatly improved the surface sensitivity and spatial resolution of already established surface spectroscopic and diffraction methods, and enabled the development of new methods for studying surfaces. The second centers on the scanning probe microscopy (SPM) techniques initially developed in the 1980's with the first scanning tunneling microscope (STM) and atomic force microscope (AFM) experiments. The direct 'observation' of individual atoms at surfaces made possible with these methods has truly revolutionized surface science. On the theoretical side, the availability of high performance computers coupled with advances in computational modeling has provided powerful new tools to complement the advances in experiment. Particularly important have been the quantum mechanics based computational approaches such as density functional theory (DFT), which can now be easily used to calculate the equilibrium crystal structures of solids and surfaces from first principles, and to provide insights into their electronic structure. In this chapter, we review current knowledge of sulfide mineral surfaces, beginning with an overview of the principles relevant to the study of the surfaces of all crystalline solids. This includes the thermodynamics of surfaces, the atomic structure of surfaces (surface crystallography and structural stability, adjustments of atoms at the surface through relaxation or reconstruction, surface defects) and the electronic structure of surfaces. We then discuss examples where specific crystal surfaces have been studied, with the main sulfide minerals organized by

  12. Simultaneous sulfide removal, nitrification, and electricity generation in a microbial fuel cell equipped with an oxic cathode.

    Science.gov (United States)

    Bao, Renbing; Zhang, Shaohui; Zhao, Li; Zhong, Liuxiang

    2017-02-01

    With sulfide as an anodic electron donor and ammonium as a cathodic substrate, the feasibility of simultaneous sulfide removal, nitrification, and electricity generation was investigated in a microbial fuel cell (MFC) equipped with an oxic cathode. Successful simultaneous sulfide removal, nitrification, and electricity generation in this MFC were achieved in 35 days, with the sulfide and ammonium removal percent of 92.7 ± 1.4 and 96.4 ± 0.3%, respectively. The maximum power density increased, but the internal resistance decreased with the increase of feeding sulfide concentration from 62.9 ± 0.3 to 238.5 ± 0.2 mg S/L. Stable ammonium removal with complete nitrification, preparing for future denitrification, was obtained throughout the current study. Sulfide removal loading significantly increased with the increase of feeding sulfide concentration at each external resistance, but no significant correlation between sulfide removal loading and external resistance was found at each feeding sulfide concentration. The charge recovery and anodic coulombic efficiency (CE) significantly decreased with the increase of external resistance. High feeding sulfide concentration led to low anodic CE. Granular sulfur deposition was found on the anode graphite fiber. The appropriate feeding sulfide concentration for sulfide removal and sulfur deposition was deemed to be 178.0 ± 1.7 mg S/L, achieving a sulfur deposition percent of 69.7 ± 0.6%.

  13. Source of boron in the Palokas gold deposit, northern Finland: evidence from boron isotopes and major element composition of tourmaline

    Science.gov (United States)

    Ranta, Jukka-Pekka; Hanski, Eero; Cook, Nick; Lahaye, Yann

    2017-06-01

    The recently discovered Palokas gold deposit is part of the larger Rompas-Rajapalot gold-mineralized system located in the Paleoproterozoic Peräpohja Belt, northern Finland. Tourmaline is an important gangue mineral in the Palokas gold mineralization. It occurs as tourmalinite veins and as tourmaline crystals in sulfide-rich metasomatized gold-bearing rocks. In order to understand the origin of tourmaline in the gold-mineralized rocks, we have investigated the major element chemistry and boron isotope composition of tourmaline from three areas: (1) the Palokas gold mineralization, (2) a pegmatitic tourmaline granite, and (3) the evaporitic Petäjäskoski Formation. Based on textural evidence, tourmaline in gold mineralization is divided into two different types. Type 1 is located within the host rock and is cut by rock-forming anthophyllite crystals. Type 2 occurs in late veins and/or breccia zones consisting of approximately 80% tourmaline and 20% sulfides, commonly adjacent to quartz veins. All the studied tourmaline samples belong to the alkali-group tourmaline and can be classified as dravite and schorl. The δ11B values of the three localities lie in the same range, from 0 to -4‰. Tourmaline from the Au mineralization and from the Petäjäskoski Formation has similar compositional trends. Mg is the major substituent for Al; inferred low Fe3+/Fe2+ ratios and Na values (age of molybdenite related to the tourmaline-sulfide-quartz veins, we propose that the tourmaline-forming process is a result of a single magmatic-hydrothermal event related to the extensive granite magmatism at around 1.79-1.77 Ga. Tourmaline was crystallized throughout the hydrothermal process, which resulted in the paragenetic variation between type 1 and type 2. The close association of tourmaline and gold suggests that the gold precipitated from the same boron-rich source as tourmaline.

  14. The loss of the hemoglobin H2S-binding function in annelids from sulfide-free habitats reveals molecular adaptation driven by Darwinian positive selection

    Science.gov (United States)

    Bailly, Xavier; Leroy, Riwanon; Carney, Susan; Collin, Olivier; Zal, Franck; Toulmond, André; Jollivet, Didier

    2003-01-01

    The hemoglobin of the deep-sea hydrothermal vent vestimentiferan Riftia pachyptila (annelid) is able to bind toxic hydrogen sulfide (H2S) to free cysteine residues and to transport it to fuel endosymbiotic sulfide-oxidising bacteria. The cysteine residues are conserved key amino acids in annelid globins living in sulfide-rich environments, but are absent in annelid globins from sulfide-free environments. Synonymous and nonsynonymous substitution analysis from two different sets of orthologous annelid globin genes from sulfide rich and sulfide free environments have been performed to understand how the sulfide-binding function of hemoglobin appeared and has been maintained during the course of evolution. This study reveals that the sites occupied by free-cysteine residues in annelids living in sulfide-rich environments and occupied by other amino acids in annelids from sulfide-free environments, have undergone positive selection in annelids from sulfide-free environments. We assumed that the high reactivity of cysteine residues became a disadvantage when H2S disappeared because free cysteines without their natural ligand had the capacity to interact with other blood components, disturb homeostasis, reduce fitness and thus could have been counterselected. To our knowledge, we pointed out for the first time a case of function loss driven by molecular adaptation rather than genetic drift. If constraint relaxation (H2S disappearance) led to the loss of the sulfide-binding function in modern annelids from sulfide-free environments, our work suggests that adaptation to sulfide-rich environments is a plesiomorphic feature, and thus that the annelid ancestor could have emerged in a sulfide-rich environment. PMID:12721359

  15. Sulfur metabolizing microbes dominate microbial communities in Andesite-hosted shallow-sea hydrothermal systems.

    Directory of Open Access Journals (Sweden)

    Yao Zhang

    Full Text Available To determine microbial community composition, community spatial structure and possible key microbial processes in the shallow-sea hydrothermal vent systems off NE Taiwan's coast, we examined the bacterial and archaeal communities of four samples collected from the water column extending over a redoxocline gradient of a yellow and four from a white hydrothermal vent. Ribosomal tag pyrosequencing based on DNA and RNA showed statistically significant differences between the bacterial and archaeal communities of the different hydrothermal plumes. The bacterial and archaeal communities from the white hydrothermal plume were dominated by sulfur-reducing Nautilia and Thermococcus, whereas the yellow hydrothermal plume and the surface water were dominated by sulfide-oxidizing Thiomicrospira and Euryarchaeota Marine Group II, respectively. Canonical correspondence analyses indicate that methane (CH(4 concentration was the only statistically significant variable that explains all community cluster patterns. However, the results of pyrosequencing showed an essential absence of methanogens and methanotrophs at the two vent fields, suggesting that CH(4 was less tied to microbial processes in this shallow-sea hydrothermal system. We speculated that mixing between hydrothermal fluids and the sea or meteoric water leads to distinctly different CH(4 concentrations and redox niches between the yellow and white vents, consequently influencing the distribution patterns of the free-living Bacteria and Archaea. We concluded that sulfur-reducing and sulfide-oxidizing chemolithoautotrophs accounted for most of the primary biomass synthesis and that microbial sulfur metabolism fueled microbial energy flow and element cycling in the shallow hydrothermal systems off the coast of NE Taiwan.

  16. Genesis of the Silsilah tin deposit, Kingdom of Saudi Arabia

    Science.gov (United States)

    Kamilli, Robert J.; Criss, R.E.

    1996-01-01

    The Silsilah tin deposit (lat 25 degrees 06' N, long 42 degrees 40' E) consists of a group of pervasively greisenized, flat-topped granite cupolas within a 12-km-diam ring complex. The greisens contain varying amounts of disseminated cassiterite and wolframite. Several types of quartz veins are peripheral to the greisens; some of these contain minor wolframite. The deposit is genetically associated with a highly differentiated, peraluminous alkali-feldspar granite (587 + or - 8 Ma) that is part of a mostly peralkaline, igneous ring complex intruded into Late Proterozoic, immature sandstones of the Murdama Group. We recognize four distinct phases of the peraluminous granite. Only the smallest, most highly differentiated cupolas contain significant tin greisen mineralization. Greisens developed beneath aplitic carapaces that overlie the granite and created impermeable barriers to rising volatiles. The geometry of a cupola correlates strongly with the intensity of alteration; cupolas with the smallest cross sectional areas and steepest marginal contacts have the most intensely greisenized apexes. The paragenetic sequence can be divided into five stages: pegmatite formation, locally pervasive albitization, locally pervasive greisenization and deposition of cassiterite, deposition of quartz-wolframite veins, and deposition of quartz veins with minor base metal sulfides. Pressure-corrected fluid inclusion filling temperatures indicate that the hydrothermal system generally cooled as it evolved and that the delta 18O values of the hydrothermal quartz increased from 10.8 to 15.7 per mil. Calculated delta 18O values of the hydrothermal fluid varied concomitantly from the pegmatite stage (delta 18O fluid approximately 8.6ppm; T [asymp] 550 degrees C) to the greisen stage (5.4 and 5.6[ppm; T [asymp] 360 degrees C), the quartz-wolframite vein stage (6.3 and 7.5ppm; T [asymp] 390 degrees C), and the late vein stage (4.0 and 5.1ppm; T [asymp] 270 degrees C). This evolution

  17. Geology and ore fluid geochemistry of the Jinduicheng porphyry molybdenum deposit, East Qinling, China

    Science.gov (United States)

    Li, Hongying; Ye, Huishou; Wang, Xiaoxia; Yang, Lei; Wang, Xiuyuan

    2014-01-01

    Jinduicheng deposit is a giant Mesozoic porphyry Mo system deposit in the East Qinling molybdenum belt, Shaanxi Province, China. The mineralization is associated with the I-type Jinduicheng granite porphyry. Both the porphyry stock and country rocks underwent intense hydrothermal alteration. The alteration, with increasing distance from the parent intrusion, changes from silicification, through potassic and phyllic assemblages, carbonation, to propylitic assemblages. Molybdenite, the dominant ore mineral, occurs in veinlets, most of which are hosted by the altered country rocks, with less than 25% of the ore in the porphyry body. The hydrothermal system comprises four stages, including pre-ore quartz and K-feldspar; two ore stages of quartz, K-feldspar, molybdenite, and Pb- And Zn-bearing sulfides; and post-ore quartz and carbonate. Six main types of primary fluid inclusions are present in hydrothermal quartz, including two-phase aqueous, one-phase aqueous, three-phase CO2-bearing, CO2-dominated fluid inclusions, gas inclusions, and melt inclusions. The homogenization temperatures of fluid inclusions range from 210 to 290 °C in the pre-ore stage, 150-310 °C in ore stage I, 150-360 °C in the ore stage II, and 195-325 °C in the post-ore stage quartz. Estimated salinities of the ore-forming fluids range from 6.9 to 13.5, 4.3 to 12.3, 6.2 to 12.4, and 3.4 to 9.9 wt.% NaCl equiv. in stages 1-4, respectively. The δ34S values of pyrite in the two ore stages range from 2.8‰ to 4.3‰, whereas the δ34S values of molybdenite range from 2.9‰ to 6.2‰. The data suggest both magmatic and crustal sources of sulfur. The δD and δ18O values for the hydrothermal fluids are -57.2‰ to -84.4‰ and 8.0‰ to -3.2‰, respectively. The fluid inclusion and stable data indicate that the pre-ore hydrothermal fluids were mostly of magmatic origin, but the fluids responsible for ore deposition were mixed magmatic and meteoric, and eventually meteoric water dominated the system

  18. Copper sulfide nanoplates as nanosensors for fast, sensitive and selective detection of DNA.

    Science.gov (United States)

    Wang, Dewen; Li, Qun; Xing, Zhicai; Yang, Xiurong

    2018-02-01

    The present communication reports on a novel high-sensitivity DNA sensor based on cooper sulfide nanoplates (CuS NPs). The CuS NPs are successfully synthesized through a mild one-step hydrothermal method. As an efficient nanosensor for the fluorescent detection of DNA, the CuS NPs possess high sensitivity and selectivity with a detection limit of 25pM. Copyright © 2017. Published by Elsevier B.V.

  19. The late cretaceous Donlin Creek gold deposit, Southwestern Alaska: Controls on epizonal ore formation

    Science.gov (United States)

    Goldfarb, R.J.; Ayuso, R.; Miller, M.L.; Ebert, S.W.; Marsh, E.E.; Petsel, S.A.; Miller, L.D.; Bradley, D.; Johnson, Chad; McClelland, W.

    2004-01-01

    The Donlin Creek gold deposit, southwestern Alaska, has an indicated and inferred resource of approximately 25 million ounces (Moz) Au at a cutoff grade of 1.5 g/t. The ca. 70 Ma deposit is hosted in the Late Cretaceous Kuskokwim flysch basin, which developed in the back part of the are region of an active continental margin, on previously accreted oceanic terranes and continental fragments. A hypabyssal, mainly rhyolitic to rhyodacitic, and commonly porphyritic, 8- ?? 3-km dike complex, part of a regional ca. 77 to 58 Ma magmatic arc, formed a structurally competent host for the mineralization. This deposit is subdivided into about one dozen distinct prospects, most of which consist of dense quartz ?? carbonate veinlet networks that fill north-northeast-striking extensional fractures in the northeast-trending igneous rocks. The sulfide mineral assemblage is dominated by arsenopyrite, pyrite, and, typically younger, stibnite; gold is refractory within the arsenopyrite. Sericitization, carbonatization, and suffidation were the main alteration processes. Fluid inclusion studies of the quartz that hosts the resource indicate dominantly aqueous ore fluids with also about 3 to 7 mol percent CO2 ?? CH4 and a few tenths to a few mole percent NaCl + KCl. The gold-bearing fluids were mainly homogeneously trapped at approximately 275?? to 300??C and at depths of 1 to 2 km. Some of the younger stibnite may have been deposited by late-stage aqueous fluids at lower temperature. Measured ??18O values for the gold-bearing quartz range between 11 and 25 per mil; the estimated ??18O fluid values range from 7 to 12 per mil, suggesting a mainly crustally derived fluid. A broad range of measured ??D values for hydrothermal micas, between -150 and -80 per mil, is suggestive of a contribution from devolatilization of organic matter and/or minor amounts of mixing with meteoric fluids. Gold-associated hydrothermal sulfide minerals are characterized by ??34S values mainly between -16 and

  20. Hydrothermal conversion of biomass

    NARCIS (Netherlands)

    Knezevic, D.

    2009-01-01

    This thesis presents research of hydrothermal conversion of biomass (HTC). In this process, hot compressed water (subcritical water) is used as the reaction medium. Therefore this technique is suitable for conversion of wet biomass/ waste streams. By working at high pressures, the evaporation of

  1. Hydrothermal Synthesis of Bi2S3 Nanostructures and ABS-Based Polymeric Nanocomposite

    Directory of Open Access Journals (Sweden)

    D. Ghanbari

    2014-04-01

    Full Text Available Bismuth sulfide nano-rods and nano-flowers were synthesized via a hydrothermal reaction at a relatively low temperature. Thioglycolic acid is used as sulfur source and capping agent simultaneously. Bi2S3 nanostructures were then added to acrylonitrile-butadiene-styrene (ABS copolymer. The thermal stability behavior of ABS filled with bismuth sulfide nano-rods were investigated by thermogravimetric analysis (TGA. Nanostructures were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM and atomic force microscopy (AFM. The flame retardancy behavior of ABS-Bi2S3 was studied by UL-94 analysis.

  2. Formation of arsenic sulfide on GaAs surface under illumination in acidified thiourea electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Khader, Mahmoud M., E-mail: mmkhader@qu.edu.qa [Department of Chemistry and Earth Sciences, College of Arts and Sciences, Qatar University, P.O. 2713, Doha (Qatar); AlJaber, Amina S. [Department of Chemistry and Earth Sciences, College of Arts and Sciences, Qatar University, P.O. 2713, Doha (Qatar)

    2011-10-15

    The present article reports the formation of arsenic sulfide films on GaAs by the potentiodynamic polarization in acidified thiourea (TU) electrolytes under photo-illumination. Oxidation of TU competes with the oxidation of GaAs itself and leads to the formation of surface arsenic-sulfide films. Surface chemical composition is investigated by X-ray photoelectron spectroscopy (XPS), demonstrating the formation of As-sulfide as the XPS peaks at binding energies of 42.6 and 162.5 eV for As 3d and S 2p, respectively, are observed. XPS results also show diminishing of Ga species from the surface while As-sulfide is forming. Though, As-sulfide is predominantly formed on the surface, but the inductive coupling plasma-mass spectroscopy (ICP-MS) analysis still shows a preferential dissolution of As ions into electrolytes. These results indicate that Ga ions diffuse into the bulk of the electrode material. The formation of As-sulfide, initially, enhances the photocurrent generation; presumably, due to suppressing electron-hole recombination processes. Further deposition of As-sulfide deteriorates GaAs photoactivity due to retarding light absorptivity because of depositing a thick As-sulfide film. The morphology of the As-sulfide film is characterized by scanning electron microscopy (SEM) that shows the formation of smooth and nonporous films in TU electrolytes acidified by H{sub 2}SO{sub 4} of concentration {>=}0.2 M. Electrochemical impedance measurements show that GaAs corrosion is limited by the growth and oxidation of the sulfide layer.

  3. Epithermal mineralization and ore controls of the Shasta Au-Ag deposit, Toodoggone District, British Columbia, Canada

    Science.gov (United States)

    Thiersch, P. C.; Williams-Jones, A. E.; Clark, J. R.

    1997-01-01

    The Shasta gold-silver deposit, British Columbia, Canada, is an adularia-sericite-type epithermal deposit in which deposition of precious metals coincided with the transition of quartz- to calcite-dominant gangue. Mineralization is associated with stockwork-breccia zones in potassically altered dacitic lapilli tuffs and flows, and consists of pyrite, sphalerite, chalcopyrite, galena, acanthite, electrum and native silver. Pre- and post-ore veins consist solely of quartz and calcite, respectively. Fluid inclusion microthermometry indicates that ore minerals were deposited between 280 ° and 225 °C, from a relatively dilute hydrothermal fluid (˜1.5 wt.% NaCl equivalent). Abundant vapor-rich inclusions in ore-stage calcite are consistent with boiling. Oxygen and hydrogen isotopic data (δ18Ofluid = -1.5 to -4.1‰; δDfluid = -148 to -171‰) suggest that the fluid had a meteoric origin, but was 18O-enriched by interaction with volcanic wallrocks. Initial (˜280 °C) fluid pH and log f O2 conditions are estimated at 5.3 to 6.0, and -32.5 to -33 bar, respectively; during ore deposition, the fluid became more alkaline and oxidizing. Ore deposition at Shasta is attributed to localization of meteoric hydrothermal fluids by extensional faults; mineralization was controlled by boiling in response to hydraulic brecciation. Calcite and base metal sulfides precipitated due to the increase in pH that accompanied boiling, and the associated decrease in H2S concentration led to precipitation of gold and silver.

  4. Mechanochemical reduction of copper sulfide

    DEFF Research Database (Denmark)

    Balaz, P.; Takacs, L.; Jiang, Jianzhong

    2002-01-01

    The mechanochemical reduction of copper sulfide with iron was induced in a Fritsch P-6 planetary mill, using WC vial filled with argon and WC balls. Samples milled for specific intervals were analyzed by XRD and Mossbauer spectroscopy. Most of the reaction takes place during the first 10 min...... of milling and only FeS and Cu are found after 60 min. The main chemical process is accompanied by phase transformations of the sulfide phases as a result of milling. Djurleite partially transformed to chalcocite and a tetragonal copper sulfide phase before reduction. The cubic modification of FeS was formed...... first, transforming to hexagonal during the later stages of the process. The formation of off-stoichiometric phases and the release of some elemental sulfur by copper sulfide are also probable....

  5. LIGNOCELLULOSE NANOCOMPOSITE CONTAINING COPPER SULFIDE

    OpenAIRE

    Sanchi Nenkova; Peter Velev; Mirela Dragnevska; Diyana Nikolova; Kiril Dimitrov

    2011-01-01

    Copper sulfide-containing lignocellulose nanocomposites with improved electroconductivity were obtained. Two methods for preparing the copper sulfide lignocellulose nanocomposites were developed. An optimization of the parameters for obtaining of the nanocomposites with respect to obtaining improved electroconductivity, economy, and lower quantities and concentration of copper and sulfur ions in waste waters was conducted. The mechanisms and schemes of delaying and subsequent connection of co...

  6. Biomimetic thin film deposition

    Energy Technology Data Exchange (ETDEWEB)

    Rieke, P.R.; Graff, G.E.; Campbell, A.A.; Bunker, B.C.; Baskaran, S.; Song, L.; Tarasevich, B.J.; Fryxell, G.E.

    1995-09-01

    Biological mineral deposition for the formation of bone, mollusk shell and other hard tissues provides materials scientists with illustrative materials processing strategies. This presentation will review the key features of biomineralization and how these features can be of technical importance. We have adapted existing knowledge of biomineralization to develop a unique method of depositing inorganic thin films and coating. Our approach to thin film deposition is to modify substrate surfaces to imitate the proteins found in nature that are responsible for controlling mineral deposition. These biomimetic surfaces control the nucleation and growth of the mineral from a supersaturated aqueous solution. This has many processing advantages including simple processing equipment, environmentally benign reagents, uniform coating of highly complex shapes, and enhanced adherence of coating. Many different types of metal oxide, hydroxide, sulfide and phosphate materials with useful mechanical, optical, electronic and biomedical properties can be deposited.

  7. Geological, fluid inclusion and isotopic studies of the Baiyangping Pb-Zn-Cu-Ag polymetallic deposit, Lanping basin, Yunnan province, China

    Science.gov (United States)

    Wang, Xiao-Hu; Hou, Zeng-Qian; Song, Yu-Cai; Zhang, Hong-Rui

    2015-11-01

    Baiyangping Pb-Zn-Cu-Ag deposit is located in Lanping basin, northwestern Yunnan province. The deposit is composed of a few ore veins and can be divided into several ore blocks. The ore bodies are primarily hosted in Mesozoic carbonate, sandstone and siltstone along the north-south-striking, NWW-striking and NE-SW-striking fault zones. There are breccia, massive, vein like and disseminated ores. The main ore minerals are sphalerite, galena, gratonite, jordanite, tetrahedrite series minerals, chalcocite, chalcopyrite, realgar, orpiment, bournonite, cobalt-bearing arsenopyrite, argentite, kongsbergite, cobaltine, siegenite. The sizes of fluid inclusions in Baiyangping deposit are generally less than 10 μm and have the shape of round, oval, irregular, etc. The ore-forming fluid system is Ca2+-Na+-K+-Mg2+-Cl--F--NO3- brine system. The freezing temperature of fluid inclusions in mineral deposits ranges from -26.4 to -0.2 °C, average -14.6 °C; the homogenization temperature is concentrated in 120-180 °C, and the salinity is between 0.35 and 24.73 wt% (NaCleq), average 16.9 wt% (NaCleq). δ13CPDB and δ18OSMOW values of hydrothermal calcite range from -4.16‰ to 3‰ and -2.5‰ to 20.4‰, respectively. δ34S values of sulfide minerals range from -10.2‰ to 11.2‰, average 5.6‰. The sulfide samples yield 206Pb/204Pb values of 18.609-18.818, 207Pb/204Pb of 15.548-15.842 and 208Pb/204Pb = 38.514-39.556. C-O-S-Pb isotope compositions of the Baiyangping deposit indicate a homogeneous carbon source, and the carbon in hydrothermal calcite is derived from the dissolution of carbonate rock strata, the ore-forming fluid belongs to basin brine fluid system, which is mixed with the precipitate water, sulfur in sulfides and sulfosalts is derived from thermal chemical sulfate reduction, and the thermal decomposition of sulfur-bearing organic matter. The metal mineralization material is from sedimentary strata and basement. The late Pb-Zn polymetallic mineralization event

  8. Origin and significance of postore dissolution collapse breccias cemented with calcite and barite at the Meikle gold deposit, Northern Carlin trend, Nevada

    Science.gov (United States)

    Emsbo, P.; Hofstra, A.H.

    2003-01-01

    The final event in a complicated hydrothermal history at the Meikle gold deposit was gold deficient but caused extensive postore dissolution of carbonate, collapse brecciation, and precipitation of calcite and barite crystals in the resulting cavities. Although previously interpreted to be part of the Carlin-type hydrothermal system, crosscutting relationships and U-Th-Pb geochronology constrain this hydrothermal event to late Pliocene time (ca. 2 Ma), nearly 36 Ma after ore formation. Mineralogic, fluid inclusion, and stable isotope data indicate that postore hydrothermal fluids were reduced, H2S-rich, unevolved meteoric waters ((??18O = -17???) of low temperature (ca. 65??C). The ??18O values of barite and calcite indicate that these minerals were in isotopic equilibrium, requiring that barite SO4 was derived from the oxidation of reduced sulfur; however, preexisting sulfides in breccia cavities were not oxidized. The ??34S (15???) values of barite are higher than those of local bulk sulfide and supergene alunite indicating that SO4 was not derived from supergene oxidation of local sulfide minerals. The 15 per mil ??34S value suggests that the H2S in the fluids may have been leached from sulfur-rich organic matter in the local carbonaceous sedimentary rocks. A reduced H2S-rich fluid is also supported by the bright cathodoluminescence of calcite which indicates that it is Mn rich and Fe poor. Calcite has a narrow range of ??13C values (0.3-1.8???) that are indistinguishable from those of the host Bootstrap limestone, indicating that CO2 in the fluid was from dissolution of the local limestone. These data suggest that dissolution and brecciation of the Bootstrap limestone occurred where H2S-rich fluids encountered more oxidizing fluids and formed sulfuric acid (H2SO4). Intense fracturing in the mine area by previous structural and hydrothermal events probably provided conduits for the descent of oxidized surface water which mixed with the underlying H2S-rich waters

  9. Facile Synthesis of Indium Sulfide/Flexible Electrospun Carbon Nanofiber for Enhanced Photocatalytic Efficiency and Its Application

    Directory of Open Access Journals (Sweden)

    Liu Han

    2017-01-01

    Full Text Available Heterojunction system has been proved as one of the best architectures for photocatalyst owing to extending specific surface area, expanding spectral response range, and increasing photoinduced charges generation, separation, and transmission, which can provide better light absorption range and higher reaction site. In this paper, Indium Sulfide/Flexible Electrospun Carbon Nanofiber (In2S3/CNF heterogeneous systems were synthesized by a facile one-pot hydrothermal method. The results from characterizations of SEM, TEM, XRD, Raman, and UV-visible diffuse reflectance spectroscopy displayed that flower-like In2S3 was deposited on the hair-like CNF template, forming a one-dimensional nanofibrous network heterojunction photocatalyst. And the newly prepared In2S3/CNF photocatalysts exhibit greatly enhanced photocatalytic activity compared to pure In2S3. In addition, the formation mechanism of the one-dimensional heterojunction In2S3/CNF photocatalyst is discussed and a promising approach to degrade Rhodamine B (RB in the photocatalytic process is processed.

  10. Sulfide oxidation and distribution of metals near abandoned copper mines in coastal environments, Prince William Sound, Alaska, USA

    Science.gov (United States)

    Koski, R.A.; Munk, L.; Foster, A.L.; Shanks, Wayne C.; Stillings, L.L.

    2008-01-01

    The oxidation of sulfide-rich rocks, mostly leftover debris from Cu mining in the early 20th century, is contributing to metal contamination of local coastal environments in Prince William Sound, Alaska. Analyses of sulfide, water, sediment, precipitate and biological samples from the Beatson, Ellamar, and Threeman mine sites show that acidic surface waters generated from sulfide weathering are pathways for redistribution of environmentally important elements into and beyond the intertidal zone at each site. Volcanogenic massive sulfide deposits composed of pyrrhotite and (or) pyrite + chalcopyrite + sphalerite with subordinate galena, arsenopyrite, and cobaltite represent potent sources of Cu, Zn, Pb, As, Co, Cd, and Hg. The resistance to oxidation among the major sulfides increases in the order pyrrhotite ??? sphalerite hydrothermal and sedimentary silicates. An inverse correlation between pH and metal concentrations is evident in water data from all three sites. Among all waters sampled, pore waters from Ellamar beach gravels have the lowest pH (???3) and highest concentrations of base metals (to ???25,000 ??g/L), which result from oxidation of abundant sulfide-rich debris in the sediment. High levels of dissolved Hg (to 4100 ng/L) in the pore waters probably result from oxidation of sphalerite-rich rocks. The low-pH and high concentrations of dissolved Fe, Al, and SO4 are conducive to precipitation of interstitial jarosite in the intertidal gravels. Although pore waters from the intertidal zone at the Threeman mine site have circumneutral pH values, small amounts of dissolved Fe2+ in the pore waters are oxidized during mixing with seawater, resulting in precipitation of Fe-oxyhydroxide flocs along the beach-seawater interface. At the Beatson site, surface waters funneled through the underground mine workings and discharged across the waste dumps have near-neutral pH (6.7-7.3) and a relatively small base-metal load; however, these streams probably play a role in

  11. Hydrothermal conversion of biomass

    OpenAIRE

    Knezevic, D.

    2009-01-01

    This thesis presents research of hydrothermal conversion of biomass (HTC). In this process, hot compressed water (subcritical water) is used as the reaction medium. Therefore this technique is suitable for conversion of wet biomass/ waste streams. By working at high pressures, the evaporation of water and high energy consumption that it requires can be avoided. The main focus of this work was HTC process aiming at production of transportation fuel intermediates. For this study, a new experime...

  12. Age constraints on Jerritt Canyon and other Carlin-type gold deposits in the western United States-relationship to mid-Tertiary extension and magmatism

    Science.gov (United States)

    Hofstra, A.H.; Snee, L.W.; Rye, R.O.; Folger, H.W.; Phinisey, J.D.; Loranger, R.J.; Dahl, A.R.; Naeser, C.W.; Stein, H.J.; Lewchuk, M.

    1999-01-01

    Carlin-type gold deposits are difficult to date and a wide range of ages has been reported for individual deposits. Therefore, several methods were employed to constrain the age of the gold deposits in the Jerritt Canyon district. Dated igneous rocks with well-documented crosscutting relationships to ore provided the most reliable constraints. K/Ar and 40Ar/39Ar dates on igneous rocks are as follows: andesite dikes 324 Ma, sericitic alteration in andesite dikes 118 Ma, basalt dikes 40.8 Ma, quartz monzonite dikes 39.2 Ma, and calc-alkaline ignimbrites 43.1 to 40.1 Ma. Of these, only the andesite and basalt dikes are clearly altered and mineralized. The gold deposits are, therefore, younger than the 40.8 Ma basalt dikes. The sericitic alteration in the andesite dikes is unrelated to the gold deposits. A number of dating techniques did not work. K/Ar and 40Ar/39Ar dates on mica from mineralized Ordovician to Devonian sedimentary rocks gave misleading results. The youngest date of 149 Ma from the smallest <0.1-??m-size fraction shows that the temperature (120??-260??C) and duration (?) of hydrothermal activity was insufficient to reset preexisting fine-grained micas in the host rocks. The temperature and duration was also insufficient to anneal fission tracks in zircon from Ordovician quartzites as they yield Middle Proterozoic dates in both mineralized and barren samples. Apatites were too small for fission track dating. Hydrothermal sulfides have pronounced crustal osmium isotope signatures (187Os/188Os(initial) = 0.9-3.6) but did not yield a meaningful isochron due to very low Re and Os concentrations and large analytical uncertainties. Paleomagnetic dating techniques failed because the hydrothermal fluids sulfidized nearly all of the iron in the host rocks leaving no remnant magnetism. When published isotopic dates from other Carlin-type deposits in Nevada and Utah are subject to the rigorous evaluation developed for the Jerritt Canyon study, most deposits can be

  13. Geomicrobiology of Hydrothermal Vents in Yellowstone Lake: Phylogenetic and Functional Analysis suggest Importance of Geochemistry (Invited)

    Science.gov (United States)

    Inskeep, W. P.; Macur, R.; Jay, Z.; Clingenpeel, S.; Tenney, A.; Lavalvo, D.; Shanks, W. C.; McDermott, T.; Kan, J.; Gorby, Y.; Morgan, L. A.; Yooseph, S.; Varley, J.; Nealson, K.

    2010-12-01

    Yellowstone Lake (Yellowstone National Park, WY, USA) is a large, high-altitude, fresh-water lake that straddles the most recent Yellowstone caldera, and is situated on top of significant hydrothermal activity. An interdisciplinary study is underway to evaluate the geochemical and geomicrobiological characteristics of several hydrothermal vent environments sampled using a remotely operated vehicle, and to determine the degree to which these vents may influence the biology of this young freshwater ecosystem. Approximately six different vent systems (locations) were sampled during 2007 and 2008, and included water obtained directly from the hydrothermal vents as well as biomass and sediment associated with these high-temperature environments. Thorough geochemical analysis of these hydrothermal environments reveals variation in pH, sulfide, hydrogen and other potential electron donors that may drive primary productivity. The concentrations of dissolved hydrogen and sulfide were extremely high in numerous vents sampled, especially the deeper (30-50 m) vents located in the Inflated Plain, West Thumb, and Mary Bay. Significant dilution of hydrothermal fluids occurs due to mixing with surrounding lake water. Despite this, the temperatures observed in many of these hydrothermal vents range from 50-90 C, and elevated concentrations of constituents typically associated with geothermal activity in Yellowstone are observed in waters sampled directly from vent discharge. Microorganisms associated with elemental sulfur mats and filamentous ‘streamer’ communities of Inflated Plain and West Thumb (pH range 5-6) were dominated by members of the deeply-rooted bacterial Order Aquificales, but also contain thermophilic members of the domain Archaea. Assembly of metagenome sequence from the Inflated Plain vent biomass and to a lesser extent, West Thumb vent biomass reveal the importance of Sulfurihydrogenibium-like organisms, also important in numerous terrestrial geothermal

  14. A Holistic Model That Physicochemically Links Iron Oxide - Apatite and Iron Oxide - Copper - Gold Deposits to Magmas

    Science.gov (United States)

    Simon, A. C.; Reich, M.; Knipping, J.; Bilenker, L.; Barra, F.; Deditius, A.; Lundstrom, C.; Bindeman, I. N.

    2015-12-01

    Iron oxide-apatite (IOA) and iron oxide-copper-gold deposits (IOCG) are important sources of their namesake metals and increasingly for rare earth metals in apatite. Studies of natural systems document that IOA and IOCG deposits are often spatially and temporally related with one another and coeval magmatism. However, a genetic model that accounts for observations of natural systems remains elusive, with few observational data able to distinguish among working hypotheses that invoke meteoric fluid, magmatic-hydrothermal fluid, and immiscible melts. Here, we use Fe and O isotope data and high-resolution trace element (e.g., Ti, V, Mn, Al) data of individual magnetite grains from the world-class Los Colorados (LC) IOA deposit in the Chilean Iron Belt to elucidate the origin of IOA and IOCG deposits. Values of d56Fe range from 0.08‰ to 0.26‰, which are within the global range of ~0.06‰ to 0.5‰ for magnetite formed at magmatic conditions. Values of δ18O for magnetite and actinolite are 2.04‰ and 6.08‰, respectively, consistent with magmatic values. Ti, V, Al, and Mn are enriched in magnetite cores and decrease systematically from core to rim. Plotting [Al + Mn] vs. [Ti + V] indicates that magnetite cores are consistent with magmatic and/or magmatic-hydrothermal (i.e., porphyry) magnetites. Decreasing Al, Mn, Ti, V is consistent with a cooling trend from porphyry to Kiruna to IOCG systems. The data from LC are consistent with the following new genetic model for IOA and IOCG systems: 1) magnetite cores crystallize from silicate melt; 2) these magnetite crystals are nucleation sites for aqueous fluid that exsolves and scavenges inter alia Fe, P, S, Cu, Au from silicate melt; 3) the magnetite-fluid suspension is less dense that the surrounding magma, allowing ascent; 4) as the suspension ascends, magnetite grows in equilibrium with the fluid and takes on a magmatic-hydrothermal character (i.e., lower Al, Mn, Ti, V); 5) during ascent, magnetite, apatite and

  15. Mercury- and silver-rich ferromanganese oxides, southern California Borderland: Deposit model and environmental implications

    Science.gov (United States)

    Hein, J.R.; Koschinsky, A.; McIntyre, B.R.

    2005-01-01

    Mercury- and silver-enriched ferromanganese oxide crusts were recovered at water depths of 1,750 tol,300 m from La Victoria knoll, located about 72 km off the coast of northern Baja California. No other ferromanganese precipitate found so far in the modern ocean basins is similarly enriched in Hg and Ag. The precipitates consist of submetallic gray, brecciated, Mn oxide layers overlain by brown earthy, laminated Fe-Mn oxide crusts. Both oxide types are rich in Hg (to 10 ppm) and Ag (to 5.5 ppm). The Mn-rich layers are composed of ??MnO2, with lesser amounts of 10A?? and 7A?? manganates, whereas the Mn phase in the Fe-Mn crusts is solely ??MnO2. The Fe phase in both layers is X-ray amorphous. Established criteria for distinguishing hydrothermal versus hydrogenetic crusts indicate that the Mn-rich layers are predominantly of low-temperature hydrothermal origin, whereas the Fe-Mn crusts are hydrogenetic, although there is some overlap in the source of chemical components in both types. La Victoria knoll is uplifted continental basement rock with basalt, andesite, and schist cropping out at the surface; the knoll may have an intrusive core. The Hg and Ag were derived from leaching by hydrothermal fluids of organic matter-rich sediments in basins adjacent to La Victoria knoll and, to a lesser extent, from continental basement rocks underlying the knoll and adjacent basins. Both rock types are notably enriched in Ag and Hg. Faults were the main fluid transport pathway, and hydrothermal circulation was driven by high heat flow associated with thinned crust. Other elements derived from the hydrothermal fluids include Tl, Cd, Cr, and Li. The main host for Hg and Ag is FeOOH, although MnO2 likely hosts some of the Ag. Minor sulfide and barite also may contain small amounts of these metals. Possible analogs in the geologic record for this deposit type are found in the Basin and Range province of the western United States and Mexico. The discovery highlights the fact that

  16. On the early fate of hydrothermal iron at deep-sea vents: A reassessment after in situ filtration

    Science.gov (United States)

    Waeles, M.; Cotte, L.; Pernet-Coudrier, B.; Chavagnac, V.; Cathalot, C.; Leleu, T.; Laës-Huon, A.; Perhirin, A.; Riso, R. D.; Sarradin, P.-M.

    2017-05-01

    Deep-sea hydrothermal venting is now recognized as a major source of iron (Fe), an essential trace element that controls marine productivity. However, the reactions occurring during dispersal from buoyant plumes to neutrally buoyant hydrothermal plumes are still poorly constrained. Here we report for the first time on the dissolved-particulate partition of Fe after in situ filtration at the early stage of mixing at different hydrothermal discharges, i.e., Lucky Strike (37°N), TAG (26°N), and Snakepit (23°N) on the Mid-Atlantic Ridge. We found that hydrothermal iron is almost completely preserved (>90%) in the dissolved fraction, arguing for low iron-bearing sulfide precipitation of iron in basalt-hosted systems with low Fe:H2S ratios. This result can only be explained by a kinetically limited formation of pyrite. The small part of Fe being precipitated as sulfides in the mixing gradient (<10%) is restricted to the inclusion of Fe in minerals of high Cu and Zn content. We also show that secondary venting is a source of Fe-depleted hydrothermal solutions. These results provide new constrains on Fe fluxes from hydrothermal venting.

  17. Tectonic setting and metallogenesis of volcanogenic massive sulfide deposits in the Bonnifield Mining District, Northern Alaska Range: Chapter B in Recent U.S. Geological Survey studies in the Tintina Gold Province, Alaska, United States, and Yukon, Canada--results of a 5-year project

    Science.gov (United States)

    Dusel-Bacon, Cynthia; Aleinikoff, John N.; Premo, Wayne R.; Paradis, Suzanne; Lohr-Schmidt, Ilana; Gough, Larry P.; Day, Warren C.

    2007-01-01

    This paper summarizes the results of field and laboratory investigations, including whole-rock geochemistry and radiogenic isotopes, of outcrop and drill core samples from volcanogenic massive sulfide (VMS) deposits and associated metaigneous rocks in the Wood River area of the Bonnifield mining district, northern Alaska Range (see fig. 1 of Editors’ Preface and Overview). U-Pb zircon igneous crystallization ages from felsic rocks indicate a prolonged period of Late Devonian to Early Mississippian (373±3 to 357±4 million years before present, or Ma) magmatism. This magmatism occurred in a basinal setting along the ancient Pacific margin of North America. The siliceous and carbonaceous compositions of metasedimentary rocks, Precambrian model ages based on U-Pb dating of zircon and neodymium ages, and for some units, radiogenic neodymium isotopic compositions and whole-rock trace-element ratios similar to those of continental crust are evidence for this setting. Red Mountain (also known as Dry Creek) and WTF, two of the largest VMS deposits, are hosted in peralkaline metarhyolite of the Mystic Creek Member of the Totatlanika Schist. The Mystic Creek Member is distinctive in having high concentrations of high-field-strength elements (HFSE) and rare-earth elements (REE), indicative of formation in a within-plate (extensional) setting. Mystic Creek metarhyolite is associated with alkalic, within-plate basalt of the Chute Creek Member; neodymium isotopic data indicate an enriched mantle component for both members of this bimodal (rhyolite-basalt) suite. Anderson Mountain, the other significant VMS deposit, is hosted by the Wood River assemblage. Metaigneous rocks in the Wood River assemblage span a wide compositional range, including andesitic rocks, which are characteristic of arc volcanism. Our data suggest that the Mystic Creek Member likely formed in an extensional, back-arc basin that was associated with an outboard continental-margin volcanic arc that included

  18. A ubiquitous thermoacidophilic archaeon from deep-sea hydrothermal vents.

    Science.gov (United States)

    Reysenbach, Anna-Louise; Liu, Yitai; Banta, Amy B; Beveridge, Terry J; Kirshtein, Julie D; Schouten, Stefan; Tivey, Margaret K; Von Damm, Karen L; Voytek, Mary A

    2006-07-27

    Deep-sea hydrothermal vents are important in global biogeochemical cycles, providing biological oases at the sea floor that are supported by the thermal and chemical flux from the Earth's interior. As hot, acidic and reduced hydrothermal fluids mix with cold, alkaline and oxygenated sea water, minerals precipitate to form porous sulphide-sulphate deposits. These structures provide microhabitats for a diversity of prokaryotes that exploit the geochemical and physical gradients in this dynamic ecosystem. It has been proposed that fluid pH in the actively venting sulphide structures is generally low (pH cycling at deep-sea vents.

  19. Cadmium sulfide solar cells

    Science.gov (United States)

    Stanley, A. G.

    1975-01-01

    Development, fabrication and applications of CdS solar cells are reviewed in detail. The suitability of CdS cells for large solar panels and microcircuitry, and their low cost, are emphasized. Developments are reviewed by manufacturer-developer. Vapor phase deposition of thin-film solar cells, doping and co-evaporation, sputtering, chemical spray, and sintered layers are reviewed, in addition to spray deposition, monograin layer structures, and silk screening. Formation of junctions by electroplating, evaporation, brushing, CuCl dip, and chemiplating are discussed, along with counterelectrode fabrication, VPD film structures, the Cu2S barrier layer, and various photovoltaic effects (contact photovoltage, light intensity variation, optical enhancement), and various other CdS topics.

  20. Sulfide mineralization in ultramafic rocks of the Faryab ophiolite complex, southern Kerman

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Rajabzadeh

    2015-10-01

    Full Text Available Introduction Worldwide, Ni-Cu and PGE magmatic sulfide deposits are confined to the lower parts of stratiform mafic and ultramafic complexes. However, ophiolite mafic and ultramafic complexes have been rarely explored for sulfide deposits despite the fact that they have been extensively explored and exploited for chromite. Sulfide saturation during magmatic evolution is necessary for sulfide mineralization, in which sulfide melts scavenge chalcophile metals from the parent magma and concentrate them in specific lithological zones. The lack of exploration for sulfides in this environment suggests that sulfide saturation is rarely attained in ophiolite-related magmas. Some ophiolites, however, contain sulfide deposits, such as at Acoje in Philippines, and Cliffs in Shetland, U.K. (Evans, 2000; Naldrett, 2004. The Faryab ophiolite complex in southern Kerman Province, the most important mining area for chromite deposits in Iran, is located in the southwest part of the Makran Zone. Evidence of sulfide mineralization has been reported there by some authors (e.g. Rajabzadeh and Moosavinasab, 2013. This paper discusses the genesis of sulfides in the Faryab ophiolite using mineral chemistry of the major mineral phases in different rocks of the ophiolite column in order to determine the possible lithological location of sulfide deposits. Materials and methods Seventy three rock samples from cumulate units were collected from surficial occurrences and drill core. The samples were studied using conventional microscopic methods and the mineralogy confirmed by x-ray diffraction. Electron microprobe analysis was carried out on different mineral phases in order to determine the chemistry of the minerals used in the interpretation of magma evolution in the Faryab ophiolite. Lithologically, the Faryab ophiolite complex is divided into two major parts: the northern part includes magmatic rocks and the southern part is comprised of rocks residual after partial

  1. The integration of physical rock properties, mineralogy and geochemistry for the exploration of large zinc silicate deposits: A case study of the Vazante zinc deposits, Minas Gerais, Brazil

    Science.gov (United States)

    McGladrey, Alexandra J.; Olivo, Gema Ribeiro; Silva, Adalene Moreira; Oliveira, Gustavo Diniz; Neto, Basilio Botura; Perrouty, Stéphane

    2017-01-01

    The Vazante deposit, which is the world's largest zinc silicate deposit, occurs in brecciated dolomite and comprises mainly willemite with various proportions of hematite, Fe-carbonate, minor franklinite and magnetite. Exploration for this type of deposit is more challenging than zinc sulfide deposits, as they do not exhibit similar geophysical anomalies. To improve the application of geophysical surveys to the exploration of hypogene silicate zinc deposits, data from 475 samples were investigated from drill holes representative of the various types of ore and host rocks as well as barren zones of known geophysical anomalies in the Vazante District. Lithogeochemical and mineralogical (optical, SEM and MLA) data were integrated with physical rock properties (density, magnetic susceptibility and Ksbnd Usbnd Th gamma-ray spectrometry) to assist in exploring for this type of deposit. The most distinct physical property of the ore is density, compared with the host rocks due to high proportion of denser minerals (hematite and willemite). However, barren hematite breccias also have high densities. The zinc ore and hematite breccias yielded higher magnetic susceptibilities than the surrounding host rocks, with the highest values associated with greater proportions of franklinite and magnetite. The density and magnetic susceptibility contrasts are a result of hydrothermal fluids interacting with and altering the carbonate host rocks. Zinc ore also yielded elevated U concentrations relative to the various host rocks, yielding higher gamma-ray spectrometric values. The results of this investigation indicate that an integration of magnetic, gravimetric and radiometric surveys would be required to identify zinc silicate ore zones.

  2. Hydrothermal Liquefaction of Biomass

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Douglas C.

    2010-12-10

    Hydrothermal liquefaction technology is describes in its relationship to fast pyrolysis of biomass. The scope of work at PNNL is discussed and some intial results are presented. HydroThermal Liquefaction (HTL), called high-pressure liquefaction in earlier years, is an alternative process for conversion of biomass into liquid products. Some experts consider it to be pyrolysis in solvent phase. It is typically performed at about 350 C and 200 atm pressure such that the water carrier for biomass slurry is maintained in a liquid phase, i.e. below super-critical conditions. In some applications catalysts and/or reducing gases have been added to the system with the expectation of producing higher yields of higher quality products. Slurry agents ('carriers') evaluated have included water, various hydrocarbon oils and recycled bio-oil. High-pressure pumping of biomass slurry has been a major limitation in the process development. Process research in this field faded away in the 1990s except for the HydroThermal Upgrading (HTU) effort in the Netherlands, but has new resurgence with other renewable fuels in light of the increased oil prices and climate change concerns. Research restarted at Pacific Northwest National Laboratory (PNNL) in 2007 with a project, 'HydroThermal Liquefaction of Agricultural and Biorefinery Residues' with partners Archer-Daniels-Midland Company and ConocoPhillips. Through bench-scale experimentation in a continuous-flow system this project investigated the bio-oil yield and quality that could be achieved from a range of biomass feedstocks and derivatives. The project was completed earlier this year with the issuance of the final report. HydroThermal Liquefaction research continues within the National Advanced Biofuels Consortium with the effort focused at PNNL. The bench-scale reactor is being used for conversion of lignocellulosic biomass including pine forest residue and corn stover. A complementary project is an international

  3. Preparation of Nanosized Crystalline CdS Particles by the Hydrothermal Treatment.

    Science.gov (United States)

    So, Won-Wook; Jang, Jum-Suk; Rhee, Young-Woo; Kim, Kwang-Je; Moon, Sang-Jin

    2001-05-01

    We report studies of the effect of hydrothermal treatment on physical properties such as crystalline phase, size, and morphology of nanosized cadmium sulfide (CdS) particles. CdS precipitates have been synthesized by the reaction of Cd(NO(3))(2) with Na(2)S at room temperature. These CdS precipitates have been hydrothermally treated in the range 120-240 degrees C with variation of the treatment time. The effects of acid catalysts and other additives were also investigated. The particles prepared were characterized by XRD, TEM, and BET methods. With increased hydrothermal treatment temperature and time, crystallization from amorphous to crystalline form, cubic or hexagonal, and an increase of particle size occurred. CdS particles of well-developed hexagonal form were obtained at a hydrothermal treatment temperature of 240 degrees C; the primary hexagonal grain size was on the order of 20-30 nm. The addition of an acid catalyst, HCl, or of Cd(NO(3))(2) into the precipitate sol promoted crystal growth and phase transformation during the hydrothermal treatment, but another additive, Na(2)S, showed the opposite trend. It appears that hydrothermal treatment combined with proper additives could be an effective method for preparation of nanosize crystalline CdS particles. Copyright 2001 Academic Press.

  4. Massive sulfide ores of the northern equatorial Mid-Atlantic Ridge

    Science.gov (United States)

    Cherkashev, G. A.; Ivanov, V. N.; Bel'tenev, V. I.; Lazareva, L. I.; Rozhdestvenskaya, I. I.; Samovarov, M. L.; Poroshina, I. M.; Sergeev, M. B.; Stepanova, T. V.; Dobretsova, I. G.; Kuznetsov, V. Yu.

    2013-09-01

    The optimal set of prospecting methods, including geophysical (geoelectrical), geological (mineralogical-geochemical), and hydrological observations, was developed during the long-term investigations of the sulfide mineralization in the northern equatorial zone of the Mid-Atlantic Ridge. The application of these methods made it possible to discover six massive sulfide deposits and considerably extend the boundaries of another two ore objects. The ores associated with ultramafic rocks are characterized by elevated Cu, Au, and Co concentrations. It is established that the ore formation was a multistage process that resulted in the accumulation of large deposits (over 10 million tons).

  5. Iron mineralization at the Songhu deposit, Chinese Western Tianshan: a type locality with regional metallogenic implications

    Science.gov (United States)

    Wang, Chun-Long; Wang, Yi-Tian; Dong, Lian-Hui; Qin, Ke-Zhang; Evans, Noreen J.; Zhang, Bing; Ren, Yi

    2017-06-01

    Hosted by volcaniclastics of the Carboniferous Dahalajunshan Formation, the Songhu iron deposit is located in the central segment of the Awulale metallogenic belt, Chinese Western Tianshan. Mineralization and alteration are structurally controlled by orogen-parallel NWW-striking faults. Integrating with mineralogical and stable isotopic analyses based on paragenetic relationships, two types of iron mineralization have been identified. The deuteric mineralization (Type I) represented by brecciated, banded, and disseminated-vein ores juxtaposed with potassic-calcic alteration in the inner zone, which was formed from a magmatic fluid generated during the late stages of regional volcanism. In contrast, the volcanic-hydrothermal mineralization (Type II) is characterized by hydrothermal features occurring in massive and agglomerated ores with abundant sulfides, and was generated from the magmatic fluid with seawater contamination. Two volcaniclastic samples from the hanging and footwall of the main orebody yield zircon U-Pb ages of 327.8 ± 3.1 and 332.0 ± 2.0 Ma, respectively, which indicate Middle Carboniferous volcanism. Timing for iron mineralization can be broadly placed in the same epoch. By reviewing geological, mineralogical, and geochemical features of the primary iron deposits in the Awulale metallogenic belt, we propose that the two types of iron mineralization in the Songhu iron deposit are representative regionally. A summary of available geochronological data reveals Middle-Late Carboniferous polycyclic ore-related volcanism, and nearly contemporaneous iron mineralization along the belt. Furthermore, petro-geochemistry of volcanic-volcaniclastic host rocks indicates that partial melting of a metasomatized mantle wedge under a continental arc setting could have triggered the continuous volcanic activities and associated metallogenesis.

  6. Partitioning of platinum-group elements and Au between sulfide liquid and basalt and the origins of mantle-crust fractionation of the chalcophile elements

    Science.gov (United States)

    Mungall, James E.; Brenan, James M.

    2014-01-01

    oxygen buffer, which causes large increases in alloy solubility. The magmas parental to the Bushveld Complex of South Africa appear, at least in part, to be partial melts of mantle that has previously been melted to the point of total sulfide exhaustion at low pressure, closely resembling mantle xenoliths of the Kaapvaal craton. Using the new extremely large DPGEsul the world-class Merensky Reef and UG2 Pt deposits of the Bushveld Complex can readily be modeled as the result of sulfide saturation due to mixing of magmas with unremarkable PGE contents, obviating the need to postulate anomalously PGE-rich parent magmas or hydrothermal inputs to the deposits.

  7. Fractionation of Boron Isotopes in Icelandic Hydrothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Aggarwal, J.K.; Palmer, M.R.

    1995-01-01

    Boron isotope ratios have been determined in a variety of different geothermal waters from hydrothermal systems across Iceland. Isotope ratios from the high temperature meteoric water recharged systems reflect the isotope ratio of the host rocks without any apparent fractionation. Seawater recharged geothermal systems exhibit more positive {delta}{sup 11}B values than the meteoric water recharged geothermal systems. Water/rock ratios can be assessed from boron isotope ratios in the saline hydrothermal systems. Low temperature hydrothermal systems also exhibit more positive {delta}{sup 11}B than the high temperature systems, indicating fractionation of boron due to adsorption of the lighter isotope onto secondary minerals. Fractionation of boron in carbonate deposits may indicate the level of equilibrium attained within the systems.

  8. Chrysanthemum-like bismuth sulfide microcrystals: Synthesis, characterization, and properties

    Science.gov (United States)

    Jiang, Jinghui; Gao, Guanhua; Yu, Runnan; Qiu, Guanzhou; Liu, Xiaohe

    2011-02-01

    Uniform chrysanthemum-like bismuth sulfide (Bi 2S 3) microcrystals assembled from nanosheet building blocks were successfully synthesized via a convenient hydrothermal synthetic route under mild conditions in which hydrated bismuth nitrate and L-cysteine were employed to supply Bi and S source and ethylenediaminetetraacetic acid disodium salt (EDTA-Na 2) was employed as chelating agent. The influences of reaction temperatures and time on the morphologies of final products were investigated. The phase structures, morphologies, and properties of as-prepared products were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscope, and photoluminescence spectra. The possible growth mechanism for the formation of chrysanthemum-like Bi 2S 3 microcrystals was discussed on the basis of the experimental results.

  9. Geology, mineralization, and geochronology of the Qianhe gold deposit, Xiong'ershan area, southern North China Craton

    Science.gov (United States)

    Tang, Ke-Fei; Li, Jian-Wei; Selby, David; Zhou, Mei-Fu; Bi, Shi-Jian; Deng, Xiao-Dong

    2013-08-01

    The Qianhe gold deposit in the Xiong'ershan area is located along the southern margin of the Archean-Paleoproterozoic North China Craton. The deposit consists of six orebodies that are hosted in Paleoproterozoic andesites to basaltic andesites and structurally controlled by roughly EW-trending faults. Individual orebodies comprise auriferous quartz veins and disseminated Au-bearing pyrite within hydrothermally altered rocks on both sides of, or close to, the veins. Ore-related hydrothermal alteration has produced various mixtures of K-feldspar, quartz, sericite, chlorite, epidote, carbonate, and sulfides. Pyrite is the most important ore mineral, associated with minor amounts of galena, sphalerite, and chalcopyrite. Other trace minerals include molybdenite, arsenopyrite, scheelite, rutile, xenotime, and parisite. Gold occurs mostly as native gold and electrum enclosed in pyrite or along microfractures of sulfides and quartz. Microthermometric measurements of primary inclusions in auriferous quartz suggest that gold and associated minerals were precipitated in the range of 160-305 °C from aqueous or carbonic-aqueous fluids with salinities of 6-22 wt% NaCl equiv. Samples of molybdenite coexisting with Au-bearing pyrite have Re-Os model ages of 134-135 Ma, whereas ore-related hydrothermal sericite separates yield 40Ar/39Ar plateau ages between 127 and 124 Ma. The Re-Os and 40Ar/39Ar ages are remarkably consistent with zircon U-Pb ages (134.5 ± 1.5 and 127.2 ± 1.4 Ma; 1 σ) of the biotite monzogranite from the Heyu-intrusive complex and granitic dikes in and close to the Qianhe gold mine, indicating a close temporal and thus possibly genetic relationship between gold mineralization and granitic magmatism in the area. Fluid inclusion waters extracted from auriferous quartz have δD values of -80 to -72 ‰, whereas the calculated δ 18OH2O values range from 3.1 to 3.8 ‰. The hydrogen and oxygen isotopes from this study and previous work indicate that ore fluids

  10. 30 CFR 250.604 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.604 Section 250.604... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Well-Workover Operations § 250.604 Hydrogen sulfide. When a well-workover operation is conducted in zones known to contain hydrogen sulfide (H2S) or in...

  11. 30 CFR 250.504 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.504 Section 250.504... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Well-Completion Operations § 250.504 Hydrogen sulfide. When a well-completion operation is conducted in zones known to contain hydrogen sulfide (H2S) or in...

  12. 30 CFR 250.808 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.808 Section 250.808... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Production Safety Systems § 250.808 Hydrogen sulfide. Production operations in zones known to contain hydrogen sulfide (H2S) or in zones where the presence of H2S...

  13. Sulfide intrusion and detoxification in Zostera marina

    DEFF Research Database (Denmark)

    Hasler-Sheetal, Harald; Holmer, Marianne

    2014-01-01

    Sulfide intrusion in seagrasses represents a global threat to seagrasses. In contrast seegrasses grow in hostile sediments, where they are constantly exposed to sulfide intrusion. Little is known about the strategies to survive sulfide intrusion, if there are detoxification mechanisms and sulfur ...

  14. Magmatic-hydrothermal fluid interaction and mineralization in alkali-syenite nodules from the Breccia Museo pyroclastic deposit, Naples, Italy: Chapter 7 in Volcanism in the Campania Plain — Vesuvius, Campi Flegrei and Ignimbrites

    Science.gov (United States)

    Fedele, Luca; Tarzia, Maurizio; Belkin, Harvey E.; De Vivo, Benedetto; Lima, Annamaria; Lowenstern, Jacob

    2007-01-01

    The Breccia Museo, a pyroclastic flow that crops out in the Campi Flegrei volcanic complex (Naples, Italy), contains alkali-syenite (trachyte) nodules with enrichment in Cl and incompatible elements (e.g., U, Zr, Th, and rare-earth elements). Zircon was dated at ≈52 ka, by U-Th isotope systematics using a SHRIMP. Scanning electron microscope and electron microprobe analysis of the constituent phases have documented the mineralogical and textural evolution of the nodules of feldspar and mafic accumulations on the magma chamber margins. Detailed electron microprobe data are given for alkali and plagioclase feldspar, salite to ferrosalite clinopyroxene, pargasite, ferrogargasite, magnesio-hastingsite hornblende amphibole, biotite mica, Cl-rich scapolite, and a member (probable davyne-type) of the cancrinite group. Detailed whole rock, major and minor element data are also presented for selected nodules. A wide variety of common and uncommon accessory minerals were identified such as zircon, baddeleyite, zirconolite, pollucite, sodalite, titanite, monazite, cheralite, apatite, titanomagnetite and its alteration products, scheelite, ferberite, uraninite/thorianite, uranpyrochlore, thorite, pyrite, chalcopyrite, and galena. Scanning electron microscope analysis of opened fluid inclusions identified halite, sylvite, anhydrite, tungstates, carbonates, silicates, sulfides, and phosphates; most are probably daughter minerals. Microthermometric determinations on secondary fluid inclusions hosted by alkali feldspar define a temperature regime dominated by hypersaline aqueous fluids. Fluid-inclusion temperature data and mineral-pair geothermometers for coexisting feldspars and hornblende and plagioclase were used to construct a pressure-temperature scenario for the development and evolution of the nodules. We have compared the environment of porphyry copper formation and the petrogenetic environment constructed for the studied nodules. The suite of ore minerals observed in

  15. Silver isotope variation in ore deposits by MC-ICP-MS

    Science.gov (United States)

    Fukuyama, M.; Lee, D.

    2010-12-01

    The isotopic composition of Ag has received special attention in the past because of its ability to trace processes in the very early solar system. These Ag isotopic measurements were previously performed by thermal ionization mass spectrometry (TIMS). The precision of TIMS analyses was limited to ~1-2 per mil, because Ag has only two isotopes, 107Ag and 109Ag. Such a level of precision is insufficient to examine small differences of silver isotope compositions on terrestrial samples. However, recent studies have taken advantage of the development in the field of multi-collector inductively-coupled-plasma mass spectrometry (MC-ICP-MS), and have been able to improve the analytical precision to resolve sub-per mil differences in Ag isotopic compositions. This has led to the establishment of a bulk silicate Earth Ag isotopic composition (Schönbächler et al., 2010) and the discovery of Ag isotopic variation in native Ag metal samples from ore deposits, which have been attributed to mass dependent stable isotope fractionations during natural chemical processing (Hauri et al., 2000). This indicates that Ag isotopes may be a useful geochemical tracer, i.e., ore deposits and hydrothermal geochemistry studies. We have started to investigate the Ag isotopic variations for a series of ore deposits in Japan in order to better constrain the formation and evolution of these ore deposits. These include the Au-Ag epithermal vein type deposits (Asahi, Ohmidani, Koryu, Seikoshi, and Yatani), Pb-Zn vein type deposits (Toyoha), polymatallic vein type deposits (Yabu), and Kuroko type deposits (Ezuri, and Matsumine), while Ag occurs as either native or sulfide minerals in these deposits. Preliminary Ag isotopic data vary from -7.1 ɛ to 1.5 ɛ relative to the NIST SRM 978a, while both the lowest and highest Ag isotopic data were obtained from the Kuroko type deposits. These deposits have similar geological settings, origins, and depositional ages (14-13 Ma), yet they exhibit the

  16. RIO Tinto Faulted Volcanosedimentary Deposits as Analog Habitats for Extant Subsurface Biospheres on Mars: A Synthesis of the MARTE Drilling Project Geobiology Results

    Science.gov (United States)

    Fernandez-Remolar, D. C.; Prieto-Ballesteros, O.; Rodriquez, N.; Davila, F.; Stevens, T.; Amils, R.; Gomez-Elvira, J.; Stoker, C.

    2005-01-01

    Geochemistry and mineralogy on Mars surface characterized by the MER Opportunity Rover suggest that early Mars hosted acidic environments in the Meridiani Planum region [1, 2]. Such extreme paleoenvironments have been suggested to be a regional expression of the global Mars geological cycle that induced acidic conditions by sulfur complexation and iron buffering of aqueous solutions [3]. Under these assumptions, underground reservoirs of acidic brines and, thereby, putative acidic cryptobiospheres, may be expected. The MARTE project [4, 5] has performed a drilling campaign to search for acidic and anaerobic biospheres in R o Tinto basement [6] that may be analogs of these hypothetical communities occurring in cryptic habitats of Mars. This Rio Tinto geological region is characterized by the occurrence of huge metallic deposits of iron sulfides [7]. Late intensive diagenesis of rocks driven by a compressive regimen [8] largely reduced the porosity of rocks and induced a cortical thickening through thrusting and inverse faulting and folding. Such structures play an essential role in transporting and storing water underground as any other aquifers do in the Earth. Once the underground water reservoirs of the Ro Tinto basement contact the hydrothermal pyrite deposits, acidic brines are produced by the release of sulfates and iron through the oxidation of sulfides [9].