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Shinkuan Chen - One of the best experts on this subject based on the ideXlab platform.
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sulfate reduction and iron Sulfide Mineral formation in the southern east china sea continental slope sediment
Deep Sea Research Part I: Oceanographic Research Papers, 2002Co-Authors: Kuoming Huang, Shinkuan ChenAbstract:Abstract Sulfate reduction rate, organic carbon and Sulfide burial rate; organic carbon, carbonate carbon, and reactive iron contents; grain size; and sedimentation rate were determined in sediments of the southern East China Sea continental slope. The results show high sulfate reduction and pyrite sulfur burial rates in slope areas with high organic carbon and sedimentation rates. Unusually high rates of organic carbon deposition enhance sulfate reduction and pyrite Sulfide burial in the region. Both sulfate reduction rates and pyrite sulfur burial rates increased linearly with increasing organic carbon burial rate, indicating that deposition of organic carbon on the slope is the primary controlling factor for pyrite formation. Abundant reactive iron indicated that iron is not limiting pyrite formation. Pyrite is the predominant Sulfide Mineral; however, acid volatile Sulfide constituted up to 50% of total Sulfide at some stations. Up to 240 μmol/g of pyrite sulfur and 5 mmol/m 2 /day of sulfate reduction rates were found in the slope sediment. Sulfate reduction rate and pyrite sulfur did not decrease with increasing overlying water depth. High organic carbon burial rates enhanced the sulfate reduction rate and subsequently the rate of pyrite sulfur burial in the slope region. As a result, the southern East China Sea continental slope environment is an efficient pyrite sulfur burial environment.
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sulfate reduction and iron Sulfide Mineral formation in the southern east china sea continental slope sediment
Deep Sea Research Part I: Oceanographic Research Papers, 2002Co-Authors: Kuoming Huang, Shinkuan ChenAbstract:Abstract Sulfate reduction rate, organic carbon and Sulfide burial rate; organic carbon, carbonate carbon, and reactive iron contents; grain size; and sedimentation rate were determined in sediments of the southern East China Sea continental slope. The results show high sulfate reduction and pyrite sulfur burial rates in slope areas with high organic carbon and sedimentation rates. Unusually high rates of organic carbon deposition enhance sulfate reduction and pyrite Sulfide burial in the region. Both sulfate reduction rates and pyrite sulfur burial rates increased linearly with increasing organic carbon burial rate, indicating that deposition of organic carbon on the slope is the primary controlling factor for pyrite formation. Abundant reactive iron indicated that iron is not limiting pyrite formation. Pyrite is the predominant Sulfide Mineral; however, acid volatile Sulfide constituted up to 50% of total Sulfide at some stations. Up to 240 μmol/g of pyrite sulfur and 5 mmol/m 2 /day of sulfate reduction rates were found in the slope sediment. Sulfate reduction rate and pyrite sulfur did not decrease with increasing overlying water depth. High organic carbon burial rates enhanced the sulfate reduction rate and subsequently the rate of pyrite sulfur burial in the slope region. As a result, the southern East China Sea continental slope environment is an efficient pyrite sulfur burial environment.
Kuoming Huang - One of the best experts on this subject based on the ideXlab platform.
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sulfate reduction and iron Sulfide Mineral formation in the southern east china sea continental slope sediment
Deep Sea Research Part I: Oceanographic Research Papers, 2002Co-Authors: Kuoming Huang, Shinkuan ChenAbstract:Abstract Sulfate reduction rate, organic carbon and Sulfide burial rate; organic carbon, carbonate carbon, and reactive iron contents; grain size; and sedimentation rate were determined in sediments of the southern East China Sea continental slope. The results show high sulfate reduction and pyrite sulfur burial rates in slope areas with high organic carbon and sedimentation rates. Unusually high rates of organic carbon deposition enhance sulfate reduction and pyrite Sulfide burial in the region. Both sulfate reduction rates and pyrite sulfur burial rates increased linearly with increasing organic carbon burial rate, indicating that deposition of organic carbon on the slope is the primary controlling factor for pyrite formation. Abundant reactive iron indicated that iron is not limiting pyrite formation. Pyrite is the predominant Sulfide Mineral; however, acid volatile Sulfide constituted up to 50% of total Sulfide at some stations. Up to 240 μmol/g of pyrite sulfur and 5 mmol/m 2 /day of sulfate reduction rates were found in the slope sediment. Sulfate reduction rate and pyrite sulfur did not decrease with increasing overlying water depth. High organic carbon burial rates enhanced the sulfate reduction rate and subsequently the rate of pyrite sulfur burial in the slope region. As a result, the southern East China Sea continental slope environment is an efficient pyrite sulfur burial environment.
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sulfate reduction and iron Sulfide Mineral formation in the southern east china sea continental slope sediment
Deep Sea Research Part I: Oceanographic Research Papers, 2002Co-Authors: Kuoming Huang, Shinkuan ChenAbstract:Abstract Sulfate reduction rate, organic carbon and Sulfide burial rate; organic carbon, carbonate carbon, and reactive iron contents; grain size; and sedimentation rate were determined in sediments of the southern East China Sea continental slope. The results show high sulfate reduction and pyrite sulfur burial rates in slope areas with high organic carbon and sedimentation rates. Unusually high rates of organic carbon deposition enhance sulfate reduction and pyrite Sulfide burial in the region. Both sulfate reduction rates and pyrite sulfur burial rates increased linearly with increasing organic carbon burial rate, indicating that deposition of organic carbon on the slope is the primary controlling factor for pyrite formation. Abundant reactive iron indicated that iron is not limiting pyrite formation. Pyrite is the predominant Sulfide Mineral; however, acid volatile Sulfide constituted up to 50% of total Sulfide at some stations. Up to 240 μmol/g of pyrite sulfur and 5 mmol/m 2 /day of sulfate reduction rates were found in the slope sediment. Sulfate reduction rate and pyrite sulfur did not decrease with increasing overlying water depth. High organic carbon burial rates enhanced the sulfate reduction rate and subsequently the rate of pyrite sulfur burial in the slope region. As a result, the southern East China Sea continental slope environment is an efficient pyrite sulfur burial environment.
John L. Jambor - One of the best experts on this subject based on the ideXlab platform.
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Long-term Mineralogical and geochemical evolution of Sulfide mine tailings under a shallow water cover
Applied Geochemistry, 2015Co-Authors: M.c. Moncur, Carol J. Ptacek, Matthew B.j. Lindsay, David W. Blowes, John L. JamborAbstract:Abstract The long-term influence of a shallow water cover limiting Sulfide-Mineral oxidation was examined in tailings deposited near the end of operation in 1951 of the former Sherritt-Gordon Zn–Cu mine (Sherridon, Manitoba, Canada). Surface-water, pore-water and core samples were collected in 2001 and 2009 from above and within tailings deposited into a natural lake. Mineralogical and geochemical characterization focused on two contrasting areas of this deposit: (i) sub-aerial tailings with the water table positioned at a depth of approximately 50 cm; and (ii) sub-aqueous tailings stored under a 100 cm water cover. Mineralogical analyses of the sub-aerial tailings showed a zone of extensive Sulfide-Mineral alteration extending 40 cm below the tailings surface. Moderate alteration was observed at depths ranging from 40 to 60 cm and was limited to depths >60 cm. In contrast, Sulfide-Mineral alteration within the submerged tailings was confined to a
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the geochemistry of acid mine drainage
Treatise on Geochemistry, 2014Co-Authors: David W. Blowes, Carol J. Ptacek, John L. Jambor, Christopher G Weisener, Dogan Paktunc, W D Gould, D B JohnsonAbstract:Mining and Mineral processing generates large volumes of waste, including waste rock, mill tailings, and Mineral refinery wastes. The oxidation of Sulfide Minerals in the materials can result in the release of acidic water containing high concentrations of dissolved metals. Recent studies have determined the mechanisms of abiotic Sulfide-Mineral oxidation. Within mine wastes, the oxidation of Sulfide Minerals is catalyzed by microorganisms. Molecular tools have been developed and applied to determine the activity and role of these organisms in Sulfide-Mineral-bearing systems. Novel tools have been developed for assessing the toxicity of mine-waste effluent. Dissolved constituents released by Sulfide oxidation may be attenuated through the precipitation of secondary Minerals, including metal sulfate, oxyhydroxide, and basic sulfate Minerals. Geochemical models have been developed to provide improved predictions of the magnitude and duration of environmental concerns. Novel techniques have been developed to prevent and remediate environmental problems associated with these materials.
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metal sulfate salts from Sulfide Mineral oxidation
Reviews in Mineralogy & Geochemistry, 2000Co-Authors: John L. Jambor, Kirk D Nordstrom, Charles N AlpersAbstract:“It is plain that almost all kinds of atramentum are made of Earth and Water. At first they were liquid and afterwards solid, and still they can be redissolved, by heat and moisture.” Albertus Magnus (1205–1280) Book of Minerals (transl. D. Wyckoff, 1967) The observation of “efflorescences,” or the flowering of salts, associated with periods of dryness in soils, in closed-basin lakes, in rock outcrops, and in mines and mine wastes has been noted since early antiquity. The formation of metal-sulfate salts, in connection with the mining of metals, was a phenomenon well known to the early Greek and Roman civilizations. Alum, most commonly potash alum KAl(SO4)2 · 12H2O, which is from the Latin alumen , was extensively mined and used by goldsmiths, dyers, paper manufacturers, and physicians in ancient civilizations. It forms from the oxidation of pyrite in shales and slates and from oxidation of sulfurous gases in geothermal areas. The Greeks and the Romans described stalactites of atramentum (soluble metal-sulfate salts) that formed within mines and along rock faces (Agricola 1546, 1556). Furthermore, the toxic effects of these salts on animals were also noted. For example, in De Natura Fossilium , Agricola (1546) stated “….I mention the congealed acid juice which usually produces cadmia . It is white, hard, and so acrid that it can eat away walls, grills and even destroy all living matter.” Cadmia is thought to be derived from the oxidation of zinc, cobalt, and arsenic Sulfides, such as cobaltite. He goes on to say that “Pyrite, unless it contains sulphates, is either a golden or silver color, rarely any other, while cadmia is black, yellow brown, or gray. The former will cure gatherings while the latter is a deadly poison and will destroy any living substance. It is used …
Katrina J. Edwards - One of the best experts on this subject based on the ideXlab platform.
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iron transformation pathways and redox micro environments in seafloor Sulfide Mineral deposits spatially resolved fe xas and δ57 54fe observations
Frontiers in Microbiology, 2016Co-Authors: Brandy M Toner, Olivier Rouxel, Cara M Santelli, Wolfgang Bach, Katrina J. EdwardsAbstract:Hydrothermal Sulfide chimneys located along the global system of oceanic spreading centers are habitats for microbial life during active venting. Hydrothermally extinct, or inactive, Sulfide deposits also host microbial communities at globally distributed sites. The main goal of this study is to describe Sulfide Mineral alteration at the seafloor, and examine alteration products for signatures of biological activity using Fe Mineralogy and stable isotope approaches. The study includes active and inactive Sulfides from the East Pacific Rise 9o50'N vent field. First, the Mineralogy of Fe(III)-bearing precipitates is investigated using microprobe X-ray absorption spectroscopy (µXAS) and X-ray diffraction (µXRD). Second, laser-ablation (LA) and micro-drilling (MD) are used to obtain samples for Fe stable isotopes by multicollector-inductively couple plasma-mass spectrometry (MC-ICP-MS). Eight Fe-bearing Minerals types are present in the samples: oxyhydroxides, secondary phyllosilicates, and Sulfides. For Fe oxyhydroxides within chimney walls and layers of Si-rich material, enrichments in both heavy and light Fe isotopes relative to pyrite are observed, yielding a range of δ57Fe values up to 6‰. Overall, several pathways for Fe transformation are observed. Pathway 1 is characterized by precipitation of primary Sulfide Minerals from Fe(II)aq-rich fluids in zones of mixing between vent fluids and seawater. Pathway 2 is also consistent with zones of mixing but involves precipitation of Sulfide Minerals from Fe(II)aq generated by Fe(III) reduction. Pathway 3 is direct oxidation of Fe(II) aq from hydrothermal fluids to form Fe(III) precipitates. Finally, Pathway 4 involves oxidative alteration of pre-existing Sulfide Minerals to form Fe(III). The Fe Mineralogy and isotope data do not support or refute a unique biological role in Sulfide alteration. The findings reveal a dynamic range of Fe transformation pathways consistent with a continuum of micro-environments having variable oxidation-reduction (redox) conditions. These micro-environments likely support redox cycling of Fe and S and are consistent with culture-dependent and -independent assessments of microbial physiology and genetic diversity of hydrothermal Sulfide deposits.
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kinetics surface chemistry and structural evolution of microbially mediated Sulfide Mineral dissolution
Geochimica et Cosmochimica Acta, 2001Co-Authors: Molly M. Mcguire, Katrina J. Edwards, Jillian F Banfield, Robert J. HamersAbstract:Abstract The effects of different microbial populations on the oxidative dissolution of Sulfide Minerals at 37°C and pH 1.5 were examined over a period of 22 days. Samples of pyrite, marcasite, and arsenopyrite were exposed to a sulfur-oxidizing isolate (Thiobacillus caldus), an iron-oxidizing isolate (Ferroplasma acidarmanus), and a mixed enrichment culture containing T. caldus, F. acidarmanus, and Leptospirillum ferrooxidans. Changes in chemical speciation of the Mineral surface products were monitored by Raman spectroscopy over the course of the experiment, structural evolution was examined with scanning electron microscopy, and the total soluble iron was used as a measure of the dissolution rate. In the case of all three Minerals, an increase in dissolution rate was observed only in the presence of iron-oxidizing microorganisms (i.e., F. acidarmanus or the enrichment culture). The chemical speciation at the Mineral surface in the presence of these iron-oxidizing species is indistinguishable from that of abiotic control reactions under the same conditions; both are dominated by elemental sulfur. In contrast, experiments with T. caldus indicate that the quantity of elemental sulfur on the Mineral surface is
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Geochemical and biological aspects of Sulfide Mineral dissolution: lessons from Iron Mountain, California
Chemical Geology, 2000Co-Authors: Katrina J. Edwards, Philip L. Bond, Molly M. Mcguire, Robert J. Hamers, Gregory K Druschel, Jillian F BanfieldAbstract:Abstract The oxidative dissolution of Sulfide Minerals leading to acid mine drainage (AMD) involves a complex interplay between microorganisms, solutions, and Mineral surfaces. Consequently, models that link molecular level reactions and the microbial communities that mediate them to field scale processes are few. Here we provide a mini-review of laboratory and field-based studies concerning the chemical, microbial, and kinetic aspects of Sulfide Mineral dissolution and generation of AMD at the Richmond ore body at Iron Mountain, California.
Jijuan Ding - One of the best experts on this subject based on the ideXlab platform.
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Hexavalent chromium remediation based on the synergistic effect between chemoautotrophic bacteria and Sulfide Minerals
Ecotoxicology and Environmental Safety, 2019Co-Authors: Chunyao Gu, Jijuan DingAbstract:Abstract Hexavalent chromium (Cr(VI)) is an environmental concern due to the carcinogenic and mutagenic effect on living organisms. Sulfide Minerals based Cr(VI) reduction is an economical and efficient strategy for Cr(VI) remediation. In this study, Cr(VI) reduction through the synergistic effect between chemoautotrophic bacteria and Sulfide Mineral is systematically investigated. Sulfide Minerals dissolution and Cr(VI) reduction performance highly depends on Mineral acid soluble property. Cr(VI) reduction capacity of pyrrhotite, pyrite, marcasite and sphalerite was 50, 104, 104 and 44 mg/g (Cr(VI)/Mineral) respectively in the biotic system. Acidithiobacillus ferrooxidans (A. ferrooxidans) significantly enhanced pyrite and marcasite based Cr(VI) reduction kinetic and capacity. Proton consumption, iron coprecipitation and the biological activity deficiency in the abiotic system significantly inhibited Cr(VI) reduction. Elemental sulfur and secondary iron Mineral as the main composition of the passivation layer inhibited sustainable Cr(VI) reduction. A. ferrooxidans facilitated acid nonsoluble Mineral dissolution and surface passivation layer removal, and promoted Cr(VI) reduction. Acid nonsoluble Sulfide Mineral diSulfide bond rapture, S°/Sn2− oxidization, and Fe(III)/Cr(III) dissolution were accelerated by A. ferrooxidans, which facilitated Cr(VI) reduction reactive sites regeneration. Our study demonstrated that chemoautotrophic bacterial accelerated Cr(VI) reduction reaction through promoting acid nonsoluble Sulfide Mineral dissolution. This research is of environmental and practical significance to remediate redox sensitive contaminant based on the synergistic effect between Sulfide Minerals and chemoautotrophic A. ferrooxidans.
