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Showing 1 to 18 of 18 for “"Sulfur Isotope"”.
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Mass-independent sulfur isotope fractionation during photochemistry of sulfur dioxide
Mass-independent sulfur isotope signatures are observed in Archean and early Paleoproterozoic sedimentary sulfate and sulfide minerals, and provide the most robust constraints on early atmospheric oxygen levels. Smaller mass-independent sulfur isotope anomalies are observed in ice cores and …
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Physiology of multiple sulfur isotope fractionation during microbial sulfate reduction
… and produces sulfide that is depleted in heavy isotopes of sulfur relative to starting sulfate. The fractionation of S-isotopes is commonly used to trace the biogeochemical cycling of sulfur in nature, but a mechanistic understanding of factors that control the range of isotope fractionation is …
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Sulfur isotope ratios and the origin of the sulfide deposits in the Bathurst area of Northern New Brunswick
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Geology and Geophysics, 1959.
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A revised monod-type rate law predicting variable sulfur isotope fractionation factors as a function of microbial sulfate reduction rate
… reduction is associated with characteristic sulfur isotope partitioning, which can serve as a proxy for the rate of this reactivity in a wide variety of reducing environments. We demonstrate a new model for this functional relationship through the use of a modified Monod-type rate expression …
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Trace Elements and Sulfur Isotope Variations in Endowed and Non-Endowed Porphyry Systems of the Dawson Range Mineral Belt, Yukon Territory
… this area, focusing on select trace elements and sulfur isotope analyses to distinguish between endowed deposits and non-endowed occurrences. The remote location, poor access, and extensive glacial deposits complicate exploration efforts. The study analyzed fifty-six samples from eight porphyry …
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Multiple Sulfur Isotope Systematics of Geothermal Fluids at Krafla, NE Iceland, and the Source and Reactions of Sulfur in Volcanic Geothermal Systems
Multiple sulfur isotope systematics of geothermal fluids at Krafla NE Iceland were studied in order to determine the source and reactions of sulfur in the systems. Fluid temperatures ranged from 192 to 437°C with liquid water, vapor and superheated vapor being present in the reservoir. Dissolved …
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Oxygen and sulfur isotope fractionation by acidithiobacillus ferrooxidans during aerobic and anaerobic oxidation of copper sulfide minerals under simulated acid mine drainage conditions
Includes bibliographical references (pages 86-94).
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Pyrite geochemistry across the Betze-Post deposit, northern Carlin Trend, Nevada
… ore stage to the late-ore stage; Pre-ore stage sulfur isotope values of multiple morphologies of pyrite overlap with values characteristic of sedimentary sulfur sources and delta 34S ranges from -15.2 to 52.3‰. However, one type of pre-ore pyrite is interpreted to have derived from the …
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The geochemistry of carbonate-hosted Pb-Zn-Ag mineralization in the Lavrion District, Attica, Greece: fluid inclusion, stable isotope, and rare earth element studies
… to 20 wt% NaCl equiv) fluids.;Carbon and oxygen isotope compositions of calcite (delta13C = -15.6 to -1.5‰ and delta18O = -9.2 to 17.3‰) intergrown with sulfides reflect variable exchange of the ore-bearing fluid with the Upper and Lower marbles and proximity to the Plaka granodiorite. Post …
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The Geochemistry of Submerged Marine Landscapes: Lipid, Isotopic and Inorganic composition of Sediment Cores from the Palaeo-landscape of Doggerland
… and thus depositional alteration. Finally, the sulfur isotope analysis identified different sources of sulfur, which were then used as environmental distinguishing proxies. An integration of these analytical results provided a detailed geochemical history of each core; importantly, a Storegga …
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Exploring the contributions of liquid-phase sulfur chemistry to the mass-independent sulfur fractionation of the Archean rock record
Archean sulfur mass-independent fractionation (S-MIF) has been widely recognized as one of the strongest indicators for the rise of atmospheric oxygen in the Early Proterozoic. A decade after its discovery, the wide-ranging implications of Archean sulfur MIF have been discussed extensively and …
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Magmatic volatiles at rifts and arcs: Sources and fractionation effects
… additional data (including carbon, oxygen ,and sulfur isotope compositions and assessment of sulfur behaviour in the magma system) from Oldoinyo Lengai that have not been published. Chapter 2 presents the first bulk gas and nitrogen isotope compositions from the Rungwe Volcanic Province, which …
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Sulfur, carbon, and oxygen isotopes of coexisting sulfides and carbonates in gas and oil seeps from the Gulf of Mexico
… reduction (BSR), bacterial disproportionation of sulfur (BDS), and BSR coupled with anaerobic oxidation of methane (BSR-AOM) occur in the Gulf of Mexico (GOM) at sites where hydrocarbon oil and gas seep through conduits to the seafloor. Thus far, no studies have measured the solid-phase sulfides …
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Metal- and alteration-zoning, and hydrothermal flow paths at the moderately-tilted, silica-saturated Mt. Milligan copper-gold alkalic porphyry deposit
… alteration with elevated gold. Sulfide S-isotope compositions range from -4.79 δ34S in the central Cu-Au orebody to near-zero values at the system periphery, typical of alkalic porphyries. Sulfur isotope contours reflect the magmatic-hydrothermal fluid evolution, and indicate late-stage …
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Implementing a new method to measure δ³⁴SSO₄ in ice cores to assess sulfate sources in West Antarctica
… Each source can be identified by its unique sulfur isotopic composition of sulfate (δ³⁴SSO₄). However, δ³⁴SSO₄ measurements in Antarctic ice cores are scarce and have poor temporal resolution due to the large sample volume required for isotopic analysis. For this thesis, I established a new …
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Contributions to the Neoproterozoic Geobiology
… affinities. Chapter 3 reports stable isotopes of the Zhamoketi cap dolostone atop the Tereeken diamictite in the Quruqtagh area, eastern Chinese Tianshan. Our new data indicate that carbonate associated sulfate (CAS) abundance decreases rapidly in the basal cap dolostone and δ34SCAS …
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Time-Space Relationships between Sediment-Hosted Gold Mineralization and Intrusion-Related Polymetallic Mineralization at Kinsley Mountain, NV
… been documented in Carlin-type mineralization. Sulfur isotope data on pyrite revealed δ34S values of ~3‰-8‰ for pyrite proximal to the stock, while pyrite from the SHGDs were significantly heavier (16‰-25‰). The differences suggest a magmatic source of sulfur for pyrite proximal to the stock and …
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Geochemical investigation of the co-evolution of life and environment in the Neoproterozoic Era
… role in this evolutionary event, nitrogen isotope compositions (δ<sup>15</sup>N) of marine carbonates from the early Tonian (ca. 1000 Ma to ca. 800 Ma) Huaibei Group in North China were measured. The data indicate nitrate limitation in early Neoproterozoic oceans. Further, a compilation of …