Publications by authors named "Virgil Pasquier"
Article Synopsis
- Sulfur cycling plays a crucial role in sedimentary environments, affecting organic carbon remineralization and influencing sulfur isotope ratios (δS) in pyrite, but the factors behind δS variations are still debated.
- Research along the Peru margin indicates that δS fluctuations during glacial-interglacial periods were driven primarily by local environmental changes, especially the expansion of the Oxygen Minimum Zone and increased organic matter deposition.
- Findings show that enhanced microbial activity during these periods led to more significant sulfur retention in porewater, linking organic carbon loading as a key influence on δS variations and stressing the importance of local factors in interpreting these records.
Rationale: Natural stable isotope ratios (δ C and δ N values) and associated elemental concentrations (i.e. total organic carbon and total nitrogen contents) preserved in marine sediments are frequently used for the determination of paleo-environmental processes such as the origin of organic matter.
View Article and Find Full Text PDFPyrite sulfur isotopes reveal glacial-interglacial environmental changes.
Proc Natl Acad Sci U S A
June 2017
The sulfur biogeochemical cycle plays a key role in regulating Earth's surface redox through diverse abiotic and biological reactions that have distinctive stable isotopic fractionations. As such, variations in the sulfur isotopic composition (δS) of sedimentary sulfate and sulfide phases over Earth history can be used to infer substantive changes to the Earth's surface environment, including the rise of atmospheric oxygen. Such inferences assume that individual δS records reflect temporal changes in the global sulfur cycle; this assumption may be well grounded for sulfate-bearing minerals but is less well established for pyrite-based records.
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