Carbon and Sulfur Composition of Authigenic Phase in Shallow Sediments of Methane Charged Continental Margins
Department of Earth Science, Rice University, Houston, TX, USA
This project aims to determine the role of biologically derived methane in continental margin sediment as a sink for sulfur. Although commonly recognized that global carbon and sulfur cycles are linked, it is not yet clear how much sulfur leaves the ocean and enters marine sediment through anaerobic oxidation of methane (AOM). This marks a fundamental gap in Earth Science knowledge with an interesting hydrocarbon perspective. In this study deep sea sediment cores are being examined from offshore Peru and the Sea of Japan. Sediment samples are being collected from cores. These will span from the seafloor to below the SMT. The samples are being analyzed for total carbon, sulfur, calcium, magnesium, manganese, strontium, barium, and aluminum in addition to sulfur isotopic composition. Our hypothesis is that significant amounts of authigenic 34-S rich Fe sulfide will coincide with diffusive fluxes of reduced sulfur resulting from AOM. Continental margins with high methane concentrations are crucial nodes of organic and inorganic carbon cycling. The methane in these regions is clearly coupled to sulfur cycling through AOM. If much of the hydrogen sulfide produced by AOM precipitate into Fe sulfides, the overall process may modulate global geochemical cycling and, ultimately, climate. This would change conventional views of geochemical cycling, including the impact of hydrocarbons as well as petroleum source models.
AAPG Search and Discovery Article #90199 © 2014 AAPG Foundation 2014 Grants-in-Aid Projects