Carbon and Sulfur Composition of Sediments in Methane Charged Continental Margins
Rice University, Department of Earth Science
Houston, Texas, United States of America
This project aims to determine the role of 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 will be examined from a variety of locations including: Blake Ridge off S. Carolina, Keathly Canyon and Atwater Valley in the Gulf of Mexico, Umitaka Spur in the Japan Sea, and the Peru slope. Sediment samples will be collected from cores. These will span from the seafloor to below the SMT. The samples will be analyzed for total carbon, total sulfur, and sulfur isotope composition. Our hypothesis is that significant amounts of 34‐S rich Fe sulfide precipitate just below the SMT at all these locations. 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 #90183©2013 AAPG Foundation 2013 Grants-in-Aid Projects