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Biogeochemistry of organic matter deposition and diagenesis in Bering-Chukchi and Gulf of Mexico sediments

Thesis/Dissertation ·
OSTI ID:5456032
The research described focused on two biogeochemical processes: (1) the formation of {sup 13}C-depleted carbonates in sediments influenced by natural, submarine hydrocarbon seepage, and (2) the distribution, deposition and early diagenesis of marine and terrigenous organic matter in continental shelf sediments from a sub-arctic and a sub-tropical environment. Active diapirism has produced extensive deformation and faulting of Quaternary sediments in the Green Canyon area of the upper slope off the Louisiana coast in the Gulf of Mexico. Piston-cored sediments from the faulted area contain macroscopic inclusions of petroleum and natural gas hydrates, as well as isotopically anomalous authigenic and skeletal carbonates. Calcite, aragonite and dolomite with {delta}{sup 13}C(PDB) values as negative as {minus}56.7 permil are found in nodules, disseminated particles and faunal remains. Anaerobic methane oxidation by sulfate-reducing bacteria is the probable source of the {sup 13}C-depleted carbonates in these samples. Oxygen isotope ratios and barite inclusions indicate that formation waters were involved in nodule precipitation.
Research Organization:
Texas Univ., Austin, TX (USA)
OSTI ID:
5456032
Country of Publication:
United States
Language:
English