EKU Faculty and Staff Scholarship
 

Department

Geosciences

Document Type

Article

Publication Date

2001

Abstract

Carbon isotopic data of interstitial dissolved CO2 (ΣCO2), CO2 gas, and methane show that a variety of microbial diagenetic processes produce the observed isotopic trends. Anaerobic methane oxidation (AMO) is an important process near the sulfate-methane interface (SMI) that strongly influences the isotopic composition of ΣCO2 in the sulfate reduction and upper methanogenic zones, which in turn impacts methane isotopic composition. Dissolved CO2 and methane are maximally depleted in 3C near the SMI, where C values are as light as –31.8‰ and –101‰ PDB for ΣCO2 and methane, respectively. CO2 reduction links the CO2 and methane pools in the methanogenic zone so that the carbon isotopic composition of both pools evolves in concert, generally showing increasing enrichments of C with increasing depth. These isotopic trends mirror those within other methane-rich continental rise sediments worldwide.

Journal Title

Proceedings ODP, Scientific Results, 172

Journal Volume

172

Article Starting Page

1

Article Ending Page

16

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