EKU Faculty and Staff Scholarship
 

Document Type

Conference Presentation

Publication Date

3-2003

Abstract

Past research shows that active sulfide mineralization occurs at the base of the sulfate reduction zone (SRZ) in modern, deep-water, continental-margin sediments that overlie methane gas hydrate. These sulfide minerals (elemental sulfur, Sº; iron monosulfides, ~FeS; and pyrite, FeS2) are enriched in 34S because of sulfate reduction and anaerobic methane oxidation (AMO) processes occurring above and near the sulfate-methane interface (SMI).

The data in this study show that 5 discrete zones of sulfide minerals are preserved in a 703.8-meter sediment column associated with methane gas hydrate. These zones of sulfide minerals are also enriched in 34S. The shallowest zone is the present-day SMI, and we infer that the other 4 zones are past locations of the SMI.

Today, enrichments of 34S in sulfide minerals occur because of anaerobic methane oxidation (AMO) carried out by methanotrophs and sulfate-reducing microbes in areas that have significant methane delivery to the SMI in methane gas hydrate terranes. Thus, these 34S enrichments are a diagenetic indicator that point out occurrences of high methane delivery to the sulfate-methane interface and the action of the AMO consortium. From the data, we infer that these conditions exist not only today, but also have existed at several discrete times since the mid-Miocene, when sulfur isotopic composition of sulfide minerals is similar to or heavier than that occurring today.

Comments

Winner of the EKU Graduate Student Research Paper Award!

Conference Name

EKU Sigma Xi, Graduate Research Competition, March 2003

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