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Sulfur-bound biomarkers of a Monterey shale and a Greenland lake sediment

Joshua G. Stern¹

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1. Brown University

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Document Type:

Manuscript

Date:

Received 05 June 2009 02:05 UTC; Posted 05 June 2009

Subjects:

Chemistry, Ecology, Earth & Environment

Tags:

• organic sulfur
• sedimentary sulfur
• sulfur cycle
• geochemical sulfurization
• nickel boride desulfurization
• insoluble organic matter
• meteoritic IOM
• alkenone sulfurization
• unresolved complex mixture
• Messinian salinity crisis
• sulfur
• diagenesis
• desulfurization
• astrobiology
• IOM
• alkenone
• Monterey
• Brayasø
• oligosaline
• Miocene
• thesis

Abstract:

Seeking to reconstruct the biogeochemical processes that produced organic sulfur compounds in two unique depositional environments, we used the nickel boride desulfurization reaction to release hydrocarbons from sulfur-bound macromolecules not otherwise amenable to chromatographic analysis. We desulfurized two geochemical extracts: one sample is a Monterey shale of late Miocene age, and the other sample is a surface sediment from the Greenland lake Brayasø. Both samples contained organic sulfur compounds, but the Monterey shale was biologically and thermally modified after deposition. A comparison of the free and sulfur-bound hydrocarbons from each sample revealed a precursor-product relationship between tocopherol and pristane, for Monterey. Greenland’s composition may indicate that photochemical sulfurization occurs in the Brayasø oxic zone. We found that sulfurization may proceed at different rates for different compound families; for example, we did not see any sulfurized alkenones in Brayasø, but we found an abundance of sulfurized isoprenoids. Greenland’s relatively high overall desulfurization yield suggests that sulfurization in Brayasø occurs in under 40 years. Our Greenland findings suggest that photochemical sulfurization may be more widespread than previously thought, and that sulfurization might not interfere with alkenone paleotemperature reconstructions.

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License:

This document is licensed to the public under the Creative Commons Attribution 3.0 License

How to cite this document:

Stern, Joshua. Sulfur-bound biomarkers of a Monterey shale and a Greenland lake sediment. Available from Nature Precedings <http://dx.doi.org/10.1038/npre.2009.3325.1> (2009)

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