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Molecular evidence of Late Archean archaea and the presence of a subsurface hydrothermal biosphere.

Molecular evidence of Late Archean archaea and the presence of a subsurface hydrothermal biosphere.

Authors :
Ventura GT
Kenig F
Reddy CM
Schieber J
Frysinger GS
Nelson RK
Dinel E
Gaines RB
Schaeffer P
Source :
Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2007 Sep 04; Vol. 104 (36), pp. 14260-5. Date of Electronic Publication: 2007 Aug 28.
Publication Year :
2007

Abstract

Highly cracked and isomerized archaeal lipids and bacterial lipids, structurally changed by thermal stress, are present in solvent extracts of 2,707- to 2,685-million-year-old (Ma) metasedimentary rocks from Timmins, ON, Canada. These lipids appear in conventional gas chromatograms as unresolved complex mixtures and include cyclic and acyclic biphytanes, C36-C39 derivatives of the biphytanes, and C31-C35 extended hopanes. Biphytane and extended hopanes are also found in high-pressure catalytic hydrogenation products released from solvent-extracted sediments, indicating that archaea and bacteria were present in Late Archean sedimentary environments. Postdepositional, hydrothermal gold mineralization and graphite precipitation occurred before metamorphism (approximately 2,665 Ma). Late Archean metamorphism significantly reduced the kerogen's adsorptive capacity and severely restricted sediment porosity, limiting the potential for post-Archean additions of organic matter to the samples. Argillites exposed to hydrothermal gold mineralization have disproportionately high concentrations of extractable archaeal and bacterial lipids relative to what is releasable from their respective high-pressure catalytic hydrogenation product and what is observed for argillites deposited away from these hydrothermal settings. The addition of these lipids to the sediments likely results from a Late Archean subsurface hydrothermal biosphere of archaea and bacteria.

Details

Language :
English
ISSN :
0027-8424
Volume :
104
Issue :
36
Database :
MEDLINE
Journal :
Proceedings of the National Academy of Sciences of the United States of America
Publication Type :
Academic Journal
Accession number :
17726114
Full Text :
https://doi.org/10.1073/pnas.0610903104