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Biologically mediated isotope fractionations - Biochemistry, geochemical significance and preservation in the earth's oldest sedimentsPreferential metabolization of isotopically light carbon and sulfur has resulted in a fractionation of the stable isotopes of these elements on a global scale, with the light species (C-12, S-32) markedly concentrated in biogenic materials. Since the biological effects are basically retained when carbon and sulfur are incorporated in sediments, the respective fractionations are propagated into the rock section of the geochemical cycle, this having consequently caused a characteristic bipartition of both elements between 'light' and 'heavy' crustal reservoirs. Preservation of the biological isotope effects in sedimentary rocks makes it possible to trace the underlying biochemical processes back over most of the geological record. According to the available evidence, biological (autotrophic) carbon fixation arose prior to 3.5(if not 3.8) billion years ago, while the emergence of dissimilatory sulfate reduction antedates the appearance of the oldest presumably bacteriogenic sulfur isotope patterns in rocks between 2.7 and 2.8 billion years old. Hence, biological control of the terrestrial carbon and sulfur cycles has been established very early in the earth's history.
Document ID
19830049941
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Schidlowski, M.
(Max-Planck-Institut fuer Chemie Mainz, Germany)
Date Acquired
August 11, 2013
Publication Date
January 1, 1983
Subject Category
Life Sciences (General)
Meeting Information
Meeting: Cosmochemistry and the origin of life; Advanced Study Institute
Location: Maratea
Country: Italy
Start Date: June 1, 1981
End Date: June 12, 1981
Accession Number
83A31159
Funding Number(s)
CONTRACT_GRANT: NSG-7489
CONTRACT_GRANT: NSF DEB-77-225-B
Distribution Limits
Public
Copyright
Other

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