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Carbon isotopic studies of organic matter in Precambrian rocks.A survey has been undertaken of the carbon composition of the total organic fraction of a suite of Precambrian sediments to detect isotopic trends possibly correlative with early evolutionary events. Early Precambrian cherts of the Fig Tree and upper and middle Onverwacht groups of South Africa were examined for this purpose. Reduced carbon in these cherts was found to be isotopically similar to photosynthetically produced organic matter of younger geological age. Reduced carbon in lower Onverwacht cherts was found to be anomalously heavy; it is suggested that this discontinuity may reflect a major event in biological evolution.
Document ID
19720039830
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Oehler, D. Z.
Schopf, J. W.
(California, University Los Angeles, Calif., United States)
Kvenvolden, K. A.
(NASA Ames Research Center Exobiology Div., Moffett Field, Calif., United States)
Date Acquired
August 6, 2013
Publication Date
March 17, 1972
Publication Information
Publication: Science
Volume: 175
Subject Category
Geophysics
Accession Number
72A23496
Funding Number(s)
CONTRACT_GRANT: NSF GA-23741
CONTRACT_GRANT: NGR-05-007-292
Distribution Limits
Public
Copyright
Other

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