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Science 17 March 1972:
Vol. 175. no. 4027, pp. 1246 - 1248
DOI: 10.1126/science.175.4027.1246
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Articles

Carbon Isotopic Studies of Organic Matter in Precambrian Rocks

Dorothy Z. Oehler 1, J. William Schopf 1, and Keith A. Kvenvolden 2

1 Department of Geology, University of California, Los Angeles 90024
2 Exobiology Division, Ames Research Center, Moffett Field, California 94035

Reduced carbon in early Precambrian cherts of the Fig Tree and upper and middle Onverwacht groups of South Africa is isotopically similar (the average value of dgr13CPDB is -28.7 per mil) to photosynthetically produced organic matter of younger geological age. Reduced carbon in lower Onverwacht cherts (Theespruit formation) is anomalously heavy (the average value of dgr13CPDB is -16.5 per mil). This discontinuity may reflect a major event in biological evolution.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Archean Microfossils Showing Cell Division from the Swaziland System of South Africa.
A. H. Knoll, A. H. KNOLL, and E. S. BARGHOORN (1977)
Science 198, 396-398
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Science. ISSN 0036-8075 (print), 1095-9203 (online)