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Published August 1991 | public
Journal Article

Precambrian/Cambrian boundary problem: Carbon isotope correlations for Vendian and Tommotian time between Siberia and Morocco


At least three distinctive cycles are preserved in the carbon-isotope patterns for the Vendian/Tommotian interval of the Siberian platform and the Anti-Atlas Mountains of Morocco. In Siberia, an early Tommotian carbon cycle provides the first detailed test of correlations based on archaeocyathid biostratigraphy between classic sequences on the Aldan and Lena rivers, and demonstrates that the Early Cambrian zone boundaries are reasonably good time lines. The carbon signal is preserved in both limestone and dolomite and across regional faties variations. The δ^(13)C results from the late Vendian section in Morocco display a pattern similar to that found in Siberia, suggesting that carbon isotopes can be used to test stratigraphic correlations on an intercontinental scale.

Additional Information

© 1991 Geological Society of America. Manuscript received December 27, 1990. Revised manuscript received April 4, 1991. Manuscript accepted April 12, 1991. Supported by National Science Foundation Grants EAR-8721391 and EAR-8351370 and by a National Engineering and Research Council grant to Latham. This work is a contribution to International Geological Correlation Project 29, the Working Group on the Precambrian/Cambrian Boundary; Project 216, Global Bioevents; and Project 303, Event Stratigraphy of the Precambrian/Cambrian Boundary. We thank R. Selnikov for mass spectrometry measurements, K. Bijan for X-ray determinations, and A. Bensaid and M. Dahmani, Ministère de l'Energie et des Mines in Morocco, for access to the field area in Morocco. California Institute of Technology Division of Geological and Planetary Sciences Contribution No. 4879.

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