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

Abstract

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.