2.5 GA SUB-TIDAL MICROFOSSILS OF THE CAMPBELLRAND-MALMANI CARBONATE PLATFORM, KAAPVAAL CRATON, SOUTH AFRICA

The Campbellrand-Malmani carbonate platform (CMCP) formed at the end of the Archean eon and beginning of the Proterozoic eon. The stratigraphy and geochemistry of the CMCP are extensively studied because of the valuable clues to understanding the Great Oxygenation Event the platform contains. The platform also contains multiple microbialites that formed in supratidal to basinal depositional environments. The presence of well-preserved microfossils in some of these microbialites was first reported in 1987, but there has been minimal examination of the potentially fossiliferous microbialites in the platform since that time.

Here we present preliminary results from a project that aims to describe the microfossils preserved across the platform and, ultimately, compare the diversity of microfossil assemblages observed in the CMCP to that of well-preserved assemblages from the Paleoarchean to Mesoproterozoic periods and assess microbialite/microfossil assemblage covariance in the CMCP. The results of this project will both enhance our understanding of the early coevolution of Earth and life and aid in the interpretation of samples to be collected by the recently launched Perseverance Rover. The results presented here include multiple morphotypes of organic-walled, three-dimensionally preserved microfossils from silicified portions of CMCP carbonate microbialites that formed in shallow sub-tidal to sub-wavebase depositional environments.