CARBON-ISOTOPE GEOCHEMISTRY AND PALEONTOLOGY OF NEOPROTEROZOIC TO EARLY CAMBRIAN SILICICLASTIC SUCCESSIONS IN THE EAST EUROPEAN PLATFORM, POLAND

A well-preserved stratigraphic record of the organic carbon isotopic c omposition across the Precambrian-Cambrian transition has been obtaine d from a sequence of entirely detrital rocks underlying the Lublin Slo pe, East European Platform, Poland. The observed delta(13)C pattern fo r organic carbon is comparable to isotope data determined for coeval c arbonate platform sequences elsewhere. These results underline the tru ly global nature of these secular variations within the carbon cycle d uring the terminal Proterozoic and early Cambrian, largely independent of host lithology and facies. The direct combination of micropalaeont ological and geochemical results from sedimentary organic matter allow s a detailed interpretation of the isotope record as probably caused b y secular changes in the net balance of burial and erosion rates of re positories of organic carbon. Furthermore, these Variations appear to be directly correlatable with changes in the diversity and abundance o f the biota and radiation/extinction events.