Biostratigraphic Zonation of Late Paleozoic Depositional Sequences

Correlation of more than seventy third-order depositional sequences in Carboniferous and Permian strata uses assemblage zones of warm water benthic and nektonic shelf faunas. These include calcareous foraminifers, bryozoans, conodonts, and ammonoids and represent tropical, subtropical, and warm temperate water faunas from carbonate shelves and adjacent cratonic basins. After the Early Carboniferous faunal zonation was highly provincial and worldwide correlations of depositional sequences are based on interpretations of evolutionary lineages and depositional patterns in each province and in identifying times of limited dispersals between provinces. Associated with these faunal zones there were times of expanded or reduced faunal diversities and temperature related latitudinal expansion or reduction of faunas. Higher sea levels during warmer times enhanced faunal evolution and diversity and lower sea levels during cooler times dampened evolution and diversity and resulted in many species becoming extinct. After the Early Carboniferous, provincial faunal zonations and evolutionary lineages developed as a consequence of the formation of Lesser Pangaea. Further isolation of these provinces resulted in faunal realms in the middle Early Permian after the formation of Greater Pangaea