CARBONIFEROUS–PERMIAN SUCCESSIONS IN SOUTH CHINA: SEDIMENTARY RESPONSE TO THE LATE PALEOZOIC ICE AGE IN EAST PALEOTETHYS REGION

The Late Paleozoic ice age (LPIA) was a time when several major global events took place including supercontinental reconfiguration, atmospheric perturbation, and significant biotic turnover. The LPIA recorded the only transition from a vegetated icehouse world to a fully greenhouse world in the geological history, and may thus provide insights into the Earth-life system of our modern world. The South China Block was located in east paleotethys region near the paleoequator during the Carboniferous to Early Permian. The Carboniferous to Early Permian successions are widely distributed in South China and contain abundant marine fossils. The successions were deposited in various marine sedimentary environments such as carbonate platform, platform-slope, and basinal settings. During the Mississippian, carbonate deposits were episodically intervened by input of siliciclastics, possibly reflecting long-term eustatic changes. Mid-Carboniferous boundary are recognized by various subaerial-exposure structures and wide distribution of siliciclastics and dolomites in shallow-water carbonate platforms and large-scale slumps and thick grainstones in deep-water settings, which was most likely ascribed to the significant eustatic drop. During the Pennsylvanian to Early Permian, cyclothems widely developed across the South China, which resulted from cyclic eustatic changes and differential subsidence. Cyclothems in shallow-marine carbonate platforms are recognized by repetitive occurrence of subaerial-exposure structures such as paleokarst, paleosol, rhizolith, and pendant cement. Deep-water cyclothems are characterized by cyclic occurrence of normal-graded grainstones (deposited from sediment gravity flows) within thin-bedded lime mudstones. Further integrated studies on the Carboniferous-Permian successions in South China including detailed sedimentological and paleontological investigations and stable isotope and trace element geochemical analyses will eventually lead to better understanding of the paleoclimatic changes, paleoceanographic conditions, and biotic evolution during the LPIA.