Early Triassic carbon isotope excursions from South China: proxies for devastation and restoration of marine ecosystems following the end‐Permian mass extinction

Abstract Early Triassic carbon isotopes are measured based on 1422 carbonate bulk samples from 10 Lower Triassic sections in different palaeogeographic settings in South China. Early Triassic fluctuation ofδ13C is used as a proxy for environmental change to discuss the devastation and restoration of marine ecosystems following the biggest Phanerozoic mass extinction at the end of the Permian. Early Triassicδ13C profiles derived from various depositional settings in South China yield comparable excursion patterns. A dramatic negative shift ofδ13C across the Permian/Triassic boundary is followed by a moderate increase inδ13C values throughout the Induan. A positiveδ13C anomaly occurs near the Induan/Olenekian boundary, followed by a Smithian interval of lowerδ13C values. A distinct positive shift inδ13C coincides with the Smithian/Spathian boundary, and is followed by a high Spathian plateau ofδ13C values. Thus the distinctδ13C anomalies coincide well with key stratigraphic boundaries. Early Triassic intervals of lowδ13C values correspond to a decline in benthic generic diversity in South China and intervals of highδ13C values are coupled with an increase in biodiversity. The Early Triassic fluctuations ofδ13C profiles are good proxies for perturbations of ecologic environments, indicating multiple phases of devastation–restoration of marine ecosystems punctuated by several unexpected extraneous events such as volcanic activity. The initial restoration of marine ecosystems may have occurred earlier in the Induan and the ecosystems were subsequently destroyed during the Smithian. Biotic and environmental recoveries occurred at the Spathian, while the ecosystems eventually returned to normal levels in the early Middle Triassic. Copyright © 2007 John Wiley & Sons, Ltd.