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Early Triassic carbon isotope excursions from South China: proxies for devastation and restoration of marine ecosystems following the end‐Permian mass extinction
Author(s) -
Jinnan Tong,
Jingxun Zuo,
Z.Q. Chen
Publication year - 2007
Publication title -
geological journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.721
H-Index - 54
eISSN - 1099-1034
pISSN - 0072-1050
DOI - 10.1002/gj.1084
Subject(s) - extinction event , early triassic , paleontology , permian , geology , phanerozoic , permian–triassic extinction event , global boundary stratotype section and point , extinction (optical mineralogy) , biostratigraphy , structural basin , cenozoic , biological dispersal , population , demography , sociology
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 of δ 13 C 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 Triassic δ 13 C profiles derived from various depositional settings in South China yield comparable excursion patterns. A dramatic negative shift of δ 13 C across the Permian/Triassic boundary is followed by a moderate increase in δ 13 C values throughout the Induan. A positive δ 13 C anomaly occurs near the Induan/Olenekian boundary, followed by a Smithian interval of lower δ 13 C values. A distinct positive shift in δ 13 C coincides with the Smithian/Spathian boundary, and is followed by a high Spathian plateau of δ 13 C values. Thus the distinct δ 13 C anomalies coincide well with key stratigraphic boundaries. Early Triassic intervals of low δ 13 C values correspond to a decline in benthic generic diversity in South China and intervals of high δ 13 C values are coupled with an increase in biodiversity. The Early Triassic fluctuations of δ 13 C 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.