The age of the Permian-Triassic boundary |
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| Authors: | JC Claou-Long Zhang Zichao Ma Guogan Du Shaohua |
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| Institution: | J.C. Claoué-Long, Zhang Zichao, Ma Guogan,Du Shaohua |
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| Abstract: | The 5 cm boundary clay bed in the Chinese stratotype section through the Permian-Triassic boundary has been recognised as a bentonite. SHRIMP ion microprobe dating of zircons in the bentonite indicates a magmatic age of 251.2 ± 3.4 Ma (2σ); this is the first direct constraint on the numerical age of the Permian-Triassic boundary.Future refinements of ages at this important, but poorly constrained, level of the Phanerozoic timescale may depend on re-analysis of this uniquely placed volcanic horizon, and other bentonites in the fossiliferous Chinese Upper Permian and Lower Triassic. The utility of defining the Permian-Triassic boundary in the Chinese stratotype section, in the vicinity of known dateable horizons, should be considered. |
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