1. Integrated Sr isotope variations and global environmental changes through the Late Permian to early Late Triassic.
- Author
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Song, Haijun, Wignall, Paul B., Tong, Jinnan, Song, Huyue, Chen, Jing, Chu, Daoliang, Tian, Li, Luo, Mao, Zong, Keqing, Chen, Yanlong, Lai, Xulong, Zhang, Kexin, and Wang, Hongmei
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STRONTIUM isotopes , *GLOBAL environmental change , *TRIASSIC Period , *CONODONTS , *PHANEROZOIC Eon - Abstract
New 87 Sr/ 86 Sr data based on 127 well-preserved and well-dated conodont samples from South China were measured using a new technique (LA-MC-ICPMS) based on single conodont albid crown analysis. These reveal a spectacular climb in seawater 87 Sr/ 86 Sr ratios during the Early Triassic that was the most rapid of the Phanerozoic. The rapid increase began in Bed 25 of the Meishan section (GSSP of the Permian–Triassic boundary, PTB), and coincided closely with the latest Permian extinction. Modeling results indicate that the accelerated rise of 87 Sr/ 86 Sr ratios can be ascribed to a rapid increase (>2.8×) of riverine flux of Sr caused by intensified weathering. This phenomenon could in turn be related to an intensification of warming-driven runoff and vegetation die-off. Continued rise of 87 Sr/ 86 Sr ratios in the Early Triassic indicates that continental weathering rates were enhanced >1.9 times compared to those of the Late Permian. Continental weathering rates began to decline in the middle–late Spathian, which may have played a role in the decrease of oceanic anoxia and recovery of marine benthos. The 87 Sr/ 86 Sr values decline gradually into the Middle Triassic to an equilibrium values around 1.2 times those of the Late Permian level, suggesting that vegetation coverage did not attain pre-extinction levels thereby allowing higher runoff. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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