| 新元古代陡山沱组－灯影组中 C-Sr 同位素演化及其古环境意义 |
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| 关键词:carbon isotope carbonate paleoenvironment change Neoproterozoic Zhejiang |
| 基金项目:国家自然科学基金项目（编号：40232020，40172041）资助 |
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| Variations of C-Sr Isotopes in Neoproterozoic Doushantuo-Dengying Formation:Implications for Paleoenvironmental Change |
| The evolution of δ18C,δ18O,87Sr/86Sr and trace elements contents in Neoproterozoic Doushantuo Formation and Deng-ying Formation of Zhejiang Province was studied. It is held that 87Sr/86Sr ratios have been modified by diagenesis. Most of the samples recorded primary C isotope compositions. The extremely low δ13C values of the cap carbonate might have resulted from several factors. As the organic productivity, the CO2 concentration in atmosphere and the ocean circulation recovered after the Snowball Earth event,δ13C steadily shifted to normal positive values in the main Doushantuo periods. After the withdraw of a large amount of CO2 from the atmosphere as a result of weathering and organic carbon burial, the climate became cool, which induced thermohaline circulation and led to the upwelling of deep ocean water rich in 12C. These factors caused the negative excursion of δ13C along the Doushantuo-Dengying boundary and increased the CO2 concentration in the atmosphere to a normal level. During most time of the Dengying period, the oceanic and climatic conditions were kept in a state favoring the ecosystem, yielding positive δ13C values in most part of the Dengying Formation. |
| CHEN Xi,LING Hongfei,PAN Jiayong,CHEN Yongquan,FENG Hongzhen,JIANG Shaoyong.2005.Variations of C-Sr Isotopes in Neoproterozoic Doushantuo-Dengying Formation:Implications for Paleoenvironmental Change[J].Acta Geoscientica Sinica,26(z1):197. |
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