Re-Os geochronology of the Cambrian stage-2 and -3 boundary in Zhijin County, Guizhou Province, Chin

• 作者: Shuaichao Wei Yong Fu Houpeng Liang Zhihua Ge Wenxi Zhou Guangzhe Wang
• 来源期刊: 地球化学学报(英文）
• 关键词: Ediacaran-Cambrian transition Black shale Re-Os isochron age Initial ratio
• 年，卷（期）: 2018,（2）
• 页码范围: 323-333
• 页数: 10页
• 语种: 英文
• DOI: 10.1007/s11631-017-0228-5

摘要

The black shale series that formed in the Ediacaran-Cambrian transition are important stratigraphic records of the co-evolution of the paleo-ocean, -climate, and -biology. In this study, we measured Re-Os isotopic compositions of the black shale in the Niutitang Formation from the Gezhongwu section in Zhijin, Guizhou Province. The samples had high Re and Os contents, with Re ranging from 21.27 to 312.78 ng/g and Os ranging from 0.455 to 7.789 ng/g. The Re-Os isotope isochron age of 522.9 ± 8.6 Ma implies deposition of the Niutitang black shale predated the Chengjiang Fauna, providing an age constraint for the expansion of oceanic anoxia in the study area. The initial 187Os/188Os ratio of 0.826 ± 0.026 indicates that enhanced continental weathering might have triggered the expansion of the oceanic anoxia.