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Sequence Stratigraphy of Upper Proterozoic Glacigenous Rocks in Southeastern Margin of yangtze platform

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Journal of Earth Science 1996年第1期15卷 38-45页

作者： Jiang Ganqing Wang Ziqiang Zhang Linghua (Department of Geology and Mineral Resources, China University of Geosciences, Beijing 100083)

The Upper Proterozoic glacigenous rocks in the southeastern margin of the yangtze platform.were accumulated in a glacially influenced marine environment with extension set- ting. Two type I depositional sequences have been identified in the glacioclastic sediments the their boundaries enhanced by both tectonism and the incision of glaciation. The lower sequence (SQ1), comprising Changan and Fulu formations (Guangxi Province), Jiangkou and Xiangmen formations(Hunan Province) and their equivalents, is bounded by erosional unconformities both at the base and on the top. The upper sequence (SQ2), composed mainly of Nantuo Formation and its equivalents, is confined by an erosional unconformity at the base and covered by an exposure surface of karstification on the top. The depositional systems tracts are difficult to be distinguished directly and mainly characterized by the variation in glacioclastic supplies. Two types of episodic parasequeuces can be identified in the glacigenous rocks and are related to the evolution of depositional systems tracts. Both the sequences and parasequences are caused by autocyclic mechanism. The present research shows that the Upper Proterozoic glacigenous deposits are of significance for the analysis of the tectonic evolution of the Late Precambrian basin in South China.

关键词： glacigenous rock sequence stratigraphy Upper Proterozoic yangtze platform.

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Sinian-Cambrian stratigraphic framework for shallow-to deep-water environments of the yangtze platform. an integrated approach

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Progress in Natural Science:Materials International 2003年第12期 71-80页

作者： ZHU Maoyan 1*, ZHANG Junming 1, Michael STEINER 2, YANG Aihua 1, LI Guoxiang 1 and Bernd D. ERDTMANN 2(1. LPS, Nanjing Institute of Geology & Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China 2. TU Berlin, Sekr. ACK 14, Ackerstrasse 71 76, D 13355 Berlin, Germany) LPS Nanjing Institute of Geology & Palaeontology Chinese Academy of Sciences Nanjing 210008 China TU Berlin Sekr. ACK 14 Ackerstrasse 71-76 D-13355 Berlin Germany

The Sinian (Terminal Proterozoic) and Early Cambrian shallow to deep water sequences of the yangtze platform.were investigated. Based on integrated lithostratigraphic, biostratigraphic, and other approaches, the shallow water sequence from the base of the Sinian (base of the Doushantuo Formation) to the top of the Qiongzhusian (top of the Yu'anshan Formation) was subdivided into 12 stratigraphic intervals. These 12 intervals were applied in turn to the subdivision and correlation of the sequences present in various facies of the yangtze platform. The high resolution stratigraphic framework here developed can serve as a time frame for ongoing multidisciplinary analyses of the “Cambrian explosion”.

关键词： Neoproterozoic Sinian Cambrian stratigraphy Cambrian Explosion yangtze platform.

Pb-Pb isotope dating of black shales from the Lower Cambrian Niutitang Formation, Guizhou Province, South China

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Progress in Natural Science:Materials International 2003年第10期 51-56页

作者： CHEN Yongquan, JIANG Shaoyong*, LING Hongfei, FENG Hongzhen, YANG Jinghong and CHEN Jianhua (State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 210093, China) State Key Laboratory for Mineral Deposits Research Department of Earth Sciences Nanjing University Nanjing 210093 China

The Lower Cambrian black shales of the Niutitang Formation and their lateral equivalents occur widely on the yangtze platform. South China. In this study, we examine two sections of the Niutitang Formation in Guizhou Province. We employ a stepwise acid leaching technique to obtain Pb isotope compositions of the black shales. At the Zhongnan section, the black shales display large Pb isotope variations, with 206 Pb/ 204 Pb of 20.5396～33.5709, and 207 Pb/ 204 Pb of 15.8407～16.5782. In contrast, Pb isotope data show a relatively limited range in 206 Pb/ 204 Pb (18.2797～18.5972) and 207 Pb/ 204 Pb (15.6813～15.7159) at the Zhijin section. Data for all acid leached black shale samples from the two sections yield a Pb Pb isochron age of 531±24 Ma. This age may represent the sedimentary age of the black shales. The initial Pb isotope composition of the black shales falls near the upper crust evolution curve in a Zartman Pb Pb evolution diagram. Hence, it is likely that the Pb in the black shales may have been derived from an upper continental crustal source.

关键词： Pb Pb isotope dating source of Pb black shales Niutitang Formation yangtze platform.

δ13Ccarb and Ceanom excursions in the post-glacial Neoproterozoic and Early Cambrian interval in Guizhou, South China

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Progress in Natural Science:Materials International 2004年第2期 92-96页

作者： FENG Hongzhen, LING Hongfei, JIANG Shaoyong and YANG Jinghong*(State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 210093, China) State Key Laboratory for Mineral Deposits Research Department of Earth Sciences Nanjing University Nanjing 210093 China

Secular δ 13 C carb and Ce anom profiles in the post-glacial Neoproterozoic and Early Cambrian interval are reported from Guizhou on the southeasten border of the yangtze platform. South China. Overall, the δ 13 C carb profile drifts to negative values in the post-glacial Nantuo and lower to middle Doushantuo Formations, and then to positive values in the upper Doushantuo and Dengying Formations of Neoproterozoic, followed by negative values in the Lower Cambrian Gezhongwu and Niutitang Formations. A detailed investigation of the relationship between the δ 13 C carb and Ce anom profiles reveals that the main anoxic and oxic episodes are coupled with negative and positive δ 13 C carb values, respectively. This may suggest a control of alternation between ocean stratification and mixing on variations in 13 C abundance in the ancient ocean of the investigated areas.

关键词： C carb and Ce anom excursions post-glacial Neoproterozoic and Early Cambrian Guizhou yangtze platform.