【作者】 郭庆军； 刘丛强； Harald Strauss； Tatiana Goldberg；

【Author】 GUO Qing-Jun, LIU Cong-Qiang, Harald STRAUSS, Tatiana GOLDBERG ( State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China; Geologisch-Palaontologisches Institut, Westf(?)lische Wilhelms-Universit(?)t Münster, 48148 Münster, Germany)

【机构】 中国科学院地球化学研究所环境地球化学国家重点实验室； Geologisch-Palontologisches；

【摘要】 震旦—寒武交变期是地史上一个重大转折期,从隐生宙向显生宙过渡,海、陆、空发生了显著不同的变化,是一个具有特殊意义的过渡时期。运用碳同位素地球化学方法,探讨扬子地台北缘四川南江地区晚震旦-早寒武交变期,碳同位素地球化学异常与环境变化和生物演化的相互联系。南江剖面沉积岩有机碳同位素组成在-35.8和-30.1‰间变化;碳酸盐碳同位素组成从-3.5变化到+0.5‰。在灯影组顶部、牛蹄塘组下部和上部,变化的碳、硫同位素组成和不同的黄铁矿与有机碳含量反映了有机碳埋藏量和环境的变化。下寒武统富有机碳和黄铁矿的黑色页岩沉积,暗示了早寒武世早期缺氧环境的存在。更多还原

【Abstract】 The Precambrian - Cambrian transition is one of the critical time intervals in Earth history. Profound geotectonic, climatic and biological changes occur during the late Neoproterozoic and its transition into the early Cambrian. This study has researched on paired carbonate and organic carbon isotope determinations from Nanjiang, Sichuan Province of the Yangtze Platform, and provided a preliminary geochemical explanation for environmental variations and bio-events observed on the northern Yangtze Platform during the Precambrian -Cambrian transitional interval and their causal relationship. Organic carbon isotopic compositions on sediments vary from -35.8 to -30.1‰ at Nanjiang section; carbonate carbon isotopic compositions change between -3.5 and +0.5‰. Various carbon and sulphur isotopic compositions, different pyrite and organic matter content reflect changing environment and burial of organic matter in the Dengying Fm., the lower and upper part of Niutitang Fm. Anoxic conditions result in widespread preservation of organic rich sediments and pyrites in the black shales on the Yangtze Platform.更多还原