华南下扬子区埃迪卡拉纪高分辨率同位素地层和古海洋环境的演化

埃迪卡拉纪是生命演化的一个关键时期，该时期古海洋环境的改变促进了早期生命的演化。我国华南地区发育了较好的埃迪卡拉纪地层，为研究冰期后古海洋环境与早期生命的协同演化关系提供了珍贵资料。以往研究主要集中在以峡东地区为代表的中上扬子区，尽管下扬子区出产了大量珍贵化石，但其化学地层学相关研究较为薄弱。本项目选取下扬子区的埃迪卡拉系典型浅水相地层为研究对象，获取高分辨率岩性变化和碳、氧、硫地化数据。本研究将完善下扬子区埃迪卡拉系不同沉积相剖面的高分辨率同位素地层，揭示华南扬子地台各沉积区同位素的异同及其可能的原因。同时，在前人地层学、古生物学的工作上，结合申请人已取得该区深水相、部分浅水相剖面数据，详细探讨下扬子区该时期古海洋从深至浅氧化还原梯度的空间变化，进一步确定埃迪卡拉纪碳同位素负漂移的引发机制、发生过程和区域对比。研究结果将为探讨冰期结束后海洋氧化还原状态与早期生命演化的关系提供新的线索。

Lying between the termination of the Neoproterozoic global glaciation and the onset of Cambrian explosion, the Ediacaran represents a key transitional period in the Earth history. The Ediacaran sequences in South China provide precious data to study the coevolution between the paleoenvironment and early life. Especially the oxygenation event immediately after the snowball Earth greatly facilitate the early life evolution. Numerous studies on the Ediacaran successions have been carried out in the middle and upper Yangtze platform, whereas studies about the lower Yangtze platform are few even though plenty of fossils have been found in this area. In this project, we will carry out high resolution litho- and isotopic chemostratigraphic studies on the shallow water facies Ediacaran successions in the lower Yangtze platform. The high-resolution Ediacaran isotopic chemostratigraphy from the lower Yangtze platform will improve our knowledge on the regional isotopic distribution patterns and their possible causation. Combined with the published biostratigraphic data and previous intergrated studies on the deep and shallow water facies successions, this project is designed to investigate the spatial variations of the palaeooxidation gradience from shallow to deep oceans, and to discuss the causation and process of the pronounced carbon isotope negative shift and their regional and global correlations. The research results will provide important clues for understanding the coevolutionary pattern of the paleoenvironmental redox status and early life.