埃迪卡拉纪是地球环境和生物演化史上一段重要的转折时期，在此时期生命的演化和环境变化是国际研究的热点问题。大陆风化作用是一个重要的环境因素，对全球的碳循环，海洋化学成分、海洋中营养物质的输入和气候有重大影响。华南地区是国内外进行埃迪卡拉纪相关研究的理想区域，前人在此开展了大量的研究工作，但是，涉及埃迪卡拉时期风化作用特征的研究并不多见，研究手段主要是Sr同位素地层学，研究工作主要针对少数浅水相沉积的、岩性以碳酸盐岩为主的地层剖面。本申请项目拟通过对该区不同沉积相区埃迪卡拉纪地层的化学蚀变指数（CIA）和Os同位素地层学的联合研究，对埃迪卡拉纪海水的Os同位素组成特征和变化规律进行探讨，结合地层CIA特征综合揭示该时期大陆风化作用的强度和变化特征以及与之相关的环境因素。

Ediacaran is an important period in the evolutionary history of earth and life. The link between life evolution and environment change have been long debated. South China is a favorable location for Ediacaran study and has been intensively investigated in recent years. Chemical weathering plays an important role in regulating the carbon cycle and climate of earth, and has great influence on the seawater chemistry and delivering nutrient elements. However ,only limited studies have focused on weathering rate of continent during Ediacaran and its influence on the paleoenviroment. 87Sr/86Sr of marine carbonate is very useful in evaluating chemical weathering intensity during deposition but application of 87Sr/86Sr is limited because of variations in facies of this region during Ediacaran. Thus the 87Sr/86Sr record is only available for shallow-water, carbonate-rich sections. In this project, we will carry out combined Os isotope stratigraphy and CIA studies of the Ediacaran strata in shallow water, slope and deep water sections in South China, with the aim to evaluating the weathering intensity during Ediacaran and its implications for the paleoenviroment.