鄂西二叠系孤峰组层状硅质岩及硅质结核成因

Genesis of Stratified Siliceous Rocks and Concretion of Permian Gufeng Formation in Western Hubei

鄂西二叠系孤峰组主要由一套薄层硅质岩、炭质硅质岩、硅质泥岩夹硅质结核的岩层所构成。笔者通过对其层状硅质岩和硅质结核的岩石学和地球化学特征进行研究,认为两种硅质岩的硅质主要是生物来源,而非热水成因。但硅质岩的形成并不受单一因素影响,可能既受到了生物、又有热水等多个因素的共同作用。硅质结核为成岩结核,其受到的热水作用影响比层状硅质岩更为明显。

Permian Gufeng formation in the western Hubei consist of thin-bedded siliceous rocks,carbonaceous-siliceous rocks and siliceous mudstone with siliceous concretion.By studying the petrologic and geochemical characteristics of the siliceous concretions and the bedded siliceous rocks,we believed in that the siliceous concretions are of biogenetic origin rather than hydrothermal genesis.However the forming genesis are not determined by single factor,and may be influenced by multiple factors such as biological,hydrothermal solution.The concretion is formed in diagenesis which was affected more obviously by the hydrothermal solution rather than the statified siliceous rocks.