一、前言岩石学研究是工程地质勘探工作中的一项基础工作。二滩电站地勘工作于1972年冬开始,至1984年间,曾采取大量岩样请多个单位作磨片鉴定。根据鉴定资料,二滩枢纽区基岩为二迭系玄武岩及后期侵入其中的正长岩以及与正长岩同源的辉长岩、因正长岩侵入而形成的各类蚀变玄武岩;三滩一带尚有三迭系砂页岩分布。玄武岩按其岩性和结构特征,曾将其分 I. Preface Petrology research is a basic work in engineering geological exploration. Ertan Hydropower Station geological prospecting work began in the winter of 1972, to 1984, had taken a large number of rock samples please multiple units for grinding identification. According to the identification data, the bedrock of the Ertan junction area is composed of two kinds of basalts and later intrusive syenite and gabbro that are homologous with the syenite, all kinds of altered basalt formed by the intrusion of the syenite; There are three Triassic sand shale distribution. Basalt according to its lithology and structural characteristics, had its points