四川雷波峨眉山玄武岩岩石学及地球化学特征

以剖面测量及野外系统观察、显微镜下及地球化学研究为基础,认为雷波地区峨眉山玄武岩主要具有以下特点:①岩石类型主要为致密块状玄武岩、斑状玄武岩、杏仁状玄武岩,发育柱状节理,为典型陆相喷发玄武岩;②岩石化学分类为碱性玄武岩,具高钛特征,为板内拉张玄武岩;③玄武岩经历了相似的岩浆演化和结晶分异,形成深度大,起源于富集地幔源,是地幔柱作用的产物;④玄武岩是攀西裂谷拉张作用的产物,无爆发角砾岩相,主要为喷溢-溢流相,可能属攀西裂谷的边缘相带。

The Petrological and Geochemical Characteristics of Emei Shan Basalt in Leibo County, Sichuan Province

Based on profile survey and microscopic and geochemical study,the authors investigated the Emei Shan basalt in Leibo County,Sichuan Province.Some conclusions have been reached:①The rock types mainly include compact basalt,porphyritic basalt,and amygdaloidal basalt with columnar joints,formed probably by typical terrestrial eruption;②The petrochemistry is classified as alkaline basalt with high titanium,resulting from stretching in plate;③The basalt originated from enriched mantle source,which was produced by mantle plume and formed at large depth,and experienced similar activities of magmatic evolution and crystallization differentiation;④The basalt has no eruptive breccia facies,and consists mainly of the spillway overflow facies.It is the product of extensional action in Panxi rift and may belong to its marginal facies.