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峨眉山区玄武岩,主要由库姆斯趋势的弱碱性不含橄榄石,富含含钛磁铁矿的斜斑玄武岩与高碱拉斑玄武岩交替出现所组成。与康迪的大陆裂谷玄武岩比较,以特高的TiO_2及较高的K_2O,U,Th,Nd,Sm,Eu和低MgO,CaO,Cr,Ni,Ce等为特征,SrI=0.7062-0.7090,SI=17-26,这些特征说明其物质来源于上地幔上部部分熔融程度偏低的弱碱性玄武岩浆,且混染了地壳的元素,并经弱的结晶分异作用而成。峨眉山区玄武岩系为扬子古板块西部晚二叠世康滇不发育大陆裂谷系东部边缘的喷溢产物。
Emeishan basalt, mainly composed of the weakly basic trend of the Coombs, does not contain olivine, and is rich in diabase-containing basalts containing titanium magnetite and high-alkali tholeiite basalts. Compared with Conti continental rift basalts, the ultrahigh TiO 2 and higher K 2 O, U, Th, Nd, Sm, Eu and low MgO, CaO, Cr, Ni and Ce are characterized by SrI = 0.7062-0.7090 , And SI = 17-26. These characteristics indicate that the materials originated from the weak alkaline basaltic magma, which has a low degree of melting in the upper part of the upper mantle and is contaminated by elements of the crust, and is characterized by weak crystallization differentiation. The Emei Mountain basalts are the products of the spillover on the eastern margin of the unconformity continental rift system in the Late Permian of the Kangdi Dian in western Yangtze, an ancient plate.