四川南江光雾山H型花岗岩的地质地球化学特征  

GEOCHEMICAL CHARACTERISTICS OF HTYPE GRANITOIDS IN GUANGWUSHAN AERA,NANJIANG,SICHUAN,CHINA

作　　者：李佑国[1] 徐新煌[1] 刘登忠[1] 

机构地区：[1]成都理工学院

出　　处：《矿物岩石》1997年第S1期51-61,共11页Mineralogy and Petrology

摘　　要：本文从地质学、岩石学、岩石化学，微量元素丰度等方面讨论了光雾山地区沙河坝超单元的地质地球化学特征，结果表明存在幔源基性岩浆与壳源花岗岩浆间的岩浆混合作用，这些岩体属于Ｈ型花岗岩。岩体中见有暗色微粒包体及熔体反应之残留矿物相，花岗质岩石及其中的暗色微粒包体，其化学成分在某些元素—元素图解和同分母双比值图上的投点均呈直线分布。经计算，沙河坝超单元中基性岩浆混合的比例为：Ｈｓ型花岗岩５．７％～３２．８％，Ｈｍ型花岗岩６８．０％～７３．６％，而暗色微粒包体则为７７．０％～８８．３％。The granitic magmatism during Neoproterozoic era was intensive in Guangwushan aera,Nanjiang.The geochemical characteristics of Shaheba superunit in Guangwushan area are discussed from geology,petrology,petrochemistry and trace element abundance etc.in this paper.The study shows that these rock bodies belong to Htype granitoids.The presence of dark microgranular enclaves and residual mineral phases from the melting reaction in the rock bodies can be taken as indicative of magma mixing processes between mafic mantlederived magmas and crustal granitoid magma.TiO2,Al2O3,FeOT,MgO,CaO,Na2O and K2O shows good rectilinear patterns on silica variation diagrams.The compositional variations characterized by rectilinear trends on Al2O3/MgO versus SiO2/MgO,Na2O/CaO versus SiO2/CaO,Na2O/CaO versus Al2O3/CaO,CaO/K2O versus MgO/K2O variation diagrams and AFM diagram.The plots of this paper on the LaCe,Ce/Sc versus La/Sc and Sm/Sc versus Nd/Sc variation diagrams shows good rectilinear trends.It is estimated that the proportion of basic magma in magma mixing processes is HStype granite 5.7%～32.8%,Hmtype granite 68.0%～73.6% and dark microgranular enclaves 77.0%～88.3%.

关 键 词：H型花岗岩 岩浆混合作用 包体 地球化学 新元古代 

分 类 号：P588.1[天文地球—岩石学]