胶东元古宙变质硅质岩的地球化学及其成因  

GEOCHEMISTRY AND GENESIS OF THE PROTEROZOIC METAMORPHIC SILICEOUS ROCK IN THE JIAODONG PENINSULA,SHANDONG PROVINCE

作　　者：倪志耀[1] 王仁民[2] 

机构地区：[1]北京大学地质学系,北京100871 [2]中国科学院地质与地球物理研究所,北京100029

出　　处：《矿物岩石》2001年第1期59-66,共8页Mineralogy and Petrology

基　　金：高等学校博士学科点专项科研基金! (960 0 0 12 1)

摘　　要：胶东元古宙变质硅质岩为蛇绿岩端员组分之一 ,其 Si O2 含量大多高于 90 % ,具轻稀土富集型的稀土配分模式 ,铕、铈异常具有明显的相关性。岩石中多硅白云母的存在显示其曾经受了中 -高压的变质作用。变质硅质岩的地球化学特征表明其原岩形成于早元古宙的大洋中脊环境 ,沉积成岩时的氧化还原条件是变化的 ,并同蛇绿岩其他端员组分一起发生过深俯冲作用。The Jiaodong Proterozoic metamorphic siliceous rock is one of the end-members of ophiolite and its SiO 2 content is more than 90%.The chondrite-normalized REE distribution pattern is characterized by LREE enrichment and shows remarkable correlation between Eu anomaly and Ce anomaly. The existence of phengites in the metamorphic siliceous rock indicates that it was formed through middle-high pressure metamorphism. Geochemical characteristics of the metamorphic siliceous rock indicate that its original rock was formed in the tectonic setting of oceanic ridge where the condition of oxidation-reduction is different, and the metamorphism was resulted from the deep-subduction with the ophiolitic residue.

关 键 词：变质硅质岩 深俯冲作用 早元古宙 成因 变质作用 形成环境 蛇绿岩 

分 类 号：P588.244[天文地球—岩石学]