胶东地区基底长英质片麻岩的地球化学特征及其构造归属  

Geochemical differences of basement felsic gneisses in Shandong peninsula and its significance to the boundary between North China plate and Sulu UHP belt

作　　者：李永刚[1] 郭敬辉[1] 翟明国[1] 刘文军[1] 关鸿[1] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029

出　　处：《岩石学报》1999年第4期557-563,共7页Acta Petrologica Sinica

基　　金：国家自然科学基金;中科院资环局重点项目

摘　　要：通过对胶东地区基底长英质片麻岩的地球化学研究发现， 莱西－栖霞一带的基底长英质片麻岩具有太古宙长英质片麻岩的典型特征， 微量元素组成与板内花岗岩类相似。该区应该属于华北陆块的一部分。荣成地区是苏鲁超高压变质带的典型地区， 其基底长英质片麻岩与栖霞一带不同， 是过铝型花岗岩类， 具有火山弧花岗岩类的地球化学特征， 结合普遍存在的０．８Ｇａ 的同位素年代资料， 可以确定荣成地区原来是扬子陆块的一部分。文登－威海地区的长英质片麻岩的常量和微量元素组成都与栖霞地区相当， 很可能也是华北陆块的一部分。从长英质片麻岩代表的基底岩石的地球化学差异来看， 超高压变质带与华北板块的界线应该在五莲－青岛－荣成断裂。威海一带含柯石英超高压岩块的出现很可能是因为大陆碰撞过程中复杂的构造原因， 使超高压岩片中的一部分进入了华北基底分布区。According to the study on the basement gneisses in Shandong peninsula, the basement gneisses, occurring in the Laixi Qixia area, are characterized by the typical features of Archaean tonalitic gneisses, and features of trace elements of the basement gneisses are comparative with the intraplate granite Different from those occurring in the Qixia area, the basement gneisses in Rongcheng area,Shangdong peninsula which belong to part of the Sulu ultra high pressure metamorphic belt, are of peraluminous granites and characterized by the geochemical features of volcanic arc granites. It is affirmative that Rongcheng area is of the part of Yangtze plate In correspondence with the features of the major and Trace elements of quartzofeldspathic gneisses in the Qixia area, Wendeng area may be part of the North China plate Because of the occurrence of coesite bearing ultra high pressure block mass in Weihai area, it is proposed that the complicated tectonic processes resulted in the emplacement of ultra high pressure block mass in the basement area of the North China plate during the process of continental collision

关 键 词：胶东地区 长英质片麻岩 微量元素 地球化学 

分 类 号：P588.345[天文地球—岩石学]