藏东巴青县以北基底变质岩系的发现  

Discovery of the basement metamorphic series north of Baqên County, eastern Tibet

作　　者：王根厚[1] 贾建称[1] 李尚林[1] 张维杰[1] 周志广[1] 杨国东[1] 

机构地区：[1]中国地质大学,北京100083

出　　处：《地质通报》2004年第5期613-615,共3页Geological Bulletin of China

基　　金：中国地质调查局青藏高原1:25万仓来拉幅(I46C004003)区域地质调查项目部分成果。

摘　　要：在1∶25万仓来拉幅区域地质调查中首次发现上三叠统结扎群底部出露的一套变质岩系,通过与区域上变质基底岩系对比,将其归并为吉塘群酉西岩组,主要岩性为云母石英构造片岩、石英钠长构造片岩等。根据野外露头接触关系及“构造角砾岩”特征,确定该套岩系与上覆上三叠统为滑脱构造接触关系,滑脱面迁就了早期的角度不整合面,并认为研究区为“浅基底”。During 1:250000 regional geological survey of the Cêgnê Sheet, a metamorphic series exposed at the base of the Upper Triassic Gyiza Group was for the first time found. By its correlation with the regional basement metamorphic series, it is assigned to the Youxi Formation-complex of the Gyitang Group. The main rocks include mica-quartz tectonic schist and quartz-albite tectonic schist. According to the contact relationships of the field outcrops and the features of 'tectonic breccia', it has been determined that this metamorphic series has detachment tectonic contact relationships with the overlying Upper Triassic. The detachment surface accommodates the early-formed angular unconformity surface, and it is thought that the study area has a 'shallow basement'.

关 键 词：藏东巴青 前震旦纪 吉塘群酉西岩组 构造片岩 上三叠统结扎群 

分 类 号：P588.3[天文地球—岩石学]