藏北羌塘中部冈玛日—桃形错蓝片岩的发现  

DISCOVERY OF BLUESCHISTS IN GANGMAR-TAOXING CO AREA, CENTRAL QIANGTANG, NORTHERN TIBET

作　　者：邓希光 丁林 刘小汉 An Yin Paul A.Kapp Michael A.Murphy CraigE.Manning 

机构地区：[1]中国科学院地质研究所岩石圈构造演化开放研究实验室,北京100029 [2]Department of Earth and Space Sciences,University of California

出　　处：《地质科学》2000年第2期227-232,共6页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家重点基础研究专项经费资助!( G1 9980 4 0 80 1 -0 1 );中国科学院青藏高原研究项目!( KZ951 -A1 -2 0 4;KZ95T-0 6)成果

摘　　要：位于藏北羌塘中部的冈玛日 -桃形错地区首次发现含典型蓝闪石的蓝片岩。蓝片岩是由蓝闪石、铁蓝闪石、青铝闪石、多硅白云母、阳起石、黝帘石、绿帘石、方解石、榍石、金红石等矿物组成 ,变质温压条件为 40 0℃±和 7kbar± ,属于高压变质作用。这是一条高压变质带 ,推测它可能向东与滇西的澜沧江高压变质带相连。冈玛日 -桃形错地区含典型蓝闪石的蓝片岩的发现对羌塘陆块的重新认识以及冈瓦纳大陆与劳亚大陆的板块边界及晚古生代古特提斯洋的闭合 。The blueschists, discovered in the Gangmar Taoxing Co area, central Qiangtang, Northern Tibet, consist of glaucophane, ferroglaucophane, crossite, phengite, actinolite, epidote, chlorite, calcite, sphene, rutite, etc., with the metamorphic temperature 400°C±,and pressure 7kbar±, which demonstrates there occurred a high pressure metamorphic belt. The 39 Ar- 40 Ar dating from the glaucophane yields 275-287Ma, which comprehends the metamorphism being related to subduction of the Paleotethyan ocean. It is thought to extend southeastwards and link up with the Lancangjiang high pressure metamorphic belt in west Yunnan, constituting a very important tectontic boundary between Gondwana and Euroasia continents.

关 键 词：蓝片岩 高压变质带 冈玛日-桃形错 羌塘中部 

分 类 号：P588.344[天文地球—岩石学]