拉萨地体中的印支造山事件及年代学证据  

The Indosinian orogenesis occurred in Lhasa terrain and the evidence from muscovite ^(40)Ar/^(39)Ar geochronology.

作　　者：李化启[1] 蔡志慧[1] 陈松永[1] 唐哲民[1] 杨梅[2] 

机构地区：[1]中国地质科学院地质研究所 国土资源部大陆动力学重点实验室,北京100037 [2]中国地质科学院水文地质环境地质研究所,石家庄050061

出　　处：《岩石学报》2008年第7期1595-1604,共10页Acta Petrologica Sinica

基　　金：中国地质调查局地质调查工作项目(1212010610105)资助成果

摘　　要：通过拉萨地体中松多群变质岩系的变形构造、韧性剪切带的研究,剪切带中石英组构的 EBSD 测定,韧性剪切带中白云母^(40)Ar-^(39)Ar 测年结果(220～230Ma),以及晚三叠世花岗闪长岩和二长花岗岩岩体侵入松多群的证据,提出拉萨地体松多群经历了印支期造山事件的认识,这一事件为二叠纪古特提斯洋盆深俯冲(代表标志为拉萨榴辉岩带)之后南、北拉萨地体碰撞的结果。拉萨地体中印支造山带的确定,使青藏高原印支山链的范围从过去认为的羌塘地体南界向南扩大到拉萨地体之中,对于研究古特提斯构造域的形成有重要意义。Based on the the deformation characteristic of Sumdo Group and the ductile sheafing zones, the quartz fabric by EBSD, the data of muscovite ^40Ar-^39Ar geochronology （220 -230Ma） from ductile shearing zones and the large scale granite of Late Triassic epoch in Sumdo Group, Lhasa terrain is thought to have experienced an important Indosinian orogenic event, which caused the closure of the Paleo-Tethys ocean along the tectonic zone of eclogite and the collision between northern part and southern part of Lhasa terrain. The discovery of Indosiniau orogenic belt in Lhasa terrain expanse the southern boundary of Indosinian orogenic belt to Lhasa terrain from Qiangtang terrain, which is very important to the research of the Paleo- Tethys ocean along Tibet.

关 键 词：拉萨地体 榴辉岩 韧性剪切带 ^40AR-^39AR年代学 印支造山事件 

分 类 号：P597.3[天文地球—地球化学]