西藏当惹雍错吉松环斑花岗岩的发现及地质意义  

The discovery and significance of the rapakivi granites in Gyisong,Tangra Yumco,Xizang

作　　者：陈振华[1] 刘云[1] 李均良[1] 

机构地区：[1]江西省地质调查研究院,江西南昌330201

出　　处：《沉积与特提斯地质》2006年第2期16-20,共5页Sedimentary Geology and Tethyan Geology

基　　金：中国地质调查局"1:25万邦多幅区域地质调查"

摘　　要：在1∶25万区域地质调查工作中,于当惹雍错中部的吉松一带发现环斑花岗岩,获同位素K-Ar法年龄45.3Ma,时代为始新世。吉松环斑花岗具特殊的卵状环斑结构,K2O+Na2O含量较高,K2O>Na2O;稀土元素含量高,具明显的铕亏损,为造山型环斑花岗岩,形成于青藏高原陆内碰撞造山晚期的后碰撞环境。The rapakivi granites were discovered during the 1：25 000 regional geological survey in Gyisong, Tangra Yumeo, Xizang. These granites give a K-Ar age of 45.3 Ma and may be traced back to the Eocene. They are characterized by special oval rapakivi textures, higher K2O ＋ Na2O contents, K2O 〉 Na2O, higher REE contents and depletion of the element Eu, and thus belong to the orogenic rapakivi granites originated from the intraeontinental post-collisional settings during the later stages of collision and mountain builaing of the Qinghai-Xizang Plateau.

关 键 词：当惹雍错 吉松 环斑花岗岩 始新世 西藏 

分 类 号：P588.121[天文地球—岩石学]