Early Oligocene anatexis in the Yardoi gneiss dome,southern Tibet and geological implications  

作　　者：ZENG LingSen LIU Jing GAO LiE XIE KeJia WEN Li 

机构地区：[1]Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China [2]Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China

出　　处：《Chinese Science Bulletin》2009年第1期104-112,共9页

基　　金：Supported by National Natural Science Foundation of China (Grant No.40673027);the Outlay Research Fund of Chinese Academy of Geological Sciences (Grant No.20071120101125);the Hundred Talent Program of Chinese Academy of Sciences

摘　　要：The Yardoi gneiss dome is located to the easternmost of the North Himalayan Gneiss Dome (NHGD),southern Tibet. It consists of metapelite,garnet amphibolite,granite and leucogranite,and is a key subject to constrain the formation and tectonic evolution of NHGD. SHRIMP zircon U/Pb data on the leucogranite yield an age of 35.3±1.1 Ma,which is substantially older than that of the similar leu-cogranites to the west. Sr and Nd isotope systematics indicate that this leucogranite was derived from partial melting of the mixed garnet amphibolite and metapelite. Our data suggest that (1) during the early stage of Himalayan magmatism,amphibolite dehydration melting overwhelmed that of the metapelite; and (2) such a melting at middle-lower crust might be a major factor that initiated the movement along the Southern Tibetan Detachment System (STDS).The Yardoi gneiss dome is located to the easternmost of the North Himalayan Gneiss Dome （NHGD）, southern Tibet. It consists of metapelite, garnet amphibolite, granite and leucogranite, and is a key subject to constrain the formation and tectonic evolution of NHGD. SHRIMP zircon U/Pb data on the leucogranite yield an age of 35.3±1.1 Ma, which is substantially older than that of the similar leucogranites to the west. Sr and Nd isotope systematics indicate that this leucogranite was derived from partial melting of the mixed garnet amphibolite and metapelite. Our data suggest that （1） during the early stage of Himalayan magmatism, amphibolite dehydration melting overwhelmed that of the metapelite; and （2） such a melting at middle-lower crust might be a major factor that initiated the movement along the Southern Tibetan Detachment System （STDS）.

关 键 词：地球 渐新世 变泥质岩 地壳深熔作用 喜马拉雅山 

分 类 号：P55[天文地球—构造地质学]