东昆仑五龙沟地区糜棱岩化花岗岩年代学、岩石成因及其构造意义  

Geochronology and Petrogenesis of Mylonitized Granite from Wulonggou Area in East Kunlun and Its Tectonic Significance

作　　者：胡继春[1] 陈静[1] 何书跃 李玉龙[1] 舒树兰[1] 王亚栋[1] 

机构地区：[1]青海省地质调查院青藏高原北部地质过程与矿产资源重点实验室,青海西宁810012 [2]青海省第三地质矿产勘查院,青海西宁810029

出　　处：《西北地质》2017年第3期54-64,共11页Northwestern Geology

基　　金：基金项目:青海省应用基础研究"东昆仑拉陵灶火地区岩浆成矿作用及靶区优选"(2015-ZJ-762)

摘　　要：位于东昆仑中段五龙沟地区深水潭矿段糜棱岩化钾长花岗岩LA-ICP-MS锆石U-Pb年龄为(390±3.9)Ma。该岩体具有较高的SiO_2(74.86%~76.64%)、K_2O(5.20%~6.06%)和全碱含量(K_2O+Na_2O=8.05%~8.83%),呈现明显的Ba、Nb-Ta、Sr、P和Ti的负异常,以及强烈的Eu负异常(δEu=0.07~0.12),显示A型花岗岩特征。结合区域上志留纪—泥盆纪岩浆岩的研究,认为东昆仑造山带早泥盆世已进入后碰撞伸展阶段,早中泥盆世之交为伸展最强烈时期,形成了颇具规模的在A型花岗岩,也代表加里东造山旋回的结束。The mylonited granite is located at Shenshuitan mining setion of Wulonggou area in the middle part of the East Kunlun, with a yielded LA-ICP-MS zircon U-Pb age of 389.7±3.9Ma. This granite has high SiO2 （74.86%~76.64%）, K2O （5.20%~6.06%） and total alkali content （K2O ＋ Na2O=8.05%~8. 83%） values. The samples are characterized by strong loss in Ba, Nb-Ta, Sr, P and Ti, as well as strong negative Eu anomaly （δ Eu=0.07~0.12）, which shows characteristics of A type granite. Combined with the studies of Silurian-Devonian magmatic rocks in this studying area, it＇s proposed that the East Kunlun Orogenic belt has entered the post-collision stage in early Devonian, and the most intense of extension was happened in the conversion period of from early Devonian to middle Devonian, forming A type granite with considerable size, and standing for the end of the Caledonian orogenic cycle.

关 键 词：东昆仑五龙沟地区 锆石U-PB年龄 岩石成因 构造意义 

分 类 号：P588.121[天文地球—岩石学]