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SiO2(74.86％～76.64％)、K2 O(5.20％～6.06％)和全碱含量(K2O+Na2O=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.
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