东昆仑哈日扎花岗闪长岩形成时代、地球化学特征及其构造意义  

THE FORMING AGE AND GEOCHEMISTRY CHARACTERISTICS OF THE GRANODIORITES IN HARIZHA, EAST KUNLUN AND ITS TECTONIC SIGNIFICANCE

作　　者：国显正 贾群子[1] 李金超[1] 孔会磊[1] 姚学钢 栗亚芝[1] 马忠元 GUO Xianzheng;JIA Qunzi;LI Jinchao;KONG Huilei;YAO Xuegang;LI Yazhi;MA Zhongyuan(Xi’an Center of Geological Survey,CGS,Xi’an 710054,Shaanxi,China;Geological Survey Institute,China University of Geosciences,Wuhan 430074,Hubei,China;The Third Geological and Mineral Exploration Academy of Qinghai Province,Xining 810029,Qinghai,China)

机构地区：[1]中国地质调查局西安地质调查中心,陕西西安710054 [2]中国地质大学(武汉)地质调查研究院,湖北武汉430074 [3]青海省第三地质矿产勘查院,青海西宁810029

出　　处：《地质力学学报》2019年第2期286-300,共15页Journal of Geomechanics

基　　金：中国地质大调查项目(DD20160013;12120115022101)

摘　　要：为探讨东昆仑哈日扎银多金属矿岩浆演化序列及其岩石成因,对哈日扎花岗闪长岩进行了年代学和地球化学研究。结果表明,哈日扎花岗闪长岩LA-ICP-MS锆石U-Pb年龄为423.8±4.3 Ma,形成于晚志留世;地球化学特征显示花岗闪长岩高硅,SiO_2介于71.21%～74.46%;高铝,Al_2O_3含量介于13.48%～14.46%;富钾贫钠,K_2O/Na_2O比值为1.32～1.54;A/CNK介于1.02～1.08,显示高钾钙碱性弱过铝质特征;稀土显示出轻稀土富集,重稀土亏损的右倾配分模式,富集Rb、Th、K元素,亏损Ba以及Nb、Ta、Ti等,具有I到S过渡型花岗岩特征,源区主要为上地壳砂屑岩部分熔融,是区域后碰撞伸展构造背景下的产物。In order to probe the genesis and magmatic evolution sequence of the granites in the Harizha sliver polymetallic deposit,geochronological and geochemical studies of the Harizha granodiorite was carried out in this paper.The results show that the Harizha granodiorite has LA-ICP-MS zircon U-Pb age of 423.8±4.3 Ma,indicating that it was formed in late Silurian epoch.It has high contents of SiO2(71.21%~74.46%),Al2O3(13.48%~14.46%),with K2O/Na2O ratios ranging from 1.32 to 1.54,and A/CNK values varying from 1.02 to 1.08,respectively.Thus,the Harizha granodiorite belongs to the high K calc-alkaline weak peraluminous granite.The granodiorite has right declined REE distribution patterns,with strong enrichment of LREE and relative depletion of HREE.It is enriched in Rb,Th,K,depleted in Ba and Nb,Ta,Ti,and has characteristics of the I to S transitional granite.It could be mainly sourced from the partial melting of upper crust gabbros,which is the product of regional post-collision extensional tectonic background.

关 键 词：地球化学 岩石成因 岩浆序列 花岗闪长岩 东昆仑哈日扎 

分 类 号：P588.12[天文地球—岩石学]