青海玉树哈秀岩体成因及^(40)Ar/^(39)Ar年代学研究  

Tectonic discrimination and ^(40)Ar/^(39)Ar geochronology of Haxiu quartz diorite in Yushu, Qinghai Province

作　　者：陈文[1,2] 张彦[1] 陈克龙[3] 张雪亭[4] 王清利[1] 金贵善[1] 

机构地区：[1]国土资源部同位素地质重点实验室,中国地质科学院地质研究所,北京100037 [2]中国科学院地质与地球物理研究所,青海西宁810008 [3]青海师范大学地理系,青海西宁810012 [4]青海省地质调查院

出　　处：《岩石矿物学杂志》2005年第5期393-396,共4页Acta Petrologica et Mineralogica

基　　金：国家自然科学基金资助项目(40373033);国家重点基础研究发展规划项目(2002CB2610);中国地质调查局资助项目(1212010560901)

摘　　要：哈秀石英闪长岩体出露于西金乌兰金沙江缝合带西段,对其进行成因和侵位时代研究可以对沿西金乌兰金沙江缝合带发生的板块俯冲、碰撞事件提供同位素年代制约。用主元素判别法判定其为造山花岗岩类(IAG型),形成于板块俯冲阶段。角闪石的40Ar/39Ar测年结果表明其侵位时代约为216.4Ma,是印支晚期岩浆活动的产物。哈秀岩体的成因和时代研究表明,沿金沙江缝合带,迟至晚三叠世,板块碰撞作用仍然没有开始,洋壳的俯冲作用仍在继续。Haxiu quartz diorite is outcropped along the western Jirkshajiang suture zone, and a study of its genesis and emplacement time can provide isotope geochronological evidence for the plate subduction and collision along the Xijinwulan-Jinshajiang suture zone. According to major element discrimination, it should belong to the lAG type formed during plate subduction. The ^40Ar/^39Ar dating results of hornblende show that its emplacement time is -216.4 Ma, suggesting a product of Late Indo-Sinian magmatism. A study of its origin and age shows that. along the Jinshajiang suture zone, the plate collision didn＇ t start and the subduction of the oceanic crust still continued in Late Triassic.

关 键 词：哈秀岩体 西金乌兰-金沙江缝合带 构造环境判别 ^40AR/^39AR年龄 

分 类 号：P588.122[天文地球—岩石学] P597.3[天文地球—地质学]