昆仑山野牛沟蛇绿岩地质特征及形成时代  

Geological Features and Age of the Yeniugou Ophiolite in the Kunlun Mts

作　　者：沈洪江[1] 杨林[1] 覃爽 彭东[1] 秦永超[1] SHEN Hong-jiang;YANG Lin;QIN Shuang;PENG Dong;QIN Yong-chao(Regional Geological Surveying Team,BGEEMRSP,Chengdu 610213)

机构地区：[1]四川省地质矿产勘查开发局区域地质调查队,成都610213

出　　处：《四川地质学报》2018年第2期179-182,共4页Acta Geologica Sichuan

基　　金：青海昆仑山世界地质公园野牛沟结合带调查与国际对比研究项目

摘　　要：野牛沟蛇绿岩带为昆仑山世界地质公园三大核心地质遗迹之一,该蛇绿岩组分由橄榄岩、蛇纹石化橄榄岩、蛇纹岩、辉长岩、橄榄辉长岩、辉绿岩、枕状玄武岩、硅质岩组成。通过对蛇绿岩进行系统的LA-ICP-MS锆石U-Pb同位素测年研究,表明蛇绿岩主体年龄值介于406.0Ma±5.2~476.5±4.0Ma之间,时代为早古生代中期-晚古生代早期,另外在没草沟西侧的辉长岩中,获得了一个936±10Ma的年龄值,时代为新元古代拉伸系。表明该蛇绿岩主体发育于奥陶纪-志留纪,可能跨入泥盆纪,不排除有前寒武古陆块残余。The Yeniugou ophiolite belt is one of the three major geoheritages of the Kunlunshan world geopark. The ophiolite belt is composed of peridotite, serpentinized peridotite, serpentine, gabbro, olivine gabbro, diabase, diabase, pillow basalt, and siliceous rock. The zircon U-Pb dating of most of the ophiolite gives age values varying from 406.0±5.2 Ma to 476.5±4.0 Ma. In addition, gabbro on the western side of the Mocao Valley yields ages of 936±10 Ma. These indicate that the ophiolite was emplaced during middle Early Paleozoic（Ordovician-Silurian） to early Late Paleozoic（Devonian）.

关 键 词：蛇绿岩带 锆石U-PB测年 古陆块 昆仑山 

分 类 号：P588.1[天文地球—岩石学]