赛什腾山一带火山岩LA-ICP-MS锆石U-Pb年龄及其地球化学特征  

LA-ICP-MS Zircon U-Pb Dating and Geochemical Characteristics of the Volcanic Rocks in the Area of Saishiteng Mountain

作　　者：徐旭明[1] 刘广[1] 梁国庆[1] Xu Xuming;Liu Guang;Liang Guoqing(Hebei Institute of Regional Geological and Mineral Resource Survey,Langfang,Hebei,065000,China)

机构地区：[1]河北省区域地质矿产调查研究所,河北廊坊065000

出　　处：《新疆地质》2017年第3期250-254,共5页Xinjiang Geology

基　　金：项目资助:青海省冷湖行委野骆驼泉地区1:5万J46E008015;J46E008016;J46E009016三幅区域地质调查

摘　　要：赛什腾火山岩广泛分布于柴北缘构造带的赛什腾山一带,为一套中基性火山熔岩,主要岩石类型有玄武岩、安山玄武岩、玄武安山岩及安山岩。前人将该套火山岩划归为寒武—奥陶纪滩间山群,但缺乏同位素测年数据及古生物化石依据,笔者对赛什腾火山岩中玄武安山岩进行了LA-ICP-MS锆石U-Pb测年,获得(256.9±0.7)Ma的测年数据,时代为晚二叠世,与滩间山群的形成时代明显不同,说明赛什腾火山岩与区域上滩间山群火山岩为不同时期岩浆喷发活动形成的产物。地球化学特征显示赛什腾火山岩具有岛弧火山岩的构造属性。The Saishiteng volcanic rocks,as a group of intermediate basic volcanic lava,are widely distributed in the Saishiteng Mountain area of structural belt of north margin of Caidam basin.The mainly rock types include basalt,andesite-basalt,basaltic andesite and andesite.The previous set the volcanic rocks into the Cambrian-Ordovician Tanjianshan Group.However,the lack of isotopic dating data and fossil as a basis for the times.So the author made LA-ICP-MS zircon U-Pb dating for the basaltic andesite of the Saishiteng volcanic rocks and obtained data of(256.9±0.7)Ma.The times is Late Permian,obviously different from the formation time of the Tanjianshan Group,which shows that the Saishiteng volcanic rocks and the volcanic rocks of the Tanjianshan Group in the region are the products of magmatic eruption in different periods.The geochemical characteristics show that the Saishiteng volcanic rocks have the tectonic settings of island arc volcanic rocks.

关 键 词：赛什腾山 火山岩 构造环境 LA-ICP-MS 晚二叠世 

分 类 号：P588.14[天文地球—岩石学] P597.3[天文地球—地质学]