西藏扎囊地区朗杰学岩浆岩带辉绿岩地球化学特征及其地质意义  

Geochemical Characteristics and Geological Significance of Mafic Rocks in Langjiexue Magmatic Belt in Zachang Area,Xizang Province

作　　者：卢锋锋 田杨杨 刘岳军 王文华 LU Fengfeng;TIAN Yangyang;LIU Yuejun;WANG Wenhua(Tibet Autonomous Region Geological and Mineral Exploration and Development Bureau Regional Geological Survey Brigade,Lhasa 851400,China)

机构地区：[1]西藏自治区地质矿产勘查开发局区域地质调查大队,西藏拉萨851400

出　　处：《四川有色金属》2024年第1期23-26,共4页Sichuan Nonferrous Metals

摘　　要：西藏扎囊地区朗杰学岩浆岩带分为北部(朗杰学)岩浆岩带和南部(羊卓雍错)岩浆岩带。以朗杰学岩浆带中辉绿岩为对象,进行了主量元素、微量元素以及锆石U-Pb年代学分析。结果表明辉绿岩锆石U-Pb年龄为140Ma,形成于早白垩世。主量元素显示为基性岩,区别于岛弧基性岩;微量元素和REE标准化图解显示出OIB和MORB两种趋势。朗杰学辉绿岩形成于洋壳俯冲背景,是新特提斯洋早白垩世俯冲的产物。Langjiexue magmatic belt in Zachang area is divided into northern(Langjiexue magmatic belt)and southern(Yangzhuoyongcuo magmatic belt).Major elements,trace elements and zircon U-Pb chronology of the diabase in the Langjiexue magmatic zone have been studied.The results show that the diabase zircon U-Pb age is 140Ma and was formed in the Early Cretaceous.The major elements are shown as mafic rocks,which are different from island arc mafic rocks.The standardization diagrams of trace elements and REE show two trends:OIB and MORB.The Langjiexue diabase formed in the subduction setting of the oceanic crust and was the product of the Early Cretaceous subduction of the NeoTethyan Ocean.

关 键 词：扎囊 朗杰学辉绿岩 早白垩世 地球化学特征 

分 类 号：P618[天文地球—矿床学]