西藏改则县麻米南地区赞塘隆巴岩体锆石U-Pb年龄、地球化学特征及其地质意义  

Zircon U-Pb Age,Geochemistry and Geological Significance of the Zantanglongba Pluton in South Mami Area in Gaize County,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2期20-23,共4页Sichuan Nonferrous Metals

摘　　要：赞塘隆巴二长花岗斑岩位于麻米南地区,锆石U-Pb定年结果显示岩体形成于晚侏罗世(145.7Ma)。岩石地球化学具有高SiO2、高全碱含量的特征,轻重稀土分馏程度较高,Eu负异常明显,无明显Ce异常,岩体富集大离子亲石元素Rb、Th,亏损高场强元素Zr、Nb、Ti,据I型花岗岩特征。结合区域上报道的同期中酸性侵入岩资料,认为赞塘隆巴二长花岗斑岩形成于洋壳俯冲背景,是班公湖-怒江特提斯洋晚侏罗世俯冲的产物。The Zantanglongba monzonite granite porphyry is located in South Mami area,and zircon U-Pb dating results show that the porphyry was formed in the Late Jurassic(145.7Ma).The geochemistry of the rock is characterized by high SiO2 and high total alkali content,high fractionation degree of LREE and HREE,obvious negative anomaly of Eu,no obvious Ce anomaly,the rock mass is rich in large ion lithophile elements Rb and Th,and deficit of high field strength elements Zr,Nb and Ti,according to the characteristics of I type granite.Combined with the medium acid intrusive rock data reported in the same period,it is believed that the Zantanglongba monzonite granite porphyry was formed in the subduction background of oceanic crust and was the product of the subduction of the Bangong-Nujiang Tethyan Ocean in the late Jurassic.

关 键 词：赞塘隆巴 二长花岗斑岩 晚侏罗世 地球化学特征 

分 类 号：P618[天文地球—矿床学]