同位素年代学和地球化学特征对西南天山库木拜勒一带构造演化的约束  

Constraints of Isotopic Chronology and Geochemical Characteristics on Tectonic Evolution in Kumbaile Area of Southern Tianshan Mountains

作　　者：赵振琯 孙平原 ZHAO Zhenguan;SUN Pingyuan(Gansu Provincial Geological and Mineral Exploration and Development Bureau Second Geological and Mineral Exploration Institute,Lanzhou 730020,China)

机构地区：[1]甘肃省地质矿产勘查开发局第二地质矿产勘查院,甘肃兰州730020

出　　处：《四川有色金属》2024年第2期28-31,共4页Sichuan Nonferrous Metals

摘　　要：研究区位于西南天山-霍拉山上叠盆地,属塔吉克-塔里木构造岩浆带,侵入岩以中粗粒二长花岗岩为主,侵位于石炭系地层中,岩体与地层的外接触带矿化蚀变强烈,成矿类型以热液型铜、铁、金、铅锌多金属矿为主。该二长花岗岩206Pb/238U同位素年龄测试,其成岩时代为早二叠世(287.1±2.3Ma)。经岩石地球化学分析属过铝质,高钾钙碱性系列与钾玄岩性系列岩石,结晶分异程度较好;稀土元素分馏作用较强,轻稀土富集,重稀土亏损;微量元素显示了大洋-岛弧相碰撞的成岩特征,为同碰撞(A型)花岗岩的产物。The study area is located in the upper Triassic basin of South Tianshan-Huolashan.The intrusive rocks in the area belong to the first-order Tajik-Tarim tectonic magmatic belt.The lithology is medium-coarse monzonite granite,which intrusions into the carboniferous strata.The ore-forming potential is great in the outer contact zone between the rock mass and the strata.The 206Pb/238U isotope age of the monzonite granite is Early Permian(287.1±2.3Ma).According to the geochemical analysis,the rocks belong to peraluminous,high potassium calc-alkaline series and potassium-basic-lithology series,and the crystal differentiation is good.The rare earth elements are enriched in light rare earth and depleted in heavy rare earth,which indicates that the rare earth elements in the rock mass have experienced strong fractionation.The trace elements show the diagenetic characteristics of the ocean-island arc collision,which is the product of syncollision(A-type)granites.

关 键 词：南天山 二长花岗岩 岩石地球化学 同位素年代学 构造环境 

分 类 号：P588[天文地球—岩石学]