新疆东天山土屋东岩体源区性质及地质意义  

Geochemistry,Geochronology,Lu-Hf Isotopes and Geological Significanceof the Tuwudong Rock Mass,East Tianshan,Xinjiang

作　　者：韩涛 李平 朱志新 王雅宁 张永禄 HAN Tao;LI Ping;ZHU Zhixin;WANG Yaning;ZHANG Yonglu(Xinjiang University,Urumqi 830047,China;Geological Survey Academy of Xinjiang,Urumqi 830000,China)

机构地区：[1]新疆大学,乌鲁木齐830047 [2]新疆地质调查院,乌鲁木齐830000

出　　处：《有色金属工程》2020年第7期107-116,共10页Nonferrous Metals Engineering

基　　金：国家重点研发计划项目(2011BAB06B04-02,2018YFC0604001-04);新疆维吾尔自治区地质勘查基金项目(Y15-1-LQ05)。

摘　　要：为进一步厘定库姆塔格沙垄以西地区镁铁—超镁铁质岩体的构造环境,通过土屋东岩体锆石U-Pb年代学确定岩体的成岩时代,结合岩石地球化学和Lu-Hf同位素结果进一步确定岩浆源区性质。地表出露岩体主要是橄榄辉长岩,化学组成以拉斑玄武岩系列为主。锆石的LA-ICP-MS U-Pb年代学研究表明,岩体形成年龄为(289.7±1.4)Ma,与东天山地区镁铁—超镁铁质含矿岩体的形成时间一致。锆石的Lu-Hf同位素特征显示源区为亏损地幔岩浆在上升侵位过程中遭受俯冲板片流体改造的富集岩石圈地幔组分和地壳物质的加入,产于碰撞后伸展环境。研究结果为东天山觉罗塔格构造带沙垄以西地区寻找镁铁—超镁铁质岩体铜镍硫化物矿体提供理论依据。In order to further determine the tectonic environment of mafic ultramafic rocks in the west of Kumtag Sand ridge,the diagenetic age of the rocks is determined by zircon U-Pb geochronology of the Tuwudong rock mass,and the properties of the magma source area are further determined by combining the results of petrochemistry and Lu-Hf isotopes.The exposed rock body is mainly olivine gabbro,and the chemical composition is mainly tholeiite series.The LA-ICP-MS U-Pb geochronology of zircon shows that the age of the formation of the body is(289.7±1.4)Ma,which is consistent with the formation time of the mafic ultramafic ore bearing body in the East Tianshan area.The Lu-Hf isotopic characteristics of zircons show that the source area is the addition of enriched lithospheric mantle components and crustal materials,which are transformed by subducted plate fluids during the upwelling and emplacement of depleted mantle magma,and they occur in the post collisional extensional environment.It provides a theoretical basis for searching for Cu-Ni sulfide ore body of mafic ultramafic rock mass in the west of sand ridge of Juelutag structural belt in the East Tianshan.

关 键 词：土屋东岩体 地球化学 LA-ICP-MS锆石U-PB定年 LU-HF同位素 地壳混染 

分 类 号：P61[天文地球—矿床学]