雅满苏地区中酸性岩浆岩同位素年代学特征及意义  

Isotopic chronological characteristics and significance of intermediate-acid magmatic rocks in Yamansu area

作　　者：黎娇 王高 刘祥 王哲 凤骏 LI Jiao;WANG Gao;LIU Xiang;WANG Zhe;FENG Jun(Ganzhongnan Institute of Geology and Mineral Exploration, Jiangxi Nanchang 330000, China;Engineering Geology Brigade of Jiangxi Geology Bureau, Jiangxi Nanchang 330000, China;College of Geology and Mining Engineering of Xinjiang University, Xinjiang Urumqi 830000, China;Geological Survey Institute of Xinjiang Uygur Autonomous Region, Xinjiang Urumqi 830000, China)

机构地区：[1]赣中南地质矿产勘查研究院,江西南昌330000 [2]江西省地质局工程地质大队,江西南昌330000 [3]新疆大学地质与矿业工程学院,新疆乌鲁木齐830000 [4]新疆维吾尔自治区地质调查院,新疆乌鲁木齐830000

出　　处：《中国地质调查》2022年第1期54-63,共10页Geological Survey of China

基　　金：新疆地质勘查基金“新疆哈密市景峡一带1∶5万K46E013017(南湖戈壁幅)、K46E013018(景峡站幅)、K46E013019(木头井子幅)三幅区域地质专项调查项目(编号:T16-1-LQ14)”项目资助。

摘　　要：雅满苏地区跨越多个区域构造带,过往研究对于每个构造带的形成、相对构造运动形式、相对构造运动规模存在较大争议。通过采集不同构造带内中酸性岩体的岩石样品,对雅满苏地区3个构造带内的中酸性岩体开展岩石学、地球化学以及锆石U-Pb同位素年代学研究。结果表明除苦水混杂岩带花岗斑岩(TW-1)为过铝质钙碱性I型花岗岩,其他2个构造带的中酸性岩体均为弱过铝质高钾钙碱性S型花岗岩类。稀土配分曲线显示样品的轻稀土相对富集,重稀土相对平坦。微量元素特征显示岩体的物质来源总体上为壳源,TW-1中混有少量幔源物质。U-Pb同位素年代学显示研究区在早二叠世(295.1 Ma和285.1 Ma)发生了2次构造岩浆作用。构造判别图解显示3个构造带的岩体均形成于碰撞作用相关的构造环境,反映了碰撞俯冲—隆起—碰撞俯冲—板内伸张的过程。结合区域地质情况,雅满苏中天山地区古特提斯洋向北俯冲碰撞的能级和影响范围远大于康古尔洋向南的俯冲碰撞。Yamansu area stretched across multiple regional tectonic belts,and there was significant controversies about the formation of each tectonic zone,the form and scale of relative tectonic movement in previous researches.The petrology,geochemistry and zircon U-Pb isotopic chronology of the intermediate-acid magmatic rocks were investigated through collecting intermediate-acid magmatic rock samples from different tectonic belts.The results show that the granite porphyry(TW-1)in the Kushui melange zone was peraluminous and calc-alkaline I-type granite,and the other two tectonic belts are weak peraluminous high potassium calcium-alkaline S-type granite.All samples were relatively enriched in LREE and are relatively even in HREE.The trace element character istics shows the source of all samples was crust and TW-1 was mixed with some mantle materials.The U-Pb isotopic chronology shows that there were two magmatic intrusions in the study area in Early Permian(295.1 Ma and 285.1 Ma).Granites from these three tectonic belts were formed under the collision-related structural environment by structural discrimination diagrams,which reflects the process of collision subduction-uplift-collision subduction-intraplate extension.Combining with the regional geology of the study area,the energy level and influence range of the northward collision and subduction of the Paleo-Tethys Ocean are much larger than the southward collision of the Kangur Ocean.

关 键 词：中酸性岩浆岩 同位素年代学 锆石U-PB测年 雅满苏地区 

分 类 号：P588.12[天文地球—岩石学] P597[天文地球—地质学]