新疆塔里木南缘埃连卡特岩群物质来源及构造环境--锆石U-Pb年代学和地球化学约束  

Material Source and Tectonic Environment of Elenkat Group in Southern Margin of Tarim in Xinjiang Uygur Autonomous Region--Zircon U-Pb Geochronology and Geochemical Constraints

作　　者：刘晓 孙景耀 张荣霞 李芝荣 吴凤萍 隋天静 LIU Xiao;SUN Jingyao;ZHANG Rongxia;LI Zhirong;WU Fengping;SUI Tianjing(No.3 Exploration Institute of Geology and Mineral Resources,Shandong Yantai 264000,China)

机构地区：[1]山东省第三地质矿产勘查院,山东烟台264000

出　　处：《山东国土资源》2023年第4期1-11,共11页Shandong Land and Resources

基　　金：“新疆墨玉县—和田县阿其克一带1∶5万J44E018006、J44E018007、J44E019006、J44E019007四幅区域地质矿产调查(项目编号∶K141 LQ03)”项目资助。

摘　　要：新疆塔里木南缘埃连卡特岩群主要分为2个岩组,岩石类型主要以含方解石二云(石英)片岩、石英片岩夹少量火山岩为主,为一套低变质岩组合。本文选取15件样品,岩石地球化学分析结果显示,原岩总体为中酸性的过铝质高钾钙碱性系列;所有样品点稀土元素配分模式图为右倾型,δEu和δCe均具有负异常特点,高场强元素Nb、Ti、P亏损,大离子亲石元素Rb、Th相对富集,显示出上地壳长英质源区特征。岩石锆石U-Pb定年为(2386±78)Ma和(1830±40)Ma两个区间,属古元古代,代表了其原岩相应地层沉积时代的下限。原岩恢复、大地构造背景投点图显示,埃连卡特岩群变质岩原岩为一套砂岩类正常碎屑沉积岩,夹少量火山岩,其形成于活动大陆边缘,该时期塔里木南缘总体为向南变深的拉张的沉陷陆表海盆地环境。The Elencat group in the southern margin of Tarim in Xinjiang Uygur Autonomous Region is mainly divided into two rock formations.The rock types are mainly calcite-containing biotite(quartz)schist,quartz schist with a small amount of volcanic rock.It is a set of low-metamorphic rock association.In this paper,15 samples have been selected,geochemical analysis has been carried out.It is indicated that the protolith is generally a moderately acidic peraluminous high-potassium calc-alkaline series.The rare earth element distribution pattern of all sample points is right-dipping,δEu andδCe is characterized by negative anomaly,high field strength elements Nb,Ti and P are depleted,and large ion lithophile elements Rb and Th are relatively enriched.It has showed the characteristics of felsic source area in the upper crust.Zircon U-Pb dating of the rocks is(2386±78)Ma and(1830±40)Ma.It belongs to the Paleoproterozoic,and represents the lower limit of the sedimentary age of the corresponding strata of the original rocks.In the original rock restoration and geotectonic background projection map,all the sample points show that the original rock of the metamorphic rocks of Erenkat group is a set of sandstone-like normal clastic sedimentary rocks,with a small amount of volcanic rocks,which was formed on the active continental margin.At this time,the southern margin of Tarim basin is generally in a southward deepening extensional subsidence epicontinental basin environment.

关 键 词：埃连卡特岩群 原岩恢复 地球化学特征 锆石U-PB定年 新疆 

分 类 号：P588.3[天文地球—岩石学]