东昆仑造山带西段乌尊科勒晚三叠世花岗岩LA-ICP-MS锆石U-Pb年龄、构造环境及地质意义  

LA-ICP-MS Zircon U-Pb Dating,Petrogenesis and Geologic Significance of Late Triassic Granites in the Western Section of theEast Kunlun Orogen,Xinjiang

作　　者：桑明帅 张建奎[1] 黄基汉[1] 刘良文 周万新 杨有生[1] 陈邦学[1] Sang Mingshuai;Zhang jiankui;Huang Jihan;Liu Liangwen;Zhou Wanxin;Yang Yousheng;Chen Bangxue(No.11 Geological Party,Xinjiang Bureau of Geology and Mineral Exploration and Development,Changji,Xinjiang,831100,China)

机构地区：[1]新疆维吾尔自治区地质矿产勘查开发局第十一地质大队,新疆昌吉831100

出　　处：《新疆地质》2020年第4期431-438,共8页Xinjiang Geology

基　　金：贵州地质调查院.新疆中昆仑地区1∶25万J45C004001等2幅区域地质调查项目,2002;新疆地矿局第十一地质大队.新疆西昆仑1∶5万J45E019001等5幅区域地质调查项目,2014。

摘　　要：乌尊科勒侵入岩位于东昆仑造山带西段,岩石类型主要为花岗斑岩和斜长花岗斑岩。利用LA-ICP-MS锆石U-Pb测年,获得花岗斑岩锆石206Pb/238U年龄为(209.3±3.3)Ma(晚三叠世)。主量元素特征显示高硅,SiO2=70.82%~72.57%、富碱,Na2O+K2O=5.90%~7.82%,相对富钾,K2O/Na2O=1.03~1.35;低钛,TiO2=0.08%~0.19%、低镁,MgO=0.19%~0.38%;A/CNK值为1.12~1.58,碱度率AR值为1.97~2.73,副矿物中富含白云母,属含白云母强过铝质花岗岩。稀土元素总量较低,ΣREE=35.95×10^-6~78.74×10^-6,Eu异常不明显,δEu=0.71~1.25。大离子亲石元素Rb,U,K富集,高场强元素Nb,Ta,Ti,P亏损。Rb/Sr值介于0.77~2.8,Nb/Ta值为8.86~12.77,CaO/Na2O值为0.48~0.81,岩浆来源于陆壳。该侵入岩形成于后碰撞环境,东昆仑造山带于晚三叠世处于后碰撞构造阶段。The granite in the research area is located in the western section of the Orogenic Belt of East Kunlun,The rock types are mainly granite porphyry and plagioclase.By means of the U-Pb age-dating with LA-ICP-MS zircon,206Pb/238U isotopic age of zircon is(209.3±3.3)Ma(late Triassic),which represents the crystallization age of granite porphyry.The characteristics of major elements suggested that it has high silicon(SiO2=70.82%~72.57%)and is rich in alkali(Na2O+K2O=5.90~7.82%rel),relatively rich in potassium(K2O/Na2O=1.03~1.35),low in titanium(TiO2=0.08%~0.19%)and low in magnesium(MgO=0.19%~0.38%).The value of A/CNK is 1.12~1.58,with a value of AR(Alkalic Rate)of 1.97-2.73.The auxilary mineral is rich in white mica,which belongs to white mica-containing strongly peraluminous granite(MPGs)and high potassium and calc-alkaline rock series.The total amount of rare earth elements is low(ΣREE=35.95×10^-6-78.74×10^-6),and no obvious Eu abnormity(δEu=0.71~1.25)was showed.The large ion lithophile elements such as Rb,U and K are concentrated,while high field-strength elements including Nb,Ta,Ti and P are scare.The value of Rb/Sr is between 0.77 and 2.8,and Nb/Ta is 8.86~12.77,CaO/Na2O being 0.48~0.81.It indicates that the magma originated from continental crust.These date indicate that the intrusive rock was formed in the post-collision environment,It is revealed that the easten Kunlun orogenic belt was in a post-collision tectonic stage in the late Triassic.

关 键 词：东昆仑 花岗斑岩 后碰撞 U-PB测年 

分 类 号：P588.12+1[天文地球—岩石学] P597+.3[天文地球—地质学]