巴里坤塔格晚古生代侵入岩岩石地球化学与Sr-Nd-Pb同位素特征  

Geochemistry and Sr-Nd-Pb Isotopes of Late Paleozoic Intrusive Rocks in Balikuntage,Xinjiang

作　　者：屈翠侠[1] 杨兴科[1] 易鹏飞 刘渭 宋宏业 

机构地区：[1]长安大学地球科学与资源学院,陕西西安710054 [2]陕西省地质调查中心,陕西西安710065 [3]陕西省核工业地质调查院,陕西西安710199 [4]中国石油集团渤海钻探工程有限公司测井分公司,天津大港300280

出　　处：《西北地质》2015年第2期17-30,共14页Northwestern Geology

基　　金：中国地质调查局地质调查工作项目(科2012-02-047-005)

摘　　要：巴里坤塔格地区晚石炭世—早二叠世侵入岩主要包括闪长岩、花岗闪长岩、花岗岩和辉绿岩,相互呈侵入接触关系,形成时代在误差范围内一致。在地球化学上,均属过铝质钙碱性和高钾钙碱性系列,富集轻稀土元素、大离子亲石元素以及不相容元素,亏损高场强元素,显示火山弧花岗岩的特征,低 Sr、低 Pb、高 Nd 的同位素组成特征表明该区侵入岩起源于亏损地幔。通过对综合区域地质演化分析,认为巴里坤塔格地区在晚石炭世—早二叠世为后碰撞拉张环境,其侵入岩的岛弧特征可能是由于岩浆源区受过早期俯冲作用的影响。T DM =1076~806 Ma,指示中酸性侵入岩类的来源可能是古亚洲洋俯冲形成的新生陆壳,该陆壳起源于亏损地幔。因此,认为晚石炭世—早二叠世晚期巴里坤塔格与邻区博格达、哈尔里克地区自晚石炭世全面进入板内构造演化阶段。The intrusive rocks of late Carboniferous and early Permian in the Balikuntage area mainly include diorite,granodiorite,granite and diabase.They show intrusive contact relation-ships and their ages are similar within the error range.All the intrusive rocks belong to peralumi-nous calc-alkaline and high-K calc-alkaline series.They are rich in LREE,LILE and incompatible elements,but deficient in HFSE,which are characteristics of the volcanic arc granite.Besides,i-sotopic composition characteristics of high Nd,low Sr and Pb content suggest that the intrusive rocks come from the depleted mantle.Based on the analysis of the regional geological evolution, the tectonic environment of Balikuntage region is the intercontinental rift valley between late Car-boniferous and early Permian,and its island arc characteristics may be induced by the early sub-duction in magma source.The T DM value （1076—806 Ma）reflects that the intermediate-acid intrusive rocks have same source area which is given priority to the partial melting of the juvenile crust,and the source of the young crust is derived from the depleted mantle.It can be deduced that Balikuntage and its adjacent area Bogda and Haerlike fully entered into the intraplate envi-ronment in late Carboniferous and early Permian.

关 键 词：陆内裂谷 SR-ND-PB 同位素 晚石炭世-早二叠世 侵入岩 巴里坤塔格 

分 类 号：P588.124[天文地球—岩石学] P597.3[天文地球—地质学]