东昆仑西段其木来克一带晚二叠世侵入岩的成因及其构造意义  

Genesis and tectonic significance of Late Permian Qimulaike intrusive rocks in the west of East Kunlun Mountains,Xinjiang

作　　者：陈邦学 徐胜利 杨有生 周能武 朱志新 CHEN Bangxue;XU Shengli;YANG Yousheng;ZHOU Nengwu;ZHU Zhixin(Shaanxi Geological Exploration Institute of Geology and Mine Bureau, Xi'an 710000,China;No.11 Geological Party, Xinjiang Bureau of Geology and Mineral Exploration and Development, Changji 831100,Xinjiang, China;Geological Research Academy of Xinjiang,Urumqi 830046,Xinjiang,China)

机构地区：[1]中化地质矿山总局陕西地质勘查院,陕西西安710000 [2]新疆地矿局第十一地质大队,新疆昌吉831100 [3]新疆地调院,新疆乌鲁木齐830046

出　　处：《地质通报》2019年第6期1040-1051,共12页Geological Bulletin of China

基　　金：中国地质调查局项目《新疆西昆仑1:5万J45E019001、J45E020001、J45E020002、J45E021001、J45E021002等5幅区调》(编号:1212011220640)

摘　　要：对东昆仑其木来克一带的花岗质岩体进行锆石U-Pb测年,获得花岗闪长岩年龄为274.6±1.2Ma,黑云母花岗岩闪长岩年龄271.2±0.6Ma,认为其形成于晚二叠世。该岩体的地球化学特征显示,其具有钙碱性、弱过铝质(A/CNK=0.99~1.1)特征;稀土元素球粒陨石标准化分布图表现为左陡右缓,具弱的负Eu异常;微量元素特征显示高场强元素Nb、Ta、Ti、P等亏损,结合构造环境认为其形成于岛弧环境,属于I型花岗岩。结合区域构造演化,认为古特提斯洋于晚二叠世开始向塔里木板块俯冲,与此同时洋中脊还在持续扩张,表明此时的特提斯洋已处于消亡期。Zircon U-Pb dating of Qimulaike granitic stocks shows that the age of the granodiorite is 274.6 ±1.2Ma and that of diatomite granitic diorite is 271.2±0.6Ma, implying the formation time of Late Permian. The geochemical characteristics of the rocks show that they have calc-alkaline and weak aluminum (A/CNK being 0.99~1.1)characteristics;the chondrite-normalized REE patterns show steepness on the left and smoothness on the rightwith weak negative anomaly of the δEu;the trace elements exhibit depletion of high field strong elements such as Nb, Ta, Ti and P.Combined with the structural environment, the authors hold that the rocks were formed in an island arc environment and belong to the I-type granite. In combination with regional tectonic evolution, it is shown that ancient Tethys in the Late Permian began subducting to the Tarim plate, while the mid-ocean ridge was still continuing to expand, indicating that the ancient Tethys at that time had been in the dying period.

关 键 词：花岗闪长岩 古特提斯洋 构造演化 东昆仑造山带 

分 类 号：P534.46[天文地球—古生物学与地层学] P588.12[天文地球—地质学]