阿尔泰巴利尔斯河一带岩体LA-MC-ICP-MS锆石U-Pb年代学、岩石成因及地质意义  

LA-MC-ICP-MS U-Pb Geochronology and Petrogenesis of Plutons in Baliersi River Area of Altay and Their Geological Implications

作　　者：朱伯鹏[1] 秦纪华[1] 何斌 张汉青 吴晓贵[1] ZHU Bopeng;QIN Jihua;HE Bin;ZHANG Hanqing;WU Xiaogui(No.4 Geological Party,Xinjiang Bureau of Geology and Mineral Resources Exploration and Development,Xinjiang 836500,China)

机构地区：[1]新疆维吾尔自治区地质矿产勘查开发局第四地质大队,新疆阿勒泰836500

出　　处：《现代地质》2018年第4期680-691,共12页Geoscience

基　　金：中国地质调查局项目"阿尔泰成矿带地质矿产调查评价"(1212011120505)

摘　　要：新疆阿尔泰巴利尔斯河一带岩体岩石类型复杂,主要岩石组合为花岗闪长岩、黑云二长花岗岩和二长花岗岩。花岗闪长岩和二长花岗岩中LA-MC-ICP-MS锆石U-Pb测年结果分别为(386.4±2.8)Ma和(386.8±1.2)Ma。花岗闪长岩、黑云二长花岗岩和二长花岗岩地球化学分析结果显示,岩石Si O2含量为74.33%~76.70%,里特曼指数为1.49~2.04,A/CNK值介于1.00~1.07,大离子亲石元素Rb、Th等和轻稀土元素相对富集,高场强元素Sr、Ti、Nb等和重稀土元素则相对亏损,具较强的负Eu异常(δEu=0.31~0.84),表明该岩石为具有富钾、钙碱性、弱过铝质特征的高分异I型花岗岩。综合研究认为,巴利尔斯河一带岩体形成于与俯冲作用有关的活动大陆边缘的岩浆弧构造环境,是古亚洲洋向北俯冲消减过程中岩浆上侵就位的产物。Rock types in the Baliersi River area of the Chinese Altay Orogen（ Xinjiang） are complex,including granodiorite,biotite monzogranite and monzogranite. LA-MC-ICP-MS zircon U-Pb dating reveals that the granodiorite and monzogranite were formed at（ 386. 4 ± 2. 8） Ma and（ 386. 8 ± 1. 2） Ma,respectively. Geochemical analysis of the granodiorite,biotite monzogranite and monzogranite show that the Si O2 contents range from74. 33% to 76. 70%,Rittman index（ σ） range from 1. 49 to 2. 04,and the A/CNK values range from 1. 00 to1. 07. In addition,the rocks show enrichments in LILEs（ e. g.,Rb,Th） and LREEs,and obvious depletions in HREEs and HFSEs（ e. g.,Sr,Ti,Nb） and strong negative Eu anomaly（ δEu = 0. 31 to 0. 84）,suggesting that the rocks are high-K calc-alkaline,peraluminous highly-fractioned I-type granites. Integrated with previous studies,it is concluded that granitoids in the Baliersi River area were formed in a continental margin magmatic arc setting,via the north-dipping subduction of the Paleo-Asian Ocean.

关 键 词：花岗岩 LA-MC-ICP-MS锆石U-Pb测年 岩石成因 巴利尔斯河 阿尔泰 新疆 

分 类 号：P588.1[天文地球—岩石学]