西准噶尔晚古生代花岗岩类侵入体40^Ar/39^Ar热年代学  

40^Ar/39^Ar Thermochronology of Late Paleozoic Granitoids in West Junggar （Xinjiang, China）, Central Asia

作　　者：李江瑜 陈宣华[1] 丁伟翠[1] 王志宏[1] 陈文[2] 李冰[1] 黄鹏辉[3] 

机构地区：[1]中国地质科学院,北京100037 [2]中国地质科学院地质研究所,北京100037 [3]北京市地质工程设计研究院,北京101500

出　　处：《大地构造与成矿学》2016年第2期386-404,共19页Geotectonica et Metallogenia

基　　金：国家科技支撑计划重点项目暨国家305项目(2007BAB25B02);中国地质调查局地质调查项目(1212011120184);深部探测技术与实验研究专项(Sino Probe-08)联合资助

摘　　要：西准噶尔成矿带夹持在天山断裂与额尔齐斯断裂之间,是中亚成矿域西部的核心区域之一,广泛发育晚古生代深成岩浆活动、走滑断裂构造和斑岩铜矿、造山型金矿成矿作用。本文在西准噶尔成矿带包古图岩体、康德岩体、加曼岩体、库鲁木苏岩体、别鲁阿嘎希岩体、哈图岩体、阿克巴斯套岩体、庙尔沟岩体、克拉玛依岩体及红山岩体采集12个样品,通过黑云母和钾长石40^Ar/39^Ar阶段升温测年,给出了该地区40^Ar/39^Ar冷却年龄。其中,黑云母40^Ar/39^Ar年龄处在326-302 Ma范围内,钾长石40^Ar/39^Ar年龄为297-264 Ma,反映了西准噶尔地区晚石炭世-中二叠世的区域中温冷却历史。结合前人报道的锆石U-Pb、角闪石40^Ar/39^Ar、辉钼矿Re-Os、磷灰石裂变径迹等年龄数据,构建了西准噶尔成矿带晚古生代岩浆侵入,成矿作用与构造抬升,以及晚中生代剥露过程的整个热历史;并与区域左行走滑断裂活动的时间进行了对比,讨论了40^Ar/39^Ar冷却年龄的构造意义。The West Junggar Metallogenic Belt（WJMB） in the western part of the Central Asian Metallogenic Domain（CAMD）, is located between the Tianshan fault system and the Ertix fault system. It is featured by the widespread Late Paleozoic granitic plutons, strike-slip faults, and porphyry copper and orogenic gold deposits. We collected twelve granitoid samples from the Jiaman, Kangde, Kulumusu, Bieluagaxi, Hatu, Akebasitao, Miaoergou, Baogutu, Karamay, and Hongshan plutons in the WJMB. 40^Ar/39^Ar thermochronological analyses yield biotite 40^Ar/39^Arages ranging from 326 Ma to 302 Ma and K-feldspar 40^Ar/39^Ar ages from 297 Ma to 264 Ma, revealing regional medium-temperature cooling history in the WJMB during the Late Carboniferous to Middle Permian. Integrated with previous zircon U-Pb, amphibole 40^Ar/39^Ar, molybdenite Re-Os and apatite fission track ages, we reconstructed the whole thermal history of the WJMB, including the Late Paleozoic magmatic intrusion, the porphyry Cu and W-Mo mineralization, and the Late Mesozoic tectonic uplifting and exhumation of the WJMB. 40^Ar/39^Ar cooling ages are consistent with the timing of the regional sinistral strike-slip faults, showing the tectonic significance of the cooling ages. We suggest that the biotite and K-feldspar 40^Ar/39^Arcooling ages may record the age of the left-lateral strike-slip faulting in the WJMB.

关 键 词：区域冷却 40^Ar/39^Ar热年代学 晚古生代 西准噶尔 中亚成矿域 

分 类 号：P595[天文地球—地球化学] P597[天文地球—地质学]