中亚巴尔喀什成矿带钼-钨矿床的地质热年代学  

Geothermochronology of Mo-W Deposits in Balkhash Metallogenic Belt,Kazakhstan,Central Asia

作　　者：陈宣华[1] 陈正乐[1] 韩淑琴[1] 王志宏[1] 杨屹 叶宝莹[3] 李学智 施炜[1] 李勇[1] 陈文[4] 

机构地区：[1]中国地质科学院地质力学研究所,北京100081 [2]新疆维吾尔自治区地质矿产开发勘查局第一区调大队,新疆乌鲁木齐830011 [3]中国地质大学地质调查研究院,北京100083 [4]中国地质科学院地质研究所,北京100037

出　　处：《地球科学（中国地质大学学报）》2012年第5期878-892,共15页Earth Science-Journal of China University of Geosciences

基　　金：国家科技支撑计划重点项目暨国家"305"项目(No.2007BAB25B02)

摘　　要：巴尔喀什成矿带是世界著名的中亚成矿域斑岩型铜钼成矿带,产出许多斑岩型铜钼矿床和一些石英脉-云英岩型钨钼矿床.对巴尔喀什成矿带西部的东科翁腊德、阿克沙套、扎涅特3个典型的石英脉-云英岩型钼钨矿床的成矿时代和剥露过程进行了地质热年代学研究.锆石SHRIMPU-Pb定年给出东科翁腊德、阿克沙套、扎涅特与成矿作用有关的花岗岩类岩浆作用的时代分别为293.6±2.7Ma、306±1Ma和304±4Ma,属海西晚期构造-岩浆活动的产物.花岗岩类40Ar/39Ar测年结果给出了与成矿有关岩体的冷却年龄,其等时线年龄分别为292±3Ma(阿克沙套黑云母)、288.8±3.6Ma(阿克沙套钾长石)和278±5Ma(东科翁腊德钾长石).磷灰石裂变径迹测年给出东科翁腊德、阿克沙套、扎涅特的年龄分别为92.1±5.7Ma、92.2±5.0Ma和80.3±4.9Ma,说明这3个矿床的剥露作用主要发生在晚白垩世.花岗岩类岩石U-Pb、40Ar/39Ar和裂变径迹热年代学研究,揭示了巴尔喀什成矿带Mo-W矿床从深成岩浆侵入活动、成矿作用、区域冷却到剥露作用的全过程.The Balkhash metallogenic belt in Kazakhstan,with many porphyritic Cu-Mo deposits and some quartz-vein greisen Mo-W deposits,is a famous porphyritic Cu-Mo metallogenic belt in Central Asian metallogenic domain.Three typical Mo-W deposits such as East Kounrad,Akshatau,and Zhanet,are studied in this paper through the application of geothermochronology.Zircon SHRIMP U-Pb geochronology yields ages of 293.6±2.7 Ma(alkaline granite),306±1 Ma(granodiorite),and 304±4 Ma(porphyry monzonite),for East Kounrad,Akshatau,and Zhanet deposits respectively,belonging to the tectonic-magmatism in the Late Hercynian.40Ar/39Ar thermochronology gives the cooling ages at 292±3 Ma for biotite from Akshatau,and 288.8±3.6 Ma and 278±5 Ma for K-feldspars from Akshatau and East Kounrad,respectively.Apatite fission track dating of granitoids gives low temperature cooling ages of 92.1±5.7 Ma,92.2±5.0 Ma and 80.3±4.9 Ma,for East Kounrad,Akshatau,and Zhanet deposits,respectively,suggesting the uplifting and exhumation of Mo-W deposits together with the granitoids during the Late Cretaceous.The geochronological data and thermal history modeling presented in this paper,together with metallogenic information from previous studies,reveal the entire thermo-history,from the intrusion of plutons and Mo-W metallogenesis in the abyssal system in the Late Carboniferous and the Early Permian,through regional cooling,to the exhumation of the deposits in the Late Cretaceous,in the western part of Balkhash metallogenic belt.

关 键 词：地质年代学 SHRIMPU-Pb 40Ar 39Ar 裂变径迹 钼-钨矿床 巴尔喀什成矿带 

分 类 号：P597[天文地球—地球化学]