巴尔喀什成矿带Cu-Mo-W矿床的辉钼矿Re-Os同位素年龄测定及其地质意义  

Re-Os Dating of Molybdenites from the Cu-Mo-W Deposits in the Balkhash Metallogenic Belt,Kazakhstan and Its Geological Significance

作　　者：陈宣华[1,2] 屈文俊[3] 韩淑琴[2] Eleonora Seitmuratova 施炜[1,2] 杨农[1,2] 陈正乐[1,2] 叶宝莹[5] 曾法刚[3] 杜安道[3] 蒋荣宝[2] 王志宏[2] 

机构地区：[1]国土资源部新构造运动与地质灾害重点实验室,北京100081 [2]中国地质科学院地质力学研究所,北京100081 [3]国家地质实验测试中心,北京100037 [4]Laboratory of Geological Formations,K.Satpaev Institute of Geological Sciences,Almaty,050010,Kazakhstan [5]中国地质大学,北京100083

出　　处：《地质学报》2010年第9期1333-1348,共16页Acta Geologica Sinica

基　　金：国家科技支撑计划重点项目(编号2007BAB25B02)资助的成果

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。中亚成矿域可能是一个多核成矿系统,具有以走滑断裂为边界构成的断裂构造体系并受之控制。本文对巴尔喀什成矿带巴尔喀什—阿克沙套地区11件辉钼矿样品进行了Re-Os同位素分析,得到博尔雷大型斑岩型铜(钼)矿床和东科翁腊德、扎涅特、阿克沙套石英脉-云英岩型钨钼矿床的辉钼矿模式年龄(平均值)分别为315.9Ma、298.0Ma、295.0Ma和289.3Ma;其中,东科温腊德、阿克沙套和扎涅特等3个矿床的Re-Os等时线年龄为297.9-+30..949Ma,MSWD值为0.97。辉钼矿Re-Os年龄说明巴尔喀什成矿带Cu-Mo-W成矿作用发生在315.9～289.3Ma期间,Cu-Mo-W矿床的形成可分为两期:一期为斑岩型铜钼矿床,约形成于315.9Ma;另一期为石英脉-云英岩型钨钼矿床,约形成于297.9Ma。根据辉钼矿模式年龄和等时线年龄,推测该地区花岗斑岩和伟晶岩的形成时代与相应的矿床基本同时,均为晚石炭世,属海西期构造岩浆活动的产物。通过与我国境内西、东准噶尔和东天山斑岩铜矿带的对比表明,巴尔喀什成矿带铜钼成矿作用的年龄介于东天山土屋—延东斑岩铜矿与西准噶尔包古图斑岩铜矿之间。分析表明,中亚成矿域大规模斑岩型铜钼成矿作用集中在晚石炭世,属海西晚期构造-岩浆活动的产物。The Balkhash metallogenic belt in Kazakhstan,with the occurrence of many porphyritic Cu-Mo deposits and some quartz-vein greisen W-Mo deposits,is a very famous porphyritic Cu-Mo metallogenic belt in the Central Asian Metallogenic domain which is represented as a multiple core metallogenic system controlled by the boundary strike-slip fault system. In this paper 11 molybdenite samples from the western Balkhash metallogenic belt were selected for Re-Os isotopic dating. The molybdenites from the porphyritic Borly Cu-Mo deposit,and East Kounrad,Zhanet and Akshatau quartz-vein greisen W-Mo deposits,gave average model Re-Os ages of 315.9 Ma,298.0 Ma,295.0 Ma and 289.3 Ma,respectively. Meanwhile,the molybdenites from East Kounrad,Zhanet and Akshatau W-Mo deposits gave a Re-Os isochron age of 297.9 Ma,with MSWD of 0.97. Re-Os dating of molybdenites indicates that the Cu-Mo-W metallogenesis in the western Balkhash metallogenic belt formed during Late Carboniferous to Early Permian （315.9-289.3 Ma）,while the porphyry Cu-Mo deposits formed at -315.9 Ma,and quartz-vein greisen W-Mo deposits formed at -297.9 Ma. The Re-Os model and isochron ages suggest that Late Carboniferous porphyry granitoid and pegmatite magmatism during Late Hercynian movement. Comparing to the Juggar-East Tianshan porphyry Cu metallogenic belt in northwestern China,the time of the Cu-Mo metallogenesis in Balkhash metallogenic belt,is between that of Tuwu-Yandong and Baogutu porphyry Cu deposits in East Tianshan and west Junggar. Concluded,the large-scale porphyry Cu-Mo metallogenesis in Central Metallogenic Domain centralized in Late Carboniferous due to Hercynian tectonic-magmatic activities.

关 键 词：RE-OS同位素年龄 辉钼矿 成矿时代 Cu-Mo-W矿床 巴尔喀什成矿带 哈萨克斯坦 

分 类 号：P618.65[天文地球—矿床学]