新疆东准噶尔金水泉金矿床地质特征、成矿时代及其地质意义  

Geological features and geochronology of the Jinshuiquan gold deposit in the east Junggar, Xinjiang

作　　者：陈伟志[1,2,3] 顾雪祥 章永梅[1,2] 何格[1,2] 黄岗[4] 李静婷 CHEN Weizhi;GU Xuexiang;ZHANG Yongmei;HE Ge;HUANG Gang;LI Jingting(School of Earth Sciences and Resources,China University of Geosciences (Beijing), Beijing 100083,China;State Key Laboratory of Geological Processes and Mineral Resources, Beijing 100083,China;No.10 Gold Geological Party of CAPF, Kunming 650111, Yunnan,China;Regional Institute of Shaanxi Bureau of Geological Exploration, Xianyang 721000,Shaanxi,China)

机构地区：[1]中国地质大学(北京)地球科学与资源学院,北京100083 [2]中国地质大学地质过程与矿产资源国家重点实验室,北京100083 [3]武警黄金第十支队,云南昆明650111 [4]陕西区域地质矿产研究院,陕西咸阳721000

出　　处：《地质通报》2019年第7期1240-1255,共16页Geological Bulletin of China

基　　金：国家自然科学基金项目《新疆西天山吐拉苏浅成低温热液-斑岩型金成矿系统物质与时空结构研究》(批准号:41572062);中央返还两权价款资金综合研究项目《新疆东准噶尔卡拉麦里金矿带控矿构造调查研究及靶区优选》(编号:Y15-1-LQ02);国家重点研发计划《西天山赛里木铅锌铜矿带成矿模式研究与深部资源预测》(编号:2018YFC0604003);中央高校基本科研业务费专项资金《新疆博罗科努成矿带浅成低温热液-斑岩型矿床岩浆、流体与成矿作用》(编号:2652017226)

摘　　要：新疆奇台县金水泉金矿床是东准噶尔卡拉麦里成矿带上一个典型的造山型金矿床,产于清水-苏吉泉大断裂和卡拉麦里深断裂之间的次级断裂带中,其成矿时代尚无确切的年代学资料。通过阴极发光(CL)、背散射图像(BSE)和矿物包体确定含金石英脉中的锆石种类,进行LA-ICP-MS锆石U-Pb同位素定年。捕获锆石主要呈柱状、长柱状,振荡环带清晰,粒径较热液锆石大,包括岩浆锆石和变质锆石;206Pb/238U年龄为365~418Ma、265Ma。热液锆石呈短柱状、棱角状、不规则状、双锥状,常含继承锆石内核,内部包裹体为磷灰石或含金磷灰石,发育不明显的波缓状振荡环带或无振荡环带;206Pb/238U年龄加权平均值为314.9±3.2Ma,指示金矿化作用发生于晚石炭世早期碰撞造山向造山后伸展转变的构造环境。成矿时代晚于赋矿围岩姜巴斯套组的年龄(约343Ma),与总结区域构造演化规律所限定的时间范围(320~310Ma)吻合。综合研究认为,金水泉金矿床成矿作用可划分为350~320Ma造山阶段含金流体生成、315Ma挤压-伸展转换阶段金迁移就位、二叠纪陆内变形阶段金矿体破碎变形3个阶段。Located in the Kalamaili metallogenic belt in the east Junggar of Xinjiang, the Jinshuiquan gold deposit is a typical orogenic gold deposit which occurs along the secondary fault zone between the Kalamaili deep fault and the major disruption of Qingshui- Sujiquan. The mineralization timing has been unclear up till now. Zircon species in auriferous quartz veins of this study were initially determined by cathodoluminescence electron (CL) images, Back Scattered Electron (BSE) image and mineral inclusions before the performance of LA- ICP- MS U- Pb isotopic dating on these zircons. The trapped zircons are mainly in the columnar and long columnar forms, with clear shock bands, consisting of magmatic zircons and metamorphic zircons. These zircons are larger than hydrothermal zircons. LA-ICP-MS U-Pb dating on these trapped zircons yielded 206Pb/238U ages of 365~418Ma and 265Ma. The hydrothermal zircons are in short columnar, angular, double cone and irregular forms and usually contain inclusions such as inherited zircon core, apatite or gold bearing apatite, some with weak band of shock waves or even without shock bands. LA-ICP-MS U-Pb dating on these hydrothermal zircons yielded a weighted average 206Pb/238U age of 314.9 ± 3.2Ma, indicating that early Late Carboniferous gold mineralization occurred during the transition from collisional orogenesis to post- collisional extension. The metallogenic epoch was later the epoch of ore hosting wall rock, i.e., the Jiangbasitao Formation (C1j,~343Ma) which coincides with the time frame (320~310Ma) limited by the summarized orderliness of regional tectonic evolution from the data obtained by previous researchers. Comprehensive studies suggest that the metallogenic process of the Jinshuiquan gold deposit can be divided into three periods: the formation of gold bearing fluid at the orogenic stage during 350~320Ma, the migration and emplacement of goldbearing hydrothermal fluid at 315Ma during compression to extension stage and the fracture and deformation of gold orebody at the P

关 键 词：U-PB同位素年龄 成矿时代 热液锆石 金水泉金矿床 卡拉麦里 东准噶尔 

分 类 号：P618.51[天文地球—矿床学] P597.3[天文地球—地质学]