广东河台金矿两阶段成矿事件:来自含金石英脉阴极发光和流体包裹体研究  

The Two Metallogenic Events of the Hetai Gold Deposit in Guangdong Province:Evidences from the Cathodoluminescence Imaging and Fluid Inclusion Studies

作　　者：王圆元 倪培[1] 潘君屹 韩亮 丁俊英 WANG Yuan-yuan;NI Pei;PAN Jun-yi;HAN Liang;DING Jun-ying(State Key Laboratory for Mineral Deposit Research,Institute of Geo-Fluids,School of Earth Science and Engineering,Nanjing 210023,China)

机构地区：[1]内生金属矿床成矿机制研究国家重点实验室,地质流体研究所,南京大学地球科学与工程学院,南京210023

出　　处：《矿物岩石地球化学通报》2021年第6期1330-1344,共15页Bulletin of Mineralogy, Petrology and Geochemistry

摘　　要：为进一步厘定广东河台金矿成矿流体的来源并深刻揭示其成矿过程,利用扫描电子显微镜-阴极发光(SEM-CL)成像技术对河台金矿含金石英脉中的石英进行了世代划分,并对不同世代石英开展了流体包裹体研究。通过观察石英的阴极发光图像,将含金石英脉中的石英分为早世代石英(Q1)和晚世代石英(Q2),两世代石英中均可见金矿化。Q1中流体包裹体可分为3类:Ⅰ_(Q1)型H_(2)O-CO_(2)包裹体、Ⅱ_(Q1)型气液两相富H_(2)O包裹体和Ⅲ_(Q1)型富CO_(2)包裹体,其中Ⅱ_(Q1)、Ⅲ_(Q1)型包裹体可见共生,其均一温度分别为214~349℃(均一到液相)和368~406℃(均一到气相),盐度分别为1.4%~9.2%NaCl_(eqv)和0.8%~3.7%NaCl_(eqv)。Q1中记录的早期成矿流体发生了不混溶作用,流体特征与造山型金矿相似。Q2中流体包裹体可分为4类:Ⅰ_(Q2)型H_(2)O-CO_(2)包裹体、Ⅱ_(Q2)型气液两相富H_(2)O包裹体、Ⅲ_(Q2)型富CO_(2)包裹体和Ⅳ_(Q2)型含子晶包裹体,其中Ⅲ_(Q2)、Ⅳ_(Q2)型包裹体密切共生,其盐度分别为0.4%~4.6%NaCl_(eqv)和32.9%~37.4%NaCl_(eqv),均一温度分别为312~398℃(均一到气相)和273~349℃(均一到液相)。Q2中记录的晚期成矿流体发生了沸腾作用,其流体特征类似一些高温岩浆热液系统。综合前人的年代学研究结果,本文认为河台金矿经历了加里东期和燕山期两期矿化事件,加里东期形成造山型金矿并在燕山期被岩浆热液作用改造。In order to further determine the source of ore-forming fluid and reveal ore-forming process of the Hetai gold deposit in Guangdong Province,scanning electron microscope-cathodoluminescence(SEM-CL)methods are used to carefully classify different generations of quartzs from the gold-bearing quartz veins of the Hetai gold deposit for studying fluid inclusions in quartzs of different generations.SEM-CL imaging revealed that gold-bearing quartz veins can be classified to two successive quartz generations including the early generation(Q1)and the late generation(Q2),which are both associated with gold mineralization.Fluid inclusions in the Q1 can be classified into three types,namely H_(2)O-CO_(2) inclusions(Ⅰ_(Q1)),aqueous inclusions(Ⅱ_(Q1)),and CO_(2)-rich inclusions(Ⅲ_(Q1)).TheⅡ_(Q1) is coexisted with theⅢ_(Q1) type inclusions,with homogenization temperatures(th)of 214-349℃(homogenized to liquid phase)and 368-406℃(homogenized to vapor phase),respectively,and salinities of 1.4%-9.2%and 0.8%-3.7%NaCl_(eqv) equivalent,respectively,indicating that the un-mixing of its early ore-forming fluid occurred in the Q1,with its fluid characteristics similar to those of many orogenic gold deposits.Fluid inclusions in the Q2 can be grouped into four types,scilicet H_(2)O-CO_(2) inclusions(Ⅰ_(Q2)),aqueous inclusions(Ⅱ_(Q2)),CO_(2)-rich inclusions(Ⅲ_(Q2)),and daughter mineral-bearing inclusions(Ⅳ_(Q2)).TheⅢ_(Q1) andⅣ_(Q2) type inclusions are closely intergrown with homogenization temperatures of 312-398℃(homogenized to vapor phase)and 273-349℃(homogenized to liquid phase),salinities of 0.4%-4.6%and 32.9%-37.4%NaCl_(eqv) equivalent,respectively,suggesting that fluid boiling of the late ore-forming fluid had occurred in the Q2,with fluid characteristics similar to those of some high temperature magmatic hydrothermal systems.Combined with previous geochronological results,it is proposed that the Hetai gold deposit underwent two mineralization events,including the primitive orogenic gold mineralization in

关 键 词：河台金矿 含金石英脉 阴极发光 流体包裹体 流体不混溶 两阶段成矿事件 

分 类 号：P585.1[天文地球—岩石学]