广西昭平湾岛金矿矿床类型、成矿时代及其地质意义  

The deposit type,mineralization age and their geological significance of the Wandao gold deposit in Zhaoping County,Guangxi Province

作　　者：肖柳阳 陈懋弘[3] 张志强[2] 蔡爱良 叶江 

机构地区：[1]中国有色桂林矿产地质研究院有限公司,广西桂林541004 [2]中国地质大学(北京)地球科学与资源学院,北京100083 [3]中国地质科学院矿产资源研究所国土资源部成矿作用与资源评价重点实验室,北京100037 [4]广西昭平黄金矿业公司,广西昭平546800

出　　处：《地学前缘》2015年第2期118-130,共13页Earth Science Frontiers

基　　金：国家重点基础研究发展计划"973"项目(2012CB416704);广西地矿局部门预算前期地质勘查项目(桂地矿地(2014)17);中国地质调查局地质调查工作项目(1212011120831)

摘　　要：广西湾岛金矿位于钦杭成矿带西南端大瑶山凸起内部的古袍金矿田西部。金矿体主要以石英大脉的形式产于花岗斑岩体与寒武系砂岩和板岩中。根据矿体走向平行于近东西向断裂而不是环绕岩浆岩呈面(环)状分布,矿石构造为大脉状而不是网脉状,确定湾岛金矿不是斑岩型金矿而是石英脉型金矿,与古袍、桃花金矿属于同一矿床类型。此外,在花岗斑岩体和接触带附近还新发现了较多的辉钼矿-白钨矿石英脉,并明显被含金硫化物石英脉切割,暗示存在两次不同期次的矿化作用。锆石LA-ICP-MS测年表明花岗斑岩年龄为(436.1±2.1)^(436.4±2.4)Ma;辉钼矿Re-Os测年表明白钨矿-辉钼矿石英脉年龄为(436.6±3.8)Ma。结合前人获得同一成矿带桃花金矿测年结果(148±10)Ma,初步认为湾岛金矿花岗斑岩为加里东期,金矿化推测为燕山期,而矿区内钨钼矿化与花岗斑岩有关,金矿化与花岗斑岩无成因关系,金矿化主要受近东西向断裂控制。提出在六岑—桃花—古袍金矿带以找金为主攻方向外,还要注意寻找社垌式的加里东期石英脉-夕卡岩-斑岩型钨钼矿床。The Wandao gold deposit is located in the west of Gupao gold field within the Dayaoshan uplift, the southwestern segment of the Qin-hang Metallogenic Belt. The gold ore bodies are characterized by quartz veins, which mostly presents within the granitic porphyry and Cambrian sandstone/slate. The trend of ore bodies is parallel to nearly EW faults rather than around the magmatic rock in surface （ring） distribution; moreover, the ore structure is of large quartz vein instead of stockwork. Therefore, the Wandao gold deposit is believed to be quartz vein deposit rather than porphyry gold deposit, like the Gupao and Taohua gold deposits. Furthermore, a great number of Molybdenite-scheelite quartz veins were found in porphyry granite and along the contact zone of porphyry granite, cut by the gold-bearing sulfide quartz veins, suggesting the presence of two different mineralization stages. Zircon LA-ICP-MS dating showed porphyry age of 436. 1±2. 1 Ma- 436. 4± 2.4 Ma; molybdenite Re-Os chronology measurement indicated the age of tungsten molybdenite quartz veins of 436.6＋3. 8 Ma. Combined with previous dating results of Taohua gold deposit 148±10 Ma, it is believed that the porphyry within the Wandao gold deposit was emplaced during the Caledonian, and was closely associated with tungsten/molybdenum mineralization; however, it was irrelevant to the local gold mineralization during the Yanshanian; the gold mineralization was mainly controlled by a set of EW trending faults. In this paper, we suggest that gold deposits are the most economic exploration targets in Liucen-Taohua-Gupao gold mineralization belt, and the Caledonian Shedong type of quartz vein-skarn-porphyry tungsten-molybdenum deposit deserves equal efforts.

关 键 词：锆石LA-ICP-MS测年 辉钼矿Re-Os测年 钨钼矿化 金矿化 湾岛金矿 广西昭平 

分 类 号：P597.3[天文地球—地球化学]