南秦岭新发现王庄金矿床矿物成分及其地质意义  

Material Composition and Geological Significance of the Newly Discovered Wangzhuang Gold Deposit in South Qinling

作　　者：孟五一 张振 高永宝 魏立勇 贾彬 郑鑫 刘宁波 MENG Wuyi;ZHANG Zhen;GAO Yongbao;WEI Liyong;JIA Bin;ZHENG Xin;LIU Ningbo(Xi'an Center of Mineral Resources Survey,China Geological Survey,Xi’an 710199,Shaanxi,China)

机构地区：[1]中国地质调查局西安矿产资源调查中心,陕西西安710199

出　　处：《西北地质》2024年第4期157-169,共13页Northwestern Geology

基　　金：陕西省自然科学基础研究计划项目“南秦岭新发现王庄金矿成矿特征与矿床成因研究”(2023-JC-QN-0363);中国地质调查局项目“南秦岭旬北地区金锑找矿靶区优选与评价”(DD20230370);“金锑锂铍矿产找矿靶区调查评价”(DD20230057);“全国金矿重点调查区调查评价”(DD20230060)联合资助。

摘　　要：王庄金矿是2021年南秦岭地区找矿新发现的矿床,矿床类型为微细浸染型,矿体受构造和地层双重控制,呈层间破碎带产出。王庄金矿床矿石矿物主要为毒砂、黄铁矿,通过镜下鉴定及电子探针分析,金主要以不可见金存于毒砂、含砷黄铁矿中,未见自然金。结合野外工作,根据矿物共生组合及其交生关系可将王庄金矿床划分为4个成矿阶段:Ⅰ.黄铁矿、石英脉成矿早阶段;Ⅱ.毒砂、黄铁矿、石英脉成矿主阶段;Ⅲ.石英脉伴少量多金属硫化物阶段;Ⅳ.碳酸盐岩晚阶段。不同阶段的黄铁矿具有不同的微量元素特征:Ⅰ阶段黄铁矿贫As、Au,富Fe、S;Ⅱ、Ⅲ阶段黄铁矿具高As、Au,低S、Fe特征,且此阶段黄铁矿当中Au、As存在一定的正相关关系。王庄金矿矿石中黄铁矿Co/Ni均值为2.03,中位数为1.34,指示成矿主阶段形成的黄铁矿有岩浆流体的加入。且在Co/Ni<1及1.2<Co/Ni<2.5范围内存在两个含金集中区,表明可能存在两种不同流体的成矿作用。综合矿床地质及矿物组构特征初步认为,王庄金矿床存在多阶段的成矿作用。The Wangzhuang gold deposit is a newly discovered deposit in South Qinling in 2021.The ore type is a fine disseminated type.The ore body is controlled by both structure and stratum,and it is produced in an interlayer fracture zone.The main metallic minerals of the Wangzhuang gold deposit are arsenopyrite and pyrite,According to microscopic identification and electron probe analysis,the gold is mainly invisible gold in arsenopyrite and arsenian pyrite,and no natural gold is found.Based on the field work,the Wangzhuang gold de-posit can be divided into four ore-forming stages:I,the early ore-forming-stage of pyrite quartz veins;II,the main stage of arsenopyrite,pyrite,and quartz veins;III,quartz veins with a small amount of polymetallic sulfide stage;IV,late carbonate stage.The pyrite in different stages has different characteristics of trace elements:stage I pyrite is poor in As and Au,rich in Fe and S;the pyrite of stage II and III are characterized by high As,Au,low S and Fe,and there is a positive correlation between Au and As in pyrite of this stage.The average Co/Ni ratio of pyrite in the Wangzhuang gold deposit is 2.03 and the median is 1.34,indicating that pyrite formed in the ore-forming master stage has the addition of magmatic fluid.In addition,there are two gold-bearing areas in the range of Co/Ni<1 and 1.2<Co/Ni<2.5,indicating that there may be mineralization of two different fluids.Based on the geological and mineral fabric characteristics of the deposit,it is preliminarily concluded that there is multi-stage mineralization in the Wangzhuang gold deposit.

关 键 词：王庄金矿 物质组成 黄铁矿 南秦岭 

分 类 号：P618.51[天文地球—矿床学]