小秦岭镰子沟金矿床地质特征、黄铁矿原位硫同位素组成及成因意义  

Geological Characteristics and S Isotopic Compositions of Pyrite from Lianzigou Gold Deposit in Xiaoqinling Area,and It's Genetic Significance

作　　者：代军治 高菊生 钱壮志[2] 张龙斌 周金隆 李平 高毅 Dai Junzhi;Gao Jusheng;Qian Zhuangzhi;Zhang Longbin;Zhou Jinlong;Li Ping;Gao Yi(Northwest Geological and Mining Group Co.Ltd.for Nonferrous Metals,Xi’an 710054,China;School of Earth Science and Resources,Chang’an University,Xi’an 710054,China;No.712 General Party Co.Ltd.of Northwest Mining and Geology for Nonferrous Metals,Xianyang 712000, Shaanxi,China)

机构地区：[1]西北有色地质矿业集团有限公司,西安710054 [2]长安大学地球科学与资源学院,西安710054 [3]咸阳西北有色七一二总队有限公司,陕西咸阳712000

出　　处：《吉林大学学报（地球科学版）》2018年第6期1669-1682,共14页Journal of Jilin University：Earth Science Edition

基　　金：西北有色地质矿业集团博士后项目(西色地发[2016]46号)~~

摘　　要：镰子沟金矿床位于华北陆块南缘小秦岭金矿矿集区西部,矿体赋存于太华群上部岩层内,受断裂构造和石英脉控制,带状钾长石化是矿床典型的围岩蚀变,矿物组合为石英-黄铁矿-方铅矿-黄铜矿±重晶石±磁铁矿。为了探讨成矿物质来源及矿床成因,采用LA-MC-ICP-MS技术对镰子沟金矿床黄铁矿进行原位微区硫同位素分析,获得单颗粒黄铁矿的硫同位素变化范围为-15.27‰^-11.98‰,平均-13.35‰,小于共生重晶石硫同位素值9.8‰~12.4‰。根据硫化物与共生硫酸盐矿物,估算成矿热源总硫值为-3.6‰,与新太古界太华群和燕山期华山花岗岩均不同。综合矿化蚀变、地球化学及同位素组成,认为太华群对金矿床成矿物质来源的影响较华山花岗岩明显,但非主要来源,金矿床成矿与深部流体或隐伏岩体有关,矿床受深部流体和构造控制,深部仍有寻找构造蚀变型或微细浸染型金矿体的潜力,但规模有限。The Lianzigou gold deposit is located in the west of Xiaoqinling gold mineralization concentrated region,the south margin of the North China craton.The orebodies are hosted in the upper strata of Taihua group and controlled by fault fracture zones or quartz veins.The surficial and zonal potassic alteration is the typical wall rock alteration.The mineral assemblage is quartz-pryite-galena-chalcopyrite±barite±magnetite.For discussion of the ore-forming materials and ore genesis,the S isotopic compositions of pyrites of the gold deposit were measured by using Laser-ablation multi-collector inductively coupled plasma mass spectrometry(LA MC ICP MS).The S isotopic compositions in different ore-forming stages range from-15.27‰to-11.98‰,with an average of-13.35‰,which is less than the S isotopic value(9.8‰-12.4‰)of barite.We calculated the total S isotopic value(-5.5‰)of the coexisting barite,which is different from Taihua group and those granites of Yanshanian.Based on the geological characteristics and isotopic compositions,Taihua group had obvious influence on the source of the ore-forming materials than those granites of Yanshanian(Huashan pluton),but not the major source.Deep fluids or pluton is the possible mineralization sources of the Lianzigou gold deposit.The gold deposit is controlled by deep fluids and structure.There is a potential to find structural altered rock type or fine disseminated type of gold deposits in the deep part,but its scale will be limited.

关 键 词：镰子沟金矿床 原位硫同位素 成矿物质 深源流体 小秦岭 

分 类 号：P618.51[天文地球—矿床学]