辽宁清原王家大沟金矿床地质特征与成因探讨

王家大沟金矿是上世纪末期在辽宁省清原县境内发现的一处小型金矿床.该金矿产于北东向浑河断裂与北西向苏子河断裂两组断裂的交汇部位,容矿构造为北西向断裂构造,区内出露的地层主要为太古宇清原群红透山组.主要载金矿物为黄铁矿,金的赋存状态有裂隙金、包裹金和晶隙金3种,金成色421~595,硅化和黄铁绢英岩化等蚀变与矿化关系极为密切.矿化阶段包括金-石英、金-石英-黄铁矿、金-石英-多金属硫化物、金-石英-碳酸盐4个阶段.黄铁矿δS³⁴值介于2.13‰~6.14‰之间,表明成矿作用与岩浆活动关系密切.石英包裹体均一温度介于149~210℃之间,平均为182℃,表明该矿床成矿温度属于低温.印支期霏细岩(192.5 Ma)等脉岩及南口前花岗岩(205、208 Ma)与金矿关系密切.结合区域成矿特征,笔者认为王家大沟金矿应形成于印支期.

GEOLOGY AND GENESIS OF WANGJIADAGOU GOLD DEPOSIT IN QINGYUAN COUNTY, LIAONING PROVINCE

The small-scaled Wangjiadagou gold deposit,which was discovered in Qingyuan County,Liaoning Province in the end of last century,occurs in the intersection of northeast-trending Hunhe fault and northwest-trending Suzihe fault.The ore-bodies are held by the northwestward structures mostly in Arche an Hongtoushan formation.Pyrite is the main gold-bearing mineral.The element of Au commonly presents as independent mineral in three attitudes: being packed,filling in fractures of minerals or crystals,with purity up to 421-595.The gold mineralizing is closely related to the wall rock's silicification and pyri te-sericite-quartz alteration.The mineralization can be divided into four stages,i.e.gold-quartz stage,gold-quartz-pyrite stage,gold-quartz-polymetallic-sulphides stage and gold-quartz-carbonates stage.The δ34S values of pyrites are calculated between 2.13‰ and 6.14‰,indicat ing that the gold mineralization is tied up with magmatic activities.The homoge nization temperature of inclusions in quartz ranges from 149 to 210℃,averagely 182℃,showing its low temperature environment.Considering the close relatio nship of the gold deposit to the Indosinian felsite dyke(192.5 Ma by K-Ar) and Nankouqian granite(205 Ma,208 Ma),combining with the regional ore-forming features,the metallogenetic period of Wangjiadagou gold deposit should be defined in Indosinian epoch.