延边地区天宝山多金属矿田的流体特征与成矿模式

Characteristics of Fluid Inclusions and Metallogenic Model of Tianbaoshan Polymetallic Ore Field,Yanbian,China

天宝山铅锌铜钼多金属矿田由新兴铅-锌矿床、东风铅-锌-铜-钼矿床和立山铜-铅-锌矿床组成,它们分别产在侏罗纪黑云母花岗闪长岩、闪长岩与古生代海相火山-沉积岩的接触带和岩体内部。矿床地质特征研究表明:新兴铅-锌矿床以石英硫化物充填胶结角砾岩筒矿体为特征,具有与中温岩浆热液矿床类似的蚀变特征;东风铅-锌-铜-钼矿床以发育浸染状硫化物、石英硫化物脉和辉钼矿石英脉为特征,具有接触交代热液矿床特征;立山铜-铅-锌矿床则以磁铁矿、方铅矿和闪锌矿等多金属硫化物矿化发育为特征,具有典型的接触交代矽卡岩型矿床特征。对主成矿阶段以及成矿晚阶段的脉石矿物石英流体包裹体研究揭示:新兴铅-锌矿床的石英-黄铁矿阶段、石英-闪锌矿-方铅矿-黄铜矿多金属硫化物阶段和石英-碳酸盐阶段对应的温度分别为270～340℃、190～260℃、130～160℃;盐度(w(NaCl))和密度分别为0.62%～9.86%和0.37～1.00g/cm3;压力为37.31～87.69MPa;激光拉曼光谱分析获得流体包裹体的成分主要为CO2、H2O,含有少量的CH4和N2。东风铅-锌-铜-钼矿床的石英-辉钼矿阶段、石英-闪锌矿-方铅矿-黄铜矿多金属硫化物阶段和石英-碳酸盐阶段对应的温度分别为280～337℃、200～260℃、101～190℃;盐度和密度分别为7.16%～23.95%和0.96～1.12g/cm3;压力为28.23～56.64MPa;激光拉曼光谱分析获得流体包裹体成分为H2O。立山铜-铅-锌矿床的磁铁矿-石英脉阶段、石英-方铅矿-闪锌矿-黄铜矿等多金属硫化物和石英-碳酸盐阶段对应的温度分别为210～240℃、170～200℃、126～160℃,盐度和密度分别为2.07%～9.47%和0.89～0.92g/cm3;压力为33.88～59.72 MPa;激光拉曼光谱分析获得流体包裹体成分为CO2和CH4。基于矿床地质特征、成矿流体性质和来源等方面的讨论,建立了天宝山多金属矿田的成矿模式。

The Tianbaoshan polymetallic ore field is composed of Xinxing lead-zinc deposit,Lishan lead-zinc-copper deposit and Dongfeng lead-zinc-copper-molybdenum deposit.Both Xinxing and Lishan are hosted in contact zone between Jurassic granodiorite,diorite and Paleozoic marine volcanic rocks-sedimentary rock and the Dongfeng deposit occurs in rock bodies.The research on the geological features of these ore deposits shows that the Xinxing lead-zinc deposit is featured by filling of quartz sulfide in breccia pipe,similar to alteration characteristics of the mesothermal magmatic ore deposit;Dongfeng lead-zinc-copper-molybdenum deposit develops disseminated sulfide orebodies,quartz sulfide veins and molybdenite-quartz vein,showing characteristic of contact metasomatic-hydrothermal deposit;while a lot of magnetite,galena,sphalerite and other metal sulfides are found in Xinxing lead-zinc deposit,which suggests it be a representative contact metasomatic skarn deposit.Based on the research of fluid inclusions in quartz from main mineralizing stages and late ore-forming stage,it can be concluded that ore-forming process of the Xinxing deposit can be divided into three stages,quartz-pyrite,quartz-sphalerite-galena-chalcopyrite and quartz-carbonate.Homogenization temperatures of fluid inclusion formed in these three atages are 270-340 ℃,190-260 ℃,130-160 ℃,respectively.The salinity（w（NaCl）） of the inclusion changes from 0.62% to 9.86%,the density from 0.37 g/cm3 to 1.00 g/cm3 and the pressure from 37.31 MPa to 87.69 MPa.Laser Raman spectroscopy analysis of the fluid inclusions reveals they mainly consist of CO2 and H2O,with minor CH4 and N2.The mineralization of the Dongfeng deposit went through three stages： quartz-molybdenite（280-337 ℃）,quartz-sphalerite-galena-chalcopyrite（200-260 ℃） and quartz-carbonate（101-190 ℃）,salinity and density of fluid inclusions for Dongfeng deposit range from 7.16% to 23.95%,and from 0.96 g/cm3 to 1.12 g/cm3,respectively,with the pressure raging from 28.23 MPa to 56.64 MPa,and analysis from Laser Raman spectroscopy shows the major compositions in the inclusions is H2O.The mineralization of the Lishan lead-zinc-copper deposit can be divided into three stages,they are magnetite-quartz（210-240 ℃）,quartz-galena-sphalerite-chalcopyrite（170-200 ℃） and quartz-carbonate（126-160 ℃）,salinity and density of fluid inclusions from that deposit range from 2.07% to 9.47%,and from 0.89 g/cm3 to 0.92 g/cm3,respectively,with the pressure of 33.88-59.72 MPa,the study on Laser Raman spectroscopy showes that the component of fluid inclusions is mainly composed of CO2 and CH4.Combined with the geological features of ore deposit,properties and sources of the metallogenic fluids,the metallogenic model of the Tianbaoshan polymetallic ore field has been constructed.