摘要
三江县老堡铅锌矿床为广西首次发现的一个中型扬子型铅锌矿床。矿区内共圈定铅锌矿体11个,均呈层状、似层状产于震旦系上统老堡组硅质岩、下统陡山沱组白云岩层间构造中,与地层同步褶曲。矿石组分相对简单,主要金属矿物有闪锌矿、方铅矿,次为黄铁矿;非金属矿物主要有白云石、石英、方解石,次为重晶石和绢云母。围岩蚀变较弱,以白云石化、硅化和方解石化为主。通过综合分析矿床地质、流体包裹体和稳定同位素等证据,笔者认为老堡铅锌矿床为热水沉积-中低温热液改造成因。成矿金属和硫源多来源于地层,少部分来自热液流体。成矿流体为地层中的环流热卤水。
Laobao Pb-Zn deposit in Sanjiang is the first found of Yangtze-type ore deposit in Guangxi Province.There are 11 stratiform and stratoid ore bodies occurred in interlayer structures of the Lower Sinian Laobao Formation silicolites and the Upper Sinian Doushantuo Formation dolomites.Ore Mineral assemblage is rather simple in this deposit,which mainly are sphalerite,galena and less pyrite.Gangue minerals are mostly dolomite,quartz,calcite,barite and sericite.Country rock alterations are predominately weak silicification and carbonatization.Intergrated with geological,fluid inclusions and stable isotopes,a genesis model of hydrothermal sedimentary mineralization reformed by epithermal or mesothermal fluid can be constructed for this deposit.Ore metals and sulfur are mainly come from host strata and minimally from hydrothermal fluid.Ore-forming fluids probably are tectonic driven circumfluent thermal brine in the host strata.
引文
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