西成地区铅-锌矿、金矿硫铅同位素特征及成矿关系的研究

甘肃省西成地区分布有多种类型的铅-锌矿和金矿，已探明海底喷流型（SEDEX）铅-锌矿资源量超过1300×10^4t（金属量）。金矿主要分布于盆地中西部泥盆系厚层碎屑岩中．受控于韧性剪切带。对矿床中硫化物硫、铅同位素研究结果表明，西成铅-锌矿田北矿带的后期改造是在相对封闭的环境下实现的、而南矿带铅-锌矿则有部分外来物质的参与，但并未发生明显的分异，同时，两个矿带喷流（气）-沉积过程的不同，这也是导致硫同位素存在差异的重要原因。在印支期的成矿过程中金矿具有明显独立于铅-锌矿的地质特点与硫、铅同位素演化过程，硫主要源自区内的围岩，而铅同位素中则有较多放射性成因铅的加入。

Study on characteristics of S, Pb isotopes of the Pb-Zn deposits, Au deposits in Xicheng area and their metallogenic relationship

Kinds of different types of Pb-Zn deposits and Au deposits distribute in Xicheng area of Gansu Province. The resources of SEDEX type Pb-Zn deposits, which are more than 1300×10^4t （metal resources） have been detected. The Au deposits mainly occurred in middle-and-western part of Devonian thick-layer clastic rocks in basin and they are controlled by ductile shear zone. The research results of S,Pb isotope of sulfide in deposits have shown that the north mineralization belt of the Xicheng Pb-Zn ore field has finished its later alteration in a relatively close condition, while south mineralization belt has involved some foreign substances in later alteration with unclear differentiation. Meanwhile, the differences of SEDEX courses between the two mineralizaiton belts are important factors that caused the differences of S isotope. During the Indo-Chinese epock metallogenic process, the Au deposits have presented obvious unique geological characteristics and S,Pb isotopes evolvement which are independent from the Pb-Zn deposits with S mainly coming from the surrounding rocks in this area while Pb isotope involving more radioactive Pb.