巴基斯坦俾路支省杜达铅锌矿区矿石学特征

    Oreological characteristics of the Duddar Lead-Zinc Mining Area in Balochistan Province, Pakistan

    • 摘要: 巴基斯坦俾路支省杜达铅锌矿主要赋存于侏罗系费罗扎巴德群安吉拉组杜达段地层,赋矿岩石为一套海相碳酸盐岩和细碎屑岩,主要岩性为黑色页岩、泥质灰岩及泥岩。矿石类型包括同生沉积型(层控/层状)铅锌矿石和后期热液充填交代型(网脉状)铅锌矿石两大类。同生沉积型矿石呈层状分布于下杜达亚段(LDM)地层,其产状与地层较为整合,根据矿物组合及赋存部位可划分为闪锌矿型、黄铁矿型和重晶石型等三种类型。热液充填交代型(网脉状)铅锌矿石主要赋存于中杜达亚段(MDM)和下杜达亚段(LDM)底部巴姆段(AB)灰岩、泥岩,矿石中闪锌矿、方铅矿和重晶石多呈网脉状充填、交代灰岩和泥岩。矿相学研究表明,杜达铅锌矿床成矿过程可划分为同生沉积(层控/层状)成矿期、热液成矿期、表生成矿期等三个成矿期。同生沉积(层控/层状)成矿期可划分为层状锌矿带(Zn带)、层状黄铁矿带(Py带)、层状重晶石带(Ba带)等三个主要矿化阶段。杜达铅锌矿床主要是同生沉积(层控/层状)成矿和后期热液充填交代成矿,是一个复成因成矿的铅锌矿床。

       

      Abstract: The Duddar Lead-Zinc Mine in Balochistan Province, Pakistan is primarily situated within the Duddar member of the Anjira formation within the Jurassic Ferozabad group. The deposit is hosted by a series of marine carbonate and fine clastic rocks, predominantly composed of black shale, argillaceous limestone, and mudstone. The ore comprises syngenetic sedimentary(stratabound/stratiform) lead-zinc deposits and late hydrothermal filling metasomatic(stockwork) lead-zinc deposits. The syngenetic sedimentary deposits are occurred in the lower Duddar Formation(LDM) in stratified layers, which is conformable contact with the stratum. Based on mineral composition and spatial distribution, these deposits can be categorized into sphalerite, pyrite, and barite types. Hydrothermal filling metasomatic(stockwork) lead-zinc ores predominantly occur in limestone and mudstone of the Bamph member(AB) situated at the base of the middle Duddar member(MDM) and lower Duddar member(LDM). Sphalerite, galena, and barite within the ore primarily fill the stockwork and undergo metasomatism in the limestone and mudstone. Mineralogical analysis reveals that the metallogenic evolution of the Duddar Lead-Zinc Mine can be categorized into three distinct metallogenic periods: syngenetic sedimentary(stratabound/stratiform), hydrothermal, and epigenetic. The syngenetic sedimentary metallogenic period unfolds in three key mineralization stages: the stratiform zinc ore belt(Zn belt), stratiform pyrite belt(Py belt), and stratiform barite belt(Ba belt). The Duddar Lead-Zinc Mine is characterized as a polygenetic lead-zinc deposit, primarily featuring syngenetic mineralization and subsequent late-stage hydrothermal filling metasomatism.

       

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