云南东川大笑铅锌矿床矿物学特征与成矿温度

    An analysis of mineralogical characteristics and mineralization temperature of the Daxiao Pb-Zn deposit in Dongchuan, Yunnan Province

    • 摘要: 云南东川大笑铅锌矿床地处康滇地轴中段东沿的次一级隆起上,矿体赋存于白河厂背斜轴部南翼昆阳群望厂组的层间裂隙及羽状裂隙中,呈脉状、似层状产出。矿石矿物主要为方铅矿、银和少量闪锌矿、黄铁矿,脉石矿物主要为石英、方解石。矿石结构以自形-半自形-他形粒状结构、交代残余结构、变晶结构为主。矿石构造以浸染状、块状、条带状、脉状构造为主。成矿作用划分为热液成矿期与表生氧化期,其中热液成矿期划分为3个成矿阶段,第二成矿阶段为铅锌的主要成矿阶段,成矿温度为140~220℃,成矿时代为印支晚期。工业矿体的形成是在印支运动强大的作用力驱动下,成矿元素活化-混合-迁移-聚集成矿,矿床成因类型为沉积-改造热液矿床。

       

      Abstract: The Daxiao Pb-Zn deposit is located on the secondary level uplift along the middle east part of the Kang-Dian axis, in Dongchuan, Yunnan Province.Its orebodies show veined and stratoid forms, and occur in interstratified crack and plume-like frac-ture of Wangchang Formation in Kunyang Group which lies in the south of Baihechang anticline.The ore minerals are composed of galena, native silver and a small quantity of sphalerite and pyrite, and the gangue minerals include quartz and calcite.Their textures mainly consist of euhedral-subhedral-anhedral granular texture, metasomatic relict texture and crystalloblastic texture, while main structures are disseminated structure, massive structure, banded structure and vein structure.Mineralization of this deposit could be di-vided into hydrothermal metallogenesis and supergenetic oxidation period, the former was made of three mineralization stages and the most important stage for Pb-Zn was the second stage, its metallogenic temperature ranged from 140℃ to 220℃, while metallogenic epoch was late Indosinian.Industrial ore was formed by the driving force of Indosinian movement that prompted activation-mix-ing-migration-accumulation of ore-forming elements to form the deposit.The genetic type of the ore deposit belongs to sedimenta-ry reformation hydrothermal ore deposit.

       

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