王文元, 高建国, 侬阳霞, 陈欣彬. 云南禄劝噜鲁铅锌矿床铷-锶同位素年代学与硫、铅同位素地球化学特征[J]. 地质通报, 2017, 36(7): 1294-1304.
    引用本文: 王文元, 高建国, 侬阳霞, 陈欣彬. 云南禄劝噜鲁铅锌矿床铷-锶同位素年代学与硫、铅同位素地球化学特征[J]. 地质通报, 2017, 36(7): 1294-1304.
    WANG Wenyuan, GAO Jianguo, NONG Yangxia, CHEN Xinbin. Rb-Sr isotopic geochronology and geochemical characteristics of S and Pb isotopes of the Lulu Pb-Zn deposit in Luquan, Yunnan Province[J]. Geological Bulletin of China, 2017, 36(7): 1294-1304.
    Citation: WANG Wenyuan, GAO Jianguo, NONG Yangxia, CHEN Xinbin. Rb-Sr isotopic geochronology and geochemical characteristics of S and Pb isotopes of the Lulu Pb-Zn deposit in Luquan, Yunnan Province[J]. Geological Bulletin of China, 2017, 36(7): 1294-1304.

    云南禄劝噜鲁铅锌矿床铷-锶同位素年代学与硫、铅同位素地球化学特征

    Rb-Sr isotopic geochronology and geochemical characteristics of S and Pb isotopes of the Lulu Pb-Zn deposit in Luquan, Yunnan Province

    • 摘要: 云南禄劝噜鲁铅锌矿床地处扬子地块西南缘,矿体赋存于下寒武统梅树村组下段,呈脉状、似层状产出。矿石矿物主要有方铅矿、闪锌矿、黄铁矿等;脉石矿物主要有重晶石、石英、方解石。噜鲁铅锌矿床硫化物成矿时的87Sr/86Sr值为0.7112~0.7115,暗示成矿物质可能来自于基底地层;Rb-Sr等时线年龄为202.8±1.4Ma,成矿年龄为印支晚期-燕山早期。硫化物硫同位素组成δ34S变化范围为6.33‰~9.75‰,暗示成矿流体中的硫主要是海相硫酸盐热化学还原的产物;铅同位素206Pb/204Pb、207Pb/204Pb、208Pb/204Pb变化范围分别为18.259~18.342、15.608~15.639、38.46~38.821,位于上地壳和造山带铅演化线之间,落入基底岩石(昆阳群)及不同时代碳酸盐岩铅同位素组成范围内,表明成矿物质具有壳源特征,主要由基底岩石提供。综合各类地质-地球化学信息认为,噜鲁铅锌矿床成矿流体中不同组分来源不同,但主要来自于基底地层,成矿机制是在印支运动强驱动力的作用下,促使含矿基底地层成矿元素活化-迁移混合-空间就位,形成工业矿床。

       

      Abstract: The Lulu Pb-Zn deposit is located on the western margin of Yangtze Block and is hosted in the dolostone of Cambrian Meishucun Formation. Ore minerals are mainly galena, sphalerite and pyrite, Gangue minerals are mainly quartz, calcite and barite. The 87Sr/86Sr ratios of sulfides are 0.7112~0.7115, indicating that the ore-forming materials were derived from basements. Rb-Sr isochron age of sphalerite is 223.5±2.9Ma, suggesting Late Indosinian to Early Yanshanian period. The δ34S ratios of S isotope of sulfides in the deposit range from 9.72‰ to 22.44‰. The δ34S values of S isotope of barite in the deposit range from 26.08‰ to 29.34‰. These data suggest that the reduced sulfur in the ore-forming fluids was the product of thermo-chemical sulfate reduction. The range of 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb are respectively from 18.259 to 18.342, from 15.608 to 15.639, and from 38.460 to 38.821. Pb isotope compositions lie in the region between the upper crust and the orogenic Pb area and fall into the field of basement rocks, which indicates that the crust source of ore-forming metals was mainly supplied by basement rocks. All the geological and geochemical information shows that the source of ore-forming metals and the fluid of the Lulu Pb-Zn deposit were the mixed products derived mainly from basement strata. The mineralization was caused by strong driving force of Indosinian movement, which prompted activation, migration, mixture and spatial emplacement of the ore-containing basement strata with ore-forming elements, thus forming industrial deposit.

       

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