反应输运数值建模对矽卡岩矿床分带性的研究——以青藏甲玛斑岩-矽卡岩型铜多金属矿床为例

    Reaction transport numerical modeling on the zonation of skarn deposits: A case study of the Jiama porphyry-skarn Cu-polymetallic deposit in Tibet, China

    • 摘要:   
        青藏甲玛斑岩-矽卡岩型铜多金属成矿系统中的矽卡岩矿体具有独特的金属矿物和矽卡岩矿物分带性。当前,对于矽卡岩矿床成矿作用的数值模拟研究较为缺乏。为推进矽卡岩矿床成矿过程的动态化和定量化,本研究依据甲玛矿床矽卡岩矿体的勘探线剖面和流体包裹体数据,建立热传递-流体流动-化学反应耦合的二维反应输运数值模拟模型,旨在研究甲玛矿床矽卡岩矿体的矿物分带性特征的形成机制。模型结果表明,甲玛矿床矽卡岩矿体的矿物分带性主要由成矿有利温度、氧化还原状态、pH值、HS-浓度和Fe2+浓度控制。其中,氧化还原状态控制矽卡岩石榴子石中钙铁榴石和钙铝榴石的比例,成矿有利温度、pH值和HS-浓度控制铅、锌和钼的沉淀,铜沉淀与Fe2+浓度密切相关。
       

       

      Abstract:   
        The skarn ore body of Jiama porphyry and skarn type copper-polymetallic mineral system, Tibet, China has a unique mineral zoning of metal and skarn minerals. At present, there are few numerical simulation studies on the mineralization of skarn deposits. In order to promote the dynamic and quantification of the mineralization process of the skarn deposit, a two-dimensional numerical simulation model coupling thermal transfer, fluid flow and chemical reaction has been established based on the exploration line profile and fluid inclusion data of the skarn ore body in the Jiama deposit, aiming at studying the formation mechanism of mineral zonation characteristics of the skarn ore body in the Jiama deposit. The model results show that the mineral zonation of skarn ore body in Jiama deposit is mainly controlled by favorable metallogenic temperature, redox state, pH value, HS- concentration and Fe2+ concentration. Among them, the redox state controls the proportion of calcium-iron garnet and calcium-aluminum garnet in skarn garnet, the favorable temperature, pH value and HS- concentration control the precipitation of lead, zinc and molybdenum, and the precipitation of copper is closely related to the concentration of Fe2+.

       

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