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福建紫金山金铜矿床下部铜矿体流体包裹体均一温度测量及地质意义
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Abstract:
紫金山金铜矿床是世界级的超大型矿床，具有上金下铜的分带特征，上部金矿已开采完毕，中下部铜矿体尚未圈闭，开展流体包裹体均一温度测量对确定成矿的热源中心和找矿方向研究具有重要的指导意义。本文在野外地质调查、流体包裹体样品采集、岩相学观察的基础上，对露天采矿场海拔560~580 m平台与铜矿体共生的蚀变石英、明矾石开展了流体包裹体均一温度和冰点温度的测量，结果表明：流体包裹体主要有液相包裹体、气相包裹体、CO2包裹体以及少量含子矿物多相包裹体4种类型；流体包裹体均一温度范围为120.9℃~430.1℃，主要集中于160℃~220℃和360℃~380℃，显示具有2个成矿温度峰值，可能暗示具有2次成矿作用；冰点温度？0.1℃~？13.0℃，对应盐度为0.18% NaCl eqv~16.89% NaCl eqv。根据流体包裹体均一温度中较高温度峰值绘制的流体包裹体均一温度等值线图显示成矿热源来自矿区的东南侧深部，并向南东方向倾伏，指示矿区东南侧深部仍具有较大的找矿前景。
The Zijinshan gold-copper deposit is a world-class super-large deposit with the zoning characteristics of upper gold and lower copper. The upper gold deposit has been mined, and the middle and lower copper ore bodies have not yet been trapped. The homogenization temperature measurement of fluid inclusions has important guiding significance for determining the heat source center and prospecting direction of mineralization. Based on field geological survey, fluid inclusion sample collection and petrographic observation, the homogenization temperature and freezing point temperature of fluid inclusions in altered quartz and alunite associated with copper ore bodies at an altitude of 560-580m in open-pit mining sites were measured. The results show that there are four types of fluid inclusions: liquid inclusions, gas inclusions, CO2 inclusions and a small amount of daughter mineral-bearing multiphase inclusions. The homogenization temperature range of fluid inclusions is 120.9℃~430.1℃, mainly concentrated in 160℃~220℃ and 360℃~380℃, showing two mineralization temperature peaks, which may imply two times mineralizations. The freezing point temperature was ？0.1℃~？13.0℃, and the corresponding salinity was 0.18% NaCl eqv~16.89% NaCl eqv. The homogenization temperature contour map of fluid inclusions drawn according to the higher temperature peak in the homogenization temperature of fluid inclusions shows that the ore-forming heat source comes from the deep part of the southeast side of the mining area and is inclined to the southeast direction, indicating that the deep part of the southeast side of the mining area still has great prospecting potential.
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