西藏甲玛斑岩成矿系统铜钼元素分离机制探讨

发布时间：2018-05-07 10:40

  本文选题：铜钼分离 + 成矿流体　； 参考：《岩石学报》2017年02期

【摘要】：西藏甲玛矿床是冈底斯成矿带中东段目前勘查程度最高、第一个规模化开发的超大型斑岩成矿系统,主要由矽卡岩铜多金属矿体、斑岩钼(铜)矿体以及角岩铜钼矿体构成。文章以甲玛矿床角岩矿体和斑岩矿体中典型的"上铜下钼"现象为切入点,借助流体包裹体显微测温、激光拉曼测试、同步辐射X射线荧光分析(SR-XRF)等研究方法,分析了甲玛矿床铜钼矿化阶段成矿流体的物化条件差异及微量元素迁移行为。流体包裹体研究结果表明:铜矿化阶段流体温度(大致在235~451℃,主要集中在340~380℃之间)总体上大于钼矿化阶段流体温度(大致在213~500℃,主要集中在310~360℃之间),但两种成矿流体的盐度大致相似,主要位于18%NaCleqv与30%NaCleqv这两个区间,缺乏盐度中间过渡区,说明成矿流体经历了沸腾作用。激光拉曼显微探针测试结果表明,Cu矿化阶段的流体氧化性较Mo矿化阶段更强,而Mo矿化阶段流体略呈还原性。单个流体包裹体同步辐射X射线荧光分析显示,Cu、Au、Fe、Mn、S、As等元素主要在气相中广泛分布,而Mo则主要残留在液相中迁移富集。因此,本文认为甲玛矿床中角岩型和斑岩型矿体呈现"上铜下钼、早铜晚钼"现象,主要由铜、钼元素本身的物化性质,含矿岩浆性质和侵位顺序与深度,以及含矿岩浆后期所分异出的成矿流体的氧化还原性以及其中S含量的差异所致。
[Abstract]:Jiama deposit in Tibet is the highest exploration level in the eastern section of the Gangdis metallogenic belt at present. The first large-scale porphyry metallogenic system developed on a large scale is mainly composed of skarn copper polymetallic orebody porphyry molybdenum ore body and hornstone copper-molybdenum ore body. In this paper, the typical "upper copper and lower molybdenum" phenomena in the hornstone and porphyry orebodies of Jiama deposit are taken as the starting point, and the research methods such as fluid inclusion microthermometry, laser Raman measurement, synchrotron radiation X-ray fluorescence analysis (SR-XRF) and so on are used. The difference of physical and chemical conditions and trace element migration behavior of ore-forming fluids in copper and molybdenum mineralization stage in Jiama deposit were analyzed. The results of fluid inclusion study show that the fluid temperature in copper mineralization stage (about 235U 451 鈩，

本文编号：1856598