投稿时间：2020-06-30
修订日期：2020-09-23
网络发布日期：2021-01-08
中文摘要:西藏多龙矿集区是中国新发现的具有世界级规模的铜金矿集区。目前，该矿集区的中部和北部已发现多个斑岩型和斑岩-浅成低温热液型矿床，而区内西南部也发现了多个铜金矿床，指示了良好的找矿潜力。拿顿是矿集区内西南部具有代表性的铜金矿床，矿化类型为浅成低温热液型。野外地质调查表明，该矿床成矿作用可分为2个阶段，早阶段矿化主要赋存于角砾岩筒中，并与角砾岩筒同时形成，而晚阶段矿化主要以脉体形式产出，切穿角砾岩筒及早阶段矿化。年代学研究结果显示，角砾岩筒中以角砾形式产出的花岗闪长斑岩锆石U-Pb年龄为（117.5±0.7）Ma，被后期花岗闪长斑岩（116.1±1.3Ma）侵入，由此指示角砾岩筒及早阶段矿化形成于116~117 Ma。此外，明矾石40Ar-39Ar年代学研究进一步表明，晚阶段石英-明矾石-硫化物脉形成于（111.3±2.5）Ma，这也证实该矿区成矿作用具有多阶段性特征。文章结果指示，拿顿铜金矿可能存在多期与浅成低温热液型矿化有关的成矿岩体，并且多龙矿集区内也可能存在更多形成于111 Ma而未被发现的矿床。
Abstract:The Duolong Cu-Au district, located in central Tibet, is a newly discovered world-class metallogenic district in China. At present, a number of porphyry and porphyry-epithermal deposits have been discovered in the central and northern parts of the district; meanwhile, several Cu-Au deposits have also been discovered in the southwestern part, implying a promising exploration potential in this region. Nadun is a representative epithermal Cu-Au deposit that located in the southwestern part. Based on field investigation, the Cu-Au mineralization could be divided into two stages, the early-stage mineralization, hosted by the breccia pipe, coincided with the formation of breccia pipe, and the late-stage veins cut the breccia pipe and the early-stage mineralization。Zircon U-Pb geochorology suggested the granodiorite clast from the breccia pipe formed at (117.5±0.7)Ma, whereas previous stu-dies indicated the breccia pipe was intruded by a granodiorite porphyry dated at (116.1±1.3)Ma, implying the breccia pipe and associated Cu-Au mineralization formed at 116~117 Ma. In addition, alunite 40Ar-39Ar geochorology revealed that quartz-alunite-sulfide veins that truncated the breccia pipe formed at (111.3±2.5) Ma, indicating the Nadun deposit was featured by episodic ore-forming events. Our study highlights the possibility of locating multiple causative porphyry intrusions in the Nadun deposit and the Duolong district as well.
keywords:geochemical zircon U-Pb geochorology alunite 40Ar-39Ar geochorology epithermal mineralization Nadun Cu-Au deposit Duolong district
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基金项目:本文得到国家重点研发计划项目（编号：2017YFC0601403）、国家自然科学基金青年科学基金项目（编号：41902098）和中国地质调查局地质调查工作项目（编号：1212011120994）联合资助
引用文本：
孙嘉,毛景文,王佳新,姚佛军,李玉彬.2020.西藏多龙矿集区拿顿铜金矿床成矿时代的厘定及其找矿指示意义[J].矿床地质,39(6):1091~1102SUN Jia,MAO JingWen,WANG JiaXin,YAO FuJun,LI YuBin.2020.Timing of Cu-Au mineralization in Nadun Cu-Au deposit of Duolong district, Tibet, and its implication for mineral exploration[J].Mineral Deposits39(6):1091~1102
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