| 西藏谢通门县雄村铜金矿床元素地球化学特征 |
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| 引用本文：TANG JuXing,HUANG Yong,LI ZhiJun,DENG Qi,LANG XingHa ,CHEN Yuan,ZHANG Li.2009.Element geochemical characteristics of Xiongcun Cu_Au deposit in Xaitongmoin County, Tibet[J].Mineral Deposits,28(1):15~28 |
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| 基金项目:国家科技支撑项目（编号2006BAB01A01）、天圆公司项目、青藏专项（编号1212010818089）、国家基础研究计划"印度_亚洲大陆主碰撞带成矿作用"973项目(2002CB412607) |
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| 中文摘要:已经查明西藏雄村铜金矿床的Cu 、Au资源量达到超大型规模。通过对雄村铜金矿床Ⅰ号矿体详细的地质编录和测年成果，发现雄村斑岩型铜（金）矿床形成于晚侏罗世，矿体的形成与晚侏罗世侵位的、含眼球状石英斑晶的闪长玢岩（J3δομ）有关，成矿岩体呈不规则的岩枝状，全岩矿化，岩体中Au的平均品位大于1g/t，Cu含量大于0.7 %。含矿围岩是早、中侏罗世的凝灰岩，近岩体部分矿化强烈。矿体被后期侵位的多种岩脉穿插，并被始新世侵位的谢通门大岩基黑云母花岗闪长岩穿插和破坏，岩脉的Cu、Au、Ag含量极低，黑云母花岗闪长岩（E2γδβ）Cu、Au、Ag的平均品位（733件样品分析结果统计）分别为0.0091%、0.0053 g/t、0.279 g/t；成矿前侵位的角闪石英闪长玢岩（J2δομ）Cu、Au、Ag的平均
品位（1 414件样品分析结果统计）分别为0.0105%、0.048 g/t、0.395 g/t；穿插矿体
的安山岩脉Cu、Au、Ag的平均品位（527件样品分析结果统计）分别为0.065%、0.068 g/t、
0.728 g/t，穿插矿体的闪长岩脉的Cu、Au、Ag的平均品位（87件样品分析结果统计）分别
为0.081%、0.091 g/t、0.818 g/t。根据167个勘探钻孔编录和化学分析（24369件化学
分析样品）资料，以及对海拔4000 m、3950 m、3900 m水平面的Cu、Au、Ag、Mo、Mn、P
b、Zn、W、K、Na、Ca、Rb元素分布规律的分析，显示矿体具有斑岩型矿床的蚀变、矿化以及元素地球化学特征，主要矿化和围岩蚀变在时间上和空间上均与含眼球状石英斑晶的角闪石英闪长玢岩（J3δομ）有关。成矿期间与矿化热液活动有关的蚀变主要有：①早期钾硅酸盐化；②红柱石次生石英岩化（硅化）；③黄铁绢英岩化；④青磐岩化。成矿期形成的脉体
类型主要有早期石英_红柱石_硫化物脉、红柱石_黑云母_硫化物脉、磁铁矿_黑云母_硫化物脉、富黄铜矿硫化物脉、黄铁矿脉和多金属矿脉。从矿体中心向外，元素具有明显的分带特征。在矿体中心局部，由于红柱石_次生石英岩化蚀变作用强烈，致使K、Rb等元素向外迁移。矿石富K贫Na，以及K与Rb具有良好的相关性的特点均与国内外典型的斑岩铜矿床相似。
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| 中文关键词:地质学 热液活动 元素地球化学 雄村斑岩型铜金矿床 冈底斯成矿带 西藏 |
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| Element geochemical characteristics of Xiongcun Cu_Au deposit in Xaitongmoin County, Tibet |
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| Abstract:The Xiongcun copper_gold deposit is a newly_discovered copper_gold deposit with resources of Cu and Au up to the superlarge size. This study was only focused on the No.Ⅰore body. Based on detailed logging and dating results, it is considered that mineralization of the Cu_Au porphyry occurred in Late Jurassic. The formation of the ore body is related to the Late Jurassic augen quartz phenocryst_bearing hornblende_quartz diorite porphyrite intrusion（J3δομ）. The intrusion occurs as totally mineralized irregular apophyses. The average grades of Au and Cu are higher than 1 g/t and 0.7 %. The wall rock is Early_Middle Jurassic tuff. Some parts of the ore body around the intrusion have been strongly mineralized. The ore body is cut and destroyed by various later dykes and Eocene biotite granodiorite batholith. The contents of Cu, Au, and Ag of the later intrusions or dykes are very low. Biotite granodiorite (E2γδβ) contains averagely 0.0091 % Cu, 0.0053 g/t Au, 0.279 g/t Ag (statistics of 733 samples). Hornblende_quartz diorite porphyry contains 0.0105 % Cu, 0.048 g/t Au, 0.395 g/t Ag (statistics of 1 414 samples). Andesite dykes contain 0.065% Cu, 0.068 g/t Au, 0.728 g/t Ag (statistics of 527 samples). Diorite dykes contain 0.081 % Cu, 0.091 g/t Au, 0.818 g/t Ag (statistics of 87 samples). According to logging results of 167 boreholes and chemical analyses of 24 369 samples as well as characteristics of element distribution at 4 000 m, 3 950 m and 3 900 m levels, the deposit is characterized by alteration, mineralization and element geochemistry of the porphyry. Alteration and mineralization are spatially and temporally related to the augen quartz phenocryst_bearing hornblendequartz diorite porphyrite (J3δομ). The main ore_stage alterations related to hydrothermal fluids include ①early K_silicate alteration, ②silicification, ③ pyrite_sericite_quartz alteration and ④propylitization. The main ore_stage vein types include early quartz_andalusite_sulfide, andalusite_biotite_sulfide, magnetite_biotite_sulfide, chacopyrite_rich sulfide, pyrite and polymetallic veins. Elements show clear zoning from the ore center outwards. K and Rb migrated outward due to strong andalusite_secondary silicified alteration at the center of the ore body. The ore body is characterized by rich K and poor Na. K and Rb also show a good relationship. These characteristics are similar to things of typical porphyry deposits in China and abroad. |
| keywords:geology, hydrothermal activity, element geochemistry, Xiongcun porphyry Cu_Ag deposit, Gangdese metallogenic belt, Tibet |
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