投稿时间：2012-07-04
修订日期：2012-10-15
中文摘要:恰夏铜矿床位于新疆阿尔泰山南缘克兰火山-沉积盆地内,赋矿地层主要为下泥盆统康布铁堡组上亚组变质岩系。脉状铜矿化主要特征为:早期顺层石英脉,呈脉状或透镜状沿变质片理分布,有星点状黄铁矿产出;晚期含铜黄铁矿-石英脉,斜切变质围岩,黄铜矿以浸染状分布于石英脉裂隙中。石英脉中流体包裹体主要为富CO2包裹体,其次为水溶液包裹体,同时含有少量的碳质流体包裹体。显微测温研究表明,早期顺层石英中原生富CO2流体包裹体,CO2三相点温度(tm,CO2)集中在-61.5~-57.5℃,CO2部分均一温度(th,CO2)集中在25~27℃,完全均一温度(th,tot)集中于223~280℃,流体密度为0.82~0.90 g/cm3; 含铜黄铁矿-石英脉中原生富CO2包裹体的tm,CO2集中于-61.5~-58.7℃,th,CO2集中在23.5~28.7℃,th,tot集中在230~310℃,流体密度0.81~0.86 g/cm3。成矿流体为中高温、中低盐度、富CO2的CO2-H2O-NaCl±CH4±N2体系。恰夏铜矿脉状铜矿化的成矿流体特征与造山型金矿床的流体包裹体特征类似,结合矿床产出的地质背景、控矿构造特征,认为脉状铜矿化的成因与造山-变质热液有关,是阿尔泰山南缘晚泥盆世—二叠纪造山-变质作用的产物。SRXRF测试富CO2流体包裹体中金属微量元素,显示其富集Au,可能表明富CO2流体对金的富集起到一定作用。
Abstract:Located in Kelan volcanic-sedimentary basin on the southern margin of the Altay Mountains in Xinjiang, the Qiaxia copper deposit occurs in Lower Devonian Kangbutiebao Formation. Veined copper mineralization is characterized by two types of quartz veins: ① the early quartz veins (Q1) occurring in lenticular or streaked form parallel to the foliation of the meta-crystal tuff and meta-basic volcanic rocks; ② copper-bearing pyrite-quartz veins (Q2) with disseminated chalcopyrite cutting meta-mafic volcanic rocks and magnetite quartzite. Fluid inclusions are abundant in various quartz veins, especially CO2-rich inclusions (LH2O-LCO2), with lots of aqueous inclusions and very little carbonic fluid inclusions. Microthermometric studies show that solid CO2 melting temperatures (tm,CO2) of early stage quartz (Q1) are concentrated in the range of-61.5~-57.5℃, and partial homogenization temperatures (th,CO2) vary from 25℃ to 27℃, with the densities being 0.82~0.90 g/cm3. The total homogenization temperatures (th,tot) for these inclusions range from 223℃ to 280℃. Copper-bearing pyrite-quartz veins (Q2) have tm,CO2 of-61.5~-58.7℃ and th,CO2 of 23.5~28.7℃, with densities being 0.81~0.86 g/cm3. The homogenization temperatures (th,tot) for Q2 range from 230℃ to 310℃. The ore-forming fluids of the Qiaxia copper deposit are similar to those of orogenic gold deposits, and are characterized by a CO2-rich, low salinity, and CO2-H2O-NaCl±CH4±N2 system. According to the geological setting, ore-controlling structures, and fluid inclusion characteristics, the veined copper mineralization in the Qiaxia copper deposit should be genetically related to orogenic and metamorphic hydrothermal fluids. The Qiaxia copper deposit was formed during orogeny and regional metamorphism in Late Devonian and Permian. The SRXRF tests indicate that the minor elements are rich in Au, suggesting that the CO2-rich fluid might have had some relationship with gold enrichment.
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中图分类号：P618.41
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基金项目:本研究得到国家自然科学基金(40972066);国家科技支撑计划资助项目(新疆305项目2007BAB25B01)和中国科学院高能物理研究所BSRF项目共同资助
引用文本：
杨蕊,徐九华,林龙华,郭旭吉,肖星,陈栋梁.2013.阿勒泰恰夏铜矿床的富CO2流体与矿床成因[J].矿床地质,32(2):323~336YANG Rui,XU JiuHua,LIN LongHua,GUO XuJi,XIAO Xing,CHEN DongLiang.2013.CO2-rich fluid inclusions and ore genesis of Qiaxia copper deposit in Altay area[J].Mineral Deposits32(2):323~336
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