| 青海大场金矿床流体包裹体特征及其地质意义 |
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| 引用本文：.2005.Fluid inclusion characteristics of Dachang gold deposit, Qinghai Province and their geological significance[J].Mineral Deposits,24(3):305~316 |
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| 基金项目:中国地质调查局国土资源大调查项目（200110200021、200310200012、200413000026）和国家重点基础研究发展规划项目(G1999043211) |
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| 中文摘要:采用Linkam冷热台和Renishaw激光拉曼光谱仪对大场金矿床石英-方解石中的原生流体包裹体进行了系统研究。结果表明，流体包裹体类型主要有气液两相、含CO2三相及富CO2包裹体。测温结果显示成矿流体温度为180～260℃，盐度w(NaCleq)为0.2%～8.3%，密度为0.69～0.78 g/cm3，计算成矿压力为40.33～86.69 MPa，由压力值估算成矿深度为5.03～7.63 km。成矿流体以H2O_CO2为主，含少量CH4、H2S、CO、N2及H2，并有微量的C2H2、C2H4、C2H6、C3H8及C6H6等有机质。成矿流体主要来源于大气降水，并混有建造水和少量岩浆水。在金的成矿作用过程中流体不混溶作用和有机质的存在起了重要作用。 |
| 中文关键词:地球化学 流体包裹体 地质意义 大场金矿床 青海 |
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| Fluid inclusion characteristics of Dachang gold deposit, Qinghai Province and their geological significance |
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| Abstract:Using advanced Linkam cooling_heating stage and Renishaw Laser Raman Spectrometer, the authors carried out systematic studies on the primary fluid inclusions in quartz and calcite from the Dachang gold deposit in Qinghai Province. The results show that quartz and calcite contain lots of primary fluid inclusions, which can be classified into aqueous two_phase type, CO2_bearing three_phase type and CO2_rich or pure CO2 type. Microthermometric studies indicate that the temperatures, salinities w(NaCleq) and densities of the ore_forming solutions vary from 180 to 260℃, 0.2% to 8.3%, and 0.69 to 0.78 g/cm3, respectively. The ore_forming fluids belong to the NaCl_H2O_CO2 type characterized by rich CO2, low_moderate temperature, low salinity, low density and strong reducibility. Meanwhile, the data of ore_forming pressure were also obtained from the fluid inclusion study. Based on the pressure and the relationship between the pressure and the depth of fracture zones, it is known that the ore_forming depth is 5.03～7.63 km. The ore_forming fluids are mainly composed of H2O and CO2, with minor amounts of CH4, H2S, CO, N2, H2 and trace amounts of such organic matters as C2H2, C2H4, C2H6, C3H8 and C6H6. The ore-forming fluids of the Dachang gold deposit were mainly derived from meteoric water mixed with formation water and a small amount of mantle_source magmatic water. Fluid immiscibi_lity and existence of organic matters play important roles in the gold mineralization process. |
| keywords:geochemistry, fluid inclusion, geological significance, Dachang gold deposit, Qinghai Province |
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