青海大场金矿床流体包裹体特征及其地质意义  

Fluid inclusion characteristics of Dachang gold deposit, Qinghai Province and their geological significance

作　　者：赵财胜[1,2] 孙丰月[3] 毛景文[1,4] 丁清峰[3] 赵俊伟[3,5] 李世金[3,5] 

机构地区：[1]中国地质科学院矿产资源研究所 [2]吉林大学地球科学学院,吉林长春130061 [3]吉林大学地球科学学院 [4]中国地质大学地球科学与资源学院,北京100083 [5]青海地质调查院,青海西宁810001

出　　处：《矿床地质》2005年第3期305-316,共12页Mineral Deposits

基　　金：中国地质调查局国土资源大调查项目(200110200021;200310200012;200413000026);国家重点基础研究发展规划项目(G1999043211)的资助

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0.69~0.78g/cm3,计算成矿压力为40.33~86.69MPa,由压力值估算成矿深度为5.03~7.63km。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。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, CO_2-bearing three-phase type and CO_2-rich or pure CO_2 type. Microthermometric studies indicate that the temperatures, salinities w(NaCl_(eq)) and densities of the ore-forming solutions vary from 180 to 260℃, 0.2% to 8.3%, and 0.69 to 0.78 g/cm^3, respectively. The ore-forming fluids belong to the NaCl-H_2O-CO_2 type characterized by rich CO_2, 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 H_2O and CO_2, with minor amounts of CH_4, H_2S, CO, N_2, H_2 and trace amounts of such organic matters as C_2H_2, C_2H_4, C_2H_6, C_3H_8 and C_6H_6. 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.

关 键 词：地球化学 流体包裹体 地质意义 大场金矿床 青海 

分 类 号：P618.51[天文地球—矿床学]