陕西青山金矿床金的迁移形式与沉淀机制研究  

TRANSPORTING STYLE AND DEPOSITIONAL MECHANISM OF GOLD IN THE QINGSHAN GOLD DEPOSIT,SHAANXI PROVINCE

作　　者：周云[1] 段其发[1] 陈兵[2] 黄惠兰[1] 李芳[1] 

机构地区：[1]中国地质调查局武汉地质调查中心,湖北武汉430205 [2]中铁二院成都地勘岩土工程有限责任公司,四川成都610031

出　　处：《地质与资源》2012年第6期546-551,共6页Geology and Resources

基　　金：国家973项目(2011CB403103);中国地质调查局"扬子型铅锌矿成矿规律研究与选区评价"项目(1212011120790)联合资助

摘　　要：青山金矿床是一个赋存于石炭系沉积岩中的中-小微细粒浸染型金矿床.采用原子吸收光谱、气相色谱仪等分析技术,利用地球化学热力学理论,对青山金矿床开展了成矿流体成分分析和热力学计算,解析了该矿床成矿物理化学条件及金的迁移形式和沉淀机制.结果显示,成矿流体呈弱酸性、弱还原性,为重碳酸钙亚型,可大致视为CO2-H2O-NaCl体系,来源于古大气降水,并且后期受到了大气降水的混合.成矿早期流体中的金主要以氯络合物形式[Au(Cl)4]-迁移,主成矿期与晚期流体中金以硫络合物形式[Au(HS)2]-迁移.成矿流体温度、盐度、pH值、Eh值、氧逸度等物理化学条件的变化、后期大气降水的混合、水-岩反应及硫酸盐还原菌是造成本矿床金沉淀的主要因素.The small-medium sized Qingshan gold deposit in Shaanxi Province, hosted in the Carboniferous sedimentary rocks, is of micro-fine dissemination type. The fluid inclusion is examined by atomic absorption spectrometry and gas chromatograph. Based on geochemical thermodynamics theory, the physical-chemical conditions of mineralization and the transportation style and deposition mechanism of the deposit are studied. The result shows that the metallogenic fluid is in weakly acid and reduced, belonging to calcium bicarbonate type, generally regarded as CO2-H2O-NaC1 system, mainly derived from ancient meteoric water, and mixed with the meteoric water during later period. The gold in the metallogenic fluid transported as Au-C1 complex [Au （HS）2]- in early mineralization stage, while as Au-S complex [Au （HS）：]- in main and late stages. Change of physical-chemical conditions, such as temperature, salinity, pH, Eh and oxygen fugaeity, as well as the mixing of meteoric water, water-rock reaction and sulfate reducing bacteria are the main factors causing the precipitation of gold.

关 键 词：成矿流体 金络合物 迁移和沉淀 青山金矿床 陕西省 

分 类 号：P618.51[天文地球—矿床学]