兰家沟钼矿成矿热力学参数研究  

Study on metallogenic thermodynamic parameters of Lanjiagou molybdenum deposit

作　　者：郭洋 刘立东 褚少雄[3] 李永兵 闫全人 石耀霖 GUO Yang;LIU Lidong;CHU Shaoxiong;LI Yongbing;YAN Quanren;SHI Yaolin(Key Laboratory of Computational Geodynamics of CAS,College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;School of Civil and Resource Engineering,University of Science and Technology Beijing,Beijing 100083,China;Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China)

机构地区：[1]中国科学院大学地球与行星科学学院中国科学院计算地球动力学重点实验室,北京100049 [2]北京科技大学土木与资源工程学院,北京100083 [3]中国科学院地质与地球物理研究所,北京100029

出　　处：《中国科学院大学学报（中英文）》2019年第6期810-816,共7页Journal of University of Chinese Academy of Sciences

基　　金：全国危机矿山接替资源综合研究项目(20089931);国家科技支撑计划项目(2011BAB03B09)资助

摘　　要：成矿热力学参数是矿床成因研究的重要内容,共生的矿物必然能共同反映其形成时的成矿热力学环境。基于此,通过分析兰家沟钼矿不同成矿阶段的矿物共生组合,利用流体包裹体测定不同成矿阶段的成矿温度和压力范围,并基于热力学计算获得不同成矿阶段的矿物共生组合相图,进而得到兰家沟钼矿床3个成矿阶段的成矿热力学参数。在石英斑晶阶段,氧逸度的区间范围为10^-40~10^-25,硫逸度的区间范围为10^-40~10^-5。在斑岩型矿化阶段,pH值为6.9~6.1,氧化还原电位在-1.3~0.3 V。在石英大脉型矿化阶段,氧逸度应小于10^-13,硫逸度为10^-14~10^-6,矿床的成矿环境属于弱还原环境。这些研究结果有助于对兰家沟钼矿成矿环境的认识。The thermodynamic parameters of ore-forming process are the important content of the genesis of the deposits, and the paragenetic minerals inevitably show the metallogenic thermodynamic environment during their formation. Based on this, the mineral assemblages at different metallogenic stages in Lanjiagou molybdenum deposit are evaluated and three mineralization stages are determined. Then the ore-forming temperatures and pressure ranges of the three mineralization stages are obtained by measuring the temperatures of the inclusions, the phase diagrams of the paragenetic compositional minerals at the different mineralization stages are calculated, and the metallogenic thermodynamic parameters of the three metallogenic stages in Lanjiagou molybdenum deposit are estimated. At the stage of quartz phenocryst, the oxygen fugacity ranged from 10^-40 to 10^-25, while the sulfur fugacity ranged from 10^-40 to 10^-5. At the porphyry mineralization stage, the pH value of the ore deposits was about 6.9-6.1, the oxidation-reduction potential was between-1.3 and 0.3 V. At the quartz large vein mineralization stage, the oxygen fugacity was less than 10^-13, the sulfur fugacity ranged from 10^-14 to 10^-6, and the ore deposit was in a weakly reducing environment. All these results help to understand the metallogenic environment of Lanjiagou molybdenum deposit.

关 键 词：兰家沟钼矿 pH值 硫逸度 氧逸度 矿物共生组合 流体包裹体 

分 类 号：P618.65[天文地球—矿床学]