云南绿春大马尖山钨多金属矿床流体包裹体特征及成矿机制探究  

Study on fluid inclusion characteristics and metallogenic mechanism of the Damajianshan tungsten polymetallic deposit in Lüchun,Southwest China

作　　者：张贵山[1] 孟乾坤 张磊[1] 温汉捷 邱红信[1] 彭仁 秦朝建 ZHANG Guishan;MENG Qiankun;ZHANG Lei;WEN Hanjie;QIU Hongxin;PENG Ren;QIN Chaojian(School of Earth Science and Resources,Chang’an University,Xi'an,Shaanxi 710054,China;State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang,Guizhou 550081,China)

机构地区：[1]长安大学地球科学与资源学院,陕西西安710054 [2]中国科学院地球化学研究所矿床地球化学国家重点实验室,贵州贵阳550081

出　　处：《地质学报》2022年第7期2464-2478,共15页Acta Geologica Sinica

基　　金：中央高校基本科研业务费(编号300102271301);国家重点研发计划项目(编号2017YFC0602500);国家自然科学基金项目(编号41173026)联合资助的成果。

摘　　要：为探究三江南段钨多金属矿床的成矿流体特征、演化及矿床成因,选取了云南绿春大马尖山钨多金属矿床为研究对象,对其512 m中段至889 m中段的铜矿化和钨矿化石英脉中的原生流体包裹体进行包裹体测温、激光拉曼等研究。研究结果表明,该矿床中主要发育气液两相型包裹体(Ⅰ型),另有少量的含子晶包裹体(Ⅱ型)、富甲烷包裹体(Ⅲ型),未见纯气相、纯液相包裹体;铜矿化石英中流体包裹体均一温度为165~335℃,盐度为4.2%~16.7%NaCleq;钨矿化石英中流体包裹体均一温度为199~265℃,盐度为2.6%~23.7%NaCleq,有少量以石盐为主的子晶矿物,流体盐类溶质从NaCl、 KCl、 MgCl_(2)为主逐步演化为CaCl_(2)为主,成矿压力为17.85~48.90 MPa,深度为0.67~1.85 km;激光拉曼光谱分析结果表明,大马尖山钨多金属矿床各中段成矿流体成分相似,以H_(2)O、CH_(4)为主,伴有少量N_(2)及微量的CO_(2)。在同一中段内两种矿化流体包裹体的均一温度相近,盐度相差较大,CH_(4)、CO_(2)含量也有较大的差异,这可能由于铜矿化流体经热化学硫酸盐还原反应(TSR)演化过程造成的,与钨矿化流体演化存在明显差异。氯化物的参与是大马尖山钨多金属矿床中W元素的运移和富集的主导因素,同时也受F~-、Ca^(2+)含量以及锰方解石、黑钨矿活度积的控制,形成了“上白(钨)下黑(钨)”且以白钨矿为主的钨矿体。从矿体的深部到浅部,成矿流体中的H、O同位素组成发生了显著变化(呈弱负相关),根据水岩反应中H、O同位素组成演化趋势,推测成矿流体与围岩之间发生了水岩反应。基于以上研究成果,认为大马尖山钨多金属矿床成矿流体是由岩浆水、大气降水构成,同时发生了水岩交换反应,成矿流体在迁移演化过程中,由于温度、压力、挥发份等物理化学条件的改变,以石英斑岩为中心,向外依次形成W、Cu-As、Pb-Zn等矿化带,形成钨多金属�To investigate the ore-forming fluid characteristics,evolution and genesis of the tungsten polymetallic deposits in the southern part of Sanjiang Tethyan,the Damajianshan tungsten polymetallic deposit in Lvchun,Yunnan,southwest China were selected as the research object.We carried out a detailed petrographic,microthermomertic and laser Raman spectroscopy study of the primary fluid inclusions in the copper mineralization and tungsten mineralization quartz veins from 512 m to 889 m level of the Damajianshan deposit.The results indicate that(i) the types of fluid inclusions are mainly gas-liquid phase inclusions(type Ⅰ),with a few subcrystal-bearing inclusions(type Ⅱ),and methane-rich inclusions(type Ⅲ),without pure gas-phase or pure liquid-phase inclusions;(ii) the homogenization temperature of fluid inclusions in copper mineralized quartz ranges from 165~335℃,and salinity from 4.2%~16.7% NaCleq;(iii) the homogeneous temperature of fluid inclusions in tungsten mineralized quartz veins ranges from 199 to 265℃,and salinity from 2.6%~23.7% NaCleq;(iv) there are a few daughter minerals dominated by stone salts;(v) the fluid solutes evolved gradually from NaCl,KCl,MgCl_(2) to CaCl_(2) with mineralization pressure of 17.85~48.90 MPa and depth of 0.67~1.85 km.The laser Raman spectroscopy indicates that the composition of the ore-forming fluid in each level of the Damajianshan deposit is similar,which are mainly H_(2)O and CH_(4),with a small amount of N_(2) and trace amount of CO_(2).The homogeneous temperature of fluid inclusions is similar within the two kinds of mineralization at the same level,but the difference in salinity is large,and the CH_(4) and CO_(2) contents also differ significantly,which may have been caused by the evolution of copper mineralized fluids through the thermochemical sulfate reduction reaction(TSR) process,which is significantly different from the evolution of tungsten mineralized fluids.The participation of chloride plays a major role in the migration and enrichment of W elements in

关 键 词：钨多金属矿床 流体包裹体 成矿流体 大马尖山 云南 

分 类 号：P618.2[天文地球—矿床学]