滇东北乐红大型铅锌矿床流体包裹体地球化学  

Characteristics of fluid inclusions geochemistry of Lehong large-sized Pb-Zn ore deposit, northeastern Yunnan Province

作　　者：赵冻 韩润生[1,2] 任涛[1,2] 王加昇[1,2] 吴海枝[1,2] 张小培[1,2] 崔峻豪[1,2] ZHAO Dong;HAN RunShen;REN Tao;WANG JiaSheng;WU HaiZhi;ZHANG XiaoPei;CUI JunHao(Faculty of Land Resource Engineering,Kunming University of Science and Technology,Kunming 650093,Yunnan,China;Southwest Institute of Geological Survey,Geological Survey Center for Nonferrous Metals Resources,Kunming 650093,Yunnan,China)

机构地区：[1]昆明理工大学国土资源工程学院,云南昆明650093 [2]有色金属矿产地质调查中心西南地质调查所,云南昆明650093

出　　处：《矿床地质》2018年第5期1018-1036,共19页Mineral Deposits

基　　金：国家自然科学基金项目(编号:41572060;U1133602);中国地调局整装勘查综合研究项目(编号:12120114013901);云南省矿产资源预测与评价工程实验室(编号:2011);云南省昆明理工大学创新团队项目(编号:2012;2010)联合资助

摘　　要：乐红铅锌矿床是扬子地块西南缘滇东北铅锌(银)多金属矿集区中的典型代表之一。通过对该矿床不同成矿阶段闪锌矿、石英、重晶石和方解石中流体包裹体岩相学、显微测温学和显微激光拉曼探针等测试,阐述了该矿床成矿流体性质和演化特征,并探讨了其成矿过程。研究发现,该矿床流体包裹体主要包括4类:Ⅰ类气相、Ⅱ类水溶液相(由Ⅱa型-富液相气液两相、Ⅱb型-富气相气液两相、Ⅱc型纯液相组成)、Ⅲ类含CO_2三相(V_(CO_2)+L_(CO)+L_(HO))及Ⅳ类含子矿物(L+V+S)包裹体。结果显示,重晶石阶段的均一温度为240.3~319.3℃,w(NaCl_(eq))为2.24~2%~1~20.73%,表现出中高温-中低盐度流体性质;白云石-黄铁矿-石英阶段具有中-高温(219.8~310.1℃),中盐度(w(NaCl_(eq))为7.02%~17.61%)特征;闪锌矿-方铅矿-黄铁矿阶段,包括S1闪锌矿具有中温(217.8~292.2℃)-中盐度(w(NaCl_(eq))为8.81%~16.71%)性质;S2闪锌矿具有中低温(180.2~241.3℃)-中盐度(w(NaCl_(eq))为7.73%~18.47%)性质;S3闪锌矿具有中低温(140.4~227.4℃)-中低等盐度(w(NaCl_(eq))为0.35%~19.21%)的流体性质,通过该阶段中含CO_2三相包裹体测试,估算成矿压力和成矿深度分别为45~74.9 MPa(平均58.2 MPa)、1.7~2.8 km。方解石阶段均一温度为165.3℃,中等盐度,w(NaCl_(eq))为11.28%,表现出低温-中等盐度的特征。不同成矿阶段的包裹体温度大致反映了该矿床成矿流体从早阶段至晚阶段,呈现中高温、中低盐度→中温、中等盐度→中低温、中低盐度的演化过程;早期高温-低盐度深部流体在热动力和构造应力驱动下大规模运移,受断裂构造影响发生减压沸腾作用,同时与大气降水发生混合,成矿流体物化性质陡变引起铅锌硫化物等的沉淀,并最终形成矿床。该研究为揭示矿床流体性质、演化及矿床成因提供了证据,深化了"构造-流体‘贯入’成矿"模型,亦对深化矿床成矿机制与指导找矿预测The Lehong lead-zinc deposit is one of the typical deposits in the northeastern Yunnan lead-zinc ore concen- tration area. According to the petrography as well as the laser Raman microspectroscopic and micro-thermometry of fluid inclusions, the authors discovered sphalerite, quartz, barite and calcite of different mineralization stages, and expounded the origin, property and evolution of ore-forming fluid and the metallogenic processes. There are four types of fluid inclusions, i.e., pure gaseous-type （ I ）, gas-aqueous-type （ I ） which is composed of aqueous- rich gas-aqueous-type inclusions （ I a）, gas-rich gas-aqueous-type inclusions （ I b） and pure liquid-type inclusions （I c）, Vco2＋LCO2＋LH2O three-phase inclusions （IU）, and three-phase inclusions containing daughter minerals （IV）, respectively. The test results show that the homogenization temperature in the barite stage varies from 240.3℃ to 319.3℃, the salinity varies from 2.24% to 10.73%, and it is shown that the fluid occurred in medium- high temperature and low-middle salinity. The dolomite-pyrite-quartz stage occurred in middle-high temperature （219.8-310.1℃） and medium-low salinity （w（NaCleq） 7.02%-17.61%）. The ore-forming fluid in the sphalerite- galena-pyrite stage shows that the sphalerite of first generation （S1） formed in medium temperature （217.8- 292.2℃） and medium salinity （w（NaCleq） 8.81%-16.71%）. The sphalerite of second generation （S2）formed in medium-low temperature （180.2-241.3℃） and medium salinity （w（NaCleq） 7.73%-18.47%）. The sphalerite of third generation （S3） formed in medium-low temperature （140.4-227.4℃） and medium-low salinity （w（NaCleq） 0.35%-19.21%）. Based on three-phase inclusions with CO2 in S3, it is estimated that the pressure and depth of mineralization varies from 45 MPa to 74.9 MPa with an average of 58.2 MPa and 1.7 km to 2.8 km, respectively. In the calcite stage, the homogenization temperature is 165.3℃, and the sa

关 键 词：地球化学 成矿过程 热液成矿阶段 乐红铅锌矿床 滇东北矿集区 

分 类 号：P618.42[天文地球—矿床学] P618.43[天文地球—地质学]