东秦岭夜长坪钼矿床流体包裹体特征及对成矿作用的指示  

Characteristics of Fluid Inclusions and Mineralization Indications of the Yechangping Mo Deposit,East Qinlin

作　　者：丁高明 晏国龙[2] 王坤明[3] 许永中 唐一昂 刘骥阳 DING Gaoming;YAN Guolong;WANG Kunming;XU Yongzhong;TANG Yi'ang;LIU Jiyang(China Coal Geology Group Co,Ltd,Beijing100038,China;China Gold Group Geological Co,Ltd,Beijing100011,China;MLR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resources,CAGS,Beijing100037,China;China Gold Group Zhongyuan Mining Co,Ltd,Sanmenxia,Henan472000,China)

机构地区：[1]中国煤炭地质总局,北京100038 [2]中国黄金集团地质有限公司,北京100011 [3]中国地质科学院矿产资源研究所自然资源部成矿作用与资源评价重点实验室,北京100037 [4]中国黄金集团中原矿业有限公司,河南三门峡472000

出　　处：《现代地质》2024年第4期1177-1191,共15页Geoscience

基　　金：中国地质调查局地质调查项目(DD20230291);中国黄金集团有限公司地质探矿增储项目(DT2023001)。

摘　　要：夜长坪钼矿床位于东秦岭钼成矿带中段,其矿石类型以矽卡岩型为主,其次为斑岩型。在东秦岭钼成矿带,针对矽卡岩型-斑岩型复合钼矿床流体包裹体研究相对较少,其流体演化特征及成矿作用机制是需要关注的重要科学问题。夜长坪钼矿床成矿阶段从早到晚划分为早期矽卡岩阶段、晚期矽卡岩石英-钾化阶段(Ⅰ阶段石英)、石英-辉钼矿阶段(Ⅱ阶段石英,主成矿阶段)、石英-多金属硫化物阶段(Ⅲ阶段石英)和石英-碳酸盐阶段(Ⅳ阶段石英)。对上述Ⅰ—Ⅳ阶段石英采集包裹体样品进行岩相学特征、显微镜下观察及显微测温和激光拉曼光谱特征分析。结果表明,矿床石英中流体包裹体类型包括WG型(NaCl-H_(2)O富气型)、WL型(NaCl-H_(2)O富液型)、C型(CO_(2)型)和S型(含子晶型)。从成矿早阶段到晚阶段,流体包裹体的均一温度依次集中在380~437℃、331~370℃、312~320℃和257~350℃,对应的平均盐度(NaCleqv.)分别为10.83%、9.29%、7.16%和4.51%,成矿流体从早阶段高中温、中高盐度与富(含)CO_(2)的NaCl-H_(2)O-CO_(2)体系逐渐演化为晚阶段中低温、低盐度与贫CO_(2)的NaCl-H_(2) O体系。流体混合作用导致流体的温度下降、盐度降低,流体由氧化状态转化为还原状态,由此造成流体中的Mo元素溶解度大幅降低并迅速卸载与沉淀富集成矿。进一步根据“岩浆流体-建造”成矿体系,构建了矿区(床)尺度成矿模式。The Yechangping molybdenum(Mo)deposit is located in the middle East Qinling molybdenum oro-genic belt.Its metallogenic type mainly belongs to the skarn type in the early stage,followed by the porphyry type.In the East Qinling molybdenum mineralization belt,there are relatively fewer studies focusing on the fluid inclusions of the skarn-porphyry composite molybdenum deposits,particularly their fluid evolution charac-teristics and the metallogenetic mechanisms,which are essential to understanding ore genesis.This study clas-sifies the hydrothermal mineralization stages of the Yechangping Mo deposit from early to late as follows:early silica and late silica quartz-potassic stage(stage I:quartz),quartz-pyroxene stage(stage II:quartz,main mineralization stage),quartz-polymetallic sulfide stage(stage III:quartz),and quartz-carbonate stage(stage IV:quartz).Based on this preliminary study,inclusion samples were collected from stagesⅠtoⅣquartz and analyzed using microscopy,micro-thermometry,and laser Raman microprobe.The results show that the types of fluid inclusions within the quartz are NaCl-H_(2)O gas-rich type(WG type),NaCl-H_(2)O liquid-rich type(WL type),CO_(2) type(C type),and daughter mineral-bearing type(S type).From the early to the late stage of mineralization,the homogeneous temperatures of fluid inclusions are concentrated at 380-437℃,331-370℃,312-320℃and 257-350℃,corresponding to average salinity(NaCleqv.)of 10.83%,9.29%,7.16%,and 4.51%,respectively.The mineralizing fluids gradually evolved from a high-temperature,medi-um-high salinity,and CO_(2)-rich NaCl-H_(2) O-CO_(2) system at the early stage to a low-temperature,low-salinity,and CO_(2)-poor NaCl-H_(2)O system at the late stage.The fluid mixing effect leads to a decrease in fluid tempera-ture and salinity,and the fluid transforms from an oxidized state to a reduced state.This results in a drastic decrease in the solubility of the Mo element in the fluid,and the rapid unloading and precipitation of Mo.Con-sequently,we constructed a mineraliza

关 键 词：东秦岭钼矿带 夜长坪钼矿床 矽卡岩-斑岩型钼矿床 流体包裹体 

分 类 号：P618.65[天文地球—矿床学] P631.81[天文地球—地质学]