安徽金寨银水寺铅锌矿床流体包裹体和同位素地球化学特征  

Geology, Fluid Inclusion and Stable Isotopes of the Yinshuisi Zn-Pb Deposit, Jinzhai County, Anhui Province

作　　者：吴皓然 谢玉玲 钟日晨 王莹 安卫军 WU Haoran;XIE Yuling;ZHONG Richen;WANG Ying;AN Weijun(School of Civil and Resources Engineering,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]北京科技大学土木与资源工程学院

出　　处：《大地构造与成矿学》2019年第5期967-990,共24页Geotectonica et Metallogenia

基　　金：国土资源部公益性行业基金项目(201011011);中国地质调查局项目(2014-01-020-010)联合资助

摘　　要：银水寺铅锌矿床位于大别造山带北缘,是该区最大的矽卡岩型矿床。矿体主要发育在中元古界庐镇关岩群仙人冲组大理岩与郑堂子组千枚岩之间的层间破碎带以及正长花岗斑岩与大理岩的接触带中。矿床先后经历了四个成矿阶段,矽卡岩阶段(Ⅰ)、石英.白钨矿阶段(Ⅱ)、石英.硫化物阶段(Ⅲ)、碳酸盐阶段(Ⅳ)。矽卡岩阶段(Ⅰ)主要发育绿帘石、阳起石、石英、绿泥石、磁铁矿及少量金属硫化物等;石英.白钨矿阶段(Ⅱ)主要发育石英、方解石、萤石及少量白钨矿和金属硫化物;石英.硫化物阶段(Ⅲ)广泛发育闪锌矿、方铅矿、黄铜矿等金属硫化物及石英、方解石、萤石、绿泥石等;碳酸盐阶段(Ⅳ)主要发育方解石、石英及少量黄铁矿。矿床中发育三种类型流体包裹体,包括富CO2水溶液包裹体(AC类)、气液两相水溶液包裹体(L类)和含子晶多相包裹体(S型)。根据流体包裹体岩相学、显微测温、激光拉曼研究结果,矽卡岩阶段主要有富CO2包裹体和气液两相水溶液包裹体,均一温度为314~400℃、盐度变化范围较大(1.1%~19.3%NaCleqv);石英.白钨矿阶段发育气液两相水溶液包裹体、含子晶多相包裹体和富CO2包裹体,后两者均一温度相近(263~349℃)、盐度差异较大(32.8%~41%NaCleqv和0.8%~6.1%NaCleqv),表明流体发生了沸腾作用;石英.硫化物阶段主要发育气液两相水溶液包裹体,均一温度为230~332℃,盐度为0.2%~8.9%NaCleqv;碳酸盐阶段只发育气液两相水溶液包裹体,显示低温(162~245℃)、低盐度(0.2%~5.6%NaCleqv)的特征。矿床不同成矿阶段石英、绿帘石中流体包裹体中水H-O同位素研究结果表明,δ18Ofluid值从早到晚逐渐减小,其中矽卡岩阶段为–1.3‰~4.7‰、石英.硫化物阶段为–5.1‰~–3.1‰,表明银水寺矿床早期成矿流体主要为岩浆来源,并在成矿过程中不断有大气降水的加入。石英流体包裹体中CO2的C同The Yinshuisi Zn-Pb deposit, located in the eastern segment of Qinling-Dabie metallogenic belt, Jinzhai county, Anhui province, is the largest skarn deposit in the Dabieshan region. Orebodies mainly occur in the fracture zones between the marble of the Xianrenchong Formation and phyllites of the Zhengtangzi Formation, Luzhenguan Group, or in the contact zone between the syenogranite porphyry and marble. Four main paragenetic stages of skarn formation and ore deposition have been recognized for the Yinshuisi deposit based on petrographic observation, The skarn stage I composed of actinolite-epidote ± quartz ± chlorite ± magnetite assemblage, the quartz-scheelite stage Ⅱ makes up of quartz-calcite ± fluorite ± scheelite assemblage, the quartz-sulfides stage Ⅲ constituted of sphaleritegalena-chalcopyrite-quartz-calcite ± fluorite ± chlorite ± pyrite ± pyrrhotite assemblage, and the carbonate stageⅣrepresented by calcite ± quartz ± pyrite assemblage. Three types of fluid inclusions have been identified in Yinshuisi Zn-Pb deposit, including aqueous three-phase CO2-rich fluid inclusions(AC-type), aqueous two-phase fluid inclusions(L-type), and daughter mineral-bearing three-phase fluid inclusions(S-type). Microthermometry and Laser Raman Spectroscopy reveal that, AC-type and L1-type fluid inclusions occur in the stage I with homogenization temperature of 314 ℃ to 400 ℃ and salinities of 1.1% to 19.3% NaCleqv, S-type and coexisting AC-type inclusions appear in the stage Ⅱ displaying homogenization temperatures of 263 ℃ to 349 ℃, salinities ranging from 32.8% to 41% NaCleqv, and 0.8% to 6.1% NaCleqv, whereas L-type inclusions occurring in stage Ⅲ and stage Ⅳ have homogenization temperatures of 230 ℃ to 332 ℃ and 162 ℃ to 245 ℃, and salinities ranges of 0.2% to 8.9% NaCleqv and 0.2% to 5.6% NaCleqv, respectively. According to these observations, it appears that fluid boiling occurred during the stage Ⅱ and mixing fluid took place during the stage Ⅲ. Oxygen isotopes data from quar

关 键 词：银水寺矽卡岩Pb-Zn矿床 流体包裹体 C-H-O-S-Pb同位素 岩浆热液 大别造山带 

分 类 号：P611[天文地球—矿床学]