滇西镇康放羊山Cu-Pb-Zn多金属矿床流体包裹体和C-O同位素研究  

Fluid inclusion and C-O isotopic compositions of the Fangyangshan Cu-Pb-Zn polymetallic deposit,Zhenkang County,west Yunnan Province

作　　者：陈伟 邓明国[2] 耿齐卫 管申进 孔志岗[2] 贾祯 张海 CHEN Wei;DENG Ming-guo;GENG Qi-wei;GUAN Shen-jin;KONG Zhi-gang;JIA Zhen;ZHANG Hai(West Yunnan University of Applied Sciences,Dali 671000,China;Faculty of Land Resource Engineering,Kunming University of Science and Technology,Kunming 650093,China;Sanxi Resource of Geology and Mineral Resources Technology Co.,Ltd.,Liupanshui 553000,China;No.113 Geological Party,Guizhou Bureau of Geology and Mineral Resources,Liupanshui 553000,China)

机构地区：[1]滇西应用技术大学,云南大理671000 [2]昆明理工大学国土资源工程学院,云南昆明650093 [3]贵州地矿三稀资源科技股份有限公司,贵州六盘水553000 [4]贵州地矿局一一三地质大队,贵州六盘水553000

出　　处：《岩石矿物学杂志》2020年第6期780-794,共15页Acta Petrologica et Mineralogica

基　　金：国家自然科学基金资助项目(41762009,41363001);黔地矿科合(2020)25号。

摘　　要：滇西镇康放羊山Cu-Pb-Zn多金属矿床是保山地块发现的首个富铜的铅锌多金属矿床。为探讨其成矿流体来源和矿床成因,对该矿床开展了流体包裹体和C-O同位素研究。结果表明,阶段Ⅱ主要发育富液相包裹体,均一温度和盐度(NaCleq,质量分数)集中在240~300℃和8.0%~18.0%;阶段Ⅲ以含CO2和子矿物包裹体为特征,均一温度和盐度的两个峰值为360~400℃、16.0%~24.0%和240~320℃、4.0%~14.0%;阶段Ⅳ以富液相和纯液相包裹体为主,均一温度和盐度降低至220~340℃和8.0%~14.0%。C-O同位素分析结果(δ13CV-PDB值为-5.88‰^-2.37‰,δ18OV-SMOW值为8.18‰~12.79‰)显示成矿流体主要来源于岩浆热液,在迁移过程中受到围岩溶解作用的影响。综合研究认为,放羊山矿床阶段Ⅱ和阶段Ⅲ的成矿流体主要来源于大陆碰撞形成的中高温、中高盐度、富CO2岩浆热液,在阶段Ⅲ晚期和阶段Ⅳ受到中低温、低盐度大气降水的影响;矿床为受构造控制明显的中高温热液矿床,预测在矿区深部有望找到矽卡岩型矿体。The Fangyangshan Cu-Pb-Zn polymetallic deposit in Zhenkang County of western Yunnan Province is the first copper-rich deposit recently discovered in the south of Baoshan block.Fluid inclusions and C-O isotopes were studied in order to reveal the source of ore-forming fluid and the genesis of the deposit.The study shows that stageⅡis dominated by liquid-rich inclusions,whose homogenization temperatures range from 240 to 300℃and salinities from 8.0% to 18.0%.StageⅢis characterized by CO2-rich and daughter minerals-bearing fluid inclusions with homogenization temperatures and salinities both showing two peaks of concentration.Their homogenization temperatures range from 360 to 400℃with salinities from 16.0% to 24.0%,and temperatures from 240 to 320℃with salinities from 4.0% to 14.0% respectively.Stage Ⅳ is mainly characterized by liquid-rich and pure-liquid inclusions,whose homogenization temperatures range from 220 to 340℃ and salinities range from 8.0% to 14.0%.The values of δ13CV-PDBand δ18OV-SMOWin different stages are plotted in the range of -5.88‰ to -2.37‰and 8.18‰ to 12.79‰ respectively,indicating that ore-forming fluid of the Fangyangshan deposit was sourced from magmatic hydrothermal solution,with its migration process influenced by the dissolution of wall rocks.According to the above studies,the authors hold that the ore-forming fluid in stageⅡand stageⅢof the Fangyangshan deposit mainly came from the medium-high temperature and salinity and CO2-rich magmatic hydrothermal solution formed by continental collision,and the ore-forming fluid was influenced by medium-low temperature and low salinity meteoric water in late stage Ⅲ and stage Ⅳ.The authors hold that the Fangyangshan Cu-Pb-Zn polymetallic deposit is a middle-high temperature hypothermal deposit which is controlled by the structure.It is also inferred that skarn type orebodies might be found in the deep part of the mining area.

关 键 词：放羊山Cu-Pb-Zn矿床 C-O同位素 流体包裹体 成矿流体 矿床成因 保山地块 

分 类 号：P597.2[天文地球—地球化学]