印度尼西亚苏门答腊岛Woyla金矿流体包裹体研究及矿床成因分析  

Fluid Inclusion Features and Origin of the Woyla Gold Deposit in Sumatra,Indonesia

作　　者：胡鹏[1] 曹亮[1,2] Tampubolon Armin 张海坤[1] 刘阿睢 程湘[1] HU Peng;CAO Liang;Tampubolon ARMIN;ZHANG Hai-kun;LIU A-sui;CHENG Xiang(Wuhan Center of Geology Survey,CGS,Wuhan,Hubei 430205;Research Center of Granitic Diagenesis and Mineralization,China Geological Survey,Wuhan,Hubei 430205;Geological Survey of Indonesia,Bandung 40254,Indonesia)

机构地区：[1]中国地质调查局武汉地质调查中心,湖北武汉430205 [2]中国地质调查局花岗岩成岩成矿地质研究中心,湖北武汉430205 [3]印度尼西亚地质局,印度尼西亚万隆40254

出　　处：《地质与勘探》2018年第6期1215-1226,共12页Geology and Exploration

基　　金：中国地质调查局印度尼西亚苏门答腊岛铜多金属资源潜力评价(DD20160114);湘西-鄂西成矿带神农架-花垣地区地质矿产调查二级项目(DD20160029)联合资助。

摘　　要：印度尼西亚Woyla金矿床位于西苏门答腊地体北段,为一中型规模的金矿床。本文通过对含矿石英脉开展详细的流体包裹体显微测温、成分分析,结合石英的H-O同位素和黄铁矿的S同位素特征分析,结果如下:其中,流体包裹体研究结果表明,含金石英脉中的石英主要发育气液两相包裹体,包裹体均一温度变化范围为152～324℃,集中在200～280℃。盐度为(0. 88～6. 16) wt%Na Cleqv,集中在(1. 00～3. 00) wt%Na Cleqv,成矿流体密度为0. 70～0. 94g/cm3,平均为0. 82g/cm3。成矿压力为9. 63～25. 84MPa,平均值为18. 37 MPa。成矿深度为0. 96～2. 58km,平均为1. 86km,以上显示Woyla矿床成矿流体具有中低温、低盐度和浅成的特征。包裹体气、液相成分测定显示气相成分以H2、N2、CO、CO2、CH4和H2O为主;液相成分中阳离子以Na+、K+和Ca2+为主,阴离子以富SO2-4和Cl-为特征,成矿流体属Cl--SO2-4-Ca2+-K+型。氢氧同位素测定显示成矿流体δ18DV-SMOW=-78. 3‰～-92. 4‰,δ18OH2O=-3. 0‰～-5. 5‰,主要来自大气降水,可能有少量岩浆水参与。黄铁矿硫同位素组成为-0. 21‰～1. 22‰,平均值为0. 34‰,说明成矿物质的S具有深源岩浆硫的特征。结合矿床地质特征和成矿流体研究,首次提出Woyla金矿床属典型的低硫型浅成低温热液型金矿床。The Woyla gold deposit,located in the northern part of the West Sumatra terrane,Indonesia,is of a medium scale.This work analyzed micro-temperature and components of its fluid inclusions in combination with H-O isotope in quartz and S isotope in pyrite.The research results of fluid inclusions show that there are major gas-liquid two-phase fluid inclusions in auriferous quartz vein.The homogenization temperature of the two-phase inclusions ranges from 152℃to 324℃and mainly from 200℃to 280℃.The salinity ranges from 0.88wt%NaCleqv to 6.16wt%NaCleqv,and mainly from 1.00wt%NaCleqv to 3.00wt%NaCleqv.The density changes from 0.70 g/cm 3 to 0.94g/cm 3,and the average value is 0.82g/cm 3.The metallogenis pressure ranges from 9.63 MPa to 25.84 MPa,with an average value of 18.37MPa.The mineralization depth ranges from 0.96 km to 2.58 km,and the average value is 1.86km.The above results show that the ore-forming fluid of Woyla deposit is characterized by medium-low temperature,low salinity and shallow mineralization.Studies on gas and liquid phase composition of inclusions show that the pure gaseous inclusions are dominated by H 2,N 2,CO,CO 2,CH 4 and H 2 O.Cations in liquid phase composition are mainly Na+,K+and Ca 2+,anions are characterized by rich SO 2-4 and Cl-,and the ore forming fluid belongs to Cl--SO 2-4-Ca 2+-K+type.Isotopic analyses show theδ18 D V-SMOW andδ18 O H 2O of the ore-forming fluids are-78.3‰^-92.4‰and-3.0‰^-5.5‰,respectively,implying that the ore-forming fluids are mainly composed of atmospheric precipitation and a little amount of magmatic water involved.Sulfur isotopes of pyrite lie in-0.21‰~1.22‰with an average value of 0.34‰,implying the sulfur of ore forming materials is characterized by deep-seated sulfur similar to that of meteorite.Based on the geological and fluid inclusion features,we conclude that the Woyla gold deposit is a typical low-sulfur epithermal deposit.

关 键 词：流体包裹体 同位素 浅成低温热液矿床 低硫型 Woyla金矿床 苏门答腊岛 

分 类 号：P618.51[天文地球—矿床学]