海南西南部抱伦金矿床流体包裹体及稳定同位素特征  

Fluid inclusion and stable isotope studies of the Baolun gold deposit, southwestern Hainan, China

作　　者：舒斌[1] 王平安[1,2] 董法先[3] 李中坚[3] 

机构地区：[1]中国地质调查局发展研究中心 [2]中国地质科学院地质力学研究所,北京100081 [3]中国地质科学院地质力学研究所

出　　处：《地质通报》2006年第7期880-893,共14页Geological Bulletin of China

基　　金：原地质矿产部定向科研项目<海南省乐东九所-抱伦地区金;银;钼多金属矿控矿构造及成矿规律研究>(地科定97-16)和国土资源部地质调查项目<海南岛高品位大型热液金矿床调查预测与典型矿床研究>(200110000003)的部分研究成果。

摘　　要：抱伦金矿床的石英和方解石中的包裹体以气液包裹体为主,石英中含大量CO2包裹体。成矿流体属Na(K)-Cl型。气相成分CH4、C2H6、H2S、O2、N2和Ar的含量反映属弱还原环境。液相成分中阴、阳离子分别以Cl-、Na+为主,含少量SO42-、F-、Mg2+和Ca2+。Au在成矿流体中以AuCl-2和Au(HS)-2络合物的形式迁移。均一温度主要为160～350℃,属中温范畴。流体水的δ18O和δD值分别为-3.4‰～+9.8‰和-61‰～-30‰,其来源主要为岩浆水与大气降水。石英的δ18O值(+10.4‰～+15.5‰)与华南陆壳型花岗岩成因的钨、锡、稀有、稀土金属矿床一致。CO2和黄铁矿的C、S同位素反映C和S以花岗岩浆来源为主,少量来自志留系或更老的地层。综合分析认为矿床成因与印支期花岗质岩浆活动有关。Inclusions in quartz and calcite from ores of the Baolun gold deposit are mainly fluid ones and plenty of CO2 inclusions are observed in quartz. The ore-forming fluids are of Na （K）-Cl type. The contents of the vapor phases CH4, C2H6, H2S, O2, N2 and Ar suggest a weak reducing environment. Cl^- and Na^＋ are the predominant anion and cation in liqnid phase, with minor SO^2-, F^-, Mg^2＋. and Ca^2＋. Au was transported as complexes of AuCl2 and Au（HS）2. The homogenization temperatures of fluid inclusions in quartz and calcite are principally in the range of 160-350℃, belonging to a medium temperature range. The δ^180 and δD values for water in fluid inclusions range from -3.4 to ＋9.8 per mil and from -61 to -30 per mil respectively, implying a mixed origin of magmatic water and meteoric water. The δ^18O values （＋10.4 to ＋ 15.5 per mil） coincide with those of W, Sn, rare metal and REE deposits in South China genetically associated with granites of continental crustal type. Carbon and sulfur isotopic compositions of CO2 in fluid, inclusions and pyrite in gold ores suggest that the carbon and sulfur as ore-forming materials in hydrothermal fluids were mainly derived from granitic magmas and some from Silurian strata or even older strata. It is concluded that the Baolun gold deposit is genetically related to Indosinian granitic magmatism.

关 键 词：抱伦金矿 流体包裹体 成矿流体 稳定同位素 海南 

分 类 号：P618.51[天文地球—矿床学] P597.1[天文地球—地质学]