粤西河台金矿床富硫化物石英脉Rb-Sr等时线年龄讨论  

Rb-Sr Isochron Age of Sulfide-rich Quartz Veins in the Hetai Gold Deposit,Western Guangdong

作　　者：翟伟[1] 李兆麟[1] 黄栋林[2] 文拥军[1] 

机构地区：[1]中山大学地球科学系,广东广州510275 [2]广东高要河台金矿,广东高要526100

出　　处：《地球学报》2004年第2期243-247,共5页Acta Geoscientica Sinica

基　　金：国家自然科学基金项目 (编号 :49873 0 18);广东省自然科学基金项目 (编号 :0 0 12 5 5 )资助

摘　　要：河台金矿床产于河台韧性剪切带中 ,成矿作用分为韧性剪切变质成矿期的韧性剪切变质成矿阶段和热液蚀变成矿期金石英脉阶段、金硫化物阶段和方铅矿闪锌矿碳酸盐脉阶段。金的成矿主要发生在金石英脉阶段和金硫化物阶段 ,形成的矿石有蚀变糜棱岩型和富硫化物石英脉型。富硫化物石英脉单矿物石英中富含以富CO2 液相为主的流体包裹体、流体熔融包裹体及熔融包裹体。与以往用流体包裹体热爆法和压碎法提取Rb、Sr的方法不同 ,本文用石英全溶法测得富硫化物石英脉中石英的Rb Sr等时线年龄为 172± 2Ma(1σ) ,初始比值为 0 .72 816± 0 .0 0 0 96 ,对比已有的同位素年龄数据及区域成矿特征 ,认为这一年龄值可能代表了河台金矿床的成矿年龄。The Hetai gold deposit is hosted in Hetai ductile shear zone. Its ore-forming process can be divided into the ductile shear metamorphic ore-forming stage of the ductile shear metamorphic metallogenic epoch and the gold quartz vein stage,gold sulfide stage and galena-sphalerite-carbonate vein stage of the hydrothermal alteration metallogenic epoch. Gold mineralization occurred mainly in the gold quartz vein stage and the gold sulfide stage. The two types of ores thus formed are altered mylonites and sulfide-rich quartz veins. Individual mineral quartz in sulfide-rich quartz veins contain many fluid inclusions consisting mainly of CO_2-rich liquid,fluid-melt inclusions and melt inclusions. Different from the previously-used Rb and Sr extraction method of decrepitation and crushing of fluid inclusions,the method used by the authors lies in dissolving quartz to obtain the Rb-Sr isochron age of quartz in sulfide-rich quartz vein. The result shows that the age is 172±2 Ma(1σ)and the initial 87 Sr/ 86 Sr ratio is 0.72816±0.00096. Considering other researchers′ isotopic ages and regional metallogenic characteristics,it is held that this isochron age may represent the metallogenic age of the Hetai gold deposit.

关 键 词：河台金矿床 富硫化物石英脉 RB-SR等时线年龄 成矿年龄 

分 类 号：P618.51[天文地球—矿床学]