广西砂子岭银多金属矿床成因:来自流体包裹体及H-O-S同位素的制约  

Genesis of Shaziling Ag polymetallic deposit in Guangxi:Constraints from fluid inclusions and H-O-S isotopes

作　　者：李尚军 韦东广 林剑飞 LI Shangjun;WEI Dongguang;LIN Jianfei(Geology Party No.307 of Nuclear Industry,Guangxi Zhuang Autonomous Region,Guigang 537100,Guangxi,China)

机构地区：[1]广西壮族自治区三〇七核地质大队,广西贵港537100

出　　处：《矿产与地质》2024年第1期53-60,共8页Mineral Resources and Geology

基　　金：广西壮族自治区自然资源厅“找矿突破战略行动地质勘查项目”(桂核办〔2019〕4号)资助。

摘　　要：砂子岭银多金属矿床位于钦杭成矿带西南端,水汶火山盆地西缘,区域性NE向博白—岑溪深大断裂带从其西侧穿过。矿体呈脉状、透镜状赋存在燕山晚期霏细斑岩内,受NW、NE向断裂构造控制。文章在系统总结矿床成矿地质特征的基础上,进行流体包裹体及氢、氧、硫同位素研究,探讨矿床成因。结果表明:流体包裹体类型主要为富液两相流体包裹体,成矿初—晚阶段流体均一温度、盐度均逐渐降低,主成矿期流体具有中温(246~351℃)、低盐度(3.1%~4.8%)特征。黄铁矿、方铅矿δ^(34)S的值为-1.45‰~2.67‰,指示硫来源于岩浆。H-O同位素研究结果指示成矿流体主要来自岩浆水,后期有大气降水混入。综合研究认为砂子岭银多金属矿床属中温热液矿床。Shaziling Ag polymetallic deposit is located at the west edge of Shuiwen volcanic basin in the southwest of Qinzhou-Hangzhou metallogenic belt.NE trending Bobai-Cenxi regional deep fault passes through its west side.Ore bodies occur in the late Yanshanian felsophyre as veins and lenticular shape,which are controlled by the NW and NE trending fault structure.On the basis of the systematic summary of the geological characteristics of mineralization,this paper has studied the characteristics of fluid inclusions and H-O-S isotopes to discuss the deposit genesis.The result shows that most of fluid inclusions are liquid-rich two-phase,from the early metallogenic stage to late metallogenic stage,the homogenization temperature and salinity of fluid decreases gradually,the ore-forming fluid in the main metallogenic period id characterized by moderate temperature(246-351℃)and low salinity(3.1 wt.%-4.8wt.%).The δ^(34) S values of pyrite and galena range from-1.45‰to 2.67‰,indicating that the sulfur is from the magma.The H-O isotopic study shows that ore-forming fluid mainly comes from magmatic water,but mixed with atmospheric precipitation in the late stage.Comprehensive research suggests that Shaziling silver polymetallic deposit belongs to a medium temperature hydrothermal deposit.

关 键 词：银多金属矿床 流体包裹体 H-O-S同位素 矿床成因 水汶火山盆地 

分 类 号：P618.52[天文地球—矿床学]