湘南江永银铅锌矿床成矿物质来源的S、Pb同位素证据

S and Pb isotopic evidences on ore-forming material sources from the Ag-Pb-Zn ore deposit in Jiangyong,southern Hunan

江永银铅锌矿床是钦-杭Cu-Au-Pb-Zn-Ag多金属成矿带内典型的矽卡岩型矿床,矿床位于铜山岭岩体西部,产于岩体与围岩的接触带及其附近。矿石中金属矿物以方铅矿、闪锌矿、磁黄铁矿、黄铁矿为主。矿石金属硫化物的S、Pb同位素组成分析显示,δ^(34)S值变化范围为0.1‰~3.6‰,平均值1.7‰,组成极为均一,指示硫主要来自岩浆;矿石铅同位素组成比较稳定,^(206)Pb/^(204)Pb、^(207)Pb/^(204)Pb、^(208)Pb/^(204)Pb值变化范围分别为18.776~18.953、15.724~15.847和39.017~39.448,平均值分别为18.884、15.775和39.224,与铜山岭花岗闪长岩铅同位素组成相似,具上地壳铅特征。江永银铅锌矿床成矿物质主要来自深部岩浆热液。

In Jiangyong, Ag - Pb - Zn deposit is the typical skarn type deposit in Qinzhou-Hangzhou Cu - Au - Pb - Zn - Ag polymetallic metallogenic belt. The deposit is located at the west of Tongshanling rock, generated in the contact zone of Tongshanling rock with strata nearby. The main metal minerals in the ore are galena, sphalerite, pyrrhotite and pyrite. The analysis results of S and Pb isotopic composition of metal sulfides of ore, show that the 834S value varies from 0. to 3. 6%o, with the average of 1. 7%o and homogeneous S isotopic composition, implying the main source of sulfur coming from the magma. The Pb isotope composition is stable. The range and average of 206Pb/204 Pb, 207Pb/204 Pb and 208Pb/204 Pb are 18. 776 - 18. 953 , 15. 724 - 15. 847, 39. 017 -39. 448 and 18. 884, 15. 775, 39. 224, respectively, the metal sulfides of ore and the granodiorite of Tongshanling with consistent Pb isotopic composition of upper crust Pb. According to the study results, it can be concluded that the ore-forming materials of Jiangyong Ag - Pb - Zn deposit mainly come from deep magmatic hy-drothermal.