广西五圩矿田箭猪坡Pb-Zn-Sb多金属矿床成因研究:来自硫同位素和闪锌矿微量元素的制约

Genesis of the Jianzhupo Pb-Zn-Sb Polymetallic Deposit in the Wuxu Ore Field,Guangxi Province:Constraints from Sulfur Isotopes of Sulfides and Trace Elements Compositions of Sphalerites

为探讨箭猪坡Pb-Zn-Sb多金属矿床的成因及物质来源,对该矿床主成矿阶段的硫化物进行了硫同位素分析、对闪锌矿进行了微量元素分析。结果表明,硫化物的δ34SVCDT值为3.92‰~8.00‰,硫化物沉淀过程中硫同位素已达平衡。利用硫同位素温度计估算的成矿温度为114~377℃,利用共生矿物对(Δ34 SPy-Sp值)估算出成矿流体中总硫的δ34 S(ΣS-fluids)为5.93‰,暗示硫主要来自岩浆,但不排除有少量地层硫的加入。箭猪坡矿床闪锌矿相对富集微量元素Fe、Cd、Mn、Cu、In等,元素对比值如Zn/Cd、Cd/Fe、Cd/Mn和Ga/In值,lnGa-lnIn关系判别图解以及地质特征均显示岩浆热液型矿床特征,说明其成矿物质来源与岩浆热液有关。

In order to constrain the material sources and ore genesis of the Jianzhupo Pb-Zn-Sb Polymetallic deposit,sulfur isotopes of sulfides and trace elements compositions of sphalerites that were formed at metallogenic stage of the deposit have been analyzed in this paper.The results show that theδ34SVCDT values of sulfides vary from 3.92‰to 8.00‰,indicating that those sulfides were formed under thermal equilibrium condition.The ore-forming temperatures range from 114 to 377℃,calculated by using Sulfur isotope geological thermometer.Based on theδ34SVCDT values of sphalerite and coexisting pyrite(Δ34SPy-Spvalues),the calculated totalδ34SΣS-fluidsvalue of the ore-forming fluid is 5.93‰,suggesting that sulfur was predominantly derived from magmatic source,with possible minor contribution of sedimentary source.The sphalerites of the Jianzhupo deposit are relatively enriched in elements such as Fe,Cd,Mn,Cu,In.Furthermore,multiple geochemical indicators(such as Zn/Cd,Cd/Fe,Cd/Mn,and Ga/In ratios),the discrimination diagram of lnGa-lnIn,and geological characteristics of the deposit show features of the magmatic hydrothermal deposit,indicating that the source of oreforming materials of the deposit is related to the magmatic hydrothermal fluid.