陕西旬阳泗人沟铅锌矿床地质及S、Pb同位素地球化学特征

陕西旬阳泗人沟铅锌矿床位于南秦岭褶皱系之大羊山复向斜南翼,赋存在上志留统水洞沟组第二岩性段的粉砂质千枚岩中.矿体受控于层间破碎带和劈理带,呈层状、似层状、透镜状产出.矿石矿物以闪锌矿、方铅矿、黄铁矿、磁黄铁矿和黄铜矿为主;矿石结构主要为它形-半自形粒状集合体结构、交代结构和固溶体分离结构;矿石构造主要为块状、条带状、浸...

Geological Characteristics and S-Pb Isotope Geochemistry of the Sirengou Pb-Zn Deposit in Xunyang,Shaanxi Province

The Sirengou Pb-Zn deposit, located in the southern limb of the Dayangshan syncline of the Southern Qinling Fold System, is hosted in the silty phyllite of the Upper Silurian Shuidonggou Formation (2^nd member).The orebodies are layered, stratoid or lenticular in the interlayer fracture zones.Metallic minerals mainly include sphalerite, galena, pyrite, pyrrhotite, and chalcopyrite.The ores are massive, band, disseminated or veined, and the ore minerals are euhedral-subhedral granular, aggregate, or have replacement or solid solution texture.LA-MC-ICP-MS in-situ sulfur isotope analyses show that the ore sulfides have relatively stable isotopic compositions, with the δ ³⁴S values of samples (0.17‰-2.03‰) showing normal distribution in the δ³⁴S histogram, which indicates that the sulfur was sourced from the mantle and/or deep crust with minor wallrock input.Nine sulfide samples yielded ²⁰⁶Pb/²⁰⁴Pb=17.198-18.213 (avg.17.845), ²⁰⁷Pb/²⁰⁴Pb=15.564-15.627 (avg.15.610) and ²⁰⁸Pb/²⁰⁴Pb=37.982-38.471 (avg.38.206).Lead isotope compositions of the ores are also similar (narrow-range), indicating that the lead was derived from the upper crust with minor mantle input.Combined with the geological and geochemical characteristics, we suggest that the Sirengou deposit belongs to epigenetic hydrothermal filling-metasomatic-type.