作　　者： ; ; ; ; ;

机构地区： 新疆大学地质与勘查工程学院

出　　处： 《岩石学报》 2010年第10期3074-3084,共11页

摘　　要： 塔木铅锌矿位于塔里木西南缘,为碳酸盐岩容矿型铅锌矿。矿床形成经历了沉积期、成岩期和后生期。沉积期以内碎屑角砾和纹层构造为标志。成岩期以成岩角砾、重结晶白云石为标志。后生期以崩塌角砾、后生角砾及管/脉构造为标志。成矿期介于成岩期和后生期并具有溶蚀-交代和充填两个阶段。细粒闪锌矿和方铅矿多为溶蚀-交代阶段产物。粗粒闪锌矿和方铅矿多为充填阶段产物。本次研究对来自14个标本的沉积期和成矿期51件闪锌矿、方铅矿、黄铁矿和黄铜矿样品进行了硫同位素测试。塔木铅锌矿硫化物硫同位素值具有较大的变化范围。沉积期形成的金属硫化物(δ34SCDT介于-17.6‰～-7.3‰)较成矿期金属硫化物(δ34SCDT介于-5.7‰～+10.2‰)多富集轻硫同位素。充填阶段形成的硫化物(δ34SCDT介于+5.1‰～+10.2‰)较溶蚀-交代阶段硫化物(δ34SCDT介于-5.7‰～+9.2‰)富重硫,并且硫同位素达到平衡。结合地质背景、矿物生成顺序、矿石结构、流体包裹研究资料和硫同位素特征可以得出热化学硫酸盐还原作用(TSR)是成矿期HS-形成的主要机制,含硫有机质热裂解硫也是成矿期硫源之一,溶蚀-交代阶段硫储库效应和硫化物溶度积(Ksp)制约硫同位素值的变化。通过本次研究厘定了塔木铅锌矿矿化形成机制、硫酸盐还原特征和硫的来源,并进一步指出其硫同位素特征支持矿床流体混合成因模型。 Tamu lead and zinc ore deposit,located in the southwest margin of Tarim,is regarded as a carbonate-hosted Pb-Zn deposit. Sedimentary period,diagenetic period and epigenetic period can be distinguished in Tamu ore deposit. Intraclast breccia and layer textures formed during the sedimentary period. Diagenetic breccia and recrystal dolomite mainly formed during the diagenetic period. Dislocation breccia,fall breccia and tube structure mainly formed during the epigenetic period. Ore deposit-forming period ranging between diagenetic period and epigenetic period,can be further subdivided into two stages:Dissolving-metasomatic stage and cavity-filling stage. Fine-grained sphalerite and galena mainly formed during the dissolving-metasomatic stage. Huge-grained sphalerite and galena mainly formed during the cavity-filling stage. Fifty one sulfur isotope analyses were determined on sphalerite,galena,pyrite,chalcopyrite (sedimentary period and ore deposit-forming period),and these sulfides were collected from fourteen specimens. Sulfur isotope values display a wide variation in Tamu deposit. The δ34S values of sulfides formed in the sedimentary period (-17.6‰ to-7.3‰ CDT) are lower than those formed in ore deposit-forming period (-5.7‰ to +10.2‰ CDT). Sulfides formed in the cavity-filling stage are rich in heavier sulfur isotope (+5.1‰ to +10.2‰ CDT) than those formed in the dissolving-metasomatic stage (-5.7‰ to +9.2‰ CDT),and at sulfur isotope equilibrium. The geologic setting,paragenesis,ore textures,fluid inclusion microthermometry,and δ34S values indicate that Thermo-chemical Sulfate Reduction (TSR) was the principal HS-production mechanism in ore deposit-forming period. Sulfur from thermal cracking of sulfur-bearing organism might have been present in the ore deposit-forming period. Sulfur reservoir effect and sulfides' solubility product constant (Ksp) of sulfides constrained the change of δ34S values,especially in the dissolving-metasomatic stage. This study places constraints on the mineralizatio

关 键 词： 硫同位素 碳酸盐岩容矿型铅锌矿 塔木铅锌矿 塔里木西南缘 中国

领　　域： [天文地球] [天文地球]