云南金顶铅锌矿碳、氧、硫同位素地球化学特征及其地质意义

Carbon,oxygen and sulfur isotope geochemistry characteristics of the Jinding lead-zinc deposit in Yunnan and their geological significance

本文对金顶铅锌多金属矿床矿石中硫化物硫同位素及碳酸盐胶结物中碳、氧同位素进行了研究分析,结果表明:成矿流体中的CO2与沉积有机物和海相碳酸盐岩有关,源自碳酸盐岩热解作用和去碳作用以及沉积有机物的氧化作用和脱羧基作用。矿床的矿石矿物组成反映了成矿环境为高氧逸度环境。硫同位素特征研究表明:矿床中石膏矿体中的硫可能来自三叠系古大洋硫酸盐矿物。而金属硫化物矿物中的硫具有多源性,其主要来源为生物或细菌还原地层中膏盐(石膏、硬石膏、有机质等)的还原硫、壳源硫和有机硫。同位素研究表明金顶铅锌多金属矿的成矿物质应源自地壳。

This article studied and analyzed S isotopic and C,O isotopic of carbonate cements in ores of the Jinding lead-zinc polymetallic deposit.The results show that the CO2 in ore-forming fluid was related to sedimentary organic matters and marine carbonates,it derived from thermal decomposition of marine carbonates and oxidation and decarbonxylation of sedimentary organic matters;the ore mineral composition of deposit reflects its metallogenic environment to be hyperoxia fugacity environment.The study of S isotopic characteristics show that S of gypsum ore body in deposit may come from Triassic ancient oceanic sulfate minerals,and S in metallic sulfide minerals is multi-sourced,which is mainly from reduced sulfur,crust-source sulfur and organic sulfur of gypsum-salt（gypsum, anhydrite,organic compounds,etc） in biological or bacteria reduction formation.The study of isotopic indicates that the Jinding lead-zinc polymetallic ore should be derived from crust.