江西省大坞金矿成矿地质特征及硫同位素地球化学特征探讨

Metallogenic Geological Characteristics and Sulfur Isotopic Geochemical Characteristics of the Dawu Gold Deposit in Jiangxi Province

江西省大坞金矿处在杨子陆块与华南造山带接壤区,杨子陆块-怀玉地体西南缘,控矿地层为上元古界青白口系叶家组变火山碎屑岩相的岩系,是海底火山喷发沉积安山岩。在野外详细的地质考察基础上,运用了稳定同位素质谱分析仪等现代分析测试技术。分析结果显示矿石硫化物硫同位素δ34的变化范围为15.11~19.9,具有海水硫的特点,但是综合硫的特征,表明矿石中硫不是来源于地层,其硫源可能是岩浆来源硫、地层中硫酸盐硫与海水的混合。通过对江西省大坞金矿床的成矿地质特征和硫同位素的综合研究,大坞金矿床在矿床成因上是属于海相变质热液型金矿。

The Dawu gold ore deposit in Jiangxi Province is located at the border between Yangzi block and South China orogenic belt, southwestern margin of Yangzi bloek-Huaiyu terrane, and the ore-controlling stratum is sub- marine volcanic eruptive sedimentary andesite, a series of meta-volcanie clastie facies at Yejia Formation, Qing- baikouan of Upper Proterozoic. On the basis of detailed field geological investigation, stable isotope mass spec- trometry and other modern analysis and testing technology are applied. It is shown that the sulfur isotope 834 of the sulfide varies 15.1 1 - 19.9, characterized by sulfur in seawater, while combining with the characteristics of sul- fur, sulfur in the ore is not derived from the stratum, and might be the mixture of sulfur in the magma, sulfate in the stratum and seawater. By the comprehensive study of metallogenic geological features and sulfur isotopic com- position, Dawu gold ore deposit can be concluded as a marine metamorphic hydrothermal gold deposit.