与剪切带有关金矿床成矿流体研究进展

PROGRESS ON RESEACH OF ORE-FORMING FLUID OF GOLD DEPOSITS RELATED TO SHEAR ZONES

与剪切带有关的金矿床是一种重要类型的金矿床 ,矿床产于与俯冲作用有关的碰撞造山带中压性或压扭性的构造环境 ,赋矿围岩岩性复杂 ,且普遍遭受了低绿片岩相到麻粒岩相的变质作用 ,成矿时代从太古代到第三系。矿床强烈受剪切带控制 ,以富集Au、Ag、As、Sb、W、Bi、Te等为特征 ,围岩蚀变以富集CO2 、S、K、H2 O、SiO2 为特征。成矿流体为低盐度 (质量百分含量为 3%～ 10 %的NaCl)的富含CO2 (≥ 5mol% )近中性流体 ,δ18OH2 O=5‰～ 12‰ ,成矿流体来源有岩浆源、幔源、天水源、变质源及混合源等多种来源 ,对这类矿床进行深入研究对成矿理论及找矿勘探都具有重要意义。

Gold deposits related to shear zones is one of the very important gold deposit types. The deposits are hosted in compressional to transpressional deformation environments at convergent plate margins in accretionary and collision orogens. These deposits formed from Archean to Tertiary, hosting complex wall-rocks, which was metamorphosed from low greenschist facies to granulite facies of metamorphic grade. The deposits had consistent enrichments in Au, Ag, As,Sb, W, Bi, Te, etc,The altered wall-rocks were characteristically rich in CO 2、S、K、H 2O、SiO 2. Ore-forming fluid is low salinity (3～10 wt%NaCl), near-neutral, enriched in CO 2 (≥5mol%),δ 18 O H 2O =5‰～12‰. There are different viewpoints on the origin of ore-forming fluid, that is magmatic origin, mantle origin, meteoric water origin, metamorphic origin and mixed fluid origin. Much deeper research into these types of deposits is very important to metallogenic theory and explorations.