国内外太古宇中金矿床的地质及地球化学特征对比兼成因分析

产于太古宇中的金矿床在国内外都属主要金矿类型，虽然有成矿物质都来自含镁铁－超镁铁火山岩的太古宇，但成矿环境在国内外却有重大差异。国外矿床产在地盾上，围岩变质浅，延深大，无垂直分带，金矿物成色高，矿石Ａｕ／Ａｇ值大，放射性成因铅同位素低，成矿压力大，盐度低，成矿时代老（太古宙）。而国内矿床产在活化地台上，围岩变质深，有的有垂直分带性，金矿物成色较低，矿石Ａｕ／Ａｇ值小，放射性成因铅同位素高，成矿压力

GEOLOGICAL AND GEOCHEMICAL COMPARISON BETWEEN ARCHEAN GOLD DEPOSITS IN CHINA AND THOSE FROM OTHER COUNTRIES,WITH DISCUSSION ON GENESIS

Gold deposits hosted in Archean rocks are an important type both within and outside China. They are significantly different from each other in gold mineralization environment despite their similarity in the source of ore-forming materials,which were derived from Archean strata intercalated with mafic-ultramafic rocks.The gold deposits abroad occur in stabilized shields. They are characterized by low grade metamorphic host rocks, great vertical extension without zonation and high fineness of gold minerals, as well as a high Au/Ag ratio of ores and less radioactive lead isotopes. The mineralization time is old (Archean),and high pressure and low salinity of fluids are common for their formation environment.In contrast,gold deposits occurring in China developed in activation zones of platforms,with high grade metamorphic host rock, occasional vertical zonation and low fineness of gold minerals. The ore has a low Au/Ag ratio,more radioactive lead isotopes and relatively young mineralization ages(Phanerozoic).In spite of the difference of geological and geochemical characteristics of these gold deposits and the dispute on the genesis, this study shows that most of them were formed by reworking processes, with the ore-forming materials derived from Archean strata, and mineralizing fluid principally from formational water or evoived meteoric water.The difference between gold deposits within and outside China is caused by the difference of mineralization environment of different mineralization epoches.