前寒武纪绿岩地体中金丰度与金成矿的关系

RELATIONSHIP BETWEEN THE ABUNDANCE AND METALLOGENESIS OF GOLD IN PRECAMBRIAN TERRAINS

摘要: 许多研究者认为,金丰度高的花岗岩和地层就是金矿床的矿源岩和矿源层.随着中子活化法和化学-光谱法的广泛应用,分析精度有了大幅度提高(可达0.01×10^-9).大量的国内外资料表明:绿岩地体中变质岩的金丰度较低,平均为0.71×10^-9~2.40×10^-9,与金矿有关的花岗岩金丰度更低,平均只有0.62×10^-9~1.20×10^-9.因此,矿源岩和矿源层并不是人们所想像的那些特定的岩石或地层.所有岩石都可能成为矿源岩或矿源层.花岗岩和地层中金的丰度与金矿床之间不存在必然的联系,金成矿与使金活化、迁移和富集的各种成矿机理有关.

Abstract: The granite and strata with high Au abundance have been considered to the source of gold by many geologists.With broad application of the method of neutron activation and chemical-spectral analysis,the accuracy of analysis has greatly improved(up to 0.01×10^-9).A wealth of data shows that the Au abundance of metamorphic rocks in greenstone terrains is rather low(0.17×10^-9 to 2.40×10^-9 in average),and in the relevant granites is only 0.62×10^-9 to 1.20×10^-9 averagely.This concludes that the concept of source rocks or source beds is ambiguous and non-specific.All rocks are possible to perform as source rocks/beds.The mineralization of gold is not related to the Au abundance in granite and strata,but to the metallogenetic mechanism involving gold activation,migration and enrichment.