Metallogenic Regularity and Prospecting Predictions of Gold Deposits in China

详细

In this paper, based on the analysis of 1572 small and above-scale gold deposits in China, the gold deposits are divided into four types for prediction purposes: sedimentary, volcanic rock, magmatic hydrothermal and shear zone types. The spatial and temporal distribution of gold deposits in China is non–uniform, as 60% of the deposits are distributed in the land block and Mesozoic deposits account for 71.5% of the national total. It is found that intrusive and sub-volcanic rocks are the main ore–forming geological bodies. Here, the method for accurately identifying the spatial positions of concealed rocks is summarized. Through the geological profile study of 450 representative gold deposits, this paper suggests that there are mainly two kinds of gold deposits in China. One is characterized as an association of Au and Ag, with formation temperatures of approximately 250°C; it has very low concentrations of As and Sb. The fineness of the gold is generally below 900. Unequal proportions of K–feldsparization and albitization formed in the early stage. The other is an association of Au, As and Sb with a formation temperature below 250°C; the fineness of the gold is generally higher than 900; it has low Ag and high As and Sb concentrations. Alterations were mainly in the form of silicon with some secondary quartz formed in the early mineralization stage. Taking into account the elemental geochemical characteristics, the mechanism of gold migration and precipitation in the transient transition process from fluid to solid minerals in the ore-forming structure is discussed. The discussion provides a reference for future gold prospecting.