Significant Geological Features of Vein Gold Metallogeny in China
published: Jan 1, 1988
ArtNo. ESP136000302008, Price: 19.00 €
The geological setting, mineralization and alteration of vein gold deposits in China was comprehensively studied. In different parts of China, the host rocks of gold deposits are of different age, from Archean to Tertiary. The gold deposits in the three tectonic domains of China occur in different structural setting. However, in the light of deep structure, they generally occur in places where the gradient of the apparent isopach of Moho is steeper or bends. Almost all the gold deposits of East China cluster in tectonic environment formed by intersection of the nearly E-W trending faulted fold systems and the NNE trending fracture zones. Many of them are confined to dome areas. The deposition of gold appears to posdate the event of mylonitization. In the host rocks dominated by sialic material, the main processes of wallrock alteration are silicification, sericitization and pyritization with minor carbonatization and chloritization, and sometimes with fluoritization. K-feldspathization may occur at deeper levels. The stages of mineralization in Chinese vein gold deposits vary from place to place. However, they can, in general, be attributed to three principal stages, i.e. the oxide stage, sulfide stage, and carbonate stage respectively. In some gold ore districts, counting from the country rock to the ore body, the variation of alteration associations indicates an intimate relationship between potassium and gold mineralization. Gold ions may migrate farther than other metallic ions away from the 'hot spot' resulted from igneous intrusion or migmatization. Among the factors relevant to the metallogenesis of gold, the most crucial factor is hydrothermal fluid rather than the gold abundance in original country rocks.