交代岩石圈地幔与金成矿作用

交代岩石圈地幔与大型金矿床之间的成因联系受到越来越多的关注.研究成矿金属在地幔源区的富集程度和幔源岩浆中的金含量,以及金从地幔源区释放、迁移并大规模富集成矿的机制和过程可以帮助我们更好地认识交代岩石圈地幔对金富集成矿的重要作用.金是高度亲铜元素,同时还具有流体活动性,在地幔岩浆作用、岩浆热液演化和富集成矿等诸多过程中的...

Metasomatized Lithospheric Mantle and Gold Mineralization

Metasomatized lithospheric mantle has been considered to play a key control on the formation of giant gold (Au) deposits. Investigating the extent of Au enrichment in the metasomatized lithospheric mantle source and Au contents of mantle-derived magmas, as well as the mechanisms that promote the transportation and enrichment of Au from mantle source to large Au mineralization, could help us to understand the major controls responsible for the formation of giant hydrothermal Au deposits. Gold is one of the highly chalcophile elements and is also mobile in fluids. The behavior of Au in many processes such as mantle melting/metasomatism, magmatic-hydrothermal evolution, and mineralization is complicated. In this study, it compiles Au contents of mantle rocks and their derivative mafic magmas, and attempts to clarify key factors that control the behavior of Au from mantle, magmatic-hydrothermal processes to gold mineralization. It suggests that the metasomatized lithospheric mantle is an important source for giant hydrothermal Au deposits, but the remarkable Au enrichment of such mantle source is not necessarily required. Metasomatic components, especially volatiles, enable efficient release of Au from the mantle source to hydrous magmas and promote subsequent transportation and enrichment during magmatic-hydrothermal processes through trans-lithospheric fault systems. It thus emphasizes the main role of the metasomatized lithospheric mantle as the source of giant Au deposits and highlight the importance of metasomatic volatiles and related magmatic-hydrothermal processes in Au enrichment rather than anomalously pre-enriched sources or primary magmas. Therefore, understanding the behavior of Au in mantle metasomatism and magmatic-hydrothermal processes during the long-term evolution of the lithospheric mantle is the key to decode the genesis of giant hydrothermal Au deposits.