五台山区金矿床的多金源多期次多成因多类型叠加成矿特征

FEATURES OF MULTI-SOURCE,POLY-PERIOD,POLY-GENETIC AND-POLY-TYPE SUPERPOSITIONAL MINERALIZATION OF GOLD DAEOSITS IN THE WUTAI MOUNTAIN,SHANXI

五台山区的金矿床都是叠加成因的矿床。金源层的微量分散金,被构造热事件所活化,迁移到容矿构造中重新就位,同一容矿构造多次活动和成矿,致使金品位逐次升高,形成矿床。这些金矿床具多源性、多期性、多成因和多类型叠加之特征。

The Wutai Mountain area is one of the gold--producing districts in China, wherethere occur Wutaian parasyngenetic stratabound gold deposits, vein gold depositsin Proterozoic-Mesozoic ductile and brittle shear zones and Proterozoic carbonatestratabound gold deposits. The gold is believed to be mainly derived from granite-greenstone belts and less commonly from conglomerate at the base of the HutuoGroup, carbonate rocks of the Changchen System, Proterozoic to Mesozoic basic dykes and granitic plutons. During the wutaian, Hutuoan, middle--late Proterozoicand Yanshanian multiple taphrogenic and extensional activities, influenced by deepfaults, regional metamorphism, magmatism and infiltrating fluids, scattered goldmigrated to ore--hosted structures such as bedding shear zones, ductite shear zones,brittle shear zones, interlayer shear zones and shear intersecting fracture sets. Golddeposits were formed by superimposition of a variety of gold ore formations suchas gold--bearing sericite schist, sulphide-bearing BIF, silicified rocks, polymetallicsulphide ores, quartz veins and altered rocks by various types of ore solutions suchas the H_2O--CO_2, H_2-Na^+, K^+-Cl^-type, H^2O--H_2-Ca^(++), Na^+-Cl^--HCO_3^- type, H_2O--H_2-Ca^(++), K^+-SO^(4-)-HCO_3^- type, H_2O--CO_2--Ca^(++), K^+--Cl^---HCO_3^- type, CH_4-CH_4--Ca^(++)--Cl^-tgpe and H_2O-CO_2--Ca^(++), K^+--F_--HCO_3^- type in various structural environments, e.g.at deep levels, relatively deep levels, shallow levels and ground surface. Each depo-sit underwent mineralization 2 or 3 times and shows the features of multi--source,poly--period, poly-genetic and poly--type superpositional mineralization. Most of thegold deposits in the world also have such features.