Origin and geological history of massive sulphide deposits associated with ultramafic and mafic paleoceanic complexes from the Urals-Mongolian fold belt

摘要

Location, composition, structure, stages of formation and transformation of VMS deposits in ultramafic and mafic rocks in the Paleozoic suture zones of the Urals-Mongolian fold belt are reviewed. Cyprus, Besshi, Ural, Kuroko, and Sedex deposit types are spatially combined here and their formation and transformation are attributed to three metallogenic stages. The first metallogenic stage is connected with development of rifts in marginal oceans where oceanic crust was created and submarine sulphide ores of Cyprus and Besshi types were deposited. The second metallogenic stage is stipulated by development of island arc structures. Apart from Kuroko and Urals types ores a new class of deposits was determined. These are cobalt-copper-sulphide deposits restricted to accretion prism of island arc slope and formed on ultramafic rocks. The third metallogenic stage accompanies collision processes and leads to combination in the same structures of different deposits with various geodynamic natures, transformation of ores, and their enrichment in cobalt, nickel and gold.