Home – Home – Jornals – Russian Geology and Geophysics 2006 number 12

In the Orhon-Selenge trough (OST) (northern Mongolia), which is part of the extended Permo-Triassic Selenge volcanoplutonic belt, the formation of ore-bearing porphyry complex and large-scale stockwork Cu-Mo mineralization (Erdenetiyn-Ovoo deposit) was preceded by multiphase magmatism, which was accompanied by ore mineralization of different scales and types. The evolution of the Permo-Triassic magmatism successively resulted in ore occurrences, which form a single metallogenic series (predominance of Cu and permanent presence of Mo): native Cu (P; differentiated basalt-andesite-rhyolite series)-Cu-Ni-sulfide, Cu-skarn, and Cu-vein (P₂-T₁; basites and granitoids of the Selenge complex)-native Cu (P₂-T₁; trachyandesite-basalt series)-porphyry Cu-Mo (T; Erdenet ore-bearing porphyry complex). In this series, the intensity of fluid flow grows and the redox potential of the endogenous system shifts to that of more oxidizing conditions, which favors the transfer of ore-forming elements from depth and increases the Cu-bearing capacity of magmatogene fluids. The development of magmatism and accompanying mineralization in the OST is assumed to be related to one of the lower-mantle plumes that existed in the vast Asian area in the Permo-Triassic.