부산대학교 도서관

Various ore deposits, mostly those of gold, tin, copper and mercury, are spatially and temporally associated with Mesozoic magmatic belts in the surroundings of the Kolyma–Omolon terrane in eastern Yakutia. The paper discusses the metallogenic significance of redox conditions in ore–magmatic processes with regard to the proportions of ferrous and ferric oxides in the magmatic rocks. It has been established that igneous rocks of the Main and Northern batholith belts, transverse rows (western continuation of the Kolyma loop), and small zones in the southwestern surroundings of the Main batholith belt crystallized under reducing conditions (ilmenite series). All of the tin and tungsten ore deposits and occurrences are concentrated above the intrusive zone. The ilmenite-series rocks are framed by magnetite-series rocks, which were formed under oxidizing conditions. The accumulations of chalcophile elements are associated with the magnetite-series rocks. The position of the boundary between the Mesozoic ilmenite- and magnetite-series rocks does not depend on the age of the rocks, their crystallization depths, and petrochemical composition. Zoning in the redox conditions had occurred before the formation of the igneous rocks and continued throughout the Cretaceous.