Labaznoe Porphyry Ore-Magmatic System (Omolon Craton Terrain, North-East of Russia): Age, Mineralogy of Mineralization and Mineral Thermobarometry of Ore-Hosting Granitoids of the Viktorinsky Complex

New data are presented on the age (U–Pb, LA-SF-ICP-MS: 86±1 Ma) of quartz monzodiorites of the Viktorinsky complex of the Kongin magmatic zone of the Omolon cratonic terrane. The Labaznoye ore occurrence, bearing veinlet-stockwork sulfide-quartz and vein polymetallic mineralization, is localized within the intrusive-dome uplift, in the central part of which a stock of monzodiorites of the Viktorinsky complex is exposed. The petrographic and geochemical characteristics and mineral thermobarometry of the ore-hosting quartz monzodiorites are presented. The mineralogy of the ores is characterized and an estimate of the isotopic age (K–Ar: 82±4 Ma) of sericite crystallization from the near-vein contact with the monzodiorite intrusion are characterized. Based on geological relationships and isotope-geochronological data, a paragenetic relationship was established between molybdenum-porphyry mineralization and the stage of Late Cretaceous magmatism — the intrusion of granitoid bodies of the Viktorinsky complex. The stages of formation of paragenetic mineral associations were reconstructed in the sequence magnetite-quartz, molybdenite-quartz, sulfide-quartz; the hypogene stage ends with a polymetallic mineralization. The isotope dating materials of ores and ore-hosting granitoids in the study region indicate a Late Cretaceous (Coniacian-Campanian) age of porphyry ore-magmatic systems of the Konginsky magmatic zone.