Structural features and mineralogical characteristics of the Noyon-Tologoi polymetallic VMS deposit ores
It was found that the Noyon-Tologoi deposit located within the Priargunskaya mineragenic zone belongs to the pyrite-polymetallic (Nojon-Tologoj) formation type in volcanogenic associations (VMS). The deposit ore is hosted by the Middle-Upper Jurassic terrigenous-volcanogenic rocks combined in a volcanogenic-siliceous-terrigenous unit. The volcanogenic section is characterized by predominance of intermediate volcanics ranging from moderately alkaline to low alkaline series. Beresites form as a result of the metasomatic transformation of the Noyon-Tologoi volcanosedimentary rocks. Within the deposit, polymetallic mineralization is concentrated in the main ore-bearing areas: Central, Southeast, East and Southwest. Silver-polymetallic mineralization is represented by multilayer veinlet, veinlet-nest-disseminated and disseminated sulfide ore zones, which can also cut host volcanosedimentary rocks. Veins and lenses of the first tens of centimeters thick composed of massive sulfide aggregates are less developed. The main ore minerals are pyrite, sphalerite, galena, arsenopyrite and tetrahedrite; minor minerals are lead and silver sulfosalts, jamsonite, marcasite, chalcopyrite and bournonite. The hydrothermal system of the Noyon-Tologoi deposit formed in response to underwater volcanism and is described by a convective-recycling model.