Specific features of pyrite ore-magmatic systems development in the island arc environments of Rudny Altai and Southern Urals

The paper provides the geological, mineralogical, and geochemical characteristics and distribution features of pyrite deposits in Rudny Altai and Southern Urals metallogenic belts. Their similar and different features are elucidated. A common feature of these regions is their close relation to island arc volcanism and large scale of mineralization that forms the world's largest pyrite provinces comparable among themselves and with pyrite belts of different regions of the world. Ore deposits in these regions have a node character and form separate ore areas controlled by volcanic central-type structures and subvolcanic bodies. In general ore deposits have multilayer distribution and are represented by lenticular, rarely tabular bodies, often localized among the hydrothermally altered rocks of quartz-sericite-chlorite and quartz-sericite composition. All deposits are attributed to the pyrite formation and include compositionally similar mineral types such as chalcopyrite-sphalerite-pyrite and gold-barite-polymetallic. Most of the deposits in these regions have a multistage origin and nearly the same mechanism of ore deposition with similar physicochemical conditions of mineralization. The specific of the regions is related to different geodynamic conditions of their formation. The Southern Urals deposits formed within the ensimatic island arcs developed on the oceanic crust while the Rudny Altai deposits occur in the ensialic island arcs developed on the crust of the continental type. This fact is responsible for the difference in volcanism and composition of mineralization