Geochronology of granitoid magmatism of Subpolar Urals

Practically till the end of last century the granitoids from Subpolar Urals, included in the Central Ural Uplift, were separated to two heteroaged complexes: salnersko-mankhambovsky (545-490 Ma) and kozhymsky (380-225 Ma). Modern isotope-geochronometric data (Rb-Sr, U-Pb and Pb-Pb) on granitoids from 20 massives, included kozhymsky-related, show that their possible formation time corresponded to 640-490 Ma, i.e. all the granitoids are pre-Ordovician and related to preuralides, therefore there are no grounds for the kozhymsky complex. The evolution of granitogenesis shows three stages: 640-580, 560-550 and 520-490 Ma. The beginning of granite-formation was caused by subduction-collision processes at the closure of Protoural ocean (Timan tectogenesis), and the cease was related to epicontinental rifting followed by opening of Paleoural ocean. In post-Ordovician time granitoids were influenced by greenshist metamorphism - 400 Ma and monofacial diaphtoresis - 250 Ma. By the substantial-genetic classification the granitoids from the Subpolar Urals are related to I-, A- and S-types. The existing representations about confinement of granites of certain types to specific time intervals, and also about relation of I-granites with convergent, and A-granites with divergent environments, are not supported isotopically. Within the specified stages all three types of granitoids are observed, therefore affiliation of the granitoids to this or that type is not connected with age or geodynamic environment, but substantial heterogeneity of the substrate.