Structure and Metamorphism of Rocks as a Criterion of Dissection and Correlation of Polymetamorphic Complexes (On Example of the Subpolar Urals)

Abstract

According to the officially accepted stratigraphic schemes, pre-Upper Riphean stratigraphic units of the Subpolar Urals are divided (bottom-up) into the Nyartin metamorphic complex (PR1), Manhobeyu (RF1), Schekurya (RF1), and Puiva (RF2) suites. Studying the structure and metamorphism of the above-mentioned structural-material units, it was found that intensively and repeatedly deformed and metamorphosed formations of the Nyartin complex, Manhobeyu and Schekurya suites can be assigned to the same structural stage. Considering the available isotopic data on the early stages of metamorphic manifestations in rocks of the Nyartin complex, it can be stated that all of these stratigraphic units are attributed to the Lower Proterozoic, with a high degree of probability. The Upper Proterozoic section in the Subpolar Urals begins with sediments of the Middle Riphean Puiva suite. In contrast to the southern regions of the Urals, there are no Lower Riphean formations there.