Provenance and U-Pb Age of Detrital Zircons from the Upper Proterozoic Deposits of the Polar Urals: To the Question of the Time of Formation of the Timan Passive Margin

New petrogeochemical data and the first results of U-Pb dating of detrital zircons from terrigenous units of the Nyarovei series, which refers to the basal level of the Meso-Neoproterozoic sections of the Polar Urals, are presented. On the basis of the analysis of the contents of petrochemical components, rare (Th, Co, Sc, Cr, and V) and rare earth elements in the rocks, and their ratios, it is suggested that sedimentary-volcanogenic rocks of the Nyarovey series were formed within rift-related settings. A possible provenance of detrital material is reconstructed. On the basis of U-Pb isotope-geochronological data, the accumulation time of the Nyarovey deposits is established. It is shown that the entire section of the series, including the Verhnekharbey and the Miniseyshor formations, was formed in the Neoproterozoic; therefore, the widely accepted idea that these units belong to the Mesoproterozoic is erroneous. On the basis of the analysis of data on the age constraints of the Precambrian units from different parts of the Timan-Northern Ural region, the following conclusion is made: contrary to the Southern Urals where the Precambrian section is complete, the post-Paleoproterozoic Precambrian section in the studied region begins with sediments referring to the Meso-Neoproterozoic boundary, but most likely Neoproterozoic ones. This indicates that the Timan passive margin formed in the Neoproterozoic.