U-Pb (LA-SF-ICP-MS) dating and probable provenance of detrital zircons from terrigenous deposits of the Upper Precambrian of the Subpolar Urals

Abstract

Research subject. Upper Precambrian metaterrigenous deposits of the northern part of the Lyapinsky anticlinorium in the Subpolar Urals.Material and methods. From the metaterrigenous rocks of the Upper Precambrian section of different stratigraphic levels, monofractions of zircons were isolated and their optical and isotope-geochronological (U-Pb LA-SF-ICPMS) studies were performed.Results. Age boundaries of the formation of the Puivinskaya, Khobeinskaya, and Moroinskaya Formations in the Subpolar Urals were specified. A comparison was carried out of age populations of detrital zircons from metaterrigenous deposits of the Subpolar Urals and terrigenous sequences of adjacent regions similar in age. The age boundaries and the proposed location of crystalline complexes, the probable provenance areas of terrigenous material, were established.Conclusions. The lower age limit of the formation of the basal layers of the Upper Precambrian of the Subpolar Urals does not go beyond the Late Riphean. The north-eastern periphery of the East European Platform, including the Subpolar Urals, in the Late Precambrian belonged to the same continental margin, and the accumulation of the Middle-North Timan and Subpolar Ural Upper Riphean sediments occurred in the common sedimentation basin. The lower age boundary of the formation of the Puivinskaya Formation (about 1000 Ma) determines the probable formation time of the Timan passive margin.