Tectonics of the Continental Barents Sea Shelf (Russia): Formation Stages of Basement and Sedimentary Cover

Abstract

Based on the results of field complex geophysical studies in the northwestern part of the Russian sector of the Barents Sea shelf, as well as on the processing and comprehensive interpretation of new and retrospective geophysical materials in the volume of 25 500 linear kilometers and deep well drilling data in the section of the Barents Sea sedimentary cover identified regional tectonostratigraphic units: (i) Paleozoic complex (between reflecting horizons VI(PR? ) and I2(P‒T)); (ii) the Triassic complex (between reflecting horizons I2(P‒T) and B(T‒J)); (iii) the Jurassic complex (between reflecting horizons B(T‒J) and V′(J3‒K1)); (iv) the Cretaceous‒Cenozoic complex (between reflecting V′(J3‒K1) and the Barents sea floor). According to the structural analysis’ results, three structural floors are established: the lower structural floor, which includes Riphean terrigenous-affusive sediments and Lower Paleozoic‒Lower Permian terrigenous-carbonate sediments; the middle structural floor is formed mainly by carbonate sediments of Upper Devonian‒Lower Permian; the upper structural floor combines terrigenous sediments of Lower and Upper Permian, Mesozoic and Cenozoic sediments. The authors present a new tectonic model of the Barents Sea region, including elements of all structural floors with subfloors. In accordance with the tectonic zoning, paleostructural and paleotectonic analyses, the article outlines the main stages of the Barents Sea shelf development: stage of the Late Proterozoic compression and Early-Middle Paleozoic continental rifting (I), Late Paleozoic stabilization stage (II), Early Mesozoic tectogenesis stage (III), Middle Mesozoic thermal subsidence stage (IV), Late Jurassic stabilization stage (V), Cretaceous sagging stage (VI) and the final stage as a Cenozoic uplift over a large part of the Barents Sea shelf (VII). In the northwestern part of the Russian sector of the Barents Sea shelf, synchronous dipping of the sedimentary cover basement took place, associated with spreading and formation of the Arctic Ocean.