The Tectonics of the Continental Barents Sea Shelf (Russia): The Formation Stages of the 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, regional tectonostratigraphic units were identified between reflecting horizons (RH): (i) a Paleozoic complex (between RH VI(PR?) and RH I₂(P‒T)); (ii) a Triassic complex (between RH I₂(P‒T) and RH B(T‒J)); (iii) a Jurassic complex (between RH B(T‒J) and RH C′(J₃‒K₁)); and (iv) a Cretaceous‒Cenozoic complex (between RH V′(J₃‒K₁) and the Barents Sea floor). According to the structural analysis results, three structural floors were established: the lower structural level, which includes Riphean terrigenous-effusive deposits and Lower Paleozoic‒Lower Permian terrigenous-carbonate deposits; the middle structural level is formed mainly by Upper Devonian‒Lower Permian carbonate deposits; the upper structural level combines Lower and Upper Permian terrigenous deposits and Mesozoic–Cenozoic deposits. This article presents a new tectonic model of the Barents Sea region, including elements of all structural levels with sublevels. 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), a Late Paleozoic stabilization stage (II), an Early Mesozoic tectonogenesis stage (III), a Middle Mesozoic thermal subsidence stage (IV), a Late Jurassic stabilization stage (V), a Cretaceous subsidence stage (VI), and the final stage as a Cenozoic uplift of a large part of the Barents Sea shelf (VII). In the northwestern part of the Russian sector of the Barents Sea shelf, synchronous subsidence of the sedimentary cover basement took place, associated with spreading and formation of the Arctic Ocean.