Evolution of the Timan–Pechora and South Barents Sea basins

Abstract

We have analysed 129 stratigraphic sections from the Timan-Pechora basin, from its adjacent continental shelf and from the South Barents Sea basin, in order to determine whether existing models of extensional sedimentary basin formation can be applied to these intracratonic basins or whether new mechanisms of formation need to be invoked. The subsidence history of each section has been calculated using standard backstripping techniques. An inverse model, based on finite-duration lithospheric stretching, has then been used to calculate the distribution of strain rate as a function of time required to fit each subsidence profile. Results demonstrate an excellent fit between theory and observation. By combining our analysis with independent field-based and geophysical observations, we show that the Timan-Pechora basin underwent at least four phases of mild lithospheric stretching during the Phanerozoic (β < 1.2). These phases occurred in Ordovician, Late Ordovician-Silurian, Middle-Late Devonian and Permian-Early Triassic times. Growth on normal faults, episodes of volcanic activity and regional considerations provide corroborative support for the existence of all four phases. Although less well constrained, subsidence data from the South Barents Sea basin are consistent with a similar Early-Middle Palaeozoic history. The main difference is that Permian-Early Triassic extension is substantially greater than that seen onshore. This similarity implies structural connectivity throughout their respective evolutions. Finally, subsidence modelling demonstrates that rapid foreland basin formation, associated with the Uralian Orogeny, was initiated in Permo-Triassic times and is confined to the eastern margin of the Timan-Pechora basin. Coeval foreland subsidence does not occur on the eastern margin of the South Barents Sea basin, supporting the allochthonous nature of Novaya Zemlya. The most puzzling result is the existence of simultaneous lithospheric extension and foreland loading in Permian-Early Triassic times. This juxtaposition is most clearly seen within the Timan-Pechora basin itself and suggests that convective drawdown may play a role in foreland basin formation.

Phanerozoic denudation across the Kola Peninsula, Northwest Russia: implications for long-term stability of Precambrian shield margins

“…Multiple phases of extension and rifting have been recognised in the southern Barents Sea from the Carboniferous, in Permo-Triassic time and also in the Late Jurassic-Early Cretaceous, with Late Cretaceous-Early Tertiary basin inversion (O'Leary et al, 2004;Shipilov, 2015). The northward-dipping wedge of Palaeozoic to Triassic sedimentary rocks in the Kola-Kanin Monocline off the Murmansk Coast reaches a total thickness of 5 km (Fig.…”

“…1), thick, very coarse-grained, sandstone turbidites are interbedded with conglomerates and a basal olistostrome-breccia (Siedlecka et al, 1995b;Mitrofanov et al, 2004). In the eastern Kola Peninsula, the Riphean sedimentary rocks are much finer grained, with thick siltstone units (Baluev et al, 2009), and were originally deposited in half-grabens within mountainous terrain (O'Leary et al, 2004). Along the north coast of the Kola Peninsula, Riphean rocks have been faulted and laterally displaced along the Karpinsky Lineament ( Fig.…”

“…Around the margins of the Kola Peninsula and in adjacent areas of northern Finland and Karelia, a maximum 1 km depth of shield and cover rocks has been removed since 360 Ma, giving average erosion rates of <3 m/Myr. As uplift-driven episodes of more rapid erosion occurred in the Early Mesozoic (O'Leary et al, 2004) and Pliocene (Knies et al, 2014) on the northern Norwegian margin, it is likely that the Kola Peninsula has experienced long intervals of negligible erosion. Since the end of KAP magmatism, the Kola fragment of the Fennoscandian Shield has developed under a cratonic tectonic regime (Fairbridge & Finkl, 1980) of slow, episodic uplift and denudation.…”

A lithosphere-scale structural model of the Barents Sea and Kara Sea region

“…1, 2). Several published studies discuss the nature of the observed rapid subsidence in the East Barents Sea basin since there are no major extensional faults and thus a classical rift scenario is unlikely (Aplonov et al, 1996;Gac et al, 2012Gac et al, , 2013Ivanova et al, 2011;Johansen, 1992;O'Leary et al, 2004;Petrov et al, 2008;Semprich et al, 2010). Oldest sediments of the South Kara Sea basin are assumed to have accumulated in response to rifting in the Late Permian to Middle Triassic followed by a post-rift thermal subsidence phase lasting until Cenozoic times (Nikishin et al, 2011).…”

Lower to Middle Ordovician trilobite faunas along the Ural border of Baltica

“…The Lower Palaeozoic Baltica Palaeoplate (Cocks & Torsvik 2005) comprises the East European Craton as its core with three major crustal segments Fennoscandia, Sarmatia and Volgo-Uralia that collided between ca 2.0 and 1.7 Ga (Bogdanova et al 2008), and the Pechora Basin that became accreted to Baltica in the late Vendian as a part of the Timanide Orogeny (Bogolepova & Gee 2004, O'Leary et al 2004. The Kara block has been interpreted as a part of Baltica ( Fig.…”