Tectonic implications of the lithospheric structure across the Barents and Kara shelves

Abstract

15We present, summarize and discuss the lithosphere structure and evolution of the wider Kara Sea region, based on compilation and integration of geophysical and geological data. Regional 17 transects are constructed at both crustal and lithospheric scales based on the available data and a 18 regional 3D model. The transects, which extend onshore and into the deep oceanic basins are used 19 to link deep and shallow structures and processes, as well as to link offshore and onshore areas. 20The study area has been affected by numerous orogenic events: (1) Precambrian-Cambrian 21 (Timanian), (2) Silurian-Devonian (Caledonian), (3) Latest Devonian-earliest Carboniferous 22 (Ellesmerian/Svalbardian), (4) Carboniferous-Permian (Uralian), (5) Late Triassic (Taimyr, Pai Khoi, 23 Novaya Zemlya), (6) Paleogene (Spitsbergen/Eurekan). It has also been affected by at least three 24 episodes of regional-scale magmatism, so-called large igneous provinces ( North Atlantic (Paleocene-Eocene transition). Additional magmatic events occurred in parts of the 27 study area in Devonian and Late Cretaceous times. 28Within this geological framework, basin development is integrated with regional tectonic events and 29 stages in basin evolution are summarized. We further discuss the timing, causes and implications of 30 basin evolution. Fault activity is related to regional stress regimes and reactivation of pre-existing 31 basement structures. Regional uplift/subsidence events are discussed in a source-to-sink context and 32 related to their regional tectonic and paleogeographic settings. 33 34 The location of our lithosphere-scale transects with respect to gravity and magnetic 113 anomalies are shown in figure 3. The free-air gravity field (Fig. 3a) is rather smooth across (Fig. 3a). The magnetic anomaly map (Fig. 3b) shows the characteristic 122 linear sea-floor spreading anomalies of oceanic basins Gaina et al., 2009; 123 Jokat et al., 2016). In the continental part magnetic anomalies reflect a heterogeneous 124 basement both onshore and offshore (Barrére et al., 2009(Barrére et al., , 2011Marello et al., 2010Marello et al., , 2013 The most prominent feature in the depth to basement map (Fig. 4a) Ivanova et al., 2011;Sakoulina et al., 2015Sakoulina et al., , 2016. Deep sedimentary basins also exist 133 in the SW Barents Sea, but these are much narrower and related to multiphase rifting 134 (Faleide et al., 1993a,b;Gudlaugsson et al., 1998) The depth to Moho map (Fig. 5a) • Transect 1 -Norwegian-Greenland Sea to Pai Khoi (Fig. 6) Keywords: 172• Transect 2 -Norwegian-Greenland Sea to southern Kara Sea (Fig. 7) 173• Transect 3 -Norwegian-Greenland Sea to Taimyr (Fig. 8) 174• Transect 4 -Mezen Bay/Kanin Peninsula to Severnaya Zemlya (Fig. 9) 175• Transect 5 -Baltic Shield/Fennoscandia to Eurasia Basin (Fig. 10) 176• Transect 6 -Northern Norway (Troms) to Morris Jessup Rise (Fig. 11

Thermochronology and Exhumation History of the Northeastern Fennoscandian Shield Since 1.9 Ga: Evidence From 40Ar/39Ar and Apatite Fission Track Data From the Kola Peninsula

“…Our AFT data can be interpreted in the same way as FT data from Sweden and Finland (Kohn & Gleadow, ), if we assume that this back bulge basin extended to the Kola Peninsula area (the Kola back bulge basin) and then fully eroded. The presence of thick late Paleozoic and Mesozoic sedimentary successions in the southwestern Barents Sea—the Kola Monocline (Faleide et al, ; Henriksen et al, )—supports this assumption.…”

“…Our AFT data can be interpreted in the same way as FT data from Sweden and Finland (Kohn & Gleadow, 2019), if we assume that this back bulge basin extended to the Kola Peninsula area (the Kola back bulge basin) and then fully eroded. The presence of thick late Paleozoic and Mesozoic sedimentary successions in the southwestern Barents Sea-the Kola Monocline (Faleide et al, 2017;Henriksen et al, 2011)supports this assumption. Thus, according to scenario #2, the cooling time of the upper crust of the Kola Peninsula after cessation of the Kola Alkaline Province magmatism (360 Ma) to a temperature below 110°C (~300 Ma) is~60…”

Crustal structure and evolution of the Arctic Caledonides: Results from controlled-source seismology

“…Map the crustal structure across the Storfjorden earthquake sequence in order to identify structures associated with the recent seismic activity and its possible link to Caledonian trends. Faleide et al, 2017. …”

Sedimentology and petrography of the Svenskøya Formation on Hopen, Svalbard: an analogue to sandstone reservoirs in the Realgrunnen Subgroup

“…This is a key sequence stratigraphic surface in Svalbard and the Barents Sea (Gjelberg et al 1987) and is comparable to the "Rhaetian Unconformity" as defined by Embry (2011) in the Sverdrup Basin of Arctic Canada. The unconformity coincides with the development of the Novaya Zemlya Fold and Thrust Belt (Drachev 2016;Faleide et al 2017). The cliff-forming, white and grey sandstone beds ( Fig.…”