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
Abstract. We introduce a regional 3-D structural model of the Barents Sea and Kara Sea region which is the first to combine information on the sediments and the crystalline crust as well as the configuration of the lithospheric mantle. Therefore, we have integrated all available geological and geophysical data, including interpreted seismic refraction and reflection data, seismological data, geological maps and previously published 3-D models into one consistent model. This model resolves four major megasequence boundaries (earliest Eocene, mid-Cretaceous, mid-Jurassic and mid-Permian) the top crystalline crust, the Moho and a newly calculated lithosphere-asthenosphere boundary (LAB). The thickness distributions of the corresponding main megasequences delineate five major subdomains (the northern Kara Sea, the southern Kara Sea, the eastern Barents Sea, the western Barents Sea and the oceanic domain comprising the NorwegianGreenland Sea and the Eurasia Basin). Relating the subsidence histories of these subdomains to the structure of the deeper crust and lithosphere sheds new light on possible causative basin forming mechanisms that we discuss.The depth configuration of the newly calculated LAB and the seismic velocity configuration of the upper mantle correlate with the younger history of this region. The western Barents Sea is underlain by a thinned lithosphere (80 km) resulting from multiple Phanerozoic rifting phases and/or the opening of the NE Atlantic from Paleocene/Eocene times on. Notably, the northwestern Barents Sea and Svalbard are underlain by thinnest continental lithosphere (60 km) and a low-velocity/hot upper mantle that correlates spatially with a region where late Cenozoic uplift was strongest. As opposed to this, the eastern Barents Sea is underlain by a thicker lithosphere (∼ 110-150 km) and a high-velocity/density anomaly in the lithospheric mantle. This anomaly, in turn, correlates with an area where only little late Cenozoic uplift/erosion was observed.
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