Configuration, history and impact of the Norwegian Channel Ice Stream

Abstract

The Norwegian Channel between Skagerrak, in the southeast, and the continental margin of the northern North Sea, in the northwest, is the result of processes related to repeated ice stream activity through the last 1.1 m yr. In such periods the Skagerrak Trough (700 m deep) has acted as a confluence area for glacial ice from southeastern Norway, southern Sweden and parts of the Baltic. Possibly related to the threshold in the Norwegian Channel off Jæren (250 m deep), the ice stream, on a number of occasions over the last 400 ka, inundated the coastal lowlands and left an imprint of NW‐oriented ice directional features (drumlins, stone orientations in tills and striations). Marine interstadial sediments found up to 200 m a.s.l. on Jæren have been suggested to reflect glacial isostasy related to the Norwegian Channel Ice Stream (NCIS). In the channel itself, the ice stream activity is evidenced by mega‐scale glacial lineations on till surfaces. As a result of subsidence, the most complete sedimentary records of early phases of the NCIS are preserved close to the continental margin in the North Sea Fan region. The strongest evidence for ice stream erosion during the last glacial phase is found in the Skagerrak. On the continental slope the ice stream activity is evidenced by the large North Sea Fan, which is mainly a result of deposition of glacial‐fed debris flows. Northwards of the North Sea Fan, rapid deposition of meltwater plume deposits, possibly related to the NCIS, is detected as far north as the Vøring Plateau. The NCIS system offers a unique possibility to study ice stream related processes and the impact the ice stream development had on open ocean sedimentation and circulation.

The last Scandinavian Ice Sheet in northwestern Russia: ice flow patterns and decay dynamics

“…It therefore appears that the peak glaciation in Russia was delayed by almost 10 kyr. In southwest Scandinavia this state was reached some time between 32 and 25 kyr BP (Sejrup et al 1994(Sejrup et al , 2003HoumarkNielsen & Kjaer 2003), when SIS eventually merged with the British Isles Ice Sheet. On the northern boundary, SIS coalesced with the Barents Sea Ice Sheet around 22 kyr BP (Svendsen et al 2004, and references therein).…”

Quaternary glaciations of northern Europe

“…Quaternary Science Reviews 44, 1-25. [Pre-proof accepted manuscript] 16 grounded ice although whether the two ice sheets were confluent is not known Sejrup et al, 2003;Graham, 2007;Davies et al, 2012).The North Sea was glaciated for a final time during the Late Weichselian (MIS 2). Well-developed seismic, geomorphological and sedimentological evidence now exists for the coalescence of both the Scandinavian and British ice sheets in the northern North Sea (Carr et al, 2006;Bradwell et al, 2007;Graham et al, 2007Graham et al, , 2009Bradwell et al, 2008c) (Figure 3) with ice reaching its maximum extent at the continental margin around 29 ka BP (Sejrup et al, 2009).…”

Glaciogenic reservoirs and hydrocarbon systems: an introduction

“…Advancing ice during the Pleistocene was, as in large modern-day ice sheets, preferentially fluxed via ice streams (Dowdeswell et al 2002;Ottesen et al 2008Ottesen et al , 2012. The 'footprint' of one such palaeo-ice stream is clearly evident in the Norwegian Channel (Ottesen et al 2012), where a large volume of sediment was transported to the shelf break and deposited as a trough-mouth fan (Sejrup et al 2003;Ottesen et al 2008).…”

“…Analogues for other parts of the glaciogenic environments encountered in the Palaeozoic include over-deepened shelves, cross shelf troughs and trough mouth fans found along the Atlantic margin of Norway (Dowdeswell et al 2002;Sejrup et al 2003;Rise et al 2004;Ottesen et al 2008Ottesen et al , 2012. Controls of reservoir quality in these systems include sediment provenance, sorting and depositional complexity (Fielding et al 2012;van der Vegt et al 2012) as well as syn-and post-depositional deformation by glaciotectonic processes, which can affect stratal depths up to 300 m beneath the glacier bed and tens of kilometres in front of the ice load (Huuse & Lykke-Andersen 2000b;Andersen et al 2005;Buckley 2012;Schack Pedersen 2012).…”

“…Glaciogenic deposits are largely preserved in formerly glaciated lowland areas, including land, lake and continental shelf areas, as well as adjacent continental slopes where large trough mouth fans constitute volumetrically important deposits from Pleistocene glaciations (Sejrup et al 2003;Ottesen et al 2012). In deep ocean settings, ice-rafted debris provides the most important physical record of the Pleistocene shelf glaciations (Hemming 2004).…”