Collapse of the Last Eurasian Ice Sheet in the North Sea Modulated by Combined Processes of Ice Flow, Surface Melt, and Marine Ice Sheet Instabilities

Abstract

The North Sea sector is a shallow marine basin, which is topographically dominated by the Norwegian Channel, a deep (∼200-600 m) trough on the southwestern Norwegian coast (Figure 1). The North Sea sector hosts an archive of palaeo ice sheet dynamics with marine, lacustrine, and terrestrial margins. Therefore, this sector has the potential to provide an analog for contemporary ice sheets and to inform long-term behavior of ice sheets with different marginal settings. For example, the northern marine margin may have been vulnerable to similar marine processes that are in effect in contemporary West Antarctica (Favier et al., 2014;Joughin et al., 2014;Shepherd et al., 2001). These marine sectors are prone to instabilities of retreat, which represent the largest source of uncertainty for future sea level projections (Edwards et al., 2019). Therefore, understanding the deglaciation of marine ice sheet sectors is a key challenge of glaciology. Ice sheet evolution over the North Sea basin is also important in understanding the Relative Sea Level (RSL) change of the basin since the last deglaciation (Bradley et al., 2011). Furthermore, the history of glaciation is a key cause of the complicated stratigraphic record that needs to be understood to plan economically viable offshore wind farm developments in the North Sea (e.g., Emery et al., 2019). All considered, the requirement to better understand the deglaciation of the North Sea sector of the Eurasian Ice Sheet complex has motivated several previous empirical and modeling studies (e.g.

Growth and retreat of the last British–Irish Ice Sheet, 31 000 to 15 000 years ago: the BRITICE‐CHRONO reconstruction

“…2021b), which host reverse bed slopes in waters deeper than is typical across the domain, marine ice‐sheet instability is predicted to have occurred using ice‐sheet modelling experiments aimed at replicating the BRITICE‐CHRONO glacial histories (Gandy et al . 2018, 2021). That the influence of marine ice‐sheet instability was found to be largely absent across the ice‐sheet domain may indicate that its operation was the exception rather than the rule, consistent with some findings elsewhere (Greenwood et al .…”

“…2019) and on understanding the role of ice saddle collapse and marine ice‐sheet instabilities in deglaciating the North Sea (Gandy et al . 2021). The development of tools for assessing model simulations against empirical data have been reported in Ely et al .…”

Timing, pace and controls on ice sheet retreat: an introduction to the BRITICE‐CHRONO transect reconstructions of the British–Irish Ice Sheet

“…(2019) ran experiments to explore the extent to which the BISICLES model could correctly simulate the location and evolution of ice streams compared against the evidence. Finally, it has been run (Gandy et al ., 2021) to assesss the physical plausibility of an empirically reconstructed ice collapse event over the North Sea (Sejrup et al ., 2016; Evans et al ., 2021). This involved choosing between 70 ensemble experiments using quantitative model–data comparison tools finding the best match regarding ice flow directions, margin positions and satisfying the new deglacial age dates.…”

Sedimentary architecture and landforms of the Late Saalian (MIS 6) ice sheet margin, offshore the Netherlands

“…The North Sea area experienced several major glaciations during the late Quaternary, of which the Elsterian (MIS 12 and/or 10), late Saalian (MIS 6) and late Middle Weichselian (MIS2) were the most extensive (Busschers et al, 2008;Cameron et al, 1992;Caston, 1979;Ehlers and Gibbard, 2004;Gandy et al, 2020;Graham et al, 2011;Laban and van der Meer, 2011;Lauer and Weiss, 2018;Lee et al, 2012;Zagwijn, 1973Zagwijn, , 1983). In the Netherlands, the late Saalian ice sheet reached furthest south (Fig.…”