Large‐scale sedimentation on the glacier‐influenced polar North Atlantic Margins: Long‐range side‐scan sonar evidence

Abstract

Long‐range side‐scan sonar (GLORIA) imagery of over 600,000 km² of the Polar North Atlantic provides a large‐scale view of sedimentation patterns on this glacier‐influenced continental margin. High‐latitude margins are influenced strongly by glacial history and ice dynamics and, linked to this, the rate of sediment supply. Extensive glacial fans (up to 350,000 km³) were built up from stacked series of large debris flows transferring sediment down the continental slope. The fans were linked with high debris inputs from Quaternary glaciers at the mouths of cross‐shelf troughs and deep fjords. Where ice was slower‐moving, but still extended to the shelf break, large‐scale slide deposits are observed. Where ice failed to cross the continental shelf during full glacials, the continental slope was sediment starved and submarine channels and smaller slides developed. A simple model for large‐scale sedimentation on the glaciated continental margins of the Polar North Atlantic is presented.

The variety and distribution of submarine glacial landforms and implications for ice-sheet reconstruction

“…Individual debris-flow deposits are up to about 50 m thick, a few kilometres wide and extend for up to about 200 km down the slope (e.g. Laberg & Vorren 1995;Dowdeswell et al 1996;King et al 1996;Taylor et al 2002). Delivery of deforming soft sediment to the shelf edge is clearly a full-glacial process, and the few radiocarbon dates available on the timing of glacigenic debris-flow activity support the view that the debris flows are full-glacial phenomena (e.g.…”

On the reconstruction of palaeo-ice sheets: Recent advances and future challenges

“…Imagery from continental slopes has revealed sedimentary depocentres (trough mouth fans : Vorren and Laberg, 1997;Batchelor and Dowdeswell, 2014), the architecture of which often indicates rapid, episodic sedimentation by ice streams (Dowdeswell et al, 1996;Dowdeswell and Elverhoi, 2002;Nygård et al, 2007). Indeed, dating of sediment packages is an important constraint on ice stream activity that is not easily available from terrestrial records, and some marine records extend back through several glacial cycles (Nygård et al, 2007).…”

The effect of sediment loading in Fennoscandia and the Barents Sea during the last glacial cycle on glacial isostatic adjustment observations

“…2 for the locations. Local observations come from sonar and seismic profiling (Dowdeswell et al, 1996) and coring (Saettem et al, 1992;Laberg and Vorren, 1996;Taylor et al, 2002;Laberg et al, 2012). Other estimates come from modeling based on bathymetry, elevation, and environmental conditions , but these are highly dependent on the amount of ice that is believed to have existed in the Barents and Kara seas.…”

“…The interest in this region stems from the fact that glacigenic sediment transport is large there (Riis and Fjeldskaar, 1992;Dowdeswell et al, 1996), with the last glaciation depositing sediment layers of up to hundreds of meters' thickness (Elverhøi, 1984). Moreover, several observations of sediment deposition are available from which the loading can be quantified (e.g., Dowdeswell, 1996;Taylor et al, 2002). Here, the focus is on present-day uplift and gravity rate of change and paleo-sea-level data, which are routinely used to constrain GIA models.…”