Assemblages of submarine landforms in the glacial troughs of the northern Barents Sea, east of Svalbard

Abstract

The Barents Sea is a wide, relatively deep epicontinental sea consisting of shallower banks ( c. 50–100 m depth) separated by broad, flat-bottomed troughs ( c. 200–400 m depth) that radiate out towards its western and northern margins (Fig. 1a). These troughs have been excavated by grounded ice during multiple glaciations through the Plio-Pleistocene (Jakobsson et al. 2014). During the Last Glacial Maximum (LGM) the Barents Sea Ice Sheet (BSIS) extended across the entire northern Barents Sea to the shelf break (Svendsen et al. 2004; Jakobsson et al. 2014). Fast-flowing ice drained the ice sheet through these troughs and produced a suite of seafloor landforms that preserves both a record of former ice-flow patterns and of how the ice sheet retreated during deglaciation (Dowdeswell et al. 2010; Hogan et al. 2010 a ). Fig. 1. Bathymetric images and sub-bottom profiles of landforms in glacial troughs east of Svalbard. Acquisition system Kongsberg EM120. Frequency 12 kHz. Grid-cell size 10–20 m. Acquisition system for profiles Kongsberg TOPAS PS018 parametric sub-bottom profiler (secondary beam frequency 0.5–6 kHz). ( a ) Location of study area (red boxes; map from IBCAO v. 3.0). KT, Kvitoya Trough; OT, Olga Trough; E, eastern Erik Eriksen Trough; W, western Erik Eriksen Trough; KKL, Kong Karls Land; No, Nordaustlandet; FVT, Franz Victoria Trough. ( b ) Glacial lineations (long dashes) overprinted in part by a debris-flow deposit (dotted) in western Erik Eriksen Trough; recessional moraine orientations shown by solid lines. Large black arrow indicates former ice-flow direction. ( c ) Saw-tooth-shaped recessional moraines in Olga Trough. ( d ) Hill–hole pairs and glacial lineations in eastern Olga Trough; same depth scale as (c). ( e ) Streamlined crag-and-tail landforms in Kvitoya Trough. ( f ) Sub-bottom profile over the till sheet and recessional moraines shown in (c). ( g ) Acoustic facies on the upper slope north of Kvitoya Trough. ( h ) Subglacial meltwater channels …