Glacial lineations and recessional moraines on the continental shelf of NE Greenland

Abstract

The NE Greenland continental shelf is only sparsely mapped due to its remoteness and harsh year-round sea-ice conditions. Mapping the distribution of submarine glacial landforms relies mainly on single track lines of multibeam echo-sounder bathymetric data with only occasional systematic surveys. Ice streams drain the modern Greenland Ice Sheet (GrIS) to its northeastern margin in several fjords near the head of the Westwind Trough (Fig. 1a). The presence of sedimentary glacial lineations and recessional moraines in the inner to middle trough indicates that the GrIS probably extended onto the continental shelf during the Last Glacial Maximum (Evans et al. 2009; Winkelmann et al. 2010). Fig. 1. Multibeam bathymetry and cross-profiles of glacial lineations and recessional moraines in middle to outer Westwind Trough, NE Greenland. ( a ) Location of study area (red boxes; map from IBCAO v. 3.0). ( b ) Image of glacial lineations indicating past expansion of the Greenland Ice Sheet onto the continental shelf (modified from Evans et al. 2009). Acquisition system Kongsberg EM120. Frequency 12 kHz. Grid-cell size 15 m. ( c , d ) 3.5 kHz sub-bottom cross-profiles (x–x′ and y–y′ in (b)) showing glacial lineations formed in an acoustically transparent sedimentary unit consistent with soft basal till. Acquisition system Kongsberg TOPAS PS 018. Secondary beam frequency 0.5–6 …