Glacial landforms in a hard bedrock terrain, Melville Bay, northwestern Greenland

Abstract

Glaciated landscapes in gneissose or granitic bedrock often show a scoured ‘hilly relief’ (Bonow et al. 2006) or ‘knock-and-lochan’ morphology (Linton 1963), characterized by a highly fractured landscape with strong relief of knolls and basins. This topography closely follows old deep-weathering fronts from previous sub-aerial exposure, and was probably formed through a multistage process including deep weathering, glacial erosion and stripping of saprolites, followed by further glacial modification (Krabbendam & Bradwell 2014). Multibeam-bathymetric data and high-resolution onshore digital elevation models (DEM) from southern Melville Bay, NW Greenland, show similar glacially modified knock-and-lochan landscapes from the inner shelf and nearby coast. Over a bathymetric range of 150–400 m on the inner Melville Bay shelf, c. 30 km from the West Greenland coast, the seafloor shows a rugose, bedrock-dominated landscape with limited sediment cover (Fig. 1a). The bedrock onshore, to the east of the study area, consists of Precambrian metaturbidites and orthogneisses (Kokfelt et al. 2013). The submarine landscape is dominated by criss-crossing incisions, numerous knolls, depressions, angular junctions and steep scarps. Minor landforms include U-shaped troughs, streamlined features and roche moutonee-type features often with stoss- and lee-side forms that have a clear …