Glacial morphology and bathymetric mapping in Melville Bay, Western Greenland - Multibeam and backscatter mosaic

Abstract: During the VEGA Expedition, in June 2013, reflectivity (backscatter) and depth data wasacquired with a multibeam echosounder from an approximately 140 km2 large area in MelvilleBay, off the coast of Western Greenland. One of the expedition objectives was to search for andmap evidences of a grounded ice sheet, which is likely to have reached the edge of the continentalshelf during the Last Glacial Maximum, about 20 000 years ago. In this study, the acquired depthdata was compiled to a detailed bathymetric map, which was used to map the extension ofmorphological features caused by the ice sheet’s progression over the area. The results showbedrock erosion in the form of linear features, melt-water channels and different types ofdepressions. The surface sediment distribution, based on the reflectivity data, presents coarsersediment such as gravel in the deeper parts of the survey area as well as in channels anddepressions, while finer sediments such as silt and clay can be found generally in the remainder ofthe area. The conclusion is that the results strongly suggests there have been glacial erosion inthis area, however it is not possible to determine when this took place without age determinationof bottom samples. For a more comprehensive understanding of the glacial history in Melvilleand Baffin Bay, more surveys of this kind are necessary.