Provenance of coarse ice-rafted detritus near the SE Greenland margin

Abstract

AbstractThe provenance of coarse-grained ice-rafted detritus has been studied, based on material collected from the SE Greenland margin. The sediment was sampled by a 1.5 m3 video-grab from 1256 m water depth. The fraction > 1cm was macroscopically investigated and a thin-section analysis was made. The results clearly show that East Greenland north of the Denmark Strait is the source region of the material sampled. The main provenance is from areas adjoining Kangerdlugssuaq Fjord, Blosseville Kyst, Scoresby Sund, Kong Oskar Fjord, and Kejser Franz Joseph Fjord. It can thus be demonstrated that significant ice-stream activity and iceberg calving occurred there. Present-day iceberg production is mainly concentrated to the Scoresby Sund, but the other areas apparently represent locations of larger ice-stream activity during periods prior to the Holocene.More generally, it can be concluded that southerly surface-water flow similar to the present East Greenland Current must also have occurred prior to the Holocene. Although either North America (Canada) or Scandinavia - or both - are generally referred to as important regions for the provenance of ice-rafted detritus, we conclude that (East) Greenland may have been an important source for (late) glacial North Atlantic ice-rafted detritus production as well.