Aligned glaciotectonic rafts on the central Barents Sea seafloor revealing extensive glacitectonic erosion during the last deglaciation

Abstract

Erosion rates on glaciated continental shelves are remarkably high, especially within ice stream troughs. Although glaciotectonic erosion may have considerably contributed to enhanced glacial erosion of these landscapes, entrainment mechanisms of glaciotectonically emplaced megablocks and rafts remain little understood. Here we report a northeast-southwest trending chain of over 1300 glacial rafts, observed on the seafloor in Bjørnøyrenna, a paleo-ice stream trough with particularly high erosion rates. The landform assemblage adjacent to the glacial rafts includes streamlined bedforms and crevasse-squeeze ridges and may represent a lateral shear zone where a paleo-ice stream met cold stagnant ice during the last deglaciation. Individual glacial rafts along the chain are up to 30 m high, tend to be elongated with lengths and widths on the order of tens of meters, and are oriented from northeast-southwest to north-south. The north-southern rearrangement of rafts may reflect a compressional strain regime along the ice stream margin.