Submarine geomorphology of northeast Baffin Bay and its implications for local paleo-ice sheet dynamics

Abstract

High-resolution bathymetric data from close to the northwest Greenland coast in northern Melville Bay, northeast Baffin Bay, reveal a range of glacial and nonglacial landforms. The glacial landforms include crag-and-tails, mega-scale glacial lineations (MSGL), rock drumlins, and roche moutonnées that indicate paleo-ice sheet dynamics. The nonglacial landforms include steep ridges that are interpreted as volcanic dykes (Neoproterozoic Thule dyke swarms and Paleoproterozoic Melville Bugt dyke swarms). These dykes are glacially overprinted and may have channeled ice and subglacial meltwater flow through narrow subglacial cavities.Some of the glacial landforms eroded into bedrock indicate a southward paleo-ice stream orientation; while other glacial landforms, including the sedimentary depositional landforms, indicate a westward paleo-ice stream orientation. The glacial landforms were likely produced during at least two epochs and under changing thickness of the ice streams. The glacial landforms eroded into the bedrock are likely older than the sedimentary glacial landforms and were likely produced by a thin south/southeastward ice stream that allowed cavity formation. The westward-oriented glacial landforms were likely produced by a thick ice stream that was probably active during the Last Glacial Maximum (LGM). The different orientations of the glacial landforms indicate a reorganization of the ice streams that may have occurred during retreat and subsequent readvance. This reorganization likely coincided with a migration of the ice divide from south to north.