Glaciohydraulic supercooling: The process and its significance

Glaciohydraulic supercooling is a process that allows water at the base of a glacier to remain liquid at a temperature below its freezing point in response to the geometry of water flow and subglacial pressure. Supercooling, and subsequent freezing, of subglacial water has implications for glacier dynamics, sediment transfer and landform evolution, and an understanding of the process is important both for understanding modern glacial environments and for reconstructing glacial environments of the past. However, recent research on glaciohydraulic supercooling has raised controversy both about the significance of the process and about the way in which it has been applied within the discipline. In this paper, we review recent work on supercooling in glaciers, assess its significance to glaciology, geomorphology and Quaternary science, and identify key issues requiring further research in order to resolve some of the controversy surrounding the topic. We suggest that, while glaciohydraulic supercooling is a very significant process, its adoption as an explanation of some phenomena has been premature, and that further research is required to test its true significance both in modern settings and in the glacial geologic record.