Basal sediment evacuation by subglacial drainage systems

Abstract

Basal sediment evacuation by subglacial meltwater plays a key role in glacial systems. Notably, the efficiency of basal sediment evacuation is likely to determine the extent to which the products of glacial erosion are retained at the ice–bed interface (Alley et al., 1997), which is likely to dictate not only rates and patterns of subglacial erosion and glacial sediment yield, but also the proportion of debris in glacial versus fluvial sediment transport pathways, and as a result will greatly influence rates and styles of sediment deposition in ice-marginal environments (Moraine, qv) (see Swift et al., 2002). Nevertheless, the importance of basal sediment evacuation by subglacial water for glacial geomorphic processes has largely until recently been neglected by the glaciohydrological and glaciogeomorphological literature.