On the formation of large subglacial lakes

The role of subglacial water storage beneath continental ice sheets is investigated, primarily for a deformable bed. Subglacial ponding is shown to occur under most regions of warm-based ice sheets, and large subglacial lakes can become established, for example in the Hudson Bay basin. The formation of large lakes depends upon the fact that the ice-surface gradient is reduced once subglacial ponding occurs and upon the feedback between the reduced ice-surface gradient and increased subglacial ponding. Subglacial ponding likely played a large role in determining the ice-sheet topography during late deglaciation and in speeding up the deglaciation process.