Figure 4: Conceptual model and geometries of periodic subglacial lake drainage.
From: Discovery of relict subglacial lakes and their geometry and mechanism of drainage
(a) Water ponding behind transverse ridges is shown; when the lake fills or the water pressure becomes high enough water drains across the ridge (b). This occurs through a canal cut down into the sediment that evolves downstream into an R-channel cut up into the ice (b). Filling and draining of the lake may occur many times, with the final drainage depositing an esker in the R-channel (c). (d) The relict lake and its drainage imprint are shown. Graphic is not to scale.
