Subglacial drainage for an ice sheet resting upon a layered deformable bed

摘要: The subglacial hydrology is considered for a temperate ice sheet resting upon deformable aquitard (till) with hydraulic conductivity several orders of magnitude lower than that an underlying aquifer. evacuation basal meltwater by the aquifer-channel-bed system studied, particularly as it affects aquifer pressurization, till deformation, and channel failure. Sensitive parameters are conductivity, length elevation, rate. A criterion developed to determine length; channels need not extend all way divide. model predicts that, in general, there region adjoining terminus where bed pore water pressure equal overburden drainage along possible. Outside this below pressure, penetrates soil prevent bed. An important result substrates beneath temperate-based sheets may be unstable, under conditions diminishing profile.