The Deformation of Subglacial Till: A Numerical Model

Abstract

Prior work has shown that ice streams in West Antarctica are probably underlain by a layer of till 6 to 12 m thick. This till layer may be similiar to mobile drift found by Kamb (1979) on Blue Glacier in Washington State and by Boulton (1979) at Breidamerjokull in Iceland. This paper presents a preliminary model for flow of this till layer. The till is assumed to be linearly viscous with a calculated viscosity of 3Xl0**8 Pa s. Flow is caused by shear stress from the ice above and by pressure differences. The thickness over time is tested by solving equations numerically using a time-centered finite-difference method. Results show that the till layer tends towards a constant thickness despite initial gradients in thickness.