Abstract

Co-author: Christian Schoof (University of British Columbia)

The dynamics of large ice sheets have many similarities with mantle and magma dynamics. Polycrystalline material undergoes intense shear and creep deformation, slow evolution of grain structure, and dissipative heating that can cause partial melting. The presence of melt (water) can enhance creep and facilitates sliding past bedrock and sediments, leading to extreme patterns of ice flow, most clearly demonstrated in the Antarctic and Greenland ice streams.

In this talk I will review this related application of the two-phase flow equations often used to describe melt in the mantle. I will focus especially on polythermal ice, when the quantities of interest are the heat and water content together with their transport, and on the subglacial drainage system, which is thought to exhibit channelized flow similar (perhaps) to the mantle. Approximations used in the ice-sheet literature will be discussed, along with numerical solution methods for the resulting models. I will highlight analogies and difference with mantle models.