Dynamics of Marine Ice Sheets

Marine ice sheets, which are those that terminate in the ocean forming a floating ice shelf, dominate the ice sheets of West Antarctica, where much of the bedrock is below sea level. The weight of the thick ice sheets keep them in contact with the bedrock until they are thin enough to float on the ocean as ice shelves. This paper reports mathematical models and associated laboratory studies of analogue systems using either Newtonian or shear-thinning viscous fluids to represent flowing ice. It is shown that the rheology has little influence on the qualitative behaviour of grounded flows but floating, shear-thinning shelves are found experimentally to be subject to a fingering instability reminiscent of features seen in Antarctic ice shelves.