Abstract

Most of the mass loss from the Antarctic Ice Sheet occurs through glaciers and ice streams, where fast-flow is partially controlled by rapid ice deformation in the margins. Deformation drives thermomechanical and recrystallization processes that influence further deformation, a feedback which may destabilize glaciers. However, few models account for the feedback between deformation and recrystallization. We derive an idealized model for ice temperature and grain-size that partitions deformational work into dissipated heat and changes in strain and surface energy, all of which drive dynamic recrystallization. Under conditions common in glacier shear margins, we show that a large portion of deformational work is stored as elastic energy, with the remainder dissipated as heat. This result revises our current picture of the amount of heat generated in glacier shear margins and suggests that changes in internal strain through dynamic recrystallization of ice likely play an important role in facilitating fast-flowing glacial ice.