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.