The plasticity of polycrystalline ice

The mechanisms by which ice can deform are described and extended. Some, like proton-rearrangement controlled glide, are unique to the structure of ice; others, like diffusional flow, are identical with those found in other polycrystalline solids. Data for each mechanism is assembled, and the results used to construct deformation-mechanism diagrams which show the regime of dominance of each mechanism, and its rate. The use of the diagrams is illustrated with two simple case studies.