Morphology and Dynamics of Ice Rises

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Abstract
Profile surveys are presented of four ice rises on the east coast of the Antarctic Peninsula. On Butler Island velocity measurements were also made. The ice rises behave as miniature ice caps frozen to flat horizontal bedrock and provide a simple system for the study of laws of ice flow. Deformation is principally by shear through the ice mass. Velocity measurements provide a value of n = 3.13±0.52 for the flow law . Each ice rise is bounded on one side by ice shelf and on the other side by open sea. Towards open sea the profiles are found to agree well with steady-state theoretical profiles and they supply a value of for temperature – 13.5°C and stress range 0.5–1.3 bar. Towards ice shelf the profiles are elongated and they deviate from the theoretical profile. This may be due to compressive stress in the ice shelf causing migration of the grounding line down sloping bedrock. No significantly anomalous behaviour is found in the summit region.