Discussion of paper by J. Weertman, ‘Sliding of nontemperate glaciers’

The theory of glacier sliding (an attractive one, as conclusions drawn from a mathematical model may guide future research and be checked by new observations) is intricate, and the debate somewhat confused. There is the theory of Weertman [1957], modified in Weertman [1964], which must be completed, for a good parallel with Lliboutry's theories, by the idea of a thick subglacial film of water that may flood the protuberances of the bedrock [Weertman, 1962]. The theory of Lliboutry [1959], modified in Lliboutry [1965], considers the interstitial pressure as an independent variable, and the part of the water-filled cavities at the lee of many bumps on the bedrock is emphasized. These bumps are not taken as far distant from and independent of each other.