Deformation of Bore Hole in Malaspina Glacier, Alaska

Demorest's (1942, p. 31-38; 1943, p. 365-373) exposition of extrusion flow in glaciers has not enjoyed universal acceptance. Skepticism has been especially strong in England where physicists have produced well-considered arguments and calculations showing that extrusion flow is a mechanical improbability (Orowan, 1949, p. 233-236; Nye, 1951, p. 565; 1952a; 1952b). Their analyses necessarily involve gross simplifications and are based in part upon assumptions concerning the physical properties and behavior of ice under long-continued confining pressure and stress so the validity of their conclusions needs independent confirmation.