The pattern of flow of moraine-carrying glaciers is studied by models whirled in a centrifuge. Because of the rather high centrifugal force (1,000 g), substances with high viscosity, such as bouncing putty and stitching wax (viscosity around 106–107 poises), can be used as glacier-imitation materials. As moraine-imitation material powdered hard wax is used. The strength and high viscosity of the model materials permit detailed structures to be studied without the disturbing effects of sagging after being run to the chosen stage in the centrifuge. Stroboscopic light makes it possible to follow the evolution of the flow and to stop the centrifuge and thus the flow at any stage.
Rather realistic-looking fold structures of the kind seen in some piedmont ice sheets develop readily after a few minutes’ run in the centrifuge.
The mechanism of fold evolution is discussed.
No slip (or shear) has taken place along a “foliation” which sometimes develops parallel to the axial planes of the folds.