Glacial deformation

Abstract

The world is an icy place. Some 10% of the earth’s land surface is currently covered by glacier ice; at glacial maxima this coverage has been much greater. Moving glacier ice is a powerful geomorphological agent and many parts of the world have been distinctively altered by the action of glacier ice. It is at the base of the glacier or ice sheet, where ice and substrate are in intimate contact, that geomorphological activity and change is greatest: it is here that most glacial sediment deformation occurs. Modern research has shown that the theoretical principles outlined in the previous chapters are relevant to both the movement of the ice sheets and to the understanding of the structures that are produced. Thus glacial movement provides a fine example of how the mechanical principles of sediment deformation are applicable in a particular geological environment. This is the subject of the present chapter.