The character of glaciotectonism

Abstract

Glaciotectonic features are those structures and landforms produced by deformation and dislocation of pre-existing soft bedrock and drift masses as a direct consequence of glacier-ice movement. Some glaciotectonic structures form essentially in-situ; however, most glaciotectonic features involve detachment of a large rock or sediment mass, called a raft, floe, or megablock, and its transportation and deposition by the ice. The main factors in determining whether glaciotectonic structures could develop are: (1) competence of the bedrock relative to glacier ice, (2) distance of megablock transportation, and (3) mode of deposition. Development of glaciotectonic features depends to a large degree on lithology of the affected rocks or sediments. Glaciotectonism does not represent a special or unique process operating within the ice; the same dynamic conditions which cause normal glacial erosion and deposition also create glaciotectonic features in appropriate kinds of bedrock.