Sediments deformed in this manner are penetratively sheared. The final product is mylonite with a strongly oriented fabric that resembles lodgement till. Deforming bed conditions may be recognized by stone pavements, which are widespread in the Great Lakes, Great Plains, and Hudson Lowlands regions. In regions of hard bedrock, small faults and seismic zones are manifestations of glaciotectonism. These features are thought to be direct results of stress changes associated with glacial loading and unloading.
Larger faults represent glacial reactivation of pre-existing structures.
Seismic zones indicate continued crustal adjustments to glacial unloading. Glaciotectonic landforms are the morphologic expressions of subsurface structural deformations brought about by glaciation. These landforms may display their original glaciotectonic morphology, where little modified by later events. More commonly, however, subsequent glacial or nonglacial erosion or deposition has altered the initial landform, in some cases obliterating any morphologic expression of the ice-pushed structures. In all cases, some knowledge of subsurface stratigraphy and structure is invaluable for properly interpreting the landforms.