The definition followed here is fairly simple and not overly restrictive, but it does exclude certain kinds of deformation related to glaciation. Likewise deformed structures within glacier ice are excluded. Glaciotectonic structures do include all deformations created in rock or sediment of the Earth's crust as a consequence of glacier loading, dragging, or pushing. Glaciotectonic structures Glaciotectonic structures range in size from microscopic to continental. Deformed materials range from hard, crystalline rocks, to poorly consolidated sedimentary strata, to loose sediments.
Deformation occurs in both frozen and thawed material under either low or high confining pressures.
Glaciotectonic structures may be created under thick ice, beneath thin ice, or in front of glaciers during advancing, maximal or recessional phases of glaciation. Photograph of fractured cobbles in gravel core of drumlin at Dollard, Saskatchewan. Brittle fracturing of these cobbles presumably took place at contact points in response to ice loading. These material may have been deformed in either a frozen or thawed condition. Clay was mobilized as a result of ice loading on the unconsolidated and water-saturated sediment.