Large‐scale glacial thrusting and related processes in North Dakota

Abstract

Large‐scale thrusting by the glacial ice occurred in many parts of the Interior Plains of North Dakota, Alberta, and Saskatchewan in late Wisconsinan time. Thrust features are especially prominent in parts of North Dakota. Many of the topographic features of the glaciated landscape of North Dakota formed, either entirely or in part, by the thrusting mechanism, and many individual ice‐thrust features have been recognized. The ice‐thrusting process was also related to fluting by the glacier, and, as a result, drumlins and other types of fluted features are commonly closely associated with ice‐thrust topography. Thrusting by the glacier was dependent primarily on groundwater conditions beneath the ice; thrusting occurred only where hydrologic conditions were appropriate. Most of the individual ice‐thrust features that have been recognized are located over discrete aquifers, and the sizes and shapes of the thrust features are dependent upon the sizes and shapes of the aquifers.