Periglacial Involutions and Mass Displacement Structures, Banks Island, Canada

Abstract

Deformed structures occurring in terrace deposits of the Bernard River, central Banks Island, are interpreted as soft-sediment deformations, the result of rapid sedimentation and entrapment of excess pore water. Other deformed structures described from terrace deposits of the Kellett River, southern Banks Island, are thought to have resulted from liquifaction and density re-adjustments in the active layer. Since permafrost conditions were involved in the latter, these structures can reasonably be termed periglacial involutions.

The presence of both soft-sediment deformations and periglacial involutions in a present periglacial environment emphasises the difficulty of interpreting involutions in Pleistocene sediments of mid-latitudes.