Thermokarst involutions, summer island, pleistocene mackenzie delta, Western Canadian arctic

• Published in: Permafrost and Periglacial Processes
• Main Authors: Murton, Julian B., French, Hugh M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1993
• Subjects: Arctic; Mackenzie Delta; Summer Island; Ice; permafrost; Permafrost and Periglacial Processes; Thermokarst
• Online Access: http://dx.doi.org/10.1002/ppp.3430040304; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fppp.3430040304; https://onlinelibrary.wiley.com/doi/pdf/10.1002/ppp.3430040304

Abstract Thermokarst involutions form primarily by loading, buoyancy and water‐escape during the degradation of ice‐rich permafrost. In the Summer Island area of the Pleistocene Mackenzie Delta, they are formed mainly by loading and buoyancy, and occur within a Late Wisconsinan‐Early Holocene thaw layer. Involutions formed by water‐escape (fluidization) occur within slump‐floor deposits. To form thermokarst involutions, ice‐rich permafrost must thaw, drainage conditions must be poor and sediments must vary in texture or composition. In addition, the sediments should be susceptible to fluidization, liquefaction or hydroplastic deformation. Thermokarst involutions formed by loading and buoyancy require a reverse density gradient; those formed by fluidization require open‐system groundwater conditions or associated water‐saturated sediments susceptible to liquefaction.