A layer of ground, now perennially frozen, lying immediately below the modern active layer. Its thickness indicates the greater annual depth of thaw that occurred during a previous period
A layer of ground, now perennially frozen, lying immediately below the modern active layer; its thickness indicates the greater annual depth of thaw that occurred during a previous period.
Permafrost existing in areas where Permafrost cannot form under present climatic conditions. Relict Permafrost (including Relict Ice) formed when the mean annual surface temperature was lower than at
present; it is in disequilibrium with the present mean annual surface temperature. This Permafrost persists in places where it could not form today. Relict Ice and associated landforms are a sign of degrading Permafrost.