Linear-Patterned Slopes in the Discontinuous Permafrost Zone of the Central Mackenzie River Valley

Abstract

In the Mackenzie River Valley between Norman Wells and Fort Simpson a study of the character, distribution and orientation of gently-inclined, linear-patterned slopes revealed that most northeast-facing, lichen-covered slopes have permafrost within about 10-25 inches of the surface, and display evidence that cryoturbation was once operative in the active layer. Most lineated slopes without near-surface permafrost face southwest, are surficially more moist, and are characteristically associated with sedges and Sphagnum. On these slopes that receive the greatest incoming solar radiation, and where the active layer is thicker, there is little evidence that cryoturbation was once operative. The northeast-facing slopes generally provide forage for caribou; the southwest-facing slopes are least subject to gully erosion.