Solifluction
A
major type of mass movement in cold polar regions and
some high mountains. Solifluction is a special type of
creep that occurs in areas of permafrost. Permafrost
refers to the layer of groundwater that fills in the
pore spaces of soil and rock that is permanently frozen.
The permafrost layer can be anywhere from a meter to
several hundred meters thick. It takes up about 20% of
the world's land. In times of warm weather, the ground
will begin to thaw from the surface downward. All of
the freshly melted water cannot absorb into or move through
the permafrost layer. This causes the upper layer of
soil and regolith to become saturated and flow down the
slightest of slopes as it slips over the frozen ground
underneath.
Another visible aspect of solifluction areas is cryoturbation.
During
cryoturbation, "small ridges and mounds of bare
soil are produced by the processes of frost churning
(cryoturbation) and soil flow (solifluction). Freeze-thaw
generates a circular motion in the surface material,
heaving the soil to the surface (the light- coloured
areas) and dragging it down at the margins to form gutters
(the darker, vegetated areas). The process creates a
network of circular patches which, on slopes, are stretched
into long stripes by an additional creeping movement.
Flowing water then deepens the gutters." (Terrain
Sciences Division)
