solifluction

n.
The slow, downhill movement of soil or other material in areas typically underlain by frozen ground.

[Latin solum, soil + Latin flūctiō, flūctiōn-, a flowing (from flūctus, past participle of fluere, to flow).]

Literally meaning soil flowage, this is the slow, downslope movement of water-saturated debris in periglacial regions and other areas with cold climates. Rates of movement may be 0.9 cm yr^-1 on gentle slopes, 12-25 cm yr^-1 on steeper slopes. Solifluction is more rapid where the active layer is deep, or on equator-facing slopes where permafrost thaws more rapidly (See aspect) and develops due to the oversaturation of soils by water from melting ground ice.

Solifluction terraces are minute terraces, with heights and widths of about 1 m, and with rough bedding, known as tumultuous bedding, if the material was very fluid. Solifluction lobes are deposits of waste which have formed bulges in the slope profile without breaking the surface. Solifluction may develop in areas without permafrost; winter freezing of the sub-surface layer may be sufficient.

[Ge]

When, in periglacial conditions, the upper layer of a soil profile thaws and the soil itself becomes waterlogged and sludgey because the water cannot drain away. Solifluction occurs when the liquid soil flows down to the lowest point available. This can cause the disruption or displacement of archaeological deposits as well as the burial of landscapes underneath displaced material.