The slippage of soil and rock particles due to the freezing and subsequent thawing of the earth; the process of mass movement of soil and sediment upon the thawing of water-laden ground. Many deposits in valleys and on the lower part of hills are due to the land having been glaciated, with the top level thawing in the spring and the water, unable to permeate the still-frozen subsoil, flowing downhill, taking with it chunks of loose material. Full glaciation is not necessary to cause solifluxion; hard winters with frozen earth and occasional thaws can cause minor solifluxion that may add to the accumulation of material. Solifluction can cause artifactual material to be moved from one deposit to another; sometimes whole areas of archaeological sites may be covered with solifluction material. When solifluction can be recognized geologically, it is a valuable indicator of glacial conditions in areas which remained free of ice.