periglacial environment

The characteristic cold and rugged appearance of high mountain areas is produced by freeze-thaw weathering, and the development of snow and ice. Such areas, having the same conditions as those experienced on a glacier, but not frozen all year round, are known as periglacial.

Lakes and marshy moorland at Thingvellir, Iceland. This is a typical periglacial landscape, which in winter becomes coated in snow and ice.

Bordering a glacial area but not actually covered by ice all year round, or having similar climatic and environmental characteristics, such as in mountainous areas. Periglacial areas today include parts of Siberia, Greenland, and North America. The rock and soil in these areas is frozen to a depth of several metres (permafrost) with only the top few centimetres thawing during the brief summer (the active layer). The vegetation is characteristic of tundra.

During the last ice age all of southern England was periglacial. Weathering by freeze–thaw (the alternate freezing and thawing of ice in rock cracks) would have been severe, and solifluction (movement of soil that is saturated by water) would have taken place on a large scale, causing wet topsoil to slip from valley sides.