|
Definition:
|
The environment, which is cold and cryogenic, but not Glaciated, above of the tree line if existent. There is no clear physical limit to the glacial environment and its boundary is diffuse. However, the limit to the non-Periglacial Environment is clearly marked by the following indicators: occurrence of Permafrost in depth, including permanently frozen soil and possibly presence of Ground Ice preserved under natural conditions for long periods of time. This constitutes the decisive element whereby an environment is called Periglacial or cryogenic environment dominated by cycles of freezing and thawing affecting rocks and the top of the soil; and presence of Solifluction / Gelifluction and other cryogenic processes (Frost Weathering, sorting, Cryoturbation, etc.) that lead to the so-called Periglacial geomorphology, such as the formation of small scale sorted ground or Rock Glaciers on a mesoscale. For some authors of the northern hemisphere the presence of Permafrost is not a prerequisite for the Periglacial Environment, however, it is for the cryo-scientists working in the Andes.
|