Movement
Rock glaciers move downslope by deformation of the ice contained within them, causing their surface to resemble those of glaciers. Some rock glaciers can reach lengths of 3 km and can have terminal embankments of 60 m high. Blocks on the surface can be up to 8 m in diameter. Flow features on the surface of rock glaciers may develop from:
- Deformation of the ice core.
- Movement of the debris cover along the debris-ice interface.
- Deformation from a period of glacial advance.
- Changes in the hydrologic balance.
Their growth and formation is subject to some debate, with three main theories:
- A permafrost origin, which implies that the features are related to permafrost action rather than glacial action;
- A mass wasting or landslide origin which does not require the presence of ice and suggests a sudden catastrophic origin with little subsequent movement.
Rock glaciers may move or creep at a very slow rate in part dependent on the amount of ice present.
Read more about this topic: Rock Glacier
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—Orson Welles (1915–1984)
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—Betty Friedan (20th century)