A salt glacier is a flow of salt (typically halite) that is created when a rising diapir in a salt dome breaches the surface. Gravity causes the salt to flow like glaciers into adjacent valleys. Most of the flow occurs during the winter, when the salt is wet, as the strength of salt is critically dependent on its water content. The resulting tongue-shaped bodies can extend for kilometers, with repeating bow-shaped ridges separated by crevasse-like gullies and with steep sides and fronts. Clays may be brought up with the salt, turning it dark.
The salt glaciers of Iran[1][2] are halite while the salt glacier of Lüneburg Kalkberg, Germany is composed of gypsum and other carbonate minerals.