A salt glacier is a flow of salt

Salt

In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...

 (typically halite

Halite

Halite , commonly known as rock salt, is the mineral form of sodium chloride . Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, pink, red, orange, yellow or gray depending on the amount and type of impurities...

) that is created when a rising diapir

Diapir

A diapir is a type of intrusion in which a more mobile and ductily-deformable material is forced into brittle overlying rocks. Depending on the tectonic environment, diapirs can range from idealized mushroom-shaped Rayleigh-Taylor instability-type structures in regions with low tectonic stress...

 in a salt dome

Salt dome

A salt dome is a type of structural dome formed when a thick bed of evaporite minerals found at depth intrudes vertically into surrounding rock strata, forming a diapir....

 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 are halite while the salt glacier of Lüneburg Kalkberg

Lüneburg Kalkberg

The Lüneburg Kalkberg is the cap rock of a salt dome in the western part of the German town of Lüneburg...

, Germany is composed of gypsum

Gypsum

Gypsum is a very soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. It is found in alabaster, a decorative stone used in Ancient Egypt. It is the second softest mineral on the Mohs Hardness Scale...

 and other carbonate minerals

Carbonate minerals

Carbonate minerals are those minerals containing the carbonate ion: CO32-.-Anhydrous carbonates:*Calcite group: Trigonal**Calcite CaCO3**Gaspeite CO3**Magnesite MgCO3**Otavite CdCO3**Rhodochrosite MnCO3**Siderite FeCO3**Smithsonite ZnCO3...

.