Salt glacier

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Salt glacier (dark areas) in Zagros , southern Fars Province , Iran

Salt glaciers are masses of salt (usually made of rock salt or halite ) that penetrate to the surface of the earth and slowly flow downhill there . They arise when rising salt domes or salt diapirs penetrate their overburden and reach the surface of the earth (so-called extrusion ). Assuming a suitable gradient, the salt then flows down the valley following gravity. Due to the solubility of salts in water, salt glaciers can only arise in areas with little precipitation ( arid ), as the salt masses slowly rising to the surface are dissolved faster in a more humid climate than they are replenished. This is the case, among other things, with the Central European salt domes, where the salt is dissolved by groundwater before it even reaches the actual surface of the terrain (see also →  Salt levels , Hutgestein ).

Today, salt glaciers are mainly known from the Zagros Mountains in Iran . The first scientific description of the phenomenon comes from George Martin Lees (1927), who also coined the term "salt glacier". The viscosity depends on the water content of the salt (intergranular water). It is lowest - and therefore the flow velocity is greatest - when the salt is saturated with precipitation. Flow velocities of about 500 mm per day at Kuh-e-Namak , about 20 km northwest of Qom , have been described during the winter rainy season. The resulting salt glacier can reach a length of several kilometers and, like glaciers made of ice, be crisscrossed by crevasses. Entrained clay material may darken.

Individual evidence

  1. ↑ George Martin Lees: Salt glacier in Persia. Mitt. Geol. Ges. Wien, 20, pp. 29–34. 1927 (PDF; 441 kB).
  2. ^ CJ Talbot, EA Rogers: Seasonal movements in a salt glacier in Iran . Science (Washington), 208, pp. 395-397, 1980.

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