Salt glacier

A salt glacier (or namakier) is a rare flow of rock salt that is created when a rising diapir in a salt dome breaches the surface of Earth. The name ‘salt glacier’ was given to this phenomenon because of the similarity of movement compared to ice glaciers. These formations are primarily due to salt's unique properties and its surrounding geologic environment. A diapir, a rising body of salt, reaches the surface and feeds the salt glacier. Salt structures are usually composed of halite, anhydrite, gypsum and clay minerals. Clays may be brought up with the salt, turning it dark. These salt flows are rare on Earth. Scientists have discovered diapirs on Mars, but they are composed of sulfates. A paper published in November 2023 suggests that salt glaciers composed of halite might also be present on Mercury.

The salt glaciers of the Zagros Mountains in Iran are halite, whereas the salt glacier of Lüneburg Kalkberg, Germany, is composed of gypsum and carbonate minerals.

Ancient flows have been preserved in various rock records by sedimentation. Late Triassic salt glaciers repeatedly flowed onto a basin in Germany and were buried with sediment to create a series of preserved glaciers. Miocene glaciers flowed into sheets in the northern Gulf of Mexico and were similarly preserved by overriding sediment.