Salt: Liquid or Solid?
Most people would agree that salt is a solid, after all its what we were taught at school. However, the existence of salt glaciers happens to throw an all mighty spanner in the works.
In the Zagros Mountains of Iran and Kurdistan salt is erupting from the subsurface and flowing out across the landscape, standing stark to the rocks around it. Pretty impressive, but how does it work?
The salt would have originally been deposited in an arid environment within an enclosed basin. This was slowly buried by subsequent layers of rock, and then compressed when the Iranian and Arabian plates started to collide. The salt is significantly less dense than the surrounding rocks and therefore the pressure from the overlying strata cause it to rise.
As the salt rises it distorts the beds above forming an anticlinal (dome) structure as it moves towards the surface. Erosion then removes the overlying rocks exposing the salt below. Normally the salt would be dissolved and carried away in solution, however the arid climate of the Zagros Mountains means salt is being supplied at a rate exceeding the rate of precipitation.
Therefore the salt flows out onto the surface and, much like an ice glacier, begins to flow downhill. While these are very rare they are impressive and I hope you find them as cool as me!
References: http://1.usa.gov/1Cuj74I
Further Reading: http://bit.ly/1DbqXES
Image Credit: Bing Satellite View (You can have fun exploring even more salt glaciers here: http://binged.it/1aFLsQ2)