Rock Salt

Rock salt is a chemical sedimentary rock which forms from the evaporation of ocean or saline lake waters.  It is also know by the mineral name "halite".  Rock salt can be found all over the world.  There are deposits ringing dry lake beds, inland marginal seas and enclosed bays and estuaries in arid regions of the world.  At various times in...

Rock salt is a chemical sedimentary rock which forms from the evaporation of ocean or saline lake waters.  It is also know by the mineral name "halite".  Rock salt can be found all over the world.  There are deposits ringing dry lake beds, inland marginal seas and enclosed bays and estuaries in arid regions of the world.  At various times in the geologic past, large bodies of water (such as the Mediterranean Sea and a huge body of water that was located where the Atlantic Ocean now sits) also evaporated to create enormous deposits of rock salt.  Rock salt deposits were later buried by marine sediments, but as halite is less dense than the material which make up the overlying sediments, the salt beds often "punched up" through the sediments to create dome-like structures.  These are now mostly buried by additional sediments.  Rock salt is rarely found at the Earth's surface, except in areas of very arid climate.  Rock salt in Great Britain was laid down around 200 million years ago, when Britain was a shallow inland sea surrounded by desert near the equator.  Rock salt is often mined for use in the chemical industry or for use as a winter highway treatment.  Some rock salt is processed for use as a seasoning for food.