Evaporites (pronounced
/i'væp?ra?t/) are water-soluble
mineral sediments that result from the
evaporation of bodies of surficial
water. Evaporites are considered sedimentary rocks.
Although all water bodies on the surface and in aquifers contain dissolved salts, the water must evaporate into the atmosphere for the minerals to precipitate. For this to happen the water body must enter a restricted environment where water input into this environment remains below the net rate of evaporation. This is usually an arid environment with a small basin fed by a limited input of water. When evaporation occurs, the remaining water is enriched in salts, and they precipitate when the water becomes oversaturated.
Evaporite depositional environments which meet the above conditions include;
Evaporite formations need not be composed entirely of halite salt. In fact, most evaporite formations do not contain more than a few percent of evaporite minerals, the remainder being composed of the more typical detrital clastic rocks and carbonates.