A basin in a semi-arid region where chemical precipitates (evaporites) are deposited due to the concentration by evaporation of natural solutions of salts. The least soluble salts (calcium and magnesium carbonates) precipitate first, on the outside of the pan, followed by sodium and potassium sulphates. Finally, in the centre, sodium and potassium chlorides and magnesium sulphate are deposited. This pattern, slightly distorted through tilting, is seen in Death Valley, California, USA.