In the northern margin of the Cameros Basin miocene evaporitics units are found related with shallow saline lakes. The lakes were fed principal)/ by groundwater loaded with dissolved salts (calcicsulphate waters) from the Lias and Keuper evaporite formations. Durin Miocene, Ebro Basin was a endorheic depression, so the dissolved salts that were carried by groundwater had to precipitate inside the basin; groundwater discharge not be concentrated in a few big springs but it should be distributed in humid areas with evaporitic precipitation