The solute concentration of fluid inclusions in halite samples have been analyzed by X-Ray microanalysis (Cryo-SEM-EDS). The results together with the mineral sequence are useful to describe the evolution of the Priabonian basin of Navarra. Thus, a lower salt unit (sal de muro) formed in a restricted basin with seawater recharge. Later, the basin closed to sea and evolved with decreasing volume and stratified brine to the deposition of potash salts. Finally, an upper salt unit (sal d e techo) formed in a continental lake without seawater influence