The behaviour of rubidium, lithium, strontium and barium in superficial waters of a granitic area are compared with the behaviour of the associated major element: potassium, magnesium, calcium and potassium. Fractionation during dissolution is important for the Rb/K couple, whereas fractionation during deposition of new-formed minerals or uptake by vegetation is important for Mg/Li and K/Ba. Auxiliary minerals seem to play an important part in the relative concentrations of strontium and calcium in the waters.