Metasomatism of groundwater at depth.

arid zones azufre bacteria bicarbonate bicarbonates bicarbonatos chemical composition chlorides chlorure classification cloruros composition chimique densidad density depth eau souterraine gases gaz groundwater hidrogeologia hydrogeologie hydrogeology oligoelementos precipitation profondeur profundidad sales salts sel soufre sulfate sulfatos sulphates sulphur temperatura temperature trace elements zone aride