Résumé
After a preliminary study of the travertine outcrop of Irdi (Errachidia province), this site was drilled and the survey was extended to other exposures in Morocco. Complementary methods of investigation were used (palynology, paleomagnetism) together with U-series analyses in order to identify the successive deposition phases and to precise the associated paleoclimatic framework. For a better understanding of the travertine formation, we have studied the travertine formations which are presently forming at Irdi. The respective (super 234) U/ (super 238) U activity ratios of the present water and fossil travertines are similar, i.e. physical and chemical conditions of travertinization were more or less similar today as in the past. Several crystallization phases were identified from Upper Pleistocene to Middle Pleistocene. These phases must be integrated into the climatic evolution of Morocco and correlated to glacial and interglacial stages defined in marine environment.