GEOLOGY OF QUATERNARY TUFA DEPOSITS IN NORTH-EAST OF THE DAKHLA OASIS, WESTERN DESERT, EGYPT. ABDEL MONIEM A. MAHMOUD*, AMRE M. EL GOHARY** and ESMAT A.ABOU EL ANWAR** *Dept. Biolog. And Geolog., Scs., Fac. Education, Ain Shams University. **Geol. And Geophysical Scs. Dept., National Research Centre, Cairo. Quaternary tufa deposits are exposed at the northeastern part of the Dakhla Oasis, Western Desert, Egypt. The tufa deposits overlie the Mut/Taref ormations of the Upper Cretaceous. Petrographically, these deposits consist of two facies which are highly porous, glauconitic, sandy micrite and porous algal micrite facies (wackestone facies). Stratigraphical, geomorphological, petrological, geochemical data and isotopic composition indicate that the tufa deposits were formed as torrential and spring-fed discharge under global warming and wet climate.