MINERALOGICAL AND ENVIRONMENTAL CHARACTERISTICS OF RECENT CONTINENTAL SABKHA FROM THE NORTHERN PART OF WADI EL-NATRUN, WESTERN DESERT, EGYPT. MAGDA M. ABO EL-SAFA Desert Environment Research Institute, Minoufia University, Egypt. The aim of the present work is to gather information about the distribution of minerals composing some continental sabkha areas as well as chemical composition in the northern part of Wadi EI-Natrun and relate these distributions to their pattern of formation. The sabkha areas were selected in such way to represent the adjacent territory of El-Jaar, EI-Bidah and El-Hamra lakes. The mineralogical composition of sabkha sediments indicates the dominance of the evaporite minerals halite, trona, and thenardite, in addition to northupite and pirssonite. The non-evaporite minerals are represented by minor amounts of calcite and quartz, and the clay minerals montmorillonite, kaolinite and illite (using XRD technique). Geochemical investigation of the studied sediments indicates the dominance of sodium oxides, chlorine, sulfates and carbonates (using XRF technique) which agree with the existence of sulfate and carbonate minerals mainly halite, trona and thenardite. The study of different evaporate minerals under scanning electron microscope revealed that, most minerals are affected with different degree of dissolution. The process of dissolution of evaporate minerals is most probably related to the dilution of brine by fresh and brackish water through groundwater seepage or irrigating water. The continental sabkhas surrounded El-Jaar and El-Bidah lakes contain mainly sulfate and chloride minerals beside the carbonate minerals. Also, the clay minerals are represented mainly with montmorillonite. This reflects their relatively higher brine concentration and alkaline medium. However, the continental sabkha of EI-Hamra Lake is composed mainly from the carbonate mineral trona with halite and a mixture of clay minerals (montmorillonite, kaolinite and illite). This reflects a relatively low concentration of brine consequently low alkaline medium.