الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Study area is a morphotectonic depression located in the northeastern part of the Western Desert adjacent to Cairo-Alexandria desert road. The northeast southwest depression lies between longitudes 30° 00′, and 30° 25′ E and latitudes 30° 15′ and30° 30′ N. The floor of the depression has relatively flat terrain and dissected with several low lying areas occupied most with free water lakes. Among them are EI-Fasda, Um-Risha, Razonia, EI-Hamra, Zaggig, EI-Beida, EI-Khadra and Gaar lakes from southeast to northwest. The surface of Wadi El-Natrun is essentially formed of sedimentary rocks and deposits belonging to Late Tertiary and Quaternary.The Miocene rocks are exposed in the area south and west of Wadi El-Natrun. While the Recent deposits are scattered all over the area especially along the low lying parts. The main goal of this study is dealt with the sequence of precipitation of salts from El-Hamra, El Gaar, El Beida and El Fasda lakes and environmental assessment of Wadi El-Natrun saline lakes. The chemical analysis for major cation, anion and trace elements was carried out and the hypothetical salts were calculated. The phase rule relationships for the salts precipitating from every lake were established, and the suitable conditions for the precipitation of every salt were elucidated. The XRD techniques are used to identify the types of minerals present