الفهرس 
المقدمةيوجد فقط 14 صفحة متاحة للعرض العام
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المستخلص
The study area ( Siwa Depression ) lies in the northwest part of the western desert of Egypt. The maximum extension of Siwa depression from east to west is about 82 km, and the maximum width from north to south is about 50 km, and it covers an area of 3400 km 2. In general, Sabkhas constitute one of the most common landforms in Siwa, and they cover about 36.19% of the total area of Siwa depression. They occure as ascattered, irregular, and closed low land areas of different sizes. The objective of the present work is to study the inland sabkhas in Siwa depression from a geomorphological point of view. The study consists of five chapters, in addition to an introduction and a conclusion as follows : The introduction handled the location of the Studied area, the reasons for selecting Sabkhas as asubject of the study, the objectives of the study, the previous studies, sources of the study, methods and stages of the study. Chapter One : Dealt with the geographical distribution of Sabkhas and their morphological and morphometric characteristics in Siwa Depression. In this chapter the Sabkhas have recorded various and tangible change through the period of (2014 –1972).The values of change have varied depending on the morphology and the position of the Sabkhas in the study area. Chapter Two : Handled the physical and human factors affecting the formation and the development of Sabkhas. It is clear that the main physical factors are geology and geomorphology of the study area, relief, climatic condition, in addition to the ground water. As far human factors, they are represented by urbanization expansion, agriculture, and increasing extraction of ground water. This chapter is conclded with a study of the geomorphic evolution of Sabkhas. Chapter Three : Concerned with the physical properties of Sabkhas deposits. It became clear from the volumetric analysis of the samples collected from Sabkhas deposits that the fine sand represent the highest proportion of Sabkhas deposits, whereas the proportion of the coarse sand, gravel and mud represent the lowest.With regards to the chemical analysis of Sabkhas water, Sodium is proved to be the major element followed by Nitrogen, Phosphours and Potassium. Furthermore, all the soil samples collected from Sabkhas are alkaline, and very salty. Chapter Four : Dealt with the surface features of Sabkhas and the factors responsible for their formation. These features are : salty muddy cracks, salty polygons, salty saucers, salty domes, blisters, microbial mates, and Karast holes. This chapter also studied the Nebkhas dunes which are clearly found in Siwa and Om Howymel Sabkhas Chapter Five : This chapter concerned with the applied aspects related to the study of Sabkhas through the human exploitation of Sabkhas. These exploitations are : Settlement, agriculture, industrial and military uses. Natural hazards associated with Sabkhas as well as the proposed solutions to eliminate these hazards were also studied in this chapter. The study ended with the conclusion which summarizes the most important results and some recommendations.