Mineralogical Study of Clay Fraction of Soil Along Nasser Lake Affected by Construction of The High Dam, Aswan, Egypt

LAY mineralogy studies were essential for understanding the weathering environments and source regions of fluvial sediments affected by construction of the High Dam. This study conducted in Aswan Governorate, Egypt, to knowing the minerals formed the clay fraction separated from some horizons of soil profiles. To achieve this purpose, were taken eight soil profiles from the western side of Nasser Lake to evaluate some soil properties and study clay mineralogy. The clay fraction was separated from the layers have a high content of clay and prepared for X-ray diffractometry which used to determination, to define of the different clay and accessory minerals. Our results showed that, the soil pH ranged from neutral (7.36) to highly alkaline (8.9), and it was classified as non-saline to highly saline and slightly to moderately calcareous. So, the values of soil EC ranged from 0.17 to 5.8 dSm -1 and CaCO 3 ranged from 0.04 to 7.39%, respectively. Moreover, the cation exchange capacity (CEC) was low to very high, ranging from 6.1 to 44.28 CmoL c kg -1 , with a predominantly sandy texture. Also, results revealed that, dominated contents of kaolinite minerals indicated followed by smectite, micasmectite, vermiculite, Sepiolite and plagioclase. The identified accessory minerals were dominant quartz followed by aragonite, calcite and hematite. In general, weathering was not severe because accessory minerals were not formed in large quantities, and perhaps these obtained results are due to the type of parent material predominated, whether present in the study area or transported across of Nile River to the place of sedimentation, and the weather conditions prevailing in the study area helped in that.