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

Clay 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, eight soil profiles were taken from the western side of Nasser Lake. The clay fraction was separated from the horizon have a high content of clay and prepared for X-ray diffractometry which used to determine the content of clay minerals.
The obtained results revealed that, the studied clay fractions that separated from soil profiles are dominated contents of quartz and Kaolinite minerals recorded average values of 39.68 and 30.57%, respectively, followed by smectite (11.06%) and micasmectite (3.31%) assemblages. Also, the mean values of the studied minerals varied in the clay fractions and were 2.11, 2.06, 1.30, 0.98, 0.93, 0.93, 0.74 and 0.50% of palygorskite, mica, calcite, plagocalsite, pyrophyllite, vermculite and hematite, respectively. The obtained mineral compositions showed that physical weathering was dominant compared to chemical weathering due to the increase amount of quartz present in the clay fractions. In general, weathering was not severe because the secondary clay 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.