Information collected from geophysical and geochemical data has been used in investigating the groundwater resources potential, hydrogeochemical characteristics, major hydrogeochemical processes that govern groundwater chemistry, quality and suitability assessment for drinking and irrigation uses from six wells of shallow quaternary aquifer in southern part of Eastern Desert, Egypt. A total of 32 Time-Domain electromagnetic soundings (TDEM) in time phase and vertical electrical soundings (VES)

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... ere measured on the same sites to detect the subsurface geological section and delineate water-bearing layers. The results of geoelectrical interpretation calibrated with gamma ray and resistivity logs of drilled wells. The findings illustrated that the subsurface section has four geoelectrical layers. The second layer represents the freshwater aquifer. Our results demonstrated that the dominant hydrogeochemical facies observed in this area is Ca + Mg-Cl + SO4 and mixed Ca + Mg-Cl + SO4 type. According to Base Exchange index (r1) and ( r2 ), the water classified as Na-SO4 type, which is associated with salinization (r1<1) and deep meteoric percolation type (r2<1). The groundwater chemistry depends on reverse ion exchange weathering of carbonate minerals as well as silicate weathering. Moreover, evaporation process controlling factors of groundwater chemistry in quaternary aquifer. Results from EC, sodium adsorption ratio (SAR), soluble sodium percentage (SSP), permeability index (PI) and magnesium hazard (MH) reveal that most of groundwater is relatively appropriate for Agricultural purposes.