Tectonic controls and subsurface structural insights for groundwater accumulation in El-Gallaba Plain, Egypt: insights from magnetic data interpretation
The groundwater distribution in southern Egypt is primarily governed by the region’s inherited rift-related tectonic framework. We integrated aeromagnetic data with available hydrogeochemical and seismic data to investigate structural controls on groundwater accumulation in El-Gallaba Plain along the western margin of the Kom Ombo Basin. The magnetic data were processed using edge-detection filters and source-parameter imaging to estimate the depth of the basement rock. Moreover, three-dimensional geophysical inversion of magnetic data was performed using the iteratively re-weighted least-squares algorithm to map the basin geometry. The results of magnetic data interpretation delineated a NW-SE major trend and minor NE-SW-trending, fault-bounded depressions extending to depths of 2.5–3.0 km, interpreted as sediment-filled or altered-basement fractured basins favorable for groundwater accumulation. Uplifted basement blocks define structural highs that act as hydraulic barriers, compartmentalizing the area’s aquifer system. The interpreted magnetic structures were correlated with previously published land-surface temperature and hydrochemical data, revealing a spatial alignment among deep structural depressions, low-temperature corridors, and zones of fresher, isotopically depleted groundwater. This correlation confirms that reactivated Pan-African and Cenozoic faults control the vertical permeability and groundwater connectivity of the Nubian Sandstone Aquifer. Overall, this study highlights the effectiveness of three-dimensional inversion, along with edge-detection and depth-estimation filters applied to magnetic data to resolve subsurface architecture and interpret groundwater potential in arid, tectonically complex regions.