Comparative Magnetic Techniques for Delineating Phosphate-Related Structures: A Case Study from Wadi Gasus, Eastern Desert, Egypt

This study targets mineral exploration, specifically the precise identification of basement structures that may have influenced the depositional framework of the economically and industrially important phosphate-bearing sequence. Airborne magnetic data from the Wadi Gasus area, Eastern Desert, Egypt, were analyzed to reveal the subsurface structures governing phosphate distribution and formation, using the Tilt Angle method, Source Parameter Imaging (SPI), and Global Particle Swarm Optimization (GPSO). The reduced-to-pole (RTP) magnetic map shows anomalies ranging from −283 to 707 nT. The Tilt Angle method indicates source depths of 395 to 950 m (average about 672 m), while SPI yields depths of 98 to 1276 m (average about 687 m). GPSO was applied to four profiles perpendicular to the strike of high-amplitude RTP anomalies, estimating source depths of 68.92 to 185.65 m, amplitude coefficients (Af) of 627.94 to 5764.71 nT, shape factors (Sf) of 0.97 to 1.3, and horizontal origins (xo) of 1505.41 to 2316.87 m. The computed depths are consistent with established geological findings. GPSO’s distinct advantage is that it determines not only source depth but also the complete set of source parameters, including location, shape, and amplitude, offering a more holistic understanding of subsurface geology than traditional depth-focused methods. These findings provide indirect structural constraints on the basement framework beneath the phosphate-bearing sedimentary cover and complement direct geological and geochemical exploration in similar settings.