Upper Cretaceous Tethyan Phosphogenic Province in the Qena-Idfu District, Egypt: Insights from Geology, Petrography, and Geochemistry

The Upper Campanian phosphorite series in Egypt, which overlies the Nubian Group, exhibits pronounced lateral lithological variations. Glauconitic, dolomitic, calcareous, and cherty sediments, together with bituminous shales, form diverse lithofacies associations that reflect the region's complex depositional environments. These lithofacies, associated with the Duwi Formation, are marine deposits originally formed in anoxic, organic-rich environments and later reworked into shallower, oxygenated settings during sea-level fluctuations. This study presents a detailed geological, petrographic, and geochemical characterization of these phosphorite deposits in North Aswan, Egypt, across five localities: Wadi Hilal, East Sibaiya, Um Higarah, Um Salama, and Um Tundbah. The lithostratigraphic succession is dominated by the Upper Cretaceous Duwi Formation, which unconformably overlies the Middle-Campanian Qusseir shale and conformably underlies the Middle-Maastrichtian Dakhla shale. Petrographically, the phosphorites comprise phosphatic grains (pellets and bioclasts such as bone fragments and shark teeth), non-phosphatic grains (quartz), and cements of silica, calcite, and iron oxides. Geochemically, P₂O₅ content ranges from 17.4 to 31.24%, uranium concentrations vary between 40.59 and 245.84 ppm, and total rare earth elements (∑REEs) range from 47.83 to 270.37 ppm. The studied phosphorites are suitable for phosphoric acid production, with potential for uranium recovery as a by-product.