Egypt hosts one of the most extensive organic-rich shale belts in North Africa and the Middle East. These shales are recorded across the Western Desert, Nile Valley, and Eastern Desert. This review integrates findings from peer-reviewed studies from 1997 to 2026, covering the Jurassic Khatatba Formation, Upper Cretaceous Quseir and Duwi formations, Cretaceous-Paleogene Dakhla Formation, Paleocene-Eocene hyperthermal-event shales, and Eocene-Oligocene black shales. They are mostly of marine origin, whereas the Jurassic Safa Formation of north Sinai and Campanian Quseir Formation represent the main non-marine end-member. Mineralogically, smectite-kaolinite clay assemblages, with variable calcite, quartz, apatite and pyrite, are dominant. Geochemically, they are enriched in redox-sensitive trace elements, including V, Mo, U, Cr, Ni, Zn, and Cd, reflecting deposition under dysoxic to euxinic bottom-water conditions, based on multi-proxy geochemical evidence. Total organic carbon ranges from 0.5 wt% to 35 wt%, with variable kerogen types and generally immature to marginally mature based on pyrolysis and vitrinite reflectance data. Oil-prone Type I/II kerogen dominates the Eastern Desert belt, whereas the Jurassic Western Desert and parts of the Cretaceous-Paleogene transition are characterized by more terrigenous, and gas-prone Type III/IV kerogen. Provenance indicators suggest derivation mainly from continental-island-arc affinity, weathered under warm humid to semi-arid conditions. Potential applications include retorting, combustion, lithium lubricating grease manufacture, uranium recovery, and biohydrogen generation. However, basin-scale 3-D assessment, reservoir engineering characterization, pilot-scale retorting, and integrated economic and environmental evaluation remain major research gaps. A national-scale assessment is needed to evaluate Egyptian black shales as integrated energy–critical metal resource targets aligned with Egypt's Sustainable Development Strategy.
The Bukan intrusive bodies, exposed in the northern part of the Sanandaj-Sirjan Zone (NW Iran), ranges in composition from quartz-diorite to quartz-monzodiorite. Zircon U-Pb dating indicates that these rocks crystallized during the Late Eocene (36.51 ± 0.42 Ma to 37.08 ± 0.17 Ma). Mineral chemistry reveals augitic pyroxene and normally zoned plagioclase, with cores ranging from labradorite to andesine. Chondrite-normalized REE patterns display mild light REE enrichment, relatively flat HREE patterns, and minor negative Eu anomalies, while the primitive-mantle normalized diagram show pronounced negative Nb and Ta anomalies. Mineralogical and geochemical features classify these rocks as metaluminous, I-type plutonic rocks. Major and trace element variations suggest that magmatic differentiation was controlled mostly by fractional crystallization of a mantle-derived magma, with limited crustal contamination. The initial isotopic ratios are characterized by (87Sr/86Sr)(i) = 0.7044–0.7051, (143Nd/144Nd)(i) = 0.51259–0.51267, and εNd(t) = 0.15–1. Coupled with the trace element geochemistry, these isotopic signatures indicate involvement of mantle-dominated parent magma. Pb isotopes also display a narrow range: 206Pb/204Pb(i) = 18.56–18.65, 207Pb/204Pb(i) = 15.62–15.66, and 208Pb/204Pb(i) = 38.57–38.70, with slightly elevated 206Pb/204Pb(i) values extending toward the GLOSS field, indicating incorporation of slab-derived sediment. The I-type signature and strong negative Nb and Ta anomalies suggest a genetic link to subduction processes beneath the Sanandaj-Sirjan zone, originating from partial melting of an metasomatized subcontinental lithospheric mantle (SCLM) source.
Groundwater resources are critical for sustainable development in arid regions, particularly in southwestern Algeria where extreme scarcity limits socio-economic growth and increasing mining activities intensify water demand. This study investigates the hydrogeophysical characteristics and groundwater potential of the Oum El Assel area (northern Tindouf Basin), focusing on the Bouakba and Khenguet Lamhar zones.An integrated approach combining vertical electrical sounding (VES) and magnetic data was employed to characterize subsurface structures and delineate aquifer systems. A total of 400 vertical electrical sounding measurements were conducted using the Schlumberger array with a maximum electrode spacing of 2000 m, allowing investigation depths of up to 400 m. Magnetic data processing, including analytic signal and derivative filters, enabled mapping of structural features controlling aquifer geometry.The results reveal a multilayered geoelectrical structure composed of a superficial Neogene Hamada formation overlying conductive clay-rich formations attributed to the Upper Visean, and deeper resistive units corresponding to Lower Visean sandstones and Tournaisian formations. These deeper units are identified as the most promising aquifer horizons due to their favorable hydraulic properties.Magnetic interpretation underscores the key role of tectonic structures, including NE–SW and NW–SE fault systems and associated horst–graben configurations, in controlling aquifer geometry and compartmentalization. Volcanic intrusions, particularly dykes emplaced along fault zones, further influence aquifer storage. Spatial comparison between the two study areas indicates that structurally controlled zones offer the highest groundwater potential. This integrated geophysical framework provides robust guidance for groundwater exploration and identifies priority targets for future drilling, contributing to sustainable water resource management in arid, mining-impacted environments.
