The effects of different regional tectonic events on the Neoproterozoic basement rocks of the Arabian–Nubian Shield in Sinai, as well as the Egyptian unstable and stable shelves, remain uncertain. Coupling fission-track thermochronometry findings with the modeling of the time–temperature history has proved to be an effective method for tackling these issues. The obtained zircon fission-track ages were differentiated into two groups from the Ediacaran–Cambrian and the Ordovician–Carboniferous periods, while the apatite fission-track data revealed two separate groups of cooling ages of the Carboniferous–Triassic and Late Cretaceous ages. The integration of these cooling ages and modeling of the time–temperature history revealed four discrete cooling pulses during the Neoproterozoic, Devonian–Carboniferous, Cretaceous, and Oligocene–Miocene eras. After integrating our findings with the regional tectonic historical and sedimentological records, these could be identified as cooling/exhumation pulses activated in response to the post-accretional event of erosion, Variscan tectonism, the disintegration of Gondwana, and the Gulf of Suez rifting, respectively. Furthermore, the southern border of the Egyptian unstable shelf was found to extend southward to South Sinai and south of the Bahariya depression.

The Abu Farayed Granite (AFG), located in the southeastern desert of Egypt, was intruded during the early to late stages of Pan-African orogeny that prevailed within the Arabian–Nubian Shield. The AFG intrudes an association of gneisses, island arc volcano–sedimentary rocks, and serpentinite masses. Field observations, supported by remote sensing and geochemical data, reveal a composite granitic intrusion that is differentiated into two magmatic phases. The early granitic phase comprises weakly deformed subduction-related calc–alkaline rocks ranging from diorite to tonalite, while the later encloses undeformed granodiorite and granite. Landsat-8 (OLI) remote sensing data have shown to be highly effective in discriminating among the different varieties of granites present in the area. Furthermore, the data have provided important insights into the structural characteristics of the AFG region. Specifically, the data indicate the presence of major tectonic trends with ENE–WSW and NW–SE directions transecting the AFG area. Geochemically, the AFG generally has a calc–alkaline metaluminous affinity with relatively high values of Cs, Rb, K, Sr, Nd, and Hf but low contents of Nb, Ta, P, and Y. The early magmatic phase has lower alkalis and REEs, while the later phases have higher alkalis and REEs with distinctly negative Eu anomalies. The AFG is structurally controlled, forming a N–S arch, which may be due to the influence of the wadi Hodein major shear zone. The diorite and tonalite are believed to have been originally derived from subduction-related magmatism during regional compression. This began with the dehydration of the descending oceanic crust with differential melting of the metasomatized mantle wedge. Magma ascent was long enough to react with the thickened crust and therefore suffered fractional crystallization and assimilation (AFC) to produce the calc–alkaline diorite–tonalite association. The granodiorite and granites were produced due to partial melting, assimilation, and fractionation of lower crustal rocks (mainly diorite–tonalite of the early stage) after subduction and arc volcanism during a late orogenic relaxation–rebound event associated with uplift transitioning to extension.

Beryl mineralization in the Nugrus-Sikait domain in the South Eastern Desert (SED) of Egypt occurs as disseminated crystals in granitic pegmatite and quartz, as well as pegmatite veins crosscutting mélange schist and ophiolitic rocks. When granitic pegmatite comes into contact with the ophiolitic rocks, phlogopite and amphibole schists are formed due to K metasomatism. The ophiolitic mélange is intruded by leucogranite and related pegmatite along the NNW to NW Nugrus shear zone. Beryl samples have been collected from Um Sleimat, Madinat Nugrus, Wadi Abu Rusheid, and Wadi Sikait. Major oxides and in situ trace and rare earth elements (REEs) of beryl and associated minerals were analyzed through EPMA and LA-ICP-MS, respectively. The investigated beryl, based on its color and chemical compositions, can be classified into the two following types: pegmatitic beryl (type I) and schist-related beryl (type II). The former is colorless to pale green, and is mainly restricted in pegmatite veins; it is poor in Cr₂O₃ (up to 0.03 wt%) and MgO (Nil). The latter, deep green in color, is rich in Cr₂O₃ (up to 0.27 wt%) and MgO (up to 2.71 wt%), and occurs within quartz veins, phlogopite schists, and tremolite schists. The abundant beryl mineralization in phlogopite schists and their related quartz veins suggests that granite and associated pegmatite are the source rocks for the Be-bearing fluids that migrate along the NW-SE trending deep-seated tectonic zone, such as the Nugrus shear zone. Therefore, the formation of beryl in schists is attributed to the interaction of granitic/pegmatitic-derived Be-bearing fluids with serpentinite and gabbro interlayered with mélange schists. Variations in the trace and REE contents of both beryl types (I and II) indicate their two-stage formation from different compositions of Be-rich fluids, where light REEs, Zr, Nb, Ba, and Th decrease from type I beryl to type II. These two phases of beryl could be attributed to the magmatic/hydrothermal fluids associated with the pegmatite emplacement. The early phase of the late-stage magmatic-derived fluids was closely related to magma evolution and pegmatite formation, forming euhedral type I beryl. The late phase of pegmatite-derived fluids was mixed with serpentinite/schist-derived fluids that cause high V and Cr content in type II beryl. The composition of parent magmas of felsic rocks, the high degree of magma fractionation or the late stage melts, fluid compositions (rich in Be, Li, Cs, Rb, K), and alkali metasomatism, as well as the linear NW-SE trending deep-seated shear zone, are all factors possibly influencing beryl mineralization in the SED of Egypt.

Serpentinites make up one of the most significant rock units associated with primary suture zones throughout the ophiolite sequence of the Arabian–Nubian Shield. Wadi Sodmein serpentinites (WSSs) represent dismembered parts of the oceanic supra-subduction system in the central Eastern Desert of Egypt. In this context, we present whole-rock major, trace, and rare earth elements (REE) analyses, as well as mineral chemical data, to constrain the petrogenesis and geotectonic setting of WSS. Antigorite represents the main serpentine mineral with minor amounts of chrysotile. The predominance of antigorite implies the formation of WSS under prograde metamorphism, similar to typical metamorphic peridotites of harzburgitic protolith compositions. The chemistry of serpentinites points to their refractory composition with notably low Al₂O₃, CaO contents, and high Mg# (90–92), indicating their origin from depleted supra-subduction zone harzburgites that likely formed in a forearc mantle wedge setting due to high degrees of hydrous partial melting and emplaced owing to the collision of the intra–oceanic arc with Meatiq Gneisses. Spinels of WSS generally exhibit pristine compositions that resemble those of residual mantle peridotites and their Cr# (0.625–0.71) and TiO₂ contents (<0.05 wt%) similar to forearc peridotite spinels. Moreover, WSS demonstrates a significant excess of fluid mobile elements (e.g., Th, U, Pb), compared to high-field strength elements (e.g., Ti, Zr, Nb, Ta), implying an interaction between mantle peridotites and fluids derived from the oceanic subducted-slab. The distinct U-shaped REE patterns coupled with high Cr# of spinel from WSS reflect their evolution from mantle wedge harzburgite protolith that underwent extensive melt extraction and re-fertilized locally.

Understanding pollution levels, ecological health risks, and sources of potentially toxic metals (PTMs) in the soil from university campuses is critical for assessing environmental safety. Soil samples were collected from 12 locations across urban parks and green areas at Sohag University in Egypt. The samples were processed and analysed for heavy metals, including iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), chromium (Cr), lead (Pb), zinc (Zn), copper (Cu), and cadmium (Cd). Pollution levels were evaluated using indices such as the pollution index (PI), pollution load index (PLI), geo-accumulation index (I_geo), and enrichment factors (EFs). Among the pollution indices, the EFs showed the highest sensitivity in detecting anthropogenic contributions, particularly for Cd, Pb, and Cr. Spatial distribution maps and multivariate statistical analyses, including correlation matrix (CM), principal component analysis (PCA), and cluster analysis (CA), were applied to identify the relationships between PTMs and soil properties, and source apportionment was performed using positive matrix factorisation (PMF). The results indicated that Mn, Ni, and Co were primarily geogenic, whereas Pb, Zn, Cr, and Cd showed higher concentrations, suggesting moderate-to-significant anthropogenic pollution. Pb and Cd pose considerable ecological risks, whereas other metals such as Cr and Cu exhibit moderate ecological threats. The non-carcinogenic and carcinogenic risks to the students were within safe limits, as defined by United States Environmental Protection Agency (USEPA) threshold values. Source apportionment using PMF identified five main sources of PTMs: industrial and anthropogenic activities (30.0%), traffic emissions (25.0%), natural soil processes (20.0%), agricultural practices (15.0%), and mixed industrial traffic sources (10.0%). These findings emphasise the importance of controlling anthropogenic activities to ensure a safer campus environment.