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Upper Cretaceous oil shales accumulated in intracratonic sedimentary basins along the Central Eastern Desert. Comprehensive geochemical analyses have been applied on 3 Maastrichtian oil shale horizons from the Duwi and Dakhla formations (El‐Beida and El‐Nakheil mines). We provide significant clues for chemical weathering, sediment recycling, petrogenesis, and tectonic setting of oil shales' source material. The mineralogical composition of the studied oil shales is generally characterized by carbonates, phyllosilicates, quartz, fluorapatite, and sulphides. The geochemistry is characterized by high Ca, P, Ni, U, and Cr values compared to standard post‐Archean Australian shales (PAAS). Their chondrite‐normalized patterns are distinguished by LREE enrichment, HREE depletion, negative Eu anomaly, and typical shale‐like PAAS‐normalized REE patterns. Furthermore, the total REE content is positively correlated with Si, K, Na, Fe, Al, Ti, and Mn, indicating that the REE of the investigated oil shales originated from terrigenous sources. Diverse proxies (e.g., CIA, CPA, and PIA) and the A–CN–K ternary diagram suppose that the source rock succession of the oil shales experienced moderate to intensive chemical weathering. Various geochemical parameters suggest that the oil shales were predominately derived from intermediate, with a minor contribution from felsic, igneous source rocks without any remarkable recycling signals. The average values of (Gd/Yb)N (1.39), Eu/Eu* (0.76), Th/U (0.29), and discrimination diagrams reveal that the oil shales were derived from Neoproterozoic island arc parent rocks. The geochemical results for oil shale provenance are in accordance with the composition and the palaeotectonic history of the igneous rocks in the Central Eastern Desert of Egypt.

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The widely distributed late-collisional calc-alkaline granitoids in the northern Arabian-Nubian Shield (ANS) have a geodynamic interest as they represent significant addition of material into the ANS juvenile crust in a short time interval . The Deleihimmi granitoids in the Egyptian Central Eastern Desert are, therefore, particularly interesting since they form a multiphase pluton composed largely of latecollisional biotite granitoids enclosing granodiorite microgranular enclaves and intruded by leuco-and muscovite granites. Geochemically, different granitoid phases share some features and distinctly vary in others. They display slightly peraluminous (ASI ¼ 1-1.16), non-alkaline (calc-alkaline and highly fractionated calc-alkaline), I-type affinities. Both biotite granitoids and leucogranites show similar rare earth element (REE) patterns [(La/Lu) N ¼ 3.04-2.92 and 1.9-1.14; Eu/Eu à ¼ 0.26-0.19 and 0.11-0.08, respectively) and related most likely by closed system crystal fractionation of a common parent. On the other hand, the late phase muscovite granites have distinctive geochemical features typical of rare-metal granites. They are remarkably depleted in Sr and Ba (4-35 and 13-18 ppm, respectively), and enriched in Rb (381-473 ppm) and many rare metals. Moreover, their REE patterns show a tetrad effect (TE 1,3 ¼ 1.13 and 1.29) and pronounced negative Eu anomalies (Eu/Eu à ¼ 0.07 and 0.08), implying extensive open system fractionation via fluid-rock interaction during the magmatic stage. Origin of the calc-alkaline granitoids by high degree of partial melting of mafic lower crust with subsequent crystal fractionation is advocated. The broad distribution of late-collisional calc-alkaline granitoids in the northern ANS is related most likely to large areal and intensive lithospheric delamination subsequent to slab break-off and crustal/mantle thickening. Such delamination caused both crustal uplift and partial melting of the remaining mantle lithosphere in response to asthenospheric uprise. The melts produced underplate the lower crust to promote its melting. The presence of microgranular enclaves, resulting from mingling of mantle-derived mafic magma with felsic crustalderived liquid, favours this process. The derivation of the late-phase rare-metal granites by open system fractionation via fluid interaction is almost related to the onset of extension above the rising asthenosphere that results in mantle degassing during the switch to post-collisional stage. Consequently, the switch from late-to post-collisional stage of crustal evolution in the northern ANS could be potentially significant not only geodynamically but also economically.

Current research has been focused on heavy metals pollution in surface water and groundwater and effect on irrigated soil from El Minia Province, north Upper Egypt. Concentration of heavy metals (e.g., As, Co, Hg, Ni, Se, Cd and Cr) in surface water, groundwater and irrigated soil samples is most significantly affected by leachate of many pollutants as the factories, agricultural activities, urban and natural processes. Microbiological parameters and microscopic investigations are revealed that some localities are common by microorganisms , which are unsuitable for drinking waters.