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Field and geochemical observations of the granitoids of the Homrit Waggat area in the central Eastern Desert of Egypt reveal two magmatic phases. The early phase of weakly deformed subduction-related calc-alkaline rocks includes tonalite and granodiorite. We name the later phase the Homrit Waggat Pluton (HWP); it includes undeformed syenogranite, alkali feldspar granite, and minor albitized granite. The tonalite and granodiorite have distinct negative Nb-Ta anomalies and lower alkalis, REE, Nb, Zr, and Hf than the HWP. The early magmatic pulse is a subduction-related suite, likely generated by underplating of mantle-derived magmas that triggered partial melting of mafic lower crust; mixing of these melts led to intermediate magma that further fractionated to tonalite and granodiorite. The HWP granites of the late magmatic pulse are transitional from a subduction-related to an anorogenic within-plate environment, plausibly generated by post-collisional lithosphere delamination. Although the parent magma of the HWP was I-type, extensive fractional crystallization produced residual liquids with A 2 -type character. Albitized granites are found only along the outer margin of the HWP, and contacts with the alkali feldspar granite are gradational, suggesting fluid interactions at a late stage of crystallization. The original textures of the albitized granites are preserved, but their bulk composition was modified by the production of Narich minerals and the removal of K, REE, and some trace elements by fluids.

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The rare-metal granites of the Nubian Shield are commonly associated with Nb−Ta and Sn mineralization. The magmatic and hydrothermal evolution of these granites and their relation to the Nb−Ta and Sn mineralization need further investigations. This study reports new mineral chemistry, wholerock geochemical, and Sr−Nd isotopic data for the Abu Dabbab granites in the Central Eastern Desert of Egypt to provide new insights into the formation mechanisms of the granites and their associated rare-metal mineralization. The granites consist mainly of albite, orthoclase, quartz, and Li-phengite, with accessory minerals including cassiterite, columbite, tantalite, wodginite, and Hf-zircon. Geochemically, they are peraluminous with high SiO 2 , alkalis, Rb, Nb, Ta, Sn, F, and low contents of MgO, CaO, and P 2 O 5 . The granites are characterized by distinct rare-earth element tetrad effects (TE 1,3 = 1.8−2.5), with strongly negative Eu anomalies and are extremely depleted in Ba, Sr, P, and Ti. These features imply that they are typical muscovite peraluminous highly evolved granites. Isotopically, they display positive εNd(t) values (+1.11 to +8.32) and two-stage Nd depleted model ages (t DM2 ) between 0.68 and 1.13 Ga, suggesting a juvenile magma source of the Neoproterozoic age. The Abu Dabbab granites could be formed by dehydration melting of muscovite-rich crustal materials followed by extensive fractional crystallization with a significant role of magmatic−hydrothermal fluids during the transitional orogenic stage of the Nubian Shield.

A highly‐fractionated garnet‐bearing muscovite granite represents the marginal granitic facies of the Abu‐Diab multiphase pluton in the Central Eastern Desert of Egypt. New electron microprobe analyses (EMPA) and laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) data from garnets are reported, in order to constrain their origin and genesis. Garnet in the Abu‐Diab host granite is euhedral to subhedral, generally homogeneous and, in rare cases, it shows weak zonation. The garnet contains appreciable amounts of MnO and FeO, with lesser amounts of MgO and CaO, yielding an end‐member formula of Sps61–72Alm25–35Prp1–4Adr0–1. Moreover, it is depleted in large ion lithophile elements (LILE) with lower values of Ba, Nb and Sr relative to the primitive mantle. Additionally, it contains high concentrations of HREE and Y and their REE pattern shows strong negative Eu anomalies. The garnet was crystallized under relatively low temperature (646°C–591°C) and pressure (< 3 kbar) conditions. The textural and chemical features indicate that the garnet is magmatic in origin and is chemically similar to that from highly‐fractionated A‐type granite. It was probably formed at the expense of biotite in a highly‐evolved MnO‐rich magma and/or by hydroxyl complexing of Mn during the ascending fluid phases.