Abstract
The termination of the collision between West and East Gondwana and the Pan-African orogeny is somewhat regarded as an endorsement for the generation and intrusion of alkaline magmatism in the Arabian-Nubian Shield. However, the current ages of the Abu Hamar-Abu Kharif alkaline granites have changed this endorsing connection. The Gebel Abu Hamr and Gebel Abu Kharif plutons, exposed in the northern Egyptian Eastern Desert, are anorogenic rift-related granite (A-type) and possess characteristics indicative of a within-plate tectonic setting. Their U[sbnd]Pb ages (616.6 ± 6.4 and 614.6 ± 3.6 Ma) are remarkable and provide insight into the initial phase of the anorogenic alkaline magmatism within the shield. The zircon U[sbnd]Pb dating, geochemical data, and zircon geochemistry together suggest that the primary magma was formed by the upwelling of a short-lived mantle plume. These alkaline granites subsequently intruded into the crustal mesozone at a thickness of 20–30 km with average temperatures of ~680 °C. The structural framework of the studied plutons reveals a noticeable correlation between their emplacement and the Najd left-lateral fault system. These alkaline granite plutons host wolframite-bearing quartz veins. The in-situ U[sbnd]Pb dating of wolframite yielded a weighted mean age of 603.7 ± 7.4 Ma. The trace and rare earth elements of wolframite, zircon, and the hosting alkaline granites share significant geochemical similarities. Nevertheless, the proximity of the U[sbnd]Pb age of wolframite and the associated granites suggests an epigenetic origin.
Original language | English |
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Article number | 126119 |
Journal | Geochemistry |
Volume | 84 |
Issue number | 3 |
Early online date | 17 Sept 2024 |
DOIs | |
Publication status | Published - Sept 2024 |