Geochemistry, age and origin of the Mons Claudianus TTG batholith (Egypt): insight into the role of Pan-African magmatism in uniting plates of Gondwana

Abstract

The tonalite–trondhjemite–granodiorite (TTG) Mons Claudianus Batholith (MCB) of Egypt is subsolvus, metaluminous to mildly peraluminous, exhibits wide ranges of SiO2, Al2O3, Sr, Rb, Zr, shows large Ba enrichment, is moderately enriched in rare earth elements (REE) and is depleted in K, Ti, Nb, Y, Hf and heavy REE (HREE), reflecting strong arc geochemical signatures. Moderate fractionation of REE and lack of Eu anomaly characterize the MCB. It is typical of high-Al TTGs of volcanic-arc affinities. U–Pb–zircon dating produced a Pan-African age of 664.12 ± 0.38 Ma. The MCB exhibits 87Sr/86Sr isotopic compositions of 0.70352–0.70626 (initial Sr ratio of 0.70259) and 143Nd/144Nd ratios of 0.51261–0.51276 (εNd; –0.5 to +2.4), suggestive of a mantle source. Anatexis of a basaltic slab under eclogitic conditions leaving garnet in the residue produces high-Al TTG rocks characterized by low Yb values (<1.8 ppm). Values (in ppm) of Yb (0.65–1.8), Y (2.2–19), Nb (1.2–6.4), and ratios of Nb/Ta (7–17), (La/Yb)N of 11.7, Sr/Y and Zr/Sm (58 and 45, respectively) are all consistent with anatexis of a basaltic slab under eclogitic conditions, leaving garnet in the residue to produce this high-Al TTG suite. The data conform to magma generation via partial melting (F = 0.25–0.50) leaving 15–25 % garnet in the residue. Voluminous synorogenic magmatic pulses, resulting from slab melting during the closure of the Mozambique Ocean via convergence of east and west Gondwana, produced the MCB and similar large batholiths forming the core of Pan-African belts. These belts welded together vestiges of fragmented Rodinia, assembling them into a united Gondwana.

Non-destructive magnetic and chemical characterization of granite column shafts traded in the Mediterranean area: the case of Piazza dei Miracoli in Pisa (Italy) and Basilica of Saint-Martin d’Ainay in Lyon (France).

“…One Claudianus shaft (already mentionned in [18]) was also positively confirmed in the Lyon Theater using this technique. Reference values from Corsica and Claudianus were obtained from our sampling on Cavallo island, and [11,12,16]. In Pisa we studied using pXRF three shafts presumed from Corsica, Mons Claudianus and Mysia (?…”

“…pXRF data on shafts, in particular Rb values, are often lower than reference or geological sample data, but the separation between Claudianus and Corsica fields is large enough to overcome this bias. [8,11,12,16,17], in pink, blue, green and orange ellipses, respectively. Our average pXRF data with s.d.…”

“…Figure 2. Rb versus Sr fields for Corsica, Mons Claudianus, Mysia and Elba sources after[8,11,12,16,17], in pink, blue, green and orange ellipses, respectively. Our average pXRF data with s.d.…”

Mineralogy of a rare Ediacaran epidote‐bearing trondhjemitic complex from the Nubian Shield: Insights into P‐T conditions of magma emplacement

“…However, due to their relative scarcity worldwide, much lesser studies on Neoproterozoic TTGs are available. In the case of the Arabian–Nubian Shield (ANS), only a few studies on TTGs have been reported in the literature (e.g., Abdel‐Rahman, 2019, 2021).…”

Petrogenesis of a rare Ediacaran tonalite–trondhjemite–granodiorite suite, Egypt, and implications for Neoproterozoic Gondwana assembly

“…Numerous investigations of other magmatic complexes within the northern part of the ANS have been carried out (e.g. Bentor, 1985;Abdel-Rahman & Doig, 1987;Abdel-Rahman & Martin, 1987;Abdel-Rahman, 1990, 1995, 2010, 2016, 2019El-Shazly & El-Sayed, 2000;Loizenbauer et al 2001;El-Sayed et al 2004;Eliwa et al 2006;Abdel-Rahman et al 2009;Bea et al 2009;Be'eri-Shlevin et al 2009, 2011Johnson et al 2011;Maurice et al 2012;Fritz et al 2013;Jarrar et al 2013;Eyal et al 2014Eyal et al , 2019Robinson et al 2014;Elisha et al 2017Elisha et al , 2019.…”