U–Pb geochronology, REE and trace element geochemistry of zircon from El Fereyid monzogranite, south Eastern Desert, Egypt

Abstract

The monzogranite of El Fereyid is one of the rare metal-rich granites, where zircon is one of the ore minerals. Thus, studying zircon here is of vital importance. Most of the studied zircon grains are metamict and thus the loss of radiogenic Pb is detected for them. Nevertheless, our study allowed us to obtain the U-Pb (SHRIMP-II) age of magmatic crystallization for the El Fereyid monzogranite: 626 ± 13 Ma. These data allowed the correction of earlier determined age (K-Ar system in biotite) for the El Fereyid massif.Zircon grains of El Fereyid monzogranite demonstrate heterogeneous structure in CL images, they are rich in rare earth elements (REE, concentration 3000-22500 ppm), trace elements (U: 2000-14800 ppm, Th: 300-2500 ppm), and has low Th/U ratios (average 0.18). Most zircon grains exhibit multiple internal oscillatory zoning in CL images, indicating a typical magmatic origin. The core of zircon grain has a dark tone on CL imaging and magmatic-type REE spectra. Zircon cores are enriched in REEs, U, Th, and Y, thus recording that the magma was rich in incompatible elements. Light CL rims of zircon grains are depleted, relative to the cores in most of the trace elements, except for P, Ca, and Ti. REE spectra in rims show similar patterns that are more often demonstrated by hydrothermal zircon grains. This explains their crystallization in the late-magmatic stage when magma was rich in fluids but depleted in most of the trace elements.

Wodginite as an indicator mineral of tantalum-bearing pegmatites and granites

“…3. Variations in composition of the wodginite group minerals in rare-metal pegmatites (1-7) and granites (8-13) of the world 1-6average fractions of Ti and Mn cations in minerals of pegmatites: wodginite (1), ferrowodginite (2), titanowodginite (3), ferrotitanowodginite (4), "wolframowodginite" (5), tantalowodginite (6); 7fields of cationic relations in minerals of pegmatites; 8-12average fractions of Ti and Mn cations in minerals of granites: wodginite (8), ferrowodginite (9), titanowodginite (10), ferrotitanowodginite (11), "wolframowodginite" (12); 13fields of cationic relations in minerals of granites. ΣA, ΣBsums of cations in position A (Mn 2+ , Fe 2+ , Li, Ca), B (Sn 4+ , Ti, Fe 3+ , B Ta, Sc, Zr) 0.5 1 0.1 Mn/ΣA 0.5 0.9 0 Ti/ΣB potentials of Ta and Sn increase and the accessory ferrowodginite of pegmatites is sequentially replaced by titanowodginite, "wolframowodginite" and wodginite [15].…”

The Presence of Wodginite in Lithium–Fluorine Granites as an Indicator of Tantalum and Tin Mineralization: A Study of Abu Dabbab and Nuweibi Massifs (Egypt)

“…The young albite granites are represented mainly by Li-F granites, specialized in Ta, Sn, Nb, Be, and W, as well as alkaline granites (Nb, Zr, Y) and apogranites (Nb, Ta, Sn, Zr, Y, U, Be, W). The rare-metal granite massifs are distinguished by small dimensions (0.1-4 km 2 ) and a characteristic morphologyintrusive domes, lens-shaped deposits, and stocks [32,33]. They are controlled by deep fault zones, represented by independent bodies or are part of large polychronous plutons of calc-alkaline granites [12,34].…”

Excess Lifetime Cancer Risk Associated with Granite Bearing Radioactive Minerals and Valuable Metals, Monqul Area, North Eastern Desert, Egypt

“…The crystal morphology of primary zircon depends on the crystallization rate, temperature, pressure, melt, and trace element composition [63]. The formation of prism faces in zircon has been attributed to the presence of U, Th, Y, and other REEs, as well as P in the Zr sites [40,47,54,64]. Chrysocolla and tenorite (Figure 5a-d) were the copper minerals identified with the EDS technique.…”

“…Rare metal mineralization is restricted to granites such as the El Missikat [35,36], El-Erediya [37,38], Ras Abda [39][40][41], Gattar [42][43][44][45], and El Sela younger granite plutons in the south of the Eastern Desert [46][47][48][49]. The post-orogenic magmatism in the ED occurred between 530-620 Ma [50][51][52][53][54]. It is well known that porphyry copper mineralization is derived largely from the fractionation process associated with igneous rocks of calc-alkaline affinities [55,56].…”