## 4 Results and Discussion
### Geochemical Characterization  
The chemical composition of representative granite samples from ElSibai-Abu EITiyur area is given in Table S1 (Supplementary Material). They are highly evolved alkaline granites, judging from the elevated SiO\({}_{2}\) contents (71.6-76.6 wt.%). They exhibit a relative depletion in Al\({}_{2}\)O\({}_{3}\) (11.75-14.8 wt.%), CaO (0.53-1.6 wt.%), and MgO (0.07 to 0.46 wt.%), with moderate enrichment in Na\({}_{2}\)O (3.73-4.69 wt.%) and K\({}_{2}\)O (3.44-5 wt.%). Most of the granites suffered from albitization, as indicated by the predominance of Na\({}_{2}\)O over K\({}_{2}\)O (Table S1). The Fe\({}_{2}\)O\({}_{3}\)\({}^{\text{tot}}\)/(Fe\({}_{2}\)O\({}_{3}\)\({}^{\text{tot}}\) + MgO) content varied from 0.78 to 0.99. The studied granites fall within the granite field on the discrimination diagram [39] (Figure 6a). The aluminum saturation index [ASI; molecular Al/(Ca-1 67P + Na + K)] [40] showed that the rocks of ElSibai-Abu EITiyur have an aluminum saturation index (ASI) ranging from 0.88 to 1.04, indicating a chemical span from the metaluminous to the peralkaline character (Figure 6b). They show high K, calc-alkaline affinity on the K\({}_{2}\)O versus SiO\({}_{2}\) diagram (Figure 6c). Figure 6: (**a**) Classification of ElSibai-Abu EITiyur granites (after Middlemost [39]); (**b**) A/CNK vs. A/NK diagram of [PERSON] et al. [41]; (**c**) Variation diagram of K\({}_{2}\)O vs. SiO\({}_{2}\) (fields after [PERSON] [42]); (**d**) chondrite-normalized REE patterns; (**e**) primitive mantle-normalized multi-element patterns (normalization values are taken from [PERSON] et al. [43]); (**f**) plot of the studied granites on: *Ga/Al versus Na\({}_{2}\)O + K\({}_{2}\)O discrimination diagram [44]; (**g**) Nb-Y-Ga*3 ternary diagram [45]; (**h**) tectonic discrimination diagram, Rb versus (Nb + Y) diagram [46]. VAG—volcanic arc granitoids, ORG—oceanic ridge granitoids, WPG—within plate granitoids and Syn-COLG—syn-collision granitoids. (Symbols as in (**a**)). In all studied rocks, thorium and uranium were found. The highest concentrations were found in samples S1, S13, S14, and S15 (Table S1). The main carriers of thorium and uranium in the rocks under investigation are the accessory minerals (zircon, apatite, and fluorite). The granites of ElSibai-Abu EITiyur are relatively enriched in the elements Rb (40-187 ppm) with an average of 90 ppm, Nb (6.8-130.5 ppm-avg. 33.6), \(Y\) (11.2-166 ppm-avg. 56.5), Zr (56-637 ppm-avg. 395.5) and Ga (20.1-33.4 ppm-avg. 25.5), compared to the crustal rocks average (19 ppm Nb; 24 ppm Y; 203 ppm Zr; 15 ppm Ga [47]. According to [PERSON] [48], the F-rich melts are able to persist to the late stage of magmatic differentiation. Therefore, they are able to concentrate incompatible elements (Rb, Li, Ga, Sn, and Y) which can form stable complexes with F or H\({}_{2}\)O at different magmatic temperatures [49]. The solubility relationships between zircon and apatite together with the high fluorine contents of the alkaline granitic melts are responsible for the enrichment of the high field strength elements (Zr, Hf, Nb, Ta, Ti, and occasionally Th), hosted in the accessory minerals [50]. The studied granites have Th/U ratios varying between 2.7 to 5.6 (average 3.8) which is within the range reported by many authors (3.5-4 [51]; 5.5 [52], 3-4 [53]). They show an increase in the Gal/Al ratio with increasing alkalinity (Table S1). The digitized granite (sample S1) exhibits the highest concentration of Ga (33.4 ppm), Nb (130.5 ppm), Ta (6.8 ppm), U (6.66 ppm) and Y (166 ppm), and HREE (Gd, Dy, Ho, Yb) compared to the normal granites. Chondrite-normalized REE patterns for the alkaline granites and the abitized granite (sample S1) are presented in Figure 6d. The alkaline granites show enrichment in the REE (\(\sum\) REE average 285 ppm). They exhibit parallel to subparallel patterns. They are characterized by the enrichment of LREE over the HREE where the average (La/Sm)\({}_{n}\) is 2.33 and (Gd/Yb)\({}_{n}\) = 1.56.