## 5 Geochemistry
### Bulk-Rock Geochemistry
Similarly to the alkaline granites and monzogranites from the ANS, the studied granitoids are characterized by an enrichment in alkalis (Na\({}_{2}\)O + K\({}_{2}\)O = 7.53-10.36 wt%). Furthermore, the data suggest that all the samples are plotted within the alkaline field (Figure 6b). In the K\({}_{2}\)O vs. SiO\({}_{2}\) diagram (Figure 6c), these samples are plotted within the field of the shoshonite series. Monzogranites, on the other hand, typically exhibit K\({}_{2}\)O/Na\({}_{2}\)O ratios less than 1, which aligns with their high-K calc-alkaline nature. However, it is also important to mention that some samples within the monzogranite group are plotted within the shoshonite series. The studied alkali granites and monzogranites are plotted within the ferroan field in the FeO\({}_{1}\)/(FeO\({}_{1}\) + MgO) versus SiO\({}_{2}\) diagram (Figure 6d). However, a few monzogranite samples are plotted in the magnesium field. The ferroan nature of the studied granitoids is similar to the most of rare-metal granites in the ANS. It is also important to note that there are exceptions within the ANS, where certain intrusions display a magnesium nature, e.g., alkali feldspar granite from the Um Taghir area, Egypt [32] and monzogranite from the El Fereyid area, Egypt [33]. The chondrite normalized REE patterns of the alkali granites and monzogranites are quite different (Figure 7a,b). The REE contents of alkali granites are higher than those of the monzogranites. The two patterns demonstrate fractionation in LREEs and flat HREEs (Figure 7a,b). The alkali granites display a strong negative Eu anomaly (Eu/Eu* = 0.025-0.144, with an average of 0.052), and show similar chondrite-normalizing REE patterns of the ANS alkali-feldspar granites. Conversely, the monzogranites show a low Eu anomaly (average Eu/Eu* = 0.73). Figure 4: Classification of the studied gramitic samples according to the R1–R2 diagram [30]. Figure 5: Harker variation diagrams, showing negative correlations of Na\({}_{2}\)O, Al\({}_{2}\)O\({}_{3}\), TiO\({}_{2}\), P\({}_{2}\)O\({}_{5}\), CaO, MgO, Fe\({}_{2}\)O\({}_{3}\), Co, V, Ba, Ni, Sr, and Ta with SiO\({}_{2}\), whereas Nb and Sn show positive correlations, K\({}_{2}\)O, Rb, Y, Hf, Th, and U show different magmatic trends for each rock type. The normalization of trace element concentrations in the alkali granites to ORG values [4] indicates that the alkali granites have broadly similar patterns to those of ANS alkali-feldspar granites. Both are enriched in K, Rb, Th, Ta, and Nb, and have negative Ba and Zr anomalies (Figure 7c). This indicates that crustal materials contributed significantly to the composition of these granites. Concerning monzogranites, as shown in Figure 7d, two groups of elements are observed in these granites and their comparison with ANS monzogranites. The first group of elements consists of large ion lithophile elements (LILE), including K, Rb, Ba, and Th, which are observed to be enriched relative to the ORG values of [4], and display higher concentrations compared to the corresponding monzogranites of the ANS. The second group of elements includes Zr, Sm, Y, and Yb, which are observed to be less than one in most cases. The observed trace element patterns in the studied monzogranites align with those typically found in ANS monzogranites associated with island/continental arc settings. Figure 6: Magma type diagrams of the Jabal Al Bayda granites; (**a**) A/CNK vs. A/NK diagram [31], (**b**) AR vs. SiO\({}_{2}\) diagram [34], AR (Alkalinity Ratio) = [Al\({}_{2}\)O\({}_{3}\) + CaO + (Na\({}_{2}\)O + K\({}_{2}\)O)]/[Al\({}_{2}\)O\({}_{3}\) + CaO(Na\({}_{2}\)O + K\({}_{2}\)O)]. (**c**) K\({}_{2}\)O vs. SiO\({}_{2}\) diagram [35], and (**d**) FeO/(FeO\({}_{1}\) + MgO) vs. SiO\({}_{2}\) diagram of [36]. **Alkaline granites from Saudi Arabia:**\(\triangle\)\(\triangle\)\(\triangle\)\(\triangle\) Monzogranite from Abanat area [37]. \(\lozenge\): Monzogranite from Jabal Khur Dukhan Complex [38]. \(\lozenge\): Alkali feldspar granite from Jabal az Zünd area [38].