## 6 Discussion
### The Petrogenesis of the Jabal Sayid and Dayheen Granitoids
#### 6.2.2 Collision-Related Granitoids  
In the discrimination diagram by [35] (Figure 12b), the Dayheen monzogranites plot as unfractionated S-, I-, and M-type granite. Furthermore, in the Zr vs. SiO\({}_{2}\) discrimination diagram of [37], the high-K calc-alkaline Dayheen monzogranites fall within the I-type field (Figure 12c). This observation aligns with the idea that the monzogranites have an intrusion-related origin, as I-type granites, and are typically related to magmatic arcs and subduction zones. However, the presence of a sedimentary component in the magma  
Figure 12: (**a**) Rb/Zr vs. SiO\({}_{2}\) (after [36]). (**b**) Zr + Nb + Ce + Y (ppm) vs. (Na\({}_{2}\)O + K\({}_{2}\)O)/CaO (after [35]). (**c**) The Zr vs. SiO\({}_{2}\) discrimination diagram for I- and A-type granitoid rocks [37]. (**d**) The ternary diagram of Al\({}_{2}\)O\({}_{3}\)/(Fe\({}_{2}\)O\({}_{3}\) + MgO)-3 CaO-5(K\({}_{2}\)O/Na\({}_{2}\)O) (after [38]). The different fields represent the compositions of melts derived from a range of potential sources (tonalites, metasediments, and low- and high-K mafic rocks), determined by major element compositions of partial melts in experimental studies. (**e**) The Sr–Rb–Ba ternary plot for the studied granites (modified after [39]). (**f**) Molar CaO/(MgO + FeO\({}_{\text{total}}\)) vs. Al\({}_{2}\)O\({}_{3}\)/(MgO + FeO\({}_{\text{total}}\)) (after [40]). Symbols as in Figure 6.  
sources of the monzogranites is indicated in Figure 12f, where the samples fall within the overlapping partial melts of metatonalites and metagraywackes. This sedimentary component could have been derived from the descending slab during subduction and collision processes. Additionally, Figure 12d proposes that the monzogranite samples plot in the field of the melting of high-K mafic rocks to tonalitic rocks. This further supports the interpretation that the Dayheen monzogranites have a complex origin involving the melting of mafic rocks, potentially related to subduction processes. It is worth noting that the lower (Na\({}_{2}\)O + K\({}_{2}\)O)/CaO values observed in the Dayheen monzogranites indicate a relatively lower alkali content compared to the calcium content. This can be indicative of a more calc-alkaline nature, which is commonly related to S-type granites that form during collision events. The presence of S-type characteristics in the monzogranites could be related to specific geological conditions and processes occurring during their formation.  
The composition of the Dayheen monzogranites suggests a mixing or hybridization process involving different source materials or a combination of magmas derived from different sources. After a collision event and crustal thickening, melting occurs in the mantle wedge due to the fractionation of an amphibole-dominated phase [41]. These melts then intrude on the base of the already hot and thickened crust, which promotes the further melting of the thickened lower crust [42]. As the magmas ascend towards the surface, they interact with the overlying continental crust, which is composed of older and more felsic rocks. This interaction leads to the assimilation of continental crustal material into the ascending magmas. The findings of [43] provide an alternative explanation for the formation of I-type granitoids, highlighting the importance of sedimentary materials in the process, i.e., how the interaction between mantle-derived magmas and sedimentary materials can lead to the formation of I-type granitoids. This suggests that the composition of the monzogranites may be influenced by the addition of sedimentary components during their formation. Collision-related magmas, such as the Dayheen monzogranites, are often characterized by their intermediate-to-felsic compositions. This composition reflects the complex processes of crustal thickening, mantle melting, and interaction with the continental crust, resulting in the generation of hybridized magmas with intermediate compositions.