## 5 Geochemistry
### Bulk-Rock Geochemistry  
The granites examined can be classified using the R1-R2 cationic classification of [30], with the monozogranite samples being assigned to the monozogranite field, with the exception of two samples that are assigned to the quartz-monzonite and quartz-serine fields (Figure 4). The majority of the alkali granites from the Jabal Al Bayda are plotted within the alkali-feldspar granite field, with one sample that straddles the boundary between alkali-feldspar granite and monozogranite fields, and another one that falls in the monozogranite field (Figure 4). The granitic samples from the study area exhibit a range of silica (SiO\({}_{2}\)) content, the low-silica monozogranite (65.10-71.58 SiO\({}_{2}\) wt%), and high-silica alkali granite that contains 72.88-79.96 SiO\({}_{2}\) wt%. Based on Figure 5, it is observed that the selected major and trace elements exhibit medium to weak correlations with silica (SiO\({}_{2}\)) variance in the granite samples. However, there is a definite clustering for different granitic types into two distinct fields. Na\({}_{2}\)O, Al\({}_{2}\)O\({}_{3}\), TiO\({}_{2}\), P\({}_{2}\)O\({}_{5}\), CaO, MgO, Fe\({}_{2}\)O\({}_{3}\), Co, V, Ba, Ni, and Sr contents show negative correlations with SiO\({}_{2}\) contents. The values of these elements are remarkably higher in monozgranites compared to alkali granites. Similarly, Ta contents display a negative correlation with silica (SiO\({}_{2}\)), while Nb and Sn contents show a positive correlation with SiO\({}_{2}\). The values of these elements are higher in alkali granites (Figure 5). The differences in magmatic trends observed for K\({}_{2}\)O, Rb, Y, Hf, Th, and U contents among  
\begin{table}
\begin{tabular}{l c c c c c c c c c c c} \hline \hline
**Sample** & **ST-74A** & **ST-75** & **ST-76** & **ST-82** & **ST-85** & **ST-86** & **ST-89** & **ST-90** & **ST-91** & **ST-92** & **ST-94** \\ \hline Er & 1.16 & 1.82 & 0.72 & 1.52 & 0.70 & 0.42 & 2.09 & 4.15 & 4.16 & 3.40 & 4.10 \\ Tm & 0.15 & 0.25 & 0.12 & 0.24 & 0.11 & 0.05 & 0.32 & 0.65 & 0.69 & 0.57 & 0.65 \\ Yb & 1.05 & 1.63 & 0.72 & 1.39 & 0.70 & 0.38 & 2.21 & 4.69 & 4.54 & 3.69 & 4.27 \\ Lu & 0.15 & 0.24 & 0.14 & 0.24 & 0.09 & 0.06 & 0.38 & 0.75 & 0.73 & 0.58 & 0.66 \\ Y & 10.77 & 17.65 & 9.37 & 15.05 & 8.97 & 4.39 & 20.94 & 39.98 & 38.68 & 33.80 & 40.48 \\ Hf & 5.38 & 7.38 & 4.69 & 5.28 & 4.39 & 4.79 & 5.28 & 10.17 & 8.87 & 8.67 & 9.07 \\ Nb & 8.97 & 10.37 & 8.18 & 9.07 & 12.26 & 7.28 & 5.98 & 9.27 & 9.77 & 9.47 & 8.57 \\ Ta & 0.60 & 0.80 & 0.70 & 0.70 & 0.80 & 0.40 & 0.50 & 0.80 & 0.90 & 0.60 & 0.80 \\ Th & 7.58 & 6.08 & 8.77 & 9.67 & 11.86 & 7.58 & 6.88 & 12.66 & 10.87 & 11.07 & 9.87 \\ Zn & 42.87 & 39.88 & 26.92 & 30.91 & 36.89 & 37.89 & 22.93 & 55.83 & 27.92 & 42.87 & 27.92 \\ Co & 6.68 & 3.19 & 7.28 & 6.48 & 2.59 & 3.39 & 7.18 & 3.19 & 3.39 & 3.09 & 3.09 \\ Ni & 11.57 & 2.29 & 9.67 & 8.57 & 2.69 & 3.89 & 10.17 & 3.29 & 3.99 & 3.59 & 3.29 \\ Ba & 1154.53 & 1409.76 & 746.75 & 968.09 & 823.52 & 925.22 & 532.40 & 372.88 & 342.97 & 370.88 & 330.01 \\ V & 47.86 & 32.90 & 43.87 & 42.87 & 19.94 & 20.94 & 42.87 & 18.94 & 23.93 & 23.93 & 21.93 \\ Cu & 6.58 & 4.09 & 2.29 & 2.19 & 3.99 & 5.88 & 7.38 & 4.59 & 25.72 & 6.98 & 3.59 \\ Sr & 837.68 & 521.03 & 650.34 & 674.17 & 328.41 & 369.39 & 259.52 & 130.01 & 125.42 & 132.00 & 101.20 \\ Zr & 200.80 & 312.46 & 172.18 & 178.16 & 159.82 & 159.12 & 213.56 & 352.44 & 317.54 & 302.89 & 328.71 \\ Rb & 68.29 & 61.12 & 88.73 & 94.81 & 134.50 & 105.08 & 98.60 & 143.07 & 129.91 & 127.62 & 114.36 \\ As & 0.90 & 1.00 & 1.20 & 0.50 & 0.60 & 1.20 & 1.10 & 7.68 & \textthe different gramitic types in the Jabal Al Bayda area suggest that a simple fractional crystallization model is inadequate to explain the origin of the gramitoids in this region. In the classification based on the ACNK versus ANK diagram [31], the monzogranites from the Jabal Al Bayda are classified as metaluminous to weakly peraluminous (Figure 6a). Conversely, alkali granites straddle the boundary between metaluminous and peralkaline fields.