## 5 Results
### Whole-Rock Geochemistry  
The whole-rock (major, trace, and REEs) compositions of serpentinites and serpentinized peridotites are given in Table 2. Loss on ignition (LOI) varies from 5.27 to 11.5 wt.% for serpentinites, and from 4.16 to 10.7 wt.% for serpentinized peridotites, indicating a various and extensive degree of hydration and serpentinization. Therefore, bulk major oxides were recalculated to 100 wt.% based on an anhydrous to compensate for the variable serpentinization effect [18,44]. The average contents of major oxides in serpentinites and serpentinized peridotites reveal that the TiO\({}_{2}\), Al\({}_{2}\)O\({}_{3}\), MnO, Na\({}_{2}\)O, K\({}_{2}\)O, and P\({}_{2}\)O\({}_{5}\) contents are less than 1 wt.%. In addition, the low CaO (av. 1.48 and 1.09 wt.%, respectively)  
Figure 7: (a) Nomenclature diagram of chlorite from [35]; (b) TSi (apfu) vs. Mg# discrimination diagram [40]; and (e) FeO-TiO\({}_{2}\)-Fe\({}_{2}\)O\({}_{3}\) discrimination diagram of magnetite and ilmenite. and Al\({}_{2}\)O\({}_{3}\) (av. 0.76 and 0.59 wt.%, respectively) contents of the examined serpentinites and serpentinized peridotites are similar to forearc periodtites and Pan-African serpentinites [18; 45]--especially those in the Egyptian Eastern Desert [8; 19; 22]--suggesting their refractory origin [19] (Figure 8a,b). \begin{table}
\begin{tabular}{l c c c c c c c c c c c c} \hline \hline  & \multicolumn{10}{c}{**Serpentinites**} \\ \cline{2-13}  & **IA1** & **IA2** & **IA3** & **IA4** & **IA5** & **IA6** & **IA7** & **IA8** & **IA9** & **IA10** & **IA11** & **IA12** \\ \hline SiO\({}_{2}\) & 43.10 & 42.02 & 42.18 & 43.57 & 41.63 & 41.14 & 43.45 & 42.66 & 40.64 & 43.06 & 40.93 & 42.09 \\ TiO\({}_{2}\) & 0.01 & 0.01 & 0.02 & 0.02 & 0.01 & 0.01 & 0.01 & 0.01 & 0.01 & 0.01 & 0.03 & 0.01 \\ Al\({}_{2}\)O\({}_{3}\) & 0.65 & 0.31 & 0.48 & 0.56 & 0.31 & 0.77 & 0.31 & 0.28 & 1.82 & 0.58 & 1.16 & 1.36 \\ MgO & 44.72 & 43.44 & 44.10 & 44.30 & 44.86 & 44.73 & 45.36 & 46.39 & 43.65 & 42.94 & 42.77 \\ CaO & 1.06 & 1.77 & 1.78 & 1.35 & 2.04 & 1.85 & 0.45 & 0.39 & 1.72 & 1.64 & 2.05 & 2.14 \\ MnO & 0.10 & 0.12 & 0.09 & 0.08 & 0.14 & 0.13 & 0.10 & 0.16 & 0.1  
The SiO\({}_{2}\)/MgO ratio of the studied rocks ranges from 0.87 to 1.22, similar to the ophiolitic peridotites in [45] (Figure 8c). In terms of the CaO-Al\({}_{2}\)O\({}_{3}\)-MgO ternary diagram, the studied rocks are located in the dunite field, with a few samples in harzburgite (Figure 8d). Lack of alteration of clinopyroxene is associated with dissolution of Ca [27] in the examined rocks; therefore, they have very low CaO contents, below the values of the depleted (DM, 3.5 wt.%) [46] and primitive mantle (PM, 3.7 wt.%) [47]. Furthermore, the Al\({}_{2}\)O\({}_{3}\) contents of the studied rocks are less than that of the PM (Al\({}_{2}\)O\({}_{3}\) ca. 4.5 wt.%) [47]. Likewise, the average MgO content is high relative to PM composition, suggesting that the mantle melting is more than 20%. Conversely, SiO\({}_{2}\) and Fe\({}_{2}\)O\({}_{3}\) concentrations are lower than the values of the PM. \begin{table}
\begin{tabular}{l c c c c c c c c c c c c} \hline \hline  & \multicolumn{10}{c}{**Sperentiunized Peridotites**} \\ \hline  & **AP1** & **AP2** & **AP3** & **AP4** & **AP5** & **AP6** & **AP7** & **AP8** & **AP9** & **AP10** & **AP11** & **AP12** & **AP13** \\ \hline SiO\({}_{2}\) & 45.33 & 45.51 & 46.50 & 44.71 & 47.96 & 44.97 & 44.19 & 43.64  
The incompatible trace elements of the examined mantle rocks are depleted in high-field-strength elements (HFSEs)--such as Zr (0.52-2.75 ppm), Hf (0.0.1-1.89 ppm), Nb (0.37-3.12 ppm), and Ta (0.17-1.36 ppm)--and low-field-strength elements (LFSEs), including Rb (0.19-1.85 ppm), Ba (3-10 ppm), and Sr (2.34-5.91 ppm) (Table 2). Multiple elements of the primitive mantle (PM)-normalized diagram [51] (Figure 9a) show a strong negative Ta anomaly and slight enrichment of LFSEs relative to HFSEs, which are consistent with SSZ geochemical affinity [52].