The Wadi El-Sheikh area is situated in south Sinai, and is distinguished by a high abundance of calc-alkaline
and alkaline/peralkaline granitoid rocks, as well as related volcanics. These granitoid rocks are of particular
geodynamic significance because they contribute to better understanding of how the continental crust of the Arabian
Nubian Shield (ANS) formed. Thus, the present study introduces new comprehensive geological field studies,
petrological data, and whole rock geochemical data of syn-tectonic granitoids along Wadi El-Sheikh. The
composition of the syn-tectonic granitoids (SNG) ranges from quartz-diorite, tonalite, to granodiorite.
Geochemically, these SNGs are mainly metaluminous, calc-alkaline, I-type, and correspond to syn-collision
volcanic arc granitoids. The investigated syn-tectonic granitoids have high (Al2O3/TiO2) ratios (17.85–80.70), rising
toward the higher silica granitoid type (granodiorite), while they also show high (CaO/Na2O) ratios (0.33–1.44)
representing a decrease from quartz-diorite to granodiorite. These characters indicate that the emplacements of SNG
were greatly influenced by the magma mixing of mafic and felsic melts. The analyzed granitoids originated at
temperatures ranging from 650°C to 700°C and water pressures ranging from 0.5 to 10 kbar. According to the depth
of magma segregation, and they were produced at depths of more than 30 km of the lower crust. The considered
SNG are commonly concerned with enrichment of LILE and LREE and depletion of HFSE in comparison to NMORB values (negative Ta and Nb anomalies).
Key words: Wadi El-Sheikh, Syn-tectonic gran |
