Mineralogy and Geochemistry of the Upper Cretaceous Mudrocks, Wadi Feiran Region, West-Central Sinai, Egypt

The present paper aims to explore the mineralogy and geochemistry of the mud rocks that have been accumulated during the Late Cretaceous in Wadi Feiran, West-Central Sinai, Egypt. The investigated section comprises three distinct lithostratigraphic units, namely the Raha, Wata, and Matulla Formations. Mineralogical examination proposes the existence of several sorts of clay minerals (e.g., kaolinite, illite, muscovite, and montmorillonite). The recognition of these clay minerals proves deposition in alkaline environmental conditions. Besides, our findings suggest that the reported clay minerals probably originated first in the form of chlorite instead of illite, as illite is likely produced from the weathering of chlorite. The overflow dispersion of both main (Al2O3, SiO2, Fe2O3, CaO, MgO, K2O, Na2O, P2O5, Cl, and SO3) and minor (Ti, Mn, Cu, Ni, and Sr) constituents was assessed through applying chemical and physicochemical factors on the studied mudrocks. Our study concludes that reducing alkaline conditions were the limiting environmental factor in the deposition of these Upper Cretaceous rocks