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Among many ring complexes in the Egyptian Basement Complex, Wadi Dib is a unique example of Cambrian age in the Northern Eastern Desert. Two distinct rock groups are recognized namely: 1) Peraluminous, oversaturated trachyte-quartz syenite-granite and 2) Metaluminous, undersaturated alkali basalt-nepheline syenite. The mineral stabilities in the light of experimental work estimated temperature and oxygen fugacities indicate that the syenite variants in the Wadi Dib complex are crystallized at relatively high f(O2) above the QMF buffer over a wide range of temperature (1000-450 degrees C).

The geochemical attributes indicate that two magmas of trachytic and basaltic composition existing at different depths are required to explain the two rock groups. The differentiation of the ma mas were followed by complex subsolidus reactions of residual F/Na-rich fluids with the magmatic rocks causing the formation of complex intergrowths of aegirine, arfvedsonite, riebeckite, fluorite, calcite and albite.

The rocks of the Wadi Dib complex have field relationships and chemical signatures such as high total alkalis and HFS elements (Nb, Zr, Y, La, Ce) indicative to a within-plate source region related to lithospheric stretching, The latter onset after the subduction magmatism ceased as a terminal phase of the Pan-African orogeny.