The general tectonic frame work of the metamorphic rock assemblage in the Wadi Khuda are, SE Desert of Egypt, is a major doubly plunging running in the NE-SW direction. This assemblage comprises paragneisses , flecked gneisses, migmatites and intercalated with amphibolite lenses.
Field data combined with petrographic description indicate that the degree of metamorphism increases toward the core of the anticline in which the hornblende gneisses grade into banded hornblende gneisses, flecked gneisses and finally migmatites. Moreover, the coexisting of plagioclase (An28-40), hornblende and epidote indicates that these rocks were developed at PT of the amphibolite facies. The flecked gneiss is distinguished into two types according to the predominate mafic minerals in the flecked cores: the first with magnetite flecks and the second with hornblende flecks. Migmatites are characterized by stromatic and ptygmatic structures.
The geochemical investigations shows that: 1) The gneisses were derived mostly from impure marls and feldspathic sandstones, while amphibolites are of basaltic parentage, 2) The fleck gneiss zones are relatively lower in CaO, MgO and fe2O3 than the non-flecked zones and the sum of products indicates that the flecked gneisses were formed by metamorphic differentiation, 3) The migmatites were formed via partial melting ( in Situ anatexis) and metamorphic differentiation, and 4) The foliated diorite has suffered limited fractional crystallization and displays calc-alkaline characters; they are metaluminous and fall within the VAG field and probably belongs to the Pan-African events.
Five phases of deformation have been recognized. The shear criteria of each phase are described and the paleostress tensors are calculated.