The Precambrian basement rocks exposed along Qift- Quseir asphaltic road, central Eastern Desert (CED) of Egypt, exhibits two contrasted tectonic units each of which has its own lithology structural style and grade of metamorphism. The older (lower infrastructural rocks) unit exposed in the Meatiq swell is composed of mylonites, cataclased gneisses, amphibolites and gneissose granite and is intruded by syn-to late-kinematic granites. The younger suprastructural or upper unit is represented by thrust sheets of ophiolitic melange folded about NW-SE axes. The melange is intruded by metadolerites and diorites masses.
The ophiolitic melange is separated from the underlying infrastructural rocks by a major thrust fault partly obliterated by later normal and sinistral lateral strike-slip faults. The ophiolitic melange comprises members of two associations, namely. 1) a dismembered ophiolitic sequence formed of serpentinites, metagabbros and metabasalts, and 2) island arc calc-alkaline metavolcanics formed of meta-andesites and their metapyroclastics, and subordinate metadacites and metabasalts. The trace elements Ti, Zr, Cr, Y and Ni indicate that the metavolcanics are calc-alkaline and were formed in an island arc.
The ophiolitic rocks suggest island arc tholeiite (IAT), i.e. are parts from the supra-subduction zone ophiolites. Moreover, the original ultramafic protoliths of the sepentinites is separated from the overlying comagmatic mafic pile forming metagabbros and metabasalts by a conspicuous compositional gap; suggesting non-consanguineous relationship.