Inverted Barrovian Metamorphic Zones in the Poly-Deformed Domains of the Western Wadi Allaqi Shear Zone (South Eastern Desert, Egypt): Geochemical and Structural Constraints

Poly-deformed late-Proterozoic metamorphic domains covering Um Ashira area at the western segment of Wadi Allaqi shear zone, South Eastern Desert of Egypt, show evidences of inverted Barrovian metamorphism. They exhibit four metamorphic zonal patterns, arranging progressively from chlorite, biotite, garnet, to sillimanite zones. The higher grade metamorphic domains appear at higher structural levels with general dipping toward the North East. Four deformational phases (D-1-D-4), associating with major planar structures (S-1-S-4), and four mesoscopic and microscopic folds are recognized. The pervasive fabric, growth of metamorphic minerals and peak metamorphism were linked to D-2 deformation phase. Structural, petrographic, microchemical, and thermobarometric data along South-North profile show possibility of inverted Barrovian metamorphic pattern with an increase in the metamorphic grade toward the North. The established structural sequence and tectonic modeling suggest that the apparent inversion coexists due to the main F-2 folding phase.

Automated summary

The poly-deformed late-Proterozoic metamorphic domains in the Um Ashira area of the South Eastern Desert of Egypt exhibit evidence of inverted Barrovian metamorphism, with four metamorphic zones progressing from chlorite to sillimanite. The structures suggest an increase in metamorphic grade towards the North, with the main inversion coexisting due to the F-2 folding phase.