Neoproterozoic formation and evolution of Eastern Desert continental crust - The importance of the infrastructure-superstructure transition

Schematic diagram illustrating crustal structure and processes beneath the Central Eastern Desert of Egypt ∼600 Ma. Partial melting of upper mantle produces large volumes of mafic, volatile-rich, mafic magma. Volatile-rich magma is underplated to the base of the crust and is emplaced higher up in the infrastructure where small batches reach near the surface (Atud Gabbro). These magmas heat infrastructure amphibolites and gneisses to generate granitic melts. Mafic magmas release volatiles as they rise into the crust and crystallize. Hydrous fluids also circulate downward from the surface. Deformation is concentrated along the Eastern Desert Detachment (EDD) where fluids from depth and surface mix and alter sheared rocks, especially serpentinized harzburgites, carbonating them into talc-carbonate (listvenite).323