The El Mayah molasse basin in the Eastern Desert of Egypt

The El Mayah basin is one of several Pan-African, sedimentary basins that formed across several hundreds of kilometres of the Eastern Desert of Egypt. Its sedimentary record shows that deposition occurred in two stages: The earlier stage is characterised by the deposition of two units of fluviatile sediments deposited in a half graben structure. Initial deposition of volcaniclastics and later influx of granitic clasts indicates that this part of the basin formed mostly after intrusion of what is known as the “older” granite generation in the Eastern Desert around 650-610 Ma. The later stage in the basin evolution is characterised by basin inversion, tilting of the older units and subsequent sedimentation of fluviatile sediments into a shallow synformal pull apart structure that formed after intrusion of the “younger” granite generation. This pull apart structure is interpreted to have formed in response to a brittle reactivation of one of the largest shear zones in the Eastern Desert causing a linking of the Um-Nar Nogrus shear zone to the Sholul dome shear zone.