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Egypt and the adjacent regions formed a segment of the passive margins of, successively, the Palaeo-Tethys, Neo-Tethys and Mediterranean Sea. Consequently, the Phanerozoic palaeogeography was dominated by the development of deep marine slopes and carbonate and mixed-marine platforms in the present-day north, giving way to elastic facies in the south. The relative positions of facies belts were influenced by eustatic sea-level changes, North African continental rifting/sagging and compressive tectonic events. During the Palaeozoic, rifting events were relatively minor, except within N-S trending basins of the Western Desert and southern Jordan. Gentle arching occurred at the end-Silurian, end-Devonian and end-Serpukhovian. Opening of the Neo-Tethys in the Permian marked the onset of a new geodynamic episode, with several phases of rifting and tectonism. Block faulting was pronounced along the Mediterranean margin up to Jurassic times. Early Cretaceous rifting occurred in the E-W trending arm of the Sirt Basin, and in the northern Western Desert. During the Santonian, dextral transpression caused the onset of Syrian are folding. By the Campanian-Maastrichtian, extension again predominated, with subsidence focused on the Sirt and Abu Gharadig basins. A compressional pulse marked the Cretaccous-Palacocene transition, followed by renewed rifting. At approximately the Bartonian-Priabonian boundary, a major compressional event affected the Syrian Arc s.l. and various fault zones. During the late Oligocene, the Gulf of Suez-Red Sea rift formed. From the middle Miocene onwards, the opening of the Red Sea resulted in shearing along the Dead Sea fault zone, continuing to Recent times. The dramatic sea-level fall of the Tortonian-Messinian initiated the development of the Nile Valley.