Sedimentological evolution of the Red Sea continental margin of Egypt and its relationship to sea-level changes

Abstract

Resting on the African Shield, there is a 230-m sedimentary sequence, interpreted as two successive cycles of sedimentation, ranging in age from middle Miocene to the present. On a formal stratigraphic basis, a generalized sequence comprising 12 vertical units is described. Based upon the lateral and vertical distribution of facies, and their bounding unconformities, a sea-level curve is produced and correlated with relative changes of sea level on a regional and global scale, and phases of Red Sea rifting. The first cycle of sedimentation fits well with the southern African middle Miocene-early Pliocene changes of sea level and implies relatively slow multiphase transgressions succeeded by rapid regression. The late Miocene anomaly of the present curve is attributed to regional tectonic movements of the shelf. The second cycle conforms to the global model and indicates a progressive regression of the sea through late Pliocene to Holocene interrupted by a transgressive pulse during the Pleistocene.