Architecture and evolution of a tectonically-induced Middle Eocene clastic wedge on the southern Tethyan carbonate shelf, North Eastern Desert, Egypt

The North Eastern Desert Basin is a series of interconnected basins located within the internal zone of the Syrian arc inversion belts. Throughout the Middle Eocene the basin was subject to pulses of transpression tectonics which led to development of a Middle Eocene clastic wedge. It is well exposed in the Shabraweet area, North Eastern Desert (Egypt). Detailed sedimentological study including facies analysis, and identification paleo-drainage directions were carried out in order to evaluate the development stages and architecture of the Middle Eocene clastic wedge and response to basin inversion. This was achieved through detailed description and measurement of eight surface profiles in the Shabraweet area. Twelve facies have been identified and can be arranged into nine facies associations. The overall architecture can be differentiated into 5 discontinuity-based sequences, described from oldest to youngest. Sequence 1 shows variation from a stream-dominated delta in the north to lagoonal deposits through the delta fringes. Sequence 2 shows downstream variation from alluvial channels, to alluvial fringes, and to distal floodbasin. Sequence 3 shows downstream variation from amalgamated fluvial channels to alluvial plain deposits. Sequence 4 shows downstream variation from deltaic to lagoon margin deposits. Sequence 5 shows variation from estuarine to offshore lagoonal environments. Tectonic inversion is interpreted as the primary control of the development of Middle Eocene clastic wedge. The sequences 1–3 reflect a progressive inversion with complete emergence and establishment of an alluvial plain, while the upper sequences 4 and 5 reflect a tectonic quiescence and gradual return to marine conditions.