Early depositional history of a rift basin: Miocene in Western Sinai
Abstract The Cenozoic stratigraphic record in the Gulf of Suez provides a model of six events for the early sedimentologic history of a rifted basin. Classic exposures on the east coast of the Suez in the Western Sinai yield a composite section of the Miocene succession. 1. (1) Oligocene?—Early Miocene (Nukul Formation) terrigenous clastics in fluvial, fandelta and littoral environments filled local valleys. 2. (2) During Early Miocene transgression (Lower Rudies Member), nearshore and shelf sediments accumulated at a rate no less than 4 cm/1000 yrs. Rates of accumulation increased dramatically at the beginning of the Middle Miocene. 3. (3) During the early part of the Middle Miocene basinal muds and evaporites (Upper Rudeis Member, Kareem Formation and part of Belayim Formation) accumulated at a rate of 106–146 cm/1000 yrs. 4. (4) Rates slowed during short-term shoaling periods when shelf carbonates (Hammam Faraun Member) were deposited. 5. (5) A fifth event is represented by more than 2 km of Late Miocene evaporites (Zeit— South Gharib Formations), which accumulated at a minimum rate of 32 cm/1000 yrs. 6. (6) The post-evaporite event of alluvial and shallow—deep marine sedimentation began in the Pliocene and is continuing today. Local carbonate buildups developed upon fault blocks during the second and fourth stages. Evaporite deposition can be a very rapid process in the filling of rifted basins.