Planktonic foraminifera and chronostratigraphy of the Oligo-Miocene in some wells in the isthmus of Suez and the North-Eastern reach of the Nile Delta, Egypt

The lithofacies and planktic foraminiferal content of the Oligo-Miocene interval penetrated by four wells (El-Temsah-2, Boughaz-1, Mallaha-1X and San El-Hagar-1) drilled in the Isthmus of Suez and in the eastern reach of the Nile Delta enable to clarify the chronostratigraphy and sedimentological and tectonic history of the studied sequence.

The Oligocene is represented by the Qantara Formation which is conformably overlain by the Aquitanian-Burdigalian (early Miocene) Rudeis Formation. The early Miocene is separated from the middle Miocene (Langhian-early Serravallian Kareem Formation) by a hiatus, probably reflecting the mid-Clysmic tectonic event that affected the Gulf of Suez region.

A stratigraphic gap between the early and late Serravallian Kareem and Serravallian to Tortonian Sidi Salim Formations may have been caused by the uplift of the isthmus of Suez which induced the beginning of evaporite sedimentation in restricted basins in the southern part of the Gulf of Suez. The Messinian is either represented by a regressive sequence of coarse siliciclastics known as the Qawasim Formation or by evaporites.