ABSTRACT
Microfossil and nannofossil-bearing marine sediments deposited in response to the Neogene opening of the Red Sea provide chronological evidence to calibrate synchronous palaeoenvironmental events from the Gulf of Suez to the Gulf of Aden. Biostratigraphic index forms include planktonic and benthonic foraminifera, and calcareous nannofossils, palynomorphs and diatoms. Following emergence, fluviatile sedimentation and sporadic volcanicity, marine transgression created brackish to miogypsinid-bearing shallow marine lagoons during the Early Miocene (Foraminiferal Letter Stage Upper Te). During the Early Miocene (Planktonic foraminiferal zones N5-N8; Nannofossil zones NN2-NN4), rapid subsidence caused deposition of deep marine mudstones, of local hydrocarbon source-rock quality, and of thinly interbedded siliciclastic and calciclastic debris flows, and of good reservoir quality. The Gulf of Suez and Red Sea experienced episodic isolation from the Indian Ocean during the latest Early Miocene and earliest Middle Miocene (Planktonic foraminiferal zones N8-N9; Nannofossil zones NN4-NN5; Foraminiferal Letter Stage Middle-Upper Tf1) that caused precipitation of submarine gypsum and halite. Synchronous Gulf of Aden successions are not evaporitic. Middle Miocene submarine hypersaline conditions were followed by latest Middle Miocene to Late Miocene hinterland rejuvenation associated with the Aqaba Fault and caused deposition of terrestrial and fluviatile siliciclastics followed by Pliocene normal salinity deep marine conditions.
