Paleodepositional Environment and Paleogeography Model of the Santonian-Coniacian Rocks in the Gulf of Suez and Eastern Desert, Egypt

Ahmed Abd - ElShafy Ibraheem, Abu Bakr Abd-Elmoneim Ahmed, and Mohamed Mahmoud El Sarawy
Gulf of Suez Petroleum Company, Cairo, Egypt

The Santonian / Coniacian sediments in Egypt have different lithofacies . It is mainly clastics and non-clastics intercalation in Gulf of Suez (GOS) and Western Desert , while it is mainly clastics in south Egypt. This variation in lithology is related to the mode of deposition dominated at that time . The Paleotectonic events had major role in this distribution where the Syrian arc in north GOS and Kharga arch in north Red Sea created highs and lows in this wide area. Sea level fluctuation and different sources of sediments were very important factors in recognizing the paleogeographic limits of the Santonian / Coniacian rocks in the area of study. Stratigraphically, Matulla Formation extends along the Gulf of Suez (GOS) covering the Turonian sediments (Wata Formation) in north and central GOS while it overlaps the early Cretaceous rocks in south Gulf of Suez.This Fm is overlained by the Thelmet Fm of the Campanian age. To the south, in Safaga – Quseir area and along the Red Sea coast, the Santonian / Coniacian sediments became mainly sandstone with some shale streaks (Nubia S.S) and unconformably overlies the basement rocks. At the same time this Fm (Nubia Sandstone) is overlained by the Quesir Shale Fm of Campanian age. The ages of the above different units were proved by the palynologic examination. Environmentally , the abrupt changes in the lithofacies of the Matulla Formation along the Gulf of Suez and Red Sea coast are related to the paleodepositional environment and sea level changes (Shallow marine to tidal flat environment and fluvial system in the Red Sea coast). A depositional environment model was constructed to illustrate the relation between these paleoenvironments and the place of the Kharga arch which separated them.