Depositional framework and sequence stratigraphy of the Cenomanian–Turonian rocks on the western side of the Gulf of Suez, Egypt

Abstract

Three stratigraphic sections (Wadi El Dakhl, Abu Darag and Gabal Ataqa) of mixed siliciclastic/carbonate rocks mark the Cenomanian–Turonian sequence exposed on the western side of the Gulf of Suez. This sequence is differentiated into two rock-units: the Galala Formation of Cenomanian age, and the Turonian Wata/Maghara El Hadida Formation. They comprise various sedimentary facies belts that reflect minor fluctuations of sea-level from mudflat to deep subtidal setting. Four facies belts are recognized in this succession. They are peritidal clastic (mudflat, mixed flat and sandflat facies), peritidal carbonate, shallow subtidal (high energy shallow subtidal; low energy, shallow subtidal; and storm-influenced, shallow subtidal, open marine facies) and deep subtidal. Five sequence boundaries marking relative sea-level falls divide the Cenomanian–Turonian succession into four depositional sequences. These boundaries are: Lower Cretaceous/Cenomanian (SB1), Middle Cenomanian (SB2), Middle Turonian (SB3), Late Turonian (SB4) and Turonian/Coniacian (SB5). These delineate four well-defined third-order depositional sequences. They enclose shallowing-upward (prograding) parasequences and record the fourth order relative sea-level fluctuations. Each depositional sequence shows lowstand (LST), transgressive (TST) and highstand (HST) systems tracts and packages of facies. These sequences are compared with those of neighbouring areas to differentiate local, regional and global factors that controlled sedimentation within the study area.