Rift Basin Development Across Inherited Defict Zones of Wrenching and Impact on Hydrocarbon System, Great Bitter Lake, Egypt

By

Sherif H. El-Bishlawy¹, Nada Krklec¹, Walid Anis¹, Adel Sehim²

(1) INA NAFTAPLIN - Egypt Branch, Cairo, Egypt (2) Cairo University, Cairo, Egypt

 Numerous published works on the Gulf of Suez basin insinuate rifting cessation at the northern Gulf tip. Present work proves the continuation of rifting further NW by integrating outcrops, seismic data and well penetrations.

The study area acquires SW-dip polarity of fault blocks as prevailing in the northern dip-province of the Gulf. The fault blocks extend in the NW-Clysmic direction with SW-trending divergent sedimentary wedging of Miocene syn-rift sediments. The western segments of the master coastal fault system show 5 km offset across an ENE-trending transfer zone. The latter is represented by mixed-dip regime and shallow basinal subsidence. The deposition of Miocene sediments above the tilted footwall of the coastal fault indicates a leaky rift shoulder at this part.

Further NW, the extensional Clysmic faults cessate across an inherited wrench belt of 11-15 km in width. This structural belt is represented by ENE-trending transpressive flower culminations that were developed during Upper Cretaceous tectonics forming ridges in the later Upper Senonian-Eocene basins. This orthogonal belt represents a rift deficit zone. Northwest of this zone, the rift dilutes and shows offset for mild faults. Further NW, the rift is additionally diluted by crossing another inherited wrench deficit zone. This progressive attenuation of rifting through interference with deficit zones marks the abortion of Gulf of Suez rifting.

The exposure of deficit zones before rifting resulted in restricted deposition of Upper Senonian-Eocene source rocks, and the diluted rift segments show shallow subsidence and thin syn-rift sequences.