Pre-Neogene Tectonics and Basin Inversion,Northern Gulf of Suez - Egypt

By

 Darwish Khaled¹, Mohamed Darwish², Adel Sehim²

(1) GUPCO, Cairo, Egypt (2) Cairo University, Cairo, Egypt

 The northern structural province of the Gulf of Suez acquires its own Neogene rift architecture and sedimentation as impacted by rift superposition on inherited ENE-cross structural belts. The excellent outcrops on both sides of the Gulf and extensive database of seismic and wells gave good opportunity in studying this part of rift.

The inherited belts represent Early Mesozoic rift segments with bounding ENE- trending extensional faults. Bimodal volcanics predominate in the southern rift blocks while sedimentation of Triassic-Jurassic rocks prevails north-ward with accelerated tectonic subsidence of the rift blocks. The fault-bounding basinal segments were tectonically inverted in Late Cretaceous, forming four transpressive belts of faults and culminations. The inversion promoted extensive uplifting of the area occupied by the younger Gulf of Suez rift, while the rift shoulders of the latter host mild culminations. This was associated with sub-aerial erosion of the structural niches and restricted deposition of the Upper Senonian and Eocene rocks. The areas of down plunge direction of the wrench-related anticlines and termination of the wrench-belts concide with thick sedimentation of stacked Senonian - Eocene carbonates source and reservoirs. Oil discoveries in the Pre-Neogene sediments are restricted to these areas.

The inherited structural belts played as deficit zones during the development of the orthogonal Neogene rift and resulted in rift segmenation and diversity in thickness and facies of the syn-rifting sediments.