GEOLOGY AND STRUCTURAL ARCHITECTURE OF SOUTHWEST GULF OF SUEZ, WITH SPECIAL EMPHASIS ON THE PRECAMBRIAN ROCKS OF GEBEL EL ZEIT, EGYPT

Abstract

The present work deals with the geologic setting and analyses of the inherited and rifting events at the southwestern margin of the Suez rift. Generally, the study area belongs to the southern SW-dipping province of the Gulf of Suez. Special attention is given to the Precambrian rocks of the Gebel El Zeit in correlation with the Geisum oil Field. Both provide the surface and subsurface examples to study the nature of the basement reservoir. The latter is a new target for the oil exploration in the southern Gulf of Suez. The summary and main conclusions achieved as a result of the present study are discussed hereunder 9.1. Geology of the Precambrian rocks of The Gebel El Zeit

The Gebel El Zeit is a rotated fault block dipping to southwest. This block consists of two distinct basement cored blocks separated by a 4 km wide topographic saddle (Sarg El Zeit). They are named the North Zeit and South or Little Zeit. The North Zeit consists of two prominent ridges separated by Wadi Kabrite. These ridges are a basement ridge on the northeast and a West Zeit underlain by Pre-Miocene and Miocene successions on the southwest. The South (Little) Zeit block lies to the southeast of the North Zeit and offsets laterally across the NNE faults of the saddle. The South Zeit shows deeper erosion where the Miocene sediments are directly overlying the basement. The basement rocks of the Gebel El Zeit represents a part of the northern segment of the Late Proterozoic shield of the Egyptian Eastern Desert. These rocks were studied as a Field analogue for the subsurface basement reservoir. The term "basement reservoir" in this work refers to the oil-bearing Late Precambrian igneous and metamorphic rocks belonging to the Arabo-Nubian shield which are unconformably overlain by the pre-rift and/or Miocene sedimentary successions. Detailed field studies and petrographic investigations of the basement rocks of the Gebel El Zeit revealed the existence of four phases of granitoids with different modal mineralogical composition and petrographical characters as well as a group of stratified volcanics and their pyroclastics of Dokhan type. These granitoids phases include older granites (quartz-diorite and granodiorite), Younger granites (monzogranite), Younger granites (biotite granite, perthitic lecugranite and graphic granite) and peralkaline Younger granites (Arfvedsonite granite). The Dokhan volcanics sequence is represented