Resolving Stratigraphic Uncertainties in East Ghazalat Area, Sharib-Sheiba High, North Western Desert, Egypt, New Insights into the Paleozoic, Jurassic and Cretaceous Rocks.

Ayed, Abdurrahman; Darwish, Mohamed; N. El Barkooky, Ahmed; Khaled, Ashraf Ahmed

doi:10.21608/egjg.2025.414603.1125

Resolving Stratigraphic Uncertainties in East Ghazalat Area, Sharib-Sheiba High, North Western Desert, Egypt, New Insights into the Paleozoic, Jurassic and Cretaceous Rocks.

Document Type : Original Article

Authors

¹ Egyptian General Petroleum Corporation (E.G.P.C)

² Professor of Petroleum Geology and Sedimentology, Geology Department, Faculty of Science, Cairo University

³ Professor of Applied Sedimentary Geology, Geology Department, Faculty of Science, Cairo University.

⁴ Biostrata Services Company

10.21608/egjg.2025.414603.1125

Abstract

Differentiating between Paleozoic and Jurassic rocks in the North Western Desert of Egypt is challenging and often results in misinterpretation of one as the other. Such discrepancies arise from several factors, including limited knowledge of the Paleozoic geology in Egypt, challenges and uncertainties in biostratigraphic age determination and similarities in facies between some Jurassic and Paleozoic units. This research contributes to resolve key stratigraphic uncertainties in the East Ghazalat area, located in Sharib-Sheiba High in the North Western Desert. It integrates regional geological insights, E-logs correlation with nearby key wells, facies analysis, palynological examination, and seismic interpretation. The study re-evaluates the age of the sedimentary section overlying the basement in the Sahab-1X well (6,440-8,180 ft.), which was previously assigned as a Jurassic age based on biostratigraphic data. The re-assessment suggests that this interval is more consistent with the Paleozoic rather than the Jurassic. Additional palynological analysis identified Middle to Late Cambrian acritarchs (palynological zone WD2) corresponding to the Shifah Formation in the North Western Desert, which led to the reclassification of much of the Jurassic units. Furthermore, the study proposes a revised stratigraphic subdivision for key Cretaceous units (Kharita, Lower Bahariya, Upper Bahariya, and A/R "G"), ensuring better consistency with age assignments from regional studies, aligning with the stratigraphic schemes of adjacent fields, and unifying local nomenclature. It also addresses uncertainties regarding the presence of the Alam El Bueib and Khoman formations due to the impact of major unconformities, extending their geographic distribution in previously unrecognized areas. The findings enhance the understanding of the study area’s geological evolution and tectono-stratigraphic framework, and aids in refining play concepts across the region. This work provides a solid foundation for future exploration, development and research, both within the area or in similar geological setting.

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