Intra basement structural-tectonic inferences in view of potential field data: A case study from Ras Gara, Gulf of Suez, Egypt

Elkhadragy, Ali; Saad, Mohamed Hussian; Azab, Ahmed Abd Elhay; Ali, Ahmed Alaa El-Din

doi:10.21608/bfszu.2020.37232.1033

Intra basement structural-tectonic inferences in view of potential field data: A case study from Ras Gara, Gulf of Suez, Egypt

Articles in Press

Document Type : Original Article

Authors

¹ Professor of Geophysics, Geology department, Zagazig university.

² Professor at Egyptian Petroleum Research institute, Exploration Department

³ Assistant Professor at Egyptian Petroleum Research Institute, Exploration Department.

⁴ Demonstrator at Egyptian Petroleum Research institute, Exploration Department

10.21608/bfszu.2020.37232.1033

Abstract

The integrated approach aims to yield a better image of basement source structures and viewing the relationship with the overlying sedimentary cover. The study is based on potential field data interpretation guided by wells information and previous works. The gravity and magnetic maps were transformed by suitable processing techniques that enhance locations, trends, depths, extents and types of causative bodies. The outputs were discussed in context of the regional geology and tectonics of the gulf. The results reveal that the Ras Gara, as seen at basement level, is a northwesterly striking southwesterly dipping fault-block, complicated by an anticlinal uplift at the center. This tilted basement-block has entirely deformed by a set of NW-SE faults that control the thickness and distribution of the overlying sedimentary cover. The NW-trending structures were cut and offset by NE-trending (cross-gulf) faults of small throw and large horizontal displacement. Most of basement faults were refreshed with time into the Pre-Miocene section and disappeared into or beneath the Upper-Miocene. The deformation style suggests the area to be subjected to two forces of tectonism; a compressive stress in NNW-SSE direction, and the ENE-WSW extension force, resulted in the primary and secondary shear fractures. The basement rocks are nearly homogenous in composition, acidic in nature, and of normal density, with no evidences support the presence of any magmatic flow into the fractures. It could be concluded that the Precambrian basement seems to be simple in lithology and complex in structure.

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