Structural Framework and Tectonic Evolution of the Northern Part of the Red Sea Basin (Egypt)

Abstract

ABSTRACT The Red Sea rift basin is considered one of the world-class examples of continental rifting and break-up. A study of the structural framework and rift domains identification was carried out in the northwestern part of the Egyptian Red Sea rift basin using surface and subsurface data. 2D seismic data, boreholes data, and published surface geology information have enabled the subdivision and characterization of the northwestern part of the basin and highlighting the tectonic rift domains. 1) The northern part of the area of study shows the continuation of the structural style observed in the southern Gulf of Suez rift. Mapped structures are mainly down to the northeast faults with southwest dipping strata. 2) The sinistral strike-slip faults related to the Gulf of Aqaba opening, have been observed in the area through several negative flower structures that commonly steeply incline at depth in the basement rocks and branch upwards to wider diffuse deformation in the overlying sedimentary cover. Left-stepping strike-slip fault zones are observed throughout the area and extend from the Gulf of Aqaba in the northeast to the southwestern part of the study area. 3)The dip of the main rift-parallel faults changes south of the Duwi accommodation zone to be mainly southwest with northeast dipping fault blocks. Based on the structural style, continental crustal stretching factor (β) and the crustal thickness; the northwestern margin of the Red Sea can be divided into proximal and necking domains as well as a potential hyperextended domain that seems to exist only to the southeast of the area of study and may represent the future locus of oceanic crust development in the northern Red Sea. Each domain is characterized by different structures, subsidence profiles and preservation and distribution of the pre-rift and syn-rift stratigraphic units. The study also highlights the hydrocarbon potential of the western margin of Egyptian Red Sea basin. Two potential play fairways and trapping styles have been described along the northern Egyptian Red Sea margin. These are mainly syn-rift Miocene Clastics and probable pre-rift fairways, similar to the Gulf of Suez petroleum system elements. However, these fairways have source and reservoir rocks distribution and quality uncertainties. The presence of thick and mobile evaporites sequence in the syn-rift section, provides the ultimate top seal for the identified fairways. This evaporites sequence impacts the quality of the seismic data whereas the seismic reflectors are hampered by multiples. Applying recent acquisition and cutting-edge seismic processing technologies can definitely help in enhancing the quality of the seismic image in the northwestern Red Sea basin.