Tectonic evolution and subsidence history of the Cretaceous basins in southern Egypt: The Komombo Basin

Abstract

The structure and tectonic evolution of the Cretaceous rift basins of southern Egypt are poorly understood. In this study, the tectonostratigraphy of the Komombo Basin has been determined using seismic, well and biostratigraphic data. The tectonostratigraphy of the basin is compared to the Kharit, Nuqra and Beni Suef basins in Egypt as well as Muglad Basin in Sudan. The Komombo Basin is a 58 km long, 28 km wide NW–SE trending half‐graben infilled with 2200 m of Berriasian‐Maastrichtian sediments and overlain by 400 m of Pliocene sediments. Four Berriasian to Maastrichtian syn‐rift and post‐rift sequences and three Pliocene channel systems of Nile sediments have been identified. Moreover, a series of normal faults, negative flower structures, reverse faults and folds are mapped in the basin. Backstripping reveals two rift phases during the Berriasian‐Barremian and Turonian‐Santonian, respectively. Additionally, the tectonic subsidence curves indicate that two major unconformities have occurred during the Aptian‐Albian and Maastrichtian‐Pliocene, which are correlated with a basement uplift during the Albian‐Cenomanian and the Oligocene‐Miocene flank uplift related to the opening of the Red Sea, respectively. The rift episodes are attributed to far‐field stress changes resulting from the initial opening of the South Atlantic and followed by the NW part of the African plate colliding and anticlockwise rotating into Europe. The highest β factors (1.20–1.11) for both rift phases are found at the centre of the basin. The rift phases thinned the crust from 32.5 to 28.2 km and 31.9 km in the depocenter and the western flank of the basin. The Komombo Basin has a similar rift history, stratigraphy and structural style to the Kharit, Nuqra and Mugland basins. All of these basins witnessed two major rift phases in the Early and Late Cretaceous, whereas the Beni Suef Basin encountered strike‐slip tectonic events in the Late Cretaceous.

Recognizing the Wadi Fluvial Structure and Stream Network in the Qena Bend of the Nile River, Egypt, on Landsat 8-9 OLI Images

“…The major geomorphic structure of the Nile Valley follows the faults oriented parallel to the Red Sea along the central current of the Nile and the Gulf of Suez in the north [75,76], with the relics of the pre-late Miocene streams remaining in the fluviatile sand and gravel sediments of the Nile delta in Lower Egypt [77]. The discovery of paleorivers in the Sahara by radar imaging systems revealed the orientation of the paleochannels and their flow directions [78].…”

Geophysical Evidence for Magmatism Southwest of the Brothers Islands, Northern Red Sea (Offshore Quseir, Egypt)

“…These units are formed by shallow‐water carbonate and siliciclastic rocks directly overlying the Precambrian basement and gradually thickening toward the northwest. The Upper Eocene and Lower Oligocene sedimentary records are missing in the Egyptian Red Sea, the southern Gulf of Suez (Moustafa & Khalil, 2020), and the Komombo basin in southern Egypt (Ali, Ali, et al., 2022; Ali et al., 2019).…”