ORCID Profile
0000-0002-9855-4137
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Publisher: Copernicus GmbH
Date: 15-05-2023
DOI: 10.5194/EGUSPHERE-EGU23-7821
Abstract: Nile River, the longest river in the world ( ,500 km), has been studied since long time ago tracing back to the fifth century yet the timing of origin of its present-day drainage is still disputed. There are two end-members of notions of the birth of the Nile, the first one believes that the present-day Nile has been connected to the Ethiopian Plateau since ~30 Ma, while the other supports the idea of young Nile around ~6 Ma. The Nile crosses today two former endorheic systems (Sudanese and Albertine & #8220 Basins& #8221 ) and one exorheic system (Tethys Margin) before finally depositing sediments in the Mediterranean Sea. Our objective here focuses on deciphering the source-to-sink scenario of the Nile through relief growth, tectonic, and climate since the uppermost Cretaceous.The timing of the uplifts and deformation wavelengths are constrained by characterizing and mapping several generations of stepped pediments on DEM and satellite images which then dated using their geometrical relationships with dated magmatic rocks. Additionally, stratigraphic records of the sedimentary basins were studied to complement the dating of the pediments. The authenticity of the approaches is to integrate those data enclosing all the source-to-sink (S2S) systems to construct a coherent scenario of the Nile paleorouting systems especially on the dynamics of its sediment sources.We proposed the following model for the S2S of the Nile where its catchment grew larger southwards through time. First, a significant deformation occurred around the Cretaceous-Paleogene boundary (66 Ma) with the uplift of western limit of the Nile catchment, the Darfur-Ennedi-Tibesti domains, followed by the formation of a main large pediment. Second, this pediment was then flooded during late Paleocene (58-57 Ma) until a subtle high bounding northward the endorheic Sudanese & #8220 Basin& #8221 . Consequently, carbonate platforms were widely deposited from Paleocene until middle Eocene in the Egypt extending southwards to the former Hudi Lakes in northeast Sudan and there was no siliciclastic supply for the Nile during that time. Third, the first evidence of a fluvial system (& #8220 Pre-Eonile& #8221 according to Said, 1981) was discovered during late Eocene (~37 Ma) by large channel incisions on top of the carbonate platforms. Contemporaneously, the Uweinat Dome was uplifted and likely acted as the main siliciclastic source during late Eocene to Oligocene. Fourth, the initiation of Red Sea rifts during the Oligocene followed by a major uplift at the scale of north-east Africa (~10 Ma) provoked another plausible siliciclastic source, the Red Sea Hill& #8217 s flanks, in addition to the Uweinat Dome. Fifth, during the capture of the Sudanese endorheic system in the Early Pliocene (~4 Ma), the Nile catchment grew significantly larger and the sources were actively provided by the Darfur and Ethiopian Plateau. Finally, during middle-late Pleistocene ( 1 Ma) the Nile completed its present-day catchment by capturing the Albertine endorheic system and the siliciclastic sediments were supplied by the Ethiopian Plateau and the East African Dome.
Publisher: Copernicus GmbH
Date: 27-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-2680
Abstract: & & Anorogenic reliefs (plateaus and plains) made up about 70% of the total emerged reliefs on Earth. They are characterized by nearly flat erosional surfaces upstream bounded by escarpments, called pediments ediplains. Africa& #8217 s landforms are constituted by very long (several thousands of kilometers) wavelength relief of broad & #8220 basins& #8221 (depressions) and swells (Holmes, 1944) possibly controlled by mantle dynamics. This & quot basin& quot and swell pattern caused Africa to be consisted of numerous endorheic and exorheic systems. Consequently, the Nile River, the longest river on Earth and main object of this study, crosses today a set of two former endorheic systems (Ugandese and Sudanese & #8220 Basins& #8221 ) and one exorheic system (Egyptian Margin) along its courses to the Mediterranean Sea. Our objective is here to unravel the paleorouting systems of the Nile River through relief growth, tectonic, and climate since the uppermost Cretaceous.& & & & Several generations of stepped pediments, proxies of relief growth, were characterized and mapped on DEM and satellite images and dated using their geometrical relationships with dated magmatic rocks. To better constrain periods of relief uplift and the deformation wavelength through time, the stratigraphic record of the sedimentary basins located in between two swells were studied using biostratigraphy and sequence stratigraphy. The originality of the approaches is to integrate data of all the source-to-sink (S2S) systems to produce a coherent scenario of the evolution of the Nile.& & & & We proposed the following model for the evolution of the Nile River. First, a main large pediplain is formed during the uppermost Cretaceous (?75-66 Ma), acting as a base of any kind of landforms that would be formed afterwards, bounded westward by the Darfur-Ennedi crest. Second, a major marine flooding during late Paleocene time (58-57 Ma) reached a subtle high bounding northward the endorheic Sudanese & #8220 Basin& #8221 . Third, Pre-Eonile started to form during the uppermost Eocene (~37 Ma) with a ide limited to the Egyptian Margin. Fourth, the Eonile was incised during late Miocene (~10 Ma) at time of a major uplift at the scale of north-east Africa. Finally, the Nile captured first the Sudanese endorheic system in the Early Pliocene (~4 Ma) and altered the Ugandese one in the Middle-Late Pleistocene (less than 1 Ma).& &
Location: Germany
No related grants have been discovered for Iwan Setiawan.