Assiut university researches
Stratigraphy, sedimentology and tectonic
evolution of the Upper Cretaceous/Paleogene
succession in north Eastern Desert, Egypt
Abdalla M. El Ayyat ⇑, Nageh A. Obaidalla
Abstract:
The stratigraphy, sedimentology and syn-depositional
tectonic events (SdTEs) of the Upper Cretaceous/ Paleogene
(K–P) succession at four localities in north Eastern Desert
(NED) of Egypt have been studied. These localities are
distributed from south-southwest to north-northeast at Gebel
Millaha, at North Wadi Qena, at Wadi El Dakhal, and at Saint
Paul Monastery. Lithostratigraphically, four rock units have
been recorded: Sudr Formation (Campanian–Maastrichtian);
Dakhla Formation (Danian–Selandian); Tarawan Formation
(Selandian–Thanetian) and Esna Formation (Thanetian–
Ypresian). These rock units are not completely represented
all over the study area because some of them are absent at
certain sites and others have variable thicknesses.
Biostratigrapgically, 18 planktonic foraminiferal zones have
been recorded. These are in stratigraphic order:
Globotruncana ventricosa Zone (Campanian); Gansserina
gansseri, Contusotruncana contusa, Recimguembelina
fructicosa, Pseudohastigerina hariaensis, Pseudohastigerina
palpebra and Plummerita hantkenenoides zones
(Maastrichtian); Praemurica incostans, Praemurica uncinata,
Morozovella angulata and Praemurica carinata/Igorina albeari
zones (Danian); Igorina albeari, Globanomanlina
pseudomenradii/Parasubbotina variospira, Acarinina
subsphaerica, Acarinina soldadoensis/ Globanomanlina
pseudomenardii and Morozovella velascoensis zones
(Selandian/Thantian); and Acarinina sibaiyaensis,
Pseudohastigerina wilcoxensis/Morozovella velascoensis
zones (earliest Ypresian). Sedimentologically, four
sedimentary facies belts forming southwest gently-dipping
slope to basin transect have been detected. They include
tidal flats, outer shelf, slumped continental slope and open
marine hemipelagic facies. This transect can be subdivided
into a stable basin plain plus outer shelf in the extreme
southwestern parts; and an unstable slope shelf platform in
the northeastern parts. The unstable slope shelf platform is
characterized by open marine hemipelagic, fine-grained
limestones and fine siliciclastic shales (Sudr, Dakhla,
Tarawan and Esna formations). The northeastern parts are
marked by little contents of planktonic foraminifera and
dolomitized, slumped carbonates, intercalated with basinal
facies. Tectonically, four remarkable syn-depositional tectonic
events (SdTEs) controlled the evolution of the studied
succession. These events took place strongly within the
Campanian–Ypresian time interval and were still active till
Late Eocene. These events took place at: the
Santonian/Campanian (S/C) boundary; the
Campanian/Maastrichtian (C/M) boundary; the
Cretaceous/Paleogene (K/P) boundary; and the Middle
Paleocene–Early Eocene interval. These tectonic events are
four pronounced phases in the tectonic history of the Syrian
Arc System (SAS), the collision of the Afro-Arabian and
Eurasian plates as well as the closure of the Tethys Sea.
Key words:
North Eastern Desert Upper Cretaceous/Paleogene Syndepositional tectonic events Syrian Arc System Facies belts
Slope to basin transect
Published in:
Journal of African Earth Sciences,,pp. 35–59