The sediments of Wadi Qena (Eastern Desert, Egypt)

Abstract

The first deposition of near-shore sandstones on basement rock in the northern Wadi Qena area occurred during Lower Carboniferous times. Paleozoic deposits are overlain by similar sandstones of Cretaceous age with a large but inconspicuous hiatus between them representing erosion and non-deposition. A Cenomanian transgression inundated sandstones in the north as well as basement rock in the south. The Cenomanian and Turonian sea deposited marine and near-shore material in the Wadi Qena area, and only to the south of it were fluviatile beds laid down. The extant Red Sea Hills, at that time, represented a high and formed a peninsula extending in northerly direction into the shelf sea of the Tethys ocean. The sea withdrew in or after Coniacian times and the following erosion removed almost all Coniacian marine deposits. During Campanian times, the sea returned and also flooded the Red Sea Hill peninsula. Phosphoritic marls, at times of unrest, were redeposited as phosphorite sands in the south. Carbonate deposition followed, ending in Maastrichtian times. An erosional phase during the Cretaceous-Tertiary transition removed most of these chalks and limestones from the Wadi Qena area, and Paleocene and Eocene seas deposited limestone and mmarly chalk before a final regression marked the closure of the Tethys ocean.