Carbonate Platform to Basin Transition along an Upper Cretaceous to Lower Tertiary Syrian Arc Uplift, Galala Plateaus, Eastern Desert of Egypt

Abstract

ABSTRACT Biostratigraphic and facies analyses were made on Upper Campanian to Lower Eocene strata along a 58-kilometer-long dip transect across the Northern and Southern Galala plateaus, west of the Gulf of Suez. The analyses enabled us to reconstruct the evolution of a platform–slope–basin transition that is roughly parallel with the trend of the plateaus. We interpret individual sedimentary cycles as processes of a southward-prograding carbonate platform that developed along a branch of the Syrian Arc Fold Belt. The Northern Galala area was a structural high as shown by hiatuses spanning Late Cretaceous (Coniacian) to Early Paleocene times. To the south, carbonate platform progradation is evident from the Late Campanian onward. Late Cretaceous platform-derived slope deposits interfinger with basinal chalks and calcareous shales farther south. Early Tertiary carbonates were deposited in platform, slope, and basin settings. The evolution of the platform–slope–basin transition is documented by the changing large-scale depositional geometry. The evolution occurs within sedimentary sequences that are interpreted by means of a high-resolution biostratigraphic framework. The facies architecture reflects the evolution from a rimmed shelf (Late Cretaceous) to a distally steepened ramp (latest Cretaceous to Paleocene) and eventually to a homoclinal ramp (Early Eocene). The reconstruction of the imprint of fluctuating sea levels on the sedimentary record has been used to establish comparisons with age-equivalent cycles from neighboring regions.