Sequence stratigraphy of the Upper Cretaceous of central-east Sinai, Egypt

Abstract

Deposition of the Upper Cretaceous of central-east Sinai was controlled by a long-term transgressive phase and several higher order sea-level fluctuations. The paper gives a first sequence stratigraphic interpretation for this interval in the region, based on detailed sedimentological, biostratigraphical and palaeoecological investigations of 13 Turonian-Maastrichtian sections and a review of all published data. Six main facies zones have been differentiated: coastal mud flats with tidal channels, gypsiferous sabkha plains, peritidal siliciclastics, peritidal carbonates, high- and low-energy carbonate inner shelf facies, and microfossil-rich outer shelf pelites. The biostratigraphy is based mainly on planktonic foraminifera, calcareous nanofossils, ostracods and ammonites. The study is restricted to an area that had been tectonically rather quiet during the Late Cretaceous-early Tertiary, lying south of the Syrian Arc intraplate foldbelt which experienced major uplifting during this period. Within the Turonian to Maastrichtian interval, six major sequence boundaries have been recognized. Cycle duration varied between 4 and 6 Ma, which indicates a cycle order intermediate between 3rd and 2nd. Correlation with other sea-level reconstructions for the region (Egypt, Israel, Jordan, Tunisia) points to a more or less synchronous regional sea-level development. Comparison of the regional sequences with the ‘eustatic’ model of Haqet al. (1987) involves uncertainties; nevertheless, some of the sea-level fluctuations recorded in Sinai may be related to worldwide eustatic sea-level changes.