Lithostratigraphy and biostratigraphy of some Lower Cretaceous outcrops from Northern Sinai, Egypt

Lower Cretaceous successions of the Risan Aneiza, El Tourkumanyia and Manzour areas (Northern Sinai, Egypt) were studied for biostratigraphic purposes. These successions were subdivided into three rock units, from base upwards: the Malha, the Risan Aneiza and the Halal formations. Each formation included enriched cephalopod horizons. Fifty cephalopod species were identified. The age and stratigraphic distribution of these cephalopods allowed the recognition of eight ammonite zones ranging in age from Barremian to late Albian. These zones are, from base to top: Subpulchellia oehlerti Zone (late Barremian), Barremites difficilis Zone (late Barremian), Deshayesites deshayesi Zone (early Aptian), Aconeceras nisus Zone (early middle Aptian), Epicheloniceras tschernyschewi Zone (late middle Aptian), Acanthohoplites nolani Zone (late Aptian), Knemiceras gracile Zone (early Albian) and Mortoniceras inflatum Zone (late Albian). The identified ammonite zones were correlated with national and standard international ammonite zones as proposed in previous studies of the same time interval.