CENOMANIAN-CONIACIAN BIOSTRATIGRAPHY OF THE NORTHERN EASTERN DESERT OF EGYPT, BASED ON AMMONITES

The Upper Cenomanian-Coniacian sequence exposed in the northern Eastern Desert of Egypt includes several ammonite horizons. These occurrences are used to establish seven ammonite interval-zones facilitating the inter-regional correlation of the sequence. The biostratigraphic zonation proposed consists of (from bottom to top): the Neolobites vibrayeanus, Metoicoceras geslinianum, Vascoceras cauvini, Pseudaspidoceras flexuosum, Choffaticeras segne, Coilopoceras requinianum, and Metatissotia fourneli Zones. The Cenomanian/Turonian boundary coincides with the base of the Pseudaspidoceras flexuosum Zone, whereas the Turonian/Coniacian boundary is defined by an erosive surface at the upper boundary of the Coilopoceras requinianum Zone.