Upper Cretaceous stratigraphy of the Gebel Somar area, north-central Sinai, Egypt

The Upper Cretaceous sequence (446 m thick) exposed at Gebel Somar (north-central Sinai) is subdivided, from base to top, into the Raha (upper Cenomanian), Abu Qada (upper Cenomanian–lower Turonian), Buttum (middle Turonian), Wata (middle–upper Turonian), Matulla (Coniacian–Santonian), and Sudr Chalk (lower–upper Maastrichtian) Formations. Foraminifera (mainly planktonic) were used to assign ages to these. Vertical variations in the bio- and lithofacies for the Cenomanian–Santonian succession reflect global changes of sea level. During the late Santonian, the area studied was uplifted in association with the generation of the Syrian arc system. This was accompanied by non-deposition of Campanian sediments. The Maastrichtian Sudr Chalk was laid down in the basin or depocenter generated as a result of the Syrian arc system.