Late Campanian-Maastrichtian foraminifera from the Simsima Formation on the western side of the Northern Oman Mountains

A precise correlation of Upper Campanian-Maastrichtian (Upper Cretaceous) sections on the western side of the Northern Oman Mountains (Jabals Qarn El Barr, El Aqabah and Malaqet in the United Arab Emirates and Jabal El Rawdah in the Sultanate of Oman), reveals two distinct facies based on microfaunal assemblages. The first indicates open marine conditions, and is represented by the Qarn El Barr section. This yields numerous planktonic foraminiferal species referable to the Globotruncana aegyptiaca (Upper Campanian), Gansserina gansseri (Upper Campanian-Middle Maastrichtian) and Abathomphalus mayaroensis (Upper Maastrichtian) planktonic foraminiferal zones. During the Campanian-Maastrichtian, this open marine environment passed laterally into shallower marine conditions that were characterized by larger foraminiferal species including Loftusia morgani, Orbitoides media, O. apiculata , Omphalocyclus macropora, Lepidorbitoides minor, Sulcoperculina dickersoni, and Siderolites calcitrapoides. This facies is well developed in the Jabal El Aqabah, Jabal El Rawdah and Jabal Malaqet sections.