Early Miocene Larger Foraminifera from Suwadi Island, Northern Oman

Suwadi Island is located off the coast of northern Oman on top of an uplifted horst block that exposes a sequence of the Early Miocene Sur Formation. These shallow-marine carbonates and calcareous clastics are unconformably overlain by continental deposits of the Middle Miocene–Pliocene Barzaman Formation. The Sur Formation microfauna is dominated by the larger foraminifera Miogypsina , Pseudotaberina and Palaeonummulites with rarer occurrences of Operculina , Borelis , Dendritina , Peneroplis , Archaias and Lepidocyclina ( Nephrolepidina ), which indicates an early Tf1 Letter Stage that is equivalent to the Shallow Benthic Zone SBZ 25 (early Burdigalian age). Microfacies and palaeoecological analysis indicate depositional environments ranging from tidal flats to proximal middle ramp with shoal development near fair-weather wave base. Similar sediments and microfaunas are observed further ‘offshore’ to the north on the Daymaniyat islands. Oman is located at the boundary between the Mediterranean and the Indo–West Pacific faunal provinces, and the described microfauna provides valuable biogeographic data on the ‘connectivity’ of these two bioprovinces during the Burdigalian.