The stratigraphic positions of the Wadi Dukhan and Al Uwayliah formations, northeast Libya – a review

The stratigraphic positions of the Wadi Dukhan and Al Uwayliah formations are reviewed. Diagnostic Maastrichtian larger foraminiferal species from the Wadi Dukhan Formation in well B7 – 41 (Cyrenaica) and in well U2 – 6 (northeastern Sirt Basin) are illustrated for the first time. These species are Omphalocyclus macroporus (Lamarck), Siderolites cf. calcitrapoides Lamarck and Orbitoides cf. media (d’Archiac). Following the rules of nomenclature, the type section of the Al Uwayliah Formation should be considered a composite stratotype. The section east of al Uwayliah village is the holostratotype (upper part of the formation) and the Jardas al Jarrari section is the parastratotype (lower part of the formation). The combined thickness of the two component stratotypes seems to be too thin to represent the whole Paleocene Series. Palaeontologic evidence also suggests that parts of the Paleocene standard foraminiferal zones are not represented in either of the two component stratotypes. Most probably, a middle part of the Al Uwayliah Formation, below the holostratotype and above the parastratotype (late Danian to Selandian), has not yet been recognised.