A Stratigraphic Review of the Al Bayda Formation, NE Libya: Calcareous Nannofossils versus Foraminifera

Abstract

Different groups of Eocene and Early Oligocene fossils have been reported from the Al Bayda Formation at Cyrenaica, northeast Libya by several authors. The formation is detrital in its lower part, and separated by disconformities from both the Darnah Formation below and the Al Abraq Formation above.
 In this review, it is confirmed that all Eocene taxa reported from the lower member of the Al Bayda Formation (the Shahhat Marl Member) are allochthonous, representing reworked bioclasts from the Eocene Darnah Formation. The Early Oligocene micro- and macrofossils reported by several authors from the Shahhat Marl Member and from the upper member (the Algal Limestone) of this formation are considered here as autochthonous, in situ biota, confirming its Early Oligocene age. The contradictory conclusion of El-Mehaghag and Ashahomi, 2005, based on calcareous nannofossils, that the Al Bayda Formation is Middle to Late Eocene, is not accepted in this present work