New implications for regional biostratigraphy and paleobiogeography of larger benthic foraminifera in the Lutetian-Bartonian succession of the el-Ramliya-Akheider block, north Eastern Desert, Egypt

Abstract

Larger benthic foraminifera (LBF) experienced rapid evolution during the Paleogene, reaching a widespread distribution in both northern and southern Tethys during the Eocene Epoch. Paleobiogeographic insights regarding their migration patterns were facilitated by this distribution. To date, there have been no investigations of LBF in the eastern Maadi-Sukhna region. In the middle Eocene succession of the El-Ramliya-Akheider block in this region, the taxonomic identification of Nummulites and larger porcelaneous foraminifera is examined in detail for this work. N. praegizehensis and N. praediscorbinus were identified, along with six larger agglutinated and porcelaneous foraminiferal species (Dictyoconus egyptiensis, Idalina cuvilleri, Rhabdorites malatyanesis, Pseudolacazina schwagerinoides, Somalina danieli). These taxa are associated with the three standard Shallow Benthic Zones (SBZ) of the Mokattam and Observatory formations. The top of the middle Lutetian SBZ 14 was characterized by a significant unconformity between the Mokattam and Observatory formations. The Nummulites gizehensis group, which started at the plateau of the Giza pyramids and expanded throughout northern Africa and the Arabian Peninsula, was shown to have dispersed, according to a new paleobiogeographic map. Due to the physical barrier of the Galala Mountains, the N. gizehensis group migrated southward in Egypt during the middle-late Lutetian stage, dispersing more quickly in the north Western Desert than the north Eastern Desert and Sinai.