Paleocene benthic foraminiferal biostratigraphy and paleobathymetry in the sections between El Sheikh Fadl and Ras Gharib, Eastern Desert, Egypt

Abstract

Analysis of Paleocene benthic foraminifers of El Sheikh Fadl-Ras Gharib traverse, Egyptian Eastern Desert, reveals the presence of Gavelinella danica Total Range Zone, which is subdivided into four benthic foraminiferal assemblage subzones and correlated with the associated planktic foraminiferal zonations. However, the eugubina Zone is characterized by Cibicidoides pseudoacutus-Spiroplectinella dentata Subzone, in addition to Cibicidoides alleni, C. susanaensis, Anomalinoides welleri, and Gaudryina pyramidata, developed in a middle to upper bathyal environment with relatively well-oxygenated conditions. The pseudobulloides-pseudomenardii (base) Zones show mainly a Velasco-type faunas, with the Angulogavelinella avnimelechi-Nuttallides truempyi Subzone, together with Gavelinella beccariiformis, Cibicidoides alleni, Anomalinoides welleri, and Coryphostoma midwayensis. Microfauna indicates a gradual deepening to bathyal and deeper environments. The third assemblage follows the pseudomenardii (top) and velascoensis (base) Zones, and is typical of continental shelf (middle to outer neritic) conditions, i.e. Midway-type faunas, with the Hoeglundina scalaris-Lenticulina midwayensis Subzone. Alabamina midwayensis, Anomalinoides midwayensis, and Cibicidodes succedens are encountered in this assemblage subzone. The topmost part of the succession (velascoensis Zone), is equated with the Loxostomoides applinae Subzone, and displays an inner neritic to littoral assemblage, dominated by Valvulineria aegyptiaca, V. scrobiculata, Osangularia plummerae, Bulimina gr. trigonalis, and Bathysiphon paleocenicus. A shallowing environment prevailed during latest Paleocene times, accompanied by oxygen deficient conditions.