Palaeoecological and palaeobiogeographic implications of Middle‐Late Eocene ostracods from the Qattamiya area, North Eastern Desert, Egypt

Abstract

In an attempt to define the palaeoecology and palaeobiogeography of the Middle‐Late Eocene rock units in the North Eastern Desert of Egypt, 121 rock samples of three representative localities, namely, Wadi Degla, Gebel Abu‐Shama, and Gebel Qattamiya sections were collected and investigated. Qualitative and quantitative analysis of ostracods associations and sedimentological data were used to identify three ostracod biozones; two acme zones (Cytherella tarabulusensis and Loxoconcha vetustopunctatella) of the Middle Eocene age and one assemblage zone (Xestoleberis subglobosa–Uromuellerina saidi) of Middle‐Late Eocene age, reflecting palaeoenvironments in the study area. The Cytherella tarabulusensis Zone, located at the bottom of all sections, is characterized by restricted shallow water, low dissolved oxygen, high salinity, and water depth below 100 m. The Loxoconcha vetustopunctatella Zone, located in Wadi Degla and Gebel Qattamiya sections, is characterized by shallow normal warm waters in the range of 20–50 m, whereas Xestoleberis subglobosa–Uromuellerina saidi Assemblage Zone, located in all studied sections, reflects restricted shallow water with a reduced dissolved oxygen condition palaeoenvironment. Palaeobiogeographically, the recorded ostracod assemblage exhibits similarities with those recorded in the Middle East and North and East Africa bioprovinces.