# Paleoenvironmental and paleobiogeographical significance of Paleocene – early Eocene ostracods in Wadi Tarfa, North Eastern Desert, Egypt

## TL;DR

This study examines ancient ostracod fossils in Egypt to understand past environments and biogeographic connections during the Paleocene to early Eocene periods.

## Contribution

The study introduces new biostratigraphic zones and paleobiogeographic insights based on ostracod assemblages in Egypt.

## Key findings

- Three ostracod zones were identified, but regional correlations showed inconsistencies due to localized depositional factors.
- Ostracod assemblages indicate a transition from outer neritic to upper bathyal environments during the late Paleocene.
- NMDS analysis revealed strong paleobiogeographic links between North African and Levantine regions, with greater differentiation in West Africa and the Middle East.

## Abstract

This study investigates ostracod faunas from the well-preserved Paleocene to lower Eocene sedimentary succession at Wadi Tarfa, North Eastern Desert, Egypt. A total of 22 species and subspecies across 16 genera and 8 families were identified across 57 samples. Three zones were identified: Doricythereis jordanica jordanica Zone, Cytheropteron toshkaensis Zone, and Phalcocythere horraensis Zone, based on the stratigraphic distribution of ostracod fauna. However, correlations with other sections revealed inconsistencies in the first and last occurrences of ostracod species, indicating complexities in regional biostratigraphic correlation by ostracod fauna and the influence of localized depositional factors. Both R-mode and Q-mode clustering analyses were applied to ostracod assemblages, identifying four distinct faunal clusters and five biofacies, reflecting depositional changes from outer neritic to upper bathyal environments. The late Paleocene revealed reduced ostracod diversity, correlating with a deepening marine environment, particularly in the Tarawan Formation. Non-Metric Multidimensional Scaling (NMDS) analyses indicated significant paleobiogeographic connections between North African and Levantine sites, while faunal differentiation was greater in West African and Middle Eastern regions due to marine barriers.