Detailed litho,-biostratigraphic analyses are carried out on the two lower Eocene
stratigraphic sections at Kharga-Baris oases namely; Gabal El Aguz and Darb Gaga.
These lower Eocene sediments are represented by two rock units: Esna Formation
(at the base) and Thebes Formation (at the top). Only the upper two members of the
Esna Formation (El Mahmiya and Abu Had) are included in the present work. Based
on the nannofossil marker species two zones are recognized covering the Early
Eocene interval; NP10 and NP11. Quantitative analyses of the calcareous nannofossil
species lead to recognize two distinct assemblages, which indicating a cool and an
eutrophic to mesotrophic marine environmental conditions. At G. El Aguz, the depositional setting are marked by deep marine environmental conditions characterize El Mahmiya and the lower part of Abu Had members, while the nannofossil contents of the upper part of Abu Had Member reflect shallow marine setting. In contrast, the whole succession of Darb Gaga section is deposited under shallow marine environmental conditions. These changes in the depositional setting could be interpreted as a result of sea level fluctuations due to the tectonic events during the Early Eocene interval with greater magnitude at Darb Gaga section.