Upper Paleocene to lower Eocene microfacies, biostratigraphy, and paleoenvironmental reconstruction in the northern Farafra Oasis, Western Desert (Egypt)

Abstract

Three Paleocene-Eocene (P-E) stratigraphic transect sections namely, from the north to south, Ain Maqfi, Farafra-Ain Dalla road, and El-Quess Abu Said in the northern Farafra Oasis,Western Desert (Egypt) are described and interpreted based upon field observations, microfacies analysis, chronostratigraphy and foraminiferal paleobathymetry, to detect the effect of the Syrian Arc Fold System (SAFS) on the lateral and vertical facies changes, various stratigraphic breaks and to reconstruct the depositional paleoenvironments. Lithostratigraphically, the P-E successions are composed of the upper part of the Dakhla Formation, Tarawan Chalk and Esna Shale Formation. Vertical and lateral facies changes are noted between tectonic paleo-highs and paleo-lows in the Farafra Oasis. Eight microfacies types are recognized. The larger benthic and planktonic foraminiferal zones are here used to correlate the shallow and deeper facies. Two larger benthic (SBZ4 and SBZ6), six planktonic foraminiferal (P4–E4) and one calcareous nannofossil (NP9b) biozones are identified. The recorded basal Eocene Dababiya Quarry Member (DQM) within the Esna Shale Formation in the central Farafra Oasis is represented by units 4 and 5 of the DQMat its GSSPwith a neritic facies types. Towards the northern part of the Farafra Oasis, the P-E interval occurs within the base of the Maqfi Limestone Member that contains the larger benthic foraminiferal SBZ6 Zone and is correlated with the DQM.Amajor sea-level fall near the upper part of P5 Zone, followed by a prominent sea-level risewith a minor hiatus across the P-E interval in the Farafra Oasis reflects the complex interplay between sea level changes and tectonic signatures. Two inferred paleoenvironments, namely inner neritic and mid-outer neritic shelf have been identified.