Calcareous nannofossil biostratigraphy and bioevents across the Ypresian/Lutetian boundary in Egypt and Jordan

The Ypresian/Lutetian boundary duration calcareous nannofossil biostratigraphy and bioevents from three sections, two from Sinai, Egypt (Wadi Ferian and El Mishatii; west-central and north-east Sinai, respectively) and one from Jordan (Outherite), are presented for the first time. Fifty-three calcareous nannofossil species are identified from 86 samples, spanning the calcareous nannofossil Zone NP14 (= Zone CP12; early-middle Eocene). In the present study, the early/middle Eocene (Ypresian/Lutetian) boundary is defined by the Lowest Occurrence (LO) of Blackites inflatus, positioned at the base of NP14b/CP12b zones. The LO of B. inflatus is slightly above the LO of Turborotalia frontosa. In general, the present data is largely consistent with what is known from the GSSP (Gorrondatxe section, Spain, Basque Provinces) of the base of Lutetian, where the LO of B. inflatus also marks the base of NP14b/CP12b subzones. In the present study, the LO of B. inflatus is reaffirmed as a reliable marker for correlating the base of the Lutetian. Discoaster sublodoensis, D. saiipenensis, D. bifax, D. martini and Tribrachiatus orthostylus show diachronous occurrences.

Automated summary

This study presents the calcareous nannofossil biostratigraphy and bioevents of the Ypresian/Lutetian boundary duration from three sections in Sinai, Egypt and Jordan for the first time. The boundary is defined by the LO of Blackites inflatus, which is slightly above the LO of Turborotalia frontosa. The data is consistent with the GSSP of the base of Lutetian, where the LO of B. inflatus also marks the base of NP14b/CP12b subzones. Discoaster sublodoensis, D. saiipenensis, D. bifax, D. martini, and Tribrachiatus orthostylus show diachronous occurrences.