The Cretaceous-Paleogene (K/Pg) boundary in the Dababiya Borehole, southern Egypt: An organic-walled dinoflagellate cyst approach

摘要

For the first time, a dinoflagellate cyst analysis is provided for the Upper Cretaceous-lower Paleogene transition in the Dababiya borehole, near Luxor, southern Egypt. Rich and relatively well-preserved dinollagellate cyst assemblages have been recovered; a total of 173 species and subspecies have been identified. Many of these were not previously known from Egyptian material. The biostratigraphical dinoflagellate cyst events recorded in the present study have allowed us to propose the first K/Pg boundary dinocyst zonation scheme for Egypt and to compare this with existing dinoflagellate cyst zonations worldwide. In ascending order, the observed latest Maastrichtian dinoflagellate cyst events include successively the last occurrence (LO) of Cannosphaeropsis utinensis, the first occurrences (FOs) of Apteodinium fallax, Disphaerogena carposphaeropsis, Kenleyia leptocerata and the LOs of Alisogymnium euclaense, Dinogymnium spp. and Pterodinium cretaceum. The most significant early Danian dinoflagellate cyst events used in this study are the FOs of Danea californica, Carpatella cornuta, Cassidium fragile, Lanternosphaeridium reinhardtii, Senoniasphaera inornata and Membranilarnacia? tenella. The dinoflagellate cyst biostratigraphical results, calibrated with data from benthic and planktonic foraminifera and calcareous nannoplankton from the same set of samples, have enabled a more accurate identification of the Cretaceous Paleogene (K/Pg) boundary than previously suggested for the succession studied. (C) 2019 Elsevier Ltd. All rights reserved.