Campanian to Danian dinoflagellate cyst assemblages from the southwestern Tethyan margin (Tattofte section, western External Rif, Morocco): Biostratigraphic and paleobiogeographic interpretations

摘要: Abstract A palynological study of the Upper Cretaceous–lower Paleocene outcrop section at Tattofte (westernmost External Rif, Morocco) has produced a well-preserved assemblage rich in dinoflagellate cysts (dinocysts). For first time, these assemblages have allowed us to determine age this section, highlight new Cretaceous–Paleogene boundary, and make paleobiogeographic interpretations. The samples analyzed yielded 209 dinocyst species 81 biostratigraphic events (first occurrence, or FO, last LO). We recognized upper Campanian based on FOs Areoligera coronata, reticulata, senonensis, Cerodinium diebelii Andalusiella mauthei subsp. mauthei, as well LOs Batiacasphaera solida, Odontochitina costata, porifera, Sentusidinium eisenackii, Trichodinium castanea Trithyrodinium suspectum. lower Maastrichtian is determined by Isabelidinium bujackii, Palaeocystodinium golzowense evittii, LO Alterbidinium acutulum, primarily speciosum speciosum, Disphaerogena carposphaeropsis, Glaphyrocysta perforata Manumiella seelandica Dinogymnium spp. Danian basis several taxa, including Carpatella cornuta, Danea californica Senoniasphaera inornata. succession uppermost part studied interval revealed relatively complete record across boundary. boundary coincides with 8 cm-thick reddish layer, which resembles those observed previously reference sections Mediterranean area, most notably stratotype El Kef (Tunisia). indicates subtropical temperate setting, while indicate warm setting. incursion few higher latitude cold-water provinces during latest around may suggest southward migration species, probably related short cooling episodes ocean circulation.