Investigation palynologique de la transition Crétacé/Paléogène (K/Pg) dans une séquence d'argiles grises de la région d'Eboinda (sud-est de la Côte d'Ivoire)

Palynological investigation of the transition Cretaceous / Paleogene (K/Pg) in a sequence from grey clay of the region of Eboinda (South-East of the Côte d'Ivoire).- The objective of this study is to specify the ages and deposit environments of a sequence of gray clays encountered in a well located in the region of Eboinda (south-eastern Côte d'Ivoire). A palynological analysis carried out on 10 marly samples of cuttings made it possible to date this series from the Upper Maastrichtian to the Danian. The Upper Maastrichtian is identified on the basis of the LADs (last appearance) of Dinogymnium muticum and Cerodinium granulostriatum, while the Danian is determined by the disappearance of Cerodinium diebelii, as well as the presence of the species Danea californica. The K/Pg transition is also marked by the passage from an internal neritic deposition environment (Upper Maastrichtian) to that of an internal to external neritic deposition environment (Danian). The association of dinoflagellate cysts observed (Suite de Malloy) suggests that these gray clays were deposited in tropical to subtropical provinces.