Early Eocene Thermal Stages in the Senegalo-Mauritanian Sedimentary Basin (Western Africa)

Eocene epoch is characterized by several warming stages which most important are the Eocene Thermal maxima ETM2, ETM3 and the Early Eocene Climate Optimum EECO defined using geochemical process. In addition to these methods, the thermal stages have been defined in oceanic areas mainly with planktonic foraminifera belonging to the genera Morozovella and Acarinina. Species belonging to these genera show a large extension during the Paleogene in the Senegalo-Mauritanian Basin. The studies of these assemblages in Eocene sediments deposits shows that the thermal maximum stages are marked by a decrease in the genera Morozovella and a simultaneous increase in the genera Acarinina. The disappearance of Morozovellavelascoensis and the diversification of Acarininasoldadoensis characterized the ETM2 stage, which occurs during the Ypresian. The EECO warming phase in the basal Lutetian was defined in the basin by the peak of Acarininapentacamerata and the abrupt disappearance of Morozovellagracilis. A similar distribution of Acarininaand Morozovella is observed in the Togolese coastal basin.