DINOFLAGELLATE CYSTS AS PALEOCLIMATE INDICATORS IN THE PALEOGENE OF WEST AFRICA
A nearly continuous sedimentary record from Ocean Drilling Program (ODP) Site 959 (Hole 959A and 959D) in the Côte d’Ivoire-Ghana Transform Margin provides the opportunity to study dinoflagellate cysts in two significant paleoclimate intervals in the Paleogene of West Africa. Dinoflagellate cysts are very sensitive to changes in climate and depositional environment. In the Paleocene-early Eocene interval of ODP Hole 959D, the dominance of warm water species of dinoflagellate cysts, such as Apectodinium spp. and Tectatodinium spp., support warm climatic conditions. These species were consistent in their abundance especially during the Selandian and Thanetian.
Later in the sedimentary record, several dinoflagellate cyst taxa record a cold interval during the early Oligocene interval of ODP Hole 959A. This interval yielded an assemblage of good stratigraphic markers that are also present in the northern high latitudes. The taxa include Bitectatodinium spp., Filisphaera filifera, Habibacysta tectata and Nematosphaeropsis spp. The presence of these dinoflagellate cyst taxa in this tropical setting may be indicative of an arctic dinoflagellate migration to low latitude regions during a narrow interval during the Oligocene epoch.