Biostratigraphic and Paleoenvironmental Characterization of Cretaceous Carbonate Deposits in the Ivorian Offshore Sedimentary Basin, Côte d'Ivoire

Abstract

The biostratigraphic characterization of the Cretaceous carbonate levels of the offshore sedimentary basin of Côte d'Ivoire was made possible by a palynological and micropaleontological study of two drilling cutting (SN-X and DH-X). These sediments provided a rich microfauna consisting of species such as Ticinella madecassiana, Ticinella primula, Ticinella raynaudi and Ticinella roberti associated with a rich microflora composed of spores and pollen grains such as Appendicisporites potomacensis, Cicatricosisporites venustus, Appendicisporites baconicus, Ephedripites sp., Schizea certa and Elaterosporites klaszi characterizing the upper Albian. This study highlights several stages including the Cenomanian foraminifera Globigerinelloides bentonensis, Globigerinelloides caseyi, and pollen grains Steevesipollenites cupuliformis, and Ephedripites barghornii and Turonian by the planktonic foraminifera Heterohelix moremani, Hedbergella planispira, Whiteinella archaeocretacea, Whiteinella baltica. The lower Senonian is marked by the planktonic foraminifera Hedbergella delrioensis, Heterohelix globulosa, Heterohelix reussi, and the dynocyst Oligosphaeridium complex and Dinogymnium westralium. The Campanian is evidenced by the presence of the dinocysts Circulodinium distinctum and Hystrichodinium pulchrum. Thanks to the lithological and biostratigraphic analysis of these carbonate sediments, the palaeo-provinces have been determined and are located in the internal, medium or external neritic domains. Massive limestones were established between the upper Albian and the lower Senonian. The matrix is generally present in the lower and medium Albian.  The full carbonate sedimentation occurs between the medium Albian and the lower Senonian, with a maximum in the upper Albian.