ISSN 2756-3251
Advanced Journal of Environmental Science and Technology ISSN 2756-3251, Vol. 16 (1), pp. 001-015, January, 2025. Available online at www.internationalscholarsjournals.org © International Scholars Journals
Full Length Research Paper
Characterization of Oligocene Terrestrial Sediments: Palynostratigraphy and Environmental Context in the Bingerville Basin, Northern Gulf of Guinea
Bruno Zeli Digbehi1*, Mamery Doukoure1, Juliette Tea-Yassi2, Raphael Konan Yao2, Jean-Paul N’goran Yao1, David Kouakou Kangah2 and Ignace TAHI2
1Université de Cocody, UFR-STRM, 22 BP 582 Abidjan 22, Côte d’Ivoire.
2Petroci, Centre d’Analyses et de Recherche (CAR), B.P. V 194, Abidjan, Côte d’Ivoire.
Accepted 24 October, 2024
A palynological investigation of two shallow boreholes in Anna, Bingerville area, at 13 km Northwest Abidjan, Southern Côte d’Ivoire, yielded rich and relatively well-preserved dinoflagellate cyst’s assemblages that allowed recognition of Oligocene age. This recognition was based on global dinoflagellate cyst events, including mainly Lejeunecysta species represented by cf. Lejeunecysta communis, L. lata, L. pulchra, Lejeunecysta sp. cf. L. granosa, cf. L. globosa, L. beninensis and other Pheolodinium magnificum, P. africanum, Selenopemphix nephroïdes and Cordosphaeridium inodes. They are associated to terrestrial spores and pollen grains such as Magnastriatites howardii, Spirosyncolpites spiralis, Perfotricolpites digitatus, Retitricoporites irregularis, Retimonocolpites irregularis, Pachydermites diederixii, Psilatricolporites operculatus and Punctodiporites harrisii. The palynostratigraphic interpretations are based on a comparison with calibrated dinoflagellate cyst ranges from several reference sections, mainly in the peri-atlantic and incidentally peri-pacific basins. This study showed changes in the relative abundances of different species or groups of morphologically related species. These changes are palaeoenvironmentally controlled, indicating a deposition occurred between the continental nearshore and marginal marine areas under continental influence. The prevalence of peridinioid dinocysts assemblage suggests deposition in a subtropical province whereas terrestrial pollen grains and spores provided by plants of coastal vegetation dominated by pteridophyts and angiosperms evoke mangrove and swamp forests. These new palynological data, notably the presence of Oligocene especially in the Ivorian terrestrial basin north of the so called “faille des lagunes”, specifies and modifies the previous local stratigraphic scale.
Key words: Palynostratigraphy, palaeoenvironment, Oligocene, sedimentary basin, Côte d’Ivoire.