Palynostratigraphy and palaeoenvironmental characterization and evidence of Oligocene in the terrestrial sedimentary basin, Bingerville area, Southern Cte dIvoire, Northern Gulf of Guinea

Abstract

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.

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

“…The great similarity of the species identified in the West African peri-Atlantic basins (Sénégal, Ghana-Côte d'Ivoire, Benoué ditch) reflects the effective opening of the central Atlantic in the Gulf of Guinée to upper Cretaceous [17]. This period is characterized by a phase of fine deposits of limestone, marls, clays and limestone clays in a shallow environment with a transgressive tendency.…”

Paleoenvironmental and paleogeographic characterization of the 12 frères borehole, fresco, southwestern Côte d’Ivoire: Palynological implication

“…Côte d'Ivoire is a West African country that for oil interests has focused its biostratigraphic studies on the Cretaceous and neglected the Paleogene which is also very poorly known. In spite of some palynological studies on the basin in the framework of thesis of Diploma of Advanced Studies [3][4][5], Doctorate [6][7] and rare publications [1,[8][9][10][11][12][13][14], this basin remains still badly known from the palynological point of view.…”

Palynological Characteristic of Dark Gray Clays in the Ivorian Onshore Basin at Southern Bingerville

“…Long remained unknown in the ivorian sedimentary basin, the Oligocene age formations were described for the first time by [1] southeast of the city of Bingerville. These results indicated lithologically that this stage is mainly composed of gray clays interspersed with thin joints of stratifications (hardground).…”