Reconstruction of Paleoecology of Early Miocene Subsurface Deposits from Microflora in the Eboïnda Area (South-Eastern Côte d'Ivoire,West Africa)

Abstract

The early Miocene palynoflora was recovered from well P1 located in the Aboisso area, about 175 km around of Abidjan (south-eastern Côte d'Ivoire, West Africa). Pteridophyta spores, angiosperm and gymnosperm pollen grains have been identified. The main objective of this work is to inventory all the palynomorphs encountered, to propose a local palynostratigraphy and to reconstitute the paleobotany of our study area during the Tertiary formations north of the lagoon fault. The samples were processed according to the classical procedure of extraction and concentration of palynomorphs. The lithology contains brown to black clays, coarse to fine sands, and reddish to motley clays. This study showed that the dominance of freshwater ferns such as Verrucatosporites usmensis, Laevigatosporites ovatus, Polypodiaceiosporites simplex, Cingulatisporites pseudocicatricosus and leiotriletes adriensis which evokes a swampy environment. Also the development of Bombacaceae (Bombacacidites annae), and the abundance of Pteridophyte spores of the Polypodiaceae family (Verrucatosporites usmensis, Laevigatosporites ovatus, and Polypodiaceiosporites simplex) indicate the climate was tropical with alternating dry and wet periods. Early Miocene sediments are placed in a continental type environment.