On the Absence of Oligocene in Onshore Part of Cote D’ivoire Sedimentary Basin. Preliminary Results of Clays Study of Samo Area, South-East of Cote D’ivoire, West Africa

Abstract

We studied the argillaceous fractions of three wells carried out in Samo area, located in the South-Eastern part of Côte d’Ivoire sedimentary basin. Preliminary works whose results are presented in this paper related to the mineralogical studies of clays of the levels crossed by these wells. They precede the study aiming at establishing the palynostratigraphy as well as the variation of the depositional environments in connection with the eustatic episodes which occurred in this sector of the Northern Gulf of Guinea. The results indicate that analyzed samples are mainly made up of quartz and kaolinite with a small proportion of illite. In the upper part sequence identified like the Continental terminal, the deposits are primarily made up of quartz and kaolinite. In bituminous gray clays of the lower section, the samples are dominated by quartz and illite. These results lead to distinguish two lithostratigraphical sequences: the variegated clays of Continental terminal Mio-Pliocene age are provided by Quaternary lateritic continental detritus; the Lower sequence of bituminous clays is mainly marine origin.