Caracterisation petro-sedimentaire des gres d’age cretace de la marge d’abidjan du bassin sedimentaire offshore de côte d’ivoire (zone abidjan-adiake)

The petro-sedimentary characterization of Cretaceous sandstones required petrographic and sedimentological analyzes in both macroscopy and microscopy. Macroscopic samples of these sandstone formations were collected in the eastern zone (Abidjan-Adiaké) of the Abidjan margin of the offshore sedimentary basin of the Côte d’Ivoire. It results from these researches that these sandstones contain mineralogical procession composed by quartz, feldspar, mica, glauconie, calcite, pyrite, tourmaline and fragment of rock. These are arkosic and lithic arenites with limestone cement and sometimes dolomitic and pyritic clay-limestone. The Cretaceous sandstone benches in the offshore basin consist of very fine to coarse sediments, moderately classified to highly grade with angular to sub-round shapes and some rounded shapes. The consolidated sediments are terrigenous (continental origin), and allochemical (marine origin). These sediments are transported by a fluviatile mode. Angular-shaped allochemas with a significant amount of feldspar have been transported for a short time while the terrigenous are transported for a long time. Cretaceous sandstones are deposited in a marine environment that extends from the shoreline to the deep basin. Cretaceous sandstones are porous and mature, resulting in respectively of the presence of cavity and the pyritization of limestone cement.