Abstract:
The Benin and Western Nigeria Offshore Basins, which are parts of an extensive basin called the
Dahomey (Benin) Embayment, were formed during the Early Cretaceous under similar tectonic
conditions and continental sedimentary environments. Based mainly on available lithological, biostratigraphic and paleoenvironmental data, this paper summarizes the stratigraphic succession
of theses basins and attempts a comparison of these stratigraphic nomenclatures. The bulk of data
shows that sedimentation begins with terrestrial at the base, passes through shallow marine, deep
marine (with restrictive bottom circulation) and ends with open deep marine conditions. The stratigraphy of the Offshore Benin Basin was established later and considering lithological and paleontological similarities with formations of various southern Nigeria basins, the stratigraphic
chart adopted for this basin was a mixed variant of various Southern Nigerian basins nomenclatures. For the first time, a correlation of stratigraphic charts of each basins and a schematic cross
section showing their lithostratigraphic units, especially the Cretaceous-Paleocene interval which
is petroliferous, are proposed. The study shows that the nomenclature adopted in Benin Republic
must be revised by using type section/locality names for some particular Formations and widely
accepted Formations names of Nigeria for the others. This will permit to avoid confusions as it is
presently the case for the name “Afowo Formation” representing a Cretaceous sequence in Nigeria
and which is use in Benin Republic to distinguish some sediments of Miocene age. Moreover, a
High Resolution Biostratigraphy summary (including micropaleontology, nannopaleontology and
palynology distributions) relating to each offshore basin is needed for sequences correlations and
entire harmonization of the stratigraphic nomenclature of these offshore basins.
