Palynological Study and Age Dating of the Early Miocene Dukku Claystone Type Section of Gwandu Formation, Sokoto Basin, Northwestern Nigeria

Abstract

Outcrop samples were collected from Dukku area for the purpose of subjecting them to palynological analysis in order to determine the relative age of Gwandu Formation and palaeoenvironment of deposition of the deposit. Field and laboratory methods were carried out in order to obtain lithological sequence description of the outcrop. The samples obtained went through processes of acid digestion with hydrochloric acid, hydrofluoric acid and separation of macerals by floatation with the use of zinc bromide. The prepared slides were observed under microscope for palynomorph contents. Diagnostic palynomorphs that are stratigraphically important for palynozonation were retrieved such as Belskipollis eligans, Verrutricolporites laevigatus. Striamonocolpites sp., Retibrevitricolporites sp., Retibrevitricolporites obodoensis, Retistephanocolpites sp., Cingulatisporites ornatus, Longapertites marginatus and Proteacidites sp. The marker fossils belong to Magnatariatites horwardii zone; Zone P600 and Subzone P630 and C1 Zone of Nigerian Niger Delta sedimentary basin zonal schemes, dated Early Miocene age. Dinoflagellate forms recovered include Batiacasphaera sp., Senegalinium sp., Andalusiella polymorpha Selenophemphix nephroides, Andalusiella sp., Andalusiella laevigata, Histrichosphaera turocona and undifferentiated dinoflagellate cysts of peridinacean forms that belong to marginal marine setting.