Abstract:
Integration of palynological, lithofacies, petrographical and micropaleontological interpretations
of Upper Cretaceous Mamu Formation has provided the basis for the age, zonation, the rock type
names and composition of the aforementioned formation in the Anambra Basin.
Palynological data shows that the shale samples yielded fairly common to abundant and diverse
palynomorphs assemblage of Longapertites marginatus, Laevigatosporites ovatus, Monocolpites
marginatus, Retidiporites magdalensis, Proxapertites cursus, Periretisyncolpites giganteus,
Constructipollenites ineffectus, Distaverrusporites simplex, Spiniferites ramosus, Echritriporites
trianguliformis and Monocolpopollenites sphaeroidites thereby enabled the assigning of
Maastrichtian age (Upper Cretaceous period) and establishing Longapertites marginatus Acme
Zone, Longapertites marginatus /Monocolpites marginatus Assemblage Zone and Retidiporites
magdalensis/Proxapertites cursus Assemblage Zone respectively. The analyses of the
stratigraphic sections distinguished four lithofacies of (i) fissile and laminated shales, (ii)
ferruginised and indurated shales, (iii) medium grained sandstone and (iv) ferruginised medium
grained sandstones while the petrographic analysis established that the lithology belongs to the
quartz arenites classification. Micropaleontologically, the analysis showed the sediments were
barren of microforaminifera, which indicate that the environment of deposition was a shallow nonmarine
environment.
