Palynostratigraphy of Upper Miocene - Pliocene Sediments in Well Z, offshore Niger Delta

Palynological analysis of ditch cutting rock samples from upper Miocene - Pliocene succession of well Z, Offshore Niger Delta, was carried out for their biostratigraphic significance. The analysis yielded a well preserved and diverse biostratigraphic important Miospores among which fifty six Miospores (forty five pollen and eleven spores) were identified. Ten miospore biozones were erected on the basis of their first and last downhole occurrences. The zones are from base to top as follows Multiaerolites formosus, Psilatriculporites Crassus, Retritricolporites irregularis, Archornea obovata, Pachydermites diederixi, Striatriculpites catatumbus, Caryadopollenites veripites, Monoporites annulatus, Pordocarpus milanjanus, and Verrutricolporites rotundiporis. These miospore zones were compared with the standard miospore biozonation schemes existing in the area and used to delineate the Upper Miocene/Pliocene boundary. From the sedimentological result, the rock succession studied are the fossilferous grey sandy shale with shells and shell fragments intercalating with medium - coarse grained, sub rounded to rounded sandstone with scattered mica flakes possibly the top of the paralic Agbada Formation and thickly bedded medium - coarse grained, sub rounded to rounded sandstone with mica flakes intercalating with very thin lenses of shaly sand with mica flakes, capped with sub angular - sub rounded quartz pebble conglomerate and pebbly sandstone representing the water bearing coastal plain sands of the Benin Formation.