Palynomorph Biostratigraphy of VIC 97 Well, Nothern Depo Belt, Niger Delta, Nigeria (Published)
Palynological and sedimentological studies were conducted on sixty ditch cutting rock samples from interval 460 to 4550 feets of VIC-97 well, located at OML 38, Northern Depo-belt, Niger-Delta, to delineate lithofacies units and the age of the rock succession. Standard methods of palynological sample analysis were used to disaggregate the palynomorphs from the rock matrix. Log signatures, sand/shale ratios, textural attributes, and accessory mineal compositions of ditch cutting rock samples were used as lithologic parameters to establish two lithofacies units; the transitional unit having a sand/shale ratio of 80:20 and the continental Unit having a 98:2 ratio ascribed to upper Agbada and Benin formation respectively. Palynological analysis revealed that the retrieved palynomorphs were numerous and reasonably diversified, particularly in the lower portion of the sample interval. Palynological zonation was based on the palynofloral assemblage of important species and their stratigraphic distribution. Thirteen informal biozones were recognised on the basis of their first and last downhole occurences and compared with P 560, P580 and P624 to delineate an early to late Oligocene age for the studied interval.
Keywords: Age, Niger-Delta, lithofacies units, palynomorphs, rock
Benin Flank of the Niger Delta: Quantitative Distribution of Palynomorphs, Palaeoecologic and Palaeoclimatic Interpretation (Published)
This study has reported on the palynomorphs and some associated elements encountered in the Abao Bore hole (BH) of the Maastritchian to the Tertiary of the Benin Flank of Niger Delta in the Southern Nigeria Sedimenatry Basin. Abao BH represented a continuous and complete sequences with total depth of about 3255 feet. The 51 core samples yielded 70 genera and 160 species of dinoflagellates cysts and 43 genera and 60 species of pollen and spores. The various analysis of lithologic formation recognized in the well are in order of succession: Nkporo shale (Maastrtician/Danian) Imo shale (Early Eocene), Ameki Formation (Middle Eocene –Late Eocene/Oligocene) and Ogwashi -Asaba Formation (Miocene) Benin Formation (Miocene/Pliocene). The Palynology analysis also permitted the recognition of 19 dinoflagellate cysts assemblages and 17 pollen/spores assemblages ranging in age from the Maastrticinan to the Miocene. Detailed Paleoenviromental and paleoclimatic interpretation was based on the fact that diversity, abundance and presence of some species reflect either local or regional ecological condition. In general, the paleoclimatic pattern appears to follow the scheme proposed by Van Der Hammen (1957) and there is a close correlation between dominant dinocyst association and pollen/spore percentage in the study area.
Keywords: Benin flank, Niger-Delta, palaeoclimatic interpretation, palaeoecologic, palynomorphs, quantitative distribution