Palynological dating and palaeoenvironments of the M1 well, Middle Miocene, Niger Delta, Nigeria
Date
2017-07
Authors
Durugbo, Ernest Uzodimma
Olayiwola, Moshood Adegboyega
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Abstract
The need to increase our knowledge of palaeo-flora is important in palaeoclimatic and palaeoenvironmental reconstruction of the
Tertiary Niger Delta as to highlight possible changes in the depositional environments over time. Hence, palynological data from the
M1well from the western Niger Delta region were employed in an attempt to reconstruct the Middle Miocene palaeoenvironment and
palaeoclimate. The detailed palynological analysis revealed diverse and abundant palynomorph assemblages. This consisted of pollen
species 60.14%, spores 25.86%, algae (Botyococcus braunii, Pediastrum sp., and Concentricytes circulus) 10.53%, miscellaneous
palynomorphs (fungal elements, diatom frustules and charred Gramineae cuticle) 2.62%, dinoflagellate cysts 0.79% and acritarchs
0.06%. The well is dated Middle Miocene based on the common occurrences of diagnostic middle Miocene Niger Delta palynomorphs.
Four informal palynofloral assemblage zones (MPAZ) I–IV were defined and correlated with major cycles of alternating dry and wet
climatic conditions. Sediments within MPAZ I and MPAZ II were assumed to have been deposited during dominantly wet periods
while MPAZ IV and III showed brief dry pulses coupled with periods of marine transgressions. The palaeoenvironment fluctuated
between nearshore and marginal marine inferred from abundant records of land-derived palynomorphs and the spotty records of the
dinoflagellate cysts Nematosphaeropsis labyrinthus, Nematosphaeropsis lemniscata and Impagidinium sp.
Description
Keywords
palynomorphs, Niger Delta, Miocene, palaeoclimate