A new Late Miocene to Pleistocene palynomorph zonation for the western offshore Niger Delta

Abstract

Existing biozonation schemes for the Niger Delta are mainly qualitative with zonal intervals too large to record subtle events. This has made it necessary to look for additional palynological events to enable recognition of shorter, more refined interval zones to improve stratigraphical definition. Hitherto unrecognised occurrence trends of palynomorphs were discovered and used to construct a new zonation scheme that can be applied in the offshore delta area. Late Miocene to Early Pleistocene sediments have been divided into five principal assemblage zones: FF1, Anthoceros abundance zone; FF2, Elaeis guineensis–Echiperiporites icacinoides zone; FF3, Lycopodium–Retibrevitricolporites obodoensis/protrudens zone; FF4, Cyperaceae abundance zone; and FF5, Echitriletes pliocenicus–Podocarpus milanjianus zone. The zones are further subdivided into 16 sub-zones based on quantitative events with some having finer subdivisions into (a) and (b). Examples of the zonations applied to three exploration wells from the western delta region are provided.

Keywords:

• Niger Delta
• palynology and palynostratigraphy
• bio-zonation
• palynomorphs
• pollen and spores
• Miocene
• Pliocene

Acknowledgements

The assistance of the Directorate of Petroleum Resources, Nigeria (DPR), is greatly appreciated for permission to work on the samples and for allowing publication of results. The encouragement from late Dr Ade Oyede, Mr Chinyere Ewenrem and Mr Kalu of Shell Petroleum Development Company, Nigeria, is greatly acknowledged. Also appreciated are the contributions of Mr Wale Yussuph of Earthprobe Nigeria Ltd., Lagos, Mr Isaac Ajisafe of Addax Petroleum Company Ltd., Lagos, Mr Toyin Bawaalla of Arctic Spatials Ltd. Lagos, Mr Taiwo Phillips, Mr Issa Olatunde and Mr Eric Erigha. Mrs Ife Oluwa Adeniyi is acknowledged for typing the manuscript. Mr Femi Fadahunsi and Mr Faleti, both of blessed memory, contributed immensely to the palynological slide preparation at the now-defunct Massoil Fields Services Ltd. Lagos, owned by Mr Bayo Sadare. The manuscript was significantly improved by comments by Dr Robert J. Morley and a second, anonymous, referee. Alison Davies of the Mapping Company, North Wales, provided the artwork for the text figures.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

Peter A. Adeonipekun

PETER ADEGBENGA ADEONIPEKUN obtained his B.Sc., M.Sc. and Ph.D. at the University of Ibadan and is currently a lecturer in Palaeobotany and Palynology in the Department of Botany, Faculty of Science, University of Lagos, Nigeria. He has twenty-one years' experience as a Palynologist/Biostratigrapher in the Nigerian oil and gas industry, being involved in regional and multi-well bio-sequence stratigraphical studies across the Niger delta. His research interests include Cenozoic and Cretaceous palynology, Bio-sequence stratigraphy, Quaternary Palynology/Palaeoecology and Aeropalynology. He is a member of the Nigerian Association of Petroleum Explorationists (NAPE), Nigerian Mining and Geosciences Society (NMGS), and Palynological Association of Nigeria (PAN).

M. Adebisi Sowunmi

PROFESSOR M. ADEBISI SOWUNMI has been engaged in post-doctoral palynological research and teaching since 1968. Her fields of interest include environmental archaeology, palaeoecology, melissopalynology, and pollen morphology. She has been visiting Professor at the Department of African Archaeology, Uppsala University, Sweden, Institute of Archaeology, University College London, England, and the Departments of African Archaeology and African Archaeobotany, Johann Wolfgang Goethe-Universität, Frankfurt am Main, Germany. She is currently an Adjunct Professor at the Department of Botany, University of Ibadan, Nigeria.

Keith Richards

KEITH RICHARDS is a palynologist with over 25 years' experience working on Cenozoic and Mesozoic sediments from all parts the world, with a particular interest in tropical Cenozoic palynology, sequence stratigraphy and deltas. He completed an MSc at Hull University on West African Holocene pollen. He is a palynologist with KrA Stratigraphic Ltd. in the UK and is a Research Associate at the Institute for Biodiversity and Ecosystem Dymanics (IBED) at the University of Amsterdam, The Netherlands.