##plugins.themes.bootstrap3.article.main##

The Maastrichtian–Eocene sediments (mainly shales and limestones) penetrated by the Itori borehole and Ilaro boreholes in the Dahomey Basin were investigated for foraminiferal biostratigraphy and palaeoecological interpretation. These boreholes penetrated Araromi, Ewekoro, and Oshosun formations at varying depths. Selected shale sediments were subjected to foraminiferal analysis and many planktonic and benthic species of foraminifera (agglutinated and calcareous) were recovered from the Cretaceous interval of the penetrated boreholes. Twelve species of planktic foraminifera (Globalomalina planocompressa, G. pseudomenardii, Globigerina inaequispira, Acarinina cf.coalingenis, Acarinina nitida, Chiloguembelina cretacea, chiloguembelina subtriangularis, Orthokasrstenia sp., Hedbergella holmdelensis, Globigerina sp., Globigerinelloids asperus, Morozovella formosa formosa) and thirteen species of benthic i.e Bolivina sp., B. Crassicostata, , E. africana, Eponides psuedoelevatus, Gavelinella cf. guineana, Gavelinella pachysuturalis, Haplophragmiodes sp., Lenticulina cyprina, L. inornata, L. olokuni, L. psuedomamilligera, L. taylorensis, Nonionella communis, N. spissa, N. panamensis, Orthokarstenia sp., Planulina oyae) were identified. In general, benthic species of infauna deposit feeder and epifauna dominate the population. These species occupy a range of environments from dyoxic to anoxic, brackish water to marsh environment down to upper bathyal depth. Based on the abundant and stratigraphical distribution of the foraminiferal species, four biostratigraphic zones were recognized: Afrobolivina afra zone of late Maastrichtian, Globigerina zone of early Paleocene, Globalomalina pseudomenardii zone of late Paleocene and Morozovella formosa formosa zone of the early Eocene.

References

  1. Klemme H. Geothermal gradient, heat flow and hydrocarbon recovery. In: Petroleum and Global Tectonics. Fischer AG, Judson S. Eds. Princeton University Press; 1975.
     Google Scholar
  2. Ogbe FGA. Stratigraphy of Strata Exposed in Ewekoro Quarry western Nigeria. In African Geology. Dessauvagie TFJ, Whiteman AJ. Eds. Ibadan, University of Ibadan Press, 1972, pp. 305-322.
     Google Scholar
  3. Omatsola ME, Adegoke OS. Tectonic Evolution and Cretaceous stratigraphy of the Dahomey Basin. Journal of Mining and Geology. 1981; 18: 130–137.
     Google Scholar
  4. Idowu J, Ajiboye S, Ilesanmi M, Tanimola A. Origin and significance of organic matter of Oshosun Formation, southwestern Dahomey basin, Nigeria. Journal of Mining and Geology. 1993; 29(1): 9–17.
     Google Scholar
  5. Whiteman AJ. Nigeria: Its Petroleum Geology, Resources and Potential. Graham and Trotman, London, U.K. 1982, pp. 394. https://doi.org/10.1007/978-94-009-7361-9
     Google Scholar
  6. Ojeda HA. Cretaceous stratigraphy of the Dahomey Embayment, west Africa. Cretaceous Research. 1982; 11: 17–27.
     Google Scholar
  7. Adekeye OA. Aspect of the Sedimentology, Geochemistry and Hydrocarbon potentials of Cretaceous- Tertiary sediments in Dahomey Basin of southwestern Nigeria. Unpublished PhD Thesis. University of Ilorin, Ilorin. 2005.
     Google Scholar
  8. Akande SO, Adekeye OA, Ojo OJ, Erdtman BD, Koutsoukos EAM. Stratigraphic evolution, paleoenvironments and hydrocarbon potential of the Benue/Dahomey basins, Nigeria and Portiguar/Ceara basins, NE Brazil. Book of Abstracts 40th NMGS Conf. Maiduguri, 23. 2004.
     Google Scholar
  9. Okosun EA. A review of the Cretaceous stratigraphy of the Dahomey Embayment, West Africa. Cretaceous Research. 1990; 11(1): 17–27. https://doi.org/10.1016/S0195-6671(05)80040-0.
     Google Scholar
  10. Kjemperud A, Agbesinyale W, Agdestein T, Gustafsson Y.A. Tectonostratigraphic history of the Keta Basin, Ghana with emphasis on the late erosional episodes. Geol. Afr. Coll. Geol. Libreville, Rec. Communic. 1992: 55-69.
     Google Scholar
  11. Persits F, Ahlbrandt T, Tuttle M, Charpentier R, Brownfield M, Takahashi K. Map showing geology, oil and gas fields and geological provinces of Africa, Version 2.0, USGS Open File Report, pp. 97-470A, 2000.
     Google Scholar
  12. Gebhardt H. Benthic foraminifera of the Maastrichtian lower Mamu Formation near Leru (Southern Nigeria): Paleoecology and Paleogeographic significance. Journal of Foraminifera Research. 1998; 28(1): 76–89.
     Google Scholar
  13. Murray J. Ecology and paleoecology of benthics foraminifera. Longman Scientific & Technical, Harlow. 1991.
     Google Scholar
  14. Peters SW. Central west Africa Cretaceous-Tertiary benthic foraminifera and Stratigraphy. In Paleontographica Abt. 1982: pp. 1–104.
     Google Scholar
  15. Adekeye OA, Gebhardt H, Akande SO, Adeoye JA, Abubakar IA. Biostratigraphic Analysis of the Cretaceous Abeokuta Group in the Eastern Dahomey Basin, Southwestern Nigeria. Journal of African Earth Sciences. 2019; 152: 171–183. https://doi.org/10.1016/j.jafrearsci.2019.01.014.
     Google Scholar
  16. Bolli H. The general Globigerina and Globorotalia in the Paleocene-Lower Eocene Lizard Spring Formation of Trinidad. United States. Bulletin US National Museum. 1957: 215, 61–81.
     Google Scholar
  17. Bolli H. Zonation of Cretaceous to Pliocene marine sediments based on Planktonic foraminifera. Boletino informative Association Venezuela Geologia. Mineria Petrole. 1966; 9: 3–32.
     Google Scholar
  18. Bolli H. The genus Globigerinatheka Bronnimann. Journal Foraminifera Research. 1972; 2: 109–136.
     Google Scholar
  19. Gebhardt H, Kuhnt W, Holbourn A. Foraminiferal response to sea-level change, organic flux and oxygen deficiency in the Cenomanian of the Tarfaya Basin, southern Morocco. Mar. Micropaleontol. Amsterdam. 2004; 53: 133–158.
     Google Scholar
  20. Gebhardt H. Adekeye OA, Akande SO. Late Paleocene to initial Eocene Thermal Maximum (IETM) Foraminiferal Biostratigraphy and Paleoecology of Dahomey Basin, Southwestern Nigeria. Jb. Geol. B.- A. 2010; 150(0016–7800): 407–419.
     Google Scholar
  21. Immam M. Biostratigraphy of the upper Cretaceous-Lower Eocene succession in the Bani Walid area, northwest Libya. Journal of Africa Earth Sciences. 2001; 33(1): 69–89.
     Google Scholar
  22. Okosun EA, Alkali YB. The Paleocene-Early Eocene Foraminiferal Biostratigraphy of Eastern Dahomey Basin, SW Nigeria. International Journal of Scientific and Engineering Research. 2012; 3(11), ISSN 2229-5518. https://www.researchgate.net/publication/270591218.
     Google Scholar
  23. Orville L. Cretaceous planktonic Foraminifera Zonation. Micropaleontology. 1967; 13(1): 1–31.
     Google Scholar
  24. Culver S, Buzas M. Distribution of selected recent benthic foraminifera genera in the western North Atlantic. In: Neale JW, and Brazier MD. (eds.), Microfossils from recent and fossil shelf seas: In British Micropaleontolgical Society Series, Ellis Horwood Limited Chichester. 1981: pp. 336–349.
     Google Scholar
  25. Bronnimann P, Whittaker JE, Zaninetti L. Brackish water foraminifera from mangrove sediments of southwestern Viti Levu, Fiji Island, Southwest Pacific: Revue de Paleobiologie. 1992; 11(1): 13–65.
     Google Scholar
  26. Adekeye OA. Quantitative and Paleocological Interpretation of foraminifera fauna from the Albian Asu River Group exposed around yandev, Nigeria. Journal of Mining and Geology. 2003; 39(2): 103–107.
     Google Scholar
  27. Koutsoukos EAM, Leary PN, Hart M. Latest Cenomanian-Earliest Turonian Low-Oxygen tolerant Benthonic foraminifera- a case study from Sergipe Basin (N.E Brazil) and the western Anglo-Paris Basin (southern England); Paleogeography, Paleoclimatology, Paleoecology. 1992; 77: 145–177.
     Google Scholar
  28. Sliter WV, Baker, RA. Cretaceous Bathymetric Distribution of benthic Foraminifera. Journal of Foraminifera research. 1972; (2): 167-183. http:// dx.doi.org/10.2113/gsjfr.2.4.167
     Google Scholar