Reservoir Potential, Environment of Deposition, Tectonic Setting, and Provenance of Rock Units in the Anambra Basin, Southeastern Nigeria

Maju-Oyovwikowhe G E^1, and Imasuen I O¹

¹Department of Geology, Faculty of Physical Sciences, University of Benin, P.M.B. 1154 Benin City, Edo State, Nigeria

Cite this paper

Maju-Oyovwikowhe G E and Imasuen I O. Reservoir Potential, Environment of Deposition, Tectonic Setting, and Provenance of Rock Units in the Anambra Basin, Southeastern Nigeria. Journal of Geosciences and Geomatics. 2019; 7(4):172-183. doi: 10.12691/JGG-7-4-2

Abstract

A total of eight (8) sandstone samples were subjected to sedimentological and inorganic geochemical analyses in the investigation of reservoir potential, environment of deposition, tectonic setting, and provenance of Campano-Maastrichtian rock units in Anambra Basin, southeastern Nigeria. Sedimentological studies reveal that samples of Owelli and Ajali Sandstones are coarse to medium grained, poorly sorted to moderately sorted sediments deposited in a fluvial environment. The heavy mineral assemblages made up of garnet, epidote and staurolite suggest a metamorphic source while tourmaline and zircon suggest igneous or metamorphic sources. The high maturity indices (58.6 to 71.4) as well as the high percentage of quartz (68 to 74%) suggest mature sandstones that can act as reservoir for generated hydrocarbon. The major oxides discriminate function diagram shows active passive margin for the sandstone samples. Quartzose sedimentary provenance was shown for the sediments which have been highly reworked from original igneous and metamorphic sources, possibly from Abakiliki uplift, Oban massif and/or Obudu basement rocks in the southeast. The high chemical index of alteration (averaging 93%) and the low ratio of K₂O/Al₂O₃ (0.02 to 0.11) in the sediments confirms sedimentary recycling and intensive source area weathering.

Keywords

Sedimentological, inorganic geochemical analysis, reservoir potential, environment of deposition, Anambra Basin

Copyright

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References

[1]	Amajor, L.C., 1990. Petrography and provenance characteristics of Albian and Turonian sandstones, southeastern Nigeria. In: Ofoegbu, C.O. (ed.), The Benue Trough structure and evolution. Friedrich Viewing. And Sohn Verlag. Braunschweig, Germany, 39-58.
[2]	Amaral, E.J. And Pryor, W.A., 1977. Depositional environments of St. Peters sandstone deduced by textural analysis. Journal of Sedimentary Petrology, vol. 40, 32-35.
[3]	Ejimofor, O.C., Umeji, A.C. and Turaki, U.M. (1996): Petrography and Major Element Geochemistry of the Basement Rocks of Northern Obudu Area, Eastern Nigeria. In: Jour. Of Min. and Geol. Vol 32. Nig. Min. and Geos. Soc. Publ. pp1-8.
[4]	Folk, R.L., 1980. Petrology of Sedimentary Rocks. Hemphills Publishing Company, Austin, Texas, 170 p.
[5]	Folk R.L. And Ward, W., 1957. Brazos River bar. A study in the significance of grain size parameters. Journal of Sedimentary Petrology, vol. 27, 3-26.
[6]	Friedman, G.M., 1967. Dynamic processes and statistical parameters compared for size frequency (sic) distribution of beach and river sands. Journal of Sedimentary Petrology, vol. 37, 327-354.
[7]	Friedman, G.M., And Sanders, J.E., 1978: Principles of Sedimentology. John Willey and Sons. New York, 792p.
[8]	Hubert, J.F., 1962. A zircon-tourmaline-rutile maturity index and interdependence of the composition of heavy mineral assemblages with the gross composition and texture of sandstones. Journal of Sedimentary Petrology, vol. 32,440-450.
[9]	Ireland, H.A., 1971. Preparation of thin sections. In: CARVIER, R.E. (ed.). Procedure in sedimentary Petrology. John Willey and sons, New York, 367-383.
[10]	Kearey, P., 2001. The penguin dictionary of geology (2nd ed.). Penguin Books Limited, London, England, 327p.
[11]	Obaje, N. G., Wehner, H., Scheeder, G., Abubakar, M. B., and Jauro A. (2004). Hydrocarbon prospectivity of Nigeria’s inland basins: From the viewpoint of organic geochemistry and organic petrology. AAPG Bulletin, v. 88, (3), 325-353.
[12]	Pettijohn, F.J., 1975. Sedimentary rocks (3rd ed.). Harper and Row, New York, 628 p.
[13]	Suttner, L.J., Basu, A., And Mach, G.M., 1981. Climate and the origin of quartz arenites. Journal of Sedimentary Petroleum formation and occurrence, 2nd ed. Springer Verlag, Berlin. 699p.
[14]	Vischer, G.S., 1969. Grain size distributions and depositional processes. Journal of Sedimentary Petrology, vol. 39 (3), 1073-1106.