Exploration for limestone deposit at Onigbedu, South–Western Nigeria

Open access


The Onigbedu limestone deposit was investigated using the aeromagnetic data, resistivity soundings and borings with the aim of characterizing the limestone deposit and estimating its reserves. The subsurface structural features and depth to basement were identified with the analysis of aeromagnetic data. Twenty nine boreholes were drilled for subsurface appraisal and correlation of the limestone deposit. Eighty nine Vertical Electrical Sounding (VES) were acquired using the Schlumberger array. The results showed NE-SW trending lineaments that segmented the limestone. Depth to basement varied from 144.2 m to 1090 m. The VES results showed four to six layers indicating the topsoil (7-315 Ωm), clay (2-25 Ωm), shale (6-31 Ωm), limestone (20-223 Ωm), sandstone (>200 Ωm) and sandy materials. The VES results correlated well with the lithological unit delineated from the borehole. The overburden thickness ranged from 3.3 m to 28 m, while the limestone thickness varies between 18.1 m and 48.3 m. The limestone reserve was estimated at 1.9 × 109 t. This study concluded that the study area had vast occurrence of the limestone deposits, which would be of economic importance, if exploited.

If the inline PDF is not rendering correctly, you can download the PDF file here.

  • [1] Omatsola M.E. and Adegoke O.S. (1981): Tectonic evolution and stratigraphy of the Dahomey basin. Journal of Mining and Geology 18(1) pp. 130-137.

  • [2] William L. (1997): Fundamental of Geophysics Cambridge University Press 206-217.

  • [3] Bell J. P (1963): A Summary of the Principal Limestone and Marble Deposits of Nigeria. Geological Survey of Nigeria Rep. 1192.

  • [4] Adegoke O.S Dessauvagie T.F. J Kogbe C. A Ogbe F.G.A (1971): Type section Ewekoro Formation biostratigraphy and microfacies 4th African Micropal. Coll. Abidjan (1970) pp. 37-39.

  • [5] Ford D.C.; Williams P.W. (2007): Karst Geomorphology and Hydrogeology 2nd ed.; John Wiley and Sons: Chichester UK 2007.

  • [6] Vouillamoz J.M. Legchenko A. Albouy Y. Bakalowicz M. Baltassat J.M. AlFares W. (2003): Localization of saturated karst aquifer with magnetic resonance sounding and resistivity imagery Ground Water 41(5) pp. 578-586.

  • [7] Van Schoor M. (2002): Detection of sinkholes using 2D electrical resistivity imaging Journal of Applied Geophysics 50 pp. 393-399.

  • [8] Zhou W. Beck B.F. and Stephenson J.B. (2000): Reliability of dipole-dipole electrical resistivity tomography for defining depth to bedrock in covered karst terrains. Environmental Geology 39 760-766.

  • [9] Ehinola O.A Oluwajana A. and Nwabueze C.O. (2012): Geophysical mapping and reserve estimation of limestone deposit at Arimogija - Okeluse parts of South-western Nigeria. Research Journal in Engineering and Applied Sciences 1(1) pp. 7-11.

  • [10] Idowu O.A. Ajayi O. and Martins O. (1998): Occurrence of Groundwater in part of the Dahomey Basin South-western Nigeria J. min. geol. 35(2) pp. 229-100.

  • [11] Martin L. (1966): Manual of Magnetic Interpretation Toronto: Computer Applications and Systems Engineering.

  • [12] Cordell L. and Grauch V.J.S. (1985): Mapping basement magnetization zones from aeromagnetic data in the San Juan Basin New Mexico in Hinze William J. (ed.) The Utility of Regional Gravity and Magnetic Anomaly Maps: Society of Exploration Geophysicists Tulsa Oklahoma pp. 181-197.

  • [13] Thurston J.B. and Smith R.S. (1997): Automatic conversion of magnetic data to depth dip and susceptibility contrast using the SPITM methods: Geophysics 62(3) pp. 8-7-813.

  • [14] Zohdy A.A. R. (1985): The auxiliary point method of electrical sounding interpretation and its relationship to the Dar Zarrouk parameters. Geophys. 30 pp. 55-64.

  • [15] Oldenburg D.W. and Brune J.N. (1975): An explanation to the orthogonality of ocean ridges and transform faults. J. Geophys. Res. 82 pp. 803-827.

  • [16] Kearey P. Brooks M. and Ian H. (2002): An Introduction to Geophysical Exploration (3rd ed.). Blackwell Science Limited pp. 262.

Journal information
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 516 263 4
PDF Downloads 477 254 4