Lineament, Qualitative Interpretation and Depth Evaluation of Potential Field Signatures in the Abeokuta Region, Southwestern Nigeria

Document Type : Research Article

Authors

1 Department of Physics, College of Physical Sciences, Federal University of Agriculture, Abeokuta, Nigeria.

2 Department of Physics, Sikiru Adetona College of Education, Science and Technology, Omu-Ajose, Nigeria.

Abstract

Ground gravity and magnetic geophysical surveys are proven veritable tool in the imagery of the subsurface through the analyses of their responses (potential field data). This research attempts to delineate subsurface linear structures that are possible conduits for mineral accumulation at a 2,500 m2 active exploration site of FUNAAB, Abeokuta region. Abeokuta is embayed in the Dahomey Basin comprising of magmatic older granites of Precambrian age to early Paleozoic age. The qualitative interpretation technique employed by visualizing the grids reveals variations in density contrasts and susceptibilities, which connote the lithological distribution of the basement. Areas of high gravity and magnetic values directly correspond to areas of high density bodies and magnetically susceptible mineral contents, respectively. While the lows and steep discontinuities of both gravity and magnetic maps predict possible entrapments of mineral accumulation in the study area. The depth evaluation techniques employed are Peter’s Half Slope Method (PHSM) and 3D Euler deconvolution, showing the magnetic depths to basement range as 3.18 m to 5.88 m for PHSM and 1.00 m to 4.43 m for 3D Euler deconvolution. The gravity depth to basement reveals 7.03 m to 14.72 m for PHSM and 0.96 m to 4.13 m for 3D Euler deconvolution. The average depth results obtained clearly show that the study location is composed of shallow depth intrusive sources.

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Abdelrahman, E.M., & Essa, K. S. (2015). Three least-squares Minimization Approaches to Interpret Gravity Data Due to Dipping Faults. Pure and Applied Geophysics, 172, 427-438.
Adegoke, J. A., & Layade, G. O. (2019). Comparative depth estimation of iron-ore deposit using the Data-Coordinate Interpolation Technique for airborne and ground magnetic survey variation. African Journal of Science, Technology, Innovation and Development (AJSTID), 11(5), 663-669. doi: 10.1080/20421338.2019.1572702.
Adejuwon, B. B., Salami, A.A., Omatola, P.S., Ashien, S.O., Adeyemo, B.K., & Ujubuonu E.G. (2018). Integrated EM (VLF) and Gravity Survey for the Delineation of Mineralized Veins in Touzuwa Area of Benue State. International Journal of Engineering Research and Technology, 7(2), 49 – 54.
Akinse, A.G., & Gbadebo, A.M. (2016). Geological mapping of Abeokuta Metropolis.
Anudu, G.K., Oluba, L.N., Onwuemesi, A. G., & Ikpokonte, A.E. (2012). Analysis of Aeromagnetic Data over Wamba and its Adjoining Areas in North-central Nigeria. Earth Science Research Journal, 16(1), 25-33.
Araffa, S. A. S., El-bohoty, M., Abou Heleika, M., Mekkawi, M., Ismail, E., Khalil, A., & Abd El-Razek, E. M. (2018). Implementation of Gravity and Magnetic Methods to delineate the subsurface structural features of the basement complex in Central Sinai Area, Egypt. NRIAG Journal of Astronomy and Geophysics, 7, 162-174, Cambridge University Press.
Cornford, C. (1990). Source Rocks and Hydrocarbons of The North Sea. In Glennie, K.W. (ed.)      Petroleum Geology of the North Sea. Basic Concepts and Recent Advances. Blackwell Science, Oxford, 376-462.
Dow, W.G. (1978). Petroleum Source Beds on Continental Slopes and Rises (2). American Association of Petroleum Geologists (AAPG) Bulletin, Vol. 62.
Edunjobi, H. O., Layade, G. O., Falufosi, M. O., & Olurin, O. T. (2021). Lineament and Depth Evaluation of Magnetic Sources in a Geological Transition Zone of Abeokuta and its Environs, Southwestern Nigeria. Pet & Coal, 63(2), 548-560.
Essa, K.S., Nady, A.G., Mostafa, M.S., & Elhussein, M. (2018). Implementation of Potential Field Data to depict the Structural Lineaments of the Sinai Peninsula, Egypt. Journal of African Earth Sciences, 147, 43-53.
Essa, K. S., & Munschy, M. (2019). Gravity Data Interpretation using the Particle Swam Optimization Method with Application to Mineral Exploration. J. Earth Syst. Sci., 128:123; DOI:doi.org/10.1007/s12040-019-1143-4.
Falufosi, M.O., & Osinowo, O.O. (2021). Evaluation of Basement Topography and Structures in the Dahomey Basin and Surrounding Environs of Southwestern Nigeria, using Satellite Gravity Data. NRIAG Journal of Astronomy and Geophysics, 10(1), 333-346.
Ferreira, F. J. F., de Castro, L. G., Bongiolo, A. B. S., de Souza, J., & Romeiro, M. A. T. (2011). Enhancement of the Total Horizontal Gradient of Magnetic Anomalies using Tilt Derivatives: Part II—Application to real data: 81st Annual International Meeting, SEG, Expanded Abstracts, 887–891.
Gluyas, J., & Swarbrick, R. (2005). Petroleum Geoscience. Blackwell Science, Oxford, 358pp.
Hesham, S.Z., & Hesham, T.O. (2016). Application of High-Pass Filtering Techniques on Gravity and Magnetic Data of the Eastern Qattara Depression Area, Western Desert, Egypt. National Research Institute of Astronomy and Geophysics, 5, 106-123.
Jones, H.A., & Hockey, R.O. (1964). The Geology of Parts of Southwestern Nigeria. Bull. Geological Survey Nigeria, 31, 101–102.
Joshua, E.O., Layade, G.O., & Adeyemi, S.A. (2017). On the use of Linear Trend Analysis in Removing Regional Gradient from Ground Magnetic Data for Qualitative Interpretation. Scholars Research Library, Archives of Physics Research, 8(1), 4-10.
Kaki. C., d'Almeida, G.A.F., Yalo, N. & Amelina, S. (2013). Geology and Petroleum Systems of the Offshore Benin Basin (Benin). Oil & Gas Science and Technology- Rev. IFP Energies nouvelles, 68(2), 363-381.
Kevin, M. (1997). Gravity method overview. Department of Geosciences, Southwest Missouri State University, Springfield, MO 65804.
Layade, G.O., Edunjobi, H.O., Makinde, V., N. Bada, B.S. (2020). Application of Forward and Inverse Modelling to High Resolution Data for Mineral Exploration. International Journal of Earth and Space Physics. DOI: 10.22059/JESPHYS.2020296560.1007192.
Layade, G.O., Edunjobi, H.O., Makinde, V., & Bada, B.S. (2020). Ground Based Gravimetric for the Detection and Depth Mapping of Subsurface Geological Structures of Ilesha, Southwest Nigeria. Journal of Earth and Space Physics, DOI:10.22059/JESPHYS.2020.301010.1007209.
Milsom, J. (2003). Field geophysics. 3rd Edition John Wiley and Sons Ltd, London, 232 pp.
Nabighian, M. N., & Hansen, R. O. (2005). Unification of Euler and Werner deconvolution in three dimensions via the generalized Hilbert transform, Geophysics, 66.
Nettleton, L.L. (1971). Elementary Gravity and Magnetics for Geologists and Seismologists: Society of Exploration Geophysicists Monograph Series, No 1, 83-87.
NGSA (2005). Nigeria Geological Survey Agency (NGSA). Geological Map of Nigeria.
Obaje, N.G. (2009). Geology and mineral resources of Nigeria. Lecture Note in Earth Science.
Paterson, N.R., & Reeves, C.V. (1985). Applications of gravity and magnetic surveys: the state-of-the-art in 1985. Geophysics, 50, 2558-94.
Peters, L.J. (1949). The direct approach to magnetic interpretation and its practical application. Geophysics 14, 290-320s.
Rahaman, O. J. (1976). Review of Basement Geology of Smith, Western Nigeria.
Rao, D.A., & Babu, H.V.R. (1984). On the Half-Slope and Straight-Slope Methods of Basement Depths Determination. Geophysics, 49, 1365–1368.
Ravat, D. (2007). Reduction to Pole. Encyclopedia of Geomagnetism and Paleomagnetism, D. Gubbins and E. Herrero-Bervera (eds.), Springer, 856–857.
Reid, A.B., Allsop, J.M., Granser, H., Millett, A.J., & Somerton, I.W. (1990). Magnetic Interpretation in Three Dimensions using Euler Deconvolution. Geophysics, 55, 80-99.
Reid, A.B., Ebbing, J., & Webb, S.J. (2012). Egregious Euler Errors – The Use and Abuse of Euler Deconvolution applied to Potential Fields. 74th EAGE Conference and Exhibition incorporating SPE EUROPEC 2012, Copenhagen, Denmark, 4-7, June 2012.
Telford, W. M., Geldart, L. P., Sheriff, R. E., & Keys, D. A. (1976). Applied Geophysics: Cambridge Univ. Press, NY, 1-860.
Telford, W.M., Geldart, L.P. and Sheriff, R.E. (1998). Applied Geophysics, 2nd Edition, Cambridge University Press, USA 770 pp.
Thompson, D. T. (1982). A new technique for making computer-assisted depth estimates from magnetic data. Geophysics, 47(1), 31-37.
Verduzco, B., Fairhead, J. D., & Green, C. M. (2004). New Insights into Magnetic Derivatives for Structural Mapping. The Leading Edge, 23(2), 116–119.
Webring, M. (1981). MINC. A Gridding Programme based on Minimum Curvature. U.S Geological Survey Open-File Report, 81-1224, 43p.
Wright, J.B., Hastings, D.A., Jones, W.B., & Williams, H.R. (1985). Geology and Mineral Resources of West Africa, George Allen and Urwin, London, 90-120.