Reconstruction and appraisal of Akunu–Akoko area iron ore deposits using geological and magnetic approaches

Open access

Abstract

Geological mapping and magnetic methods were applied for the exploration of iron ore deposits in the Akunu–Akoko area of Southwestern Nigeria for the purpose of evaluating their geological characteristics and resource potentials. A proton magnetometer measures the vertical, horizontal and total magnetic intensities in gammas. The subsurface geology was interpreted qualitatively and quantitatively. The downward continuations and second vertical derivatives, the small-sized mineralised bodies and shallow features in the study area were mapped. The faults are trending in the following directions: NE–SW, NW–SE, N–S and E–W groups, while the iron ore mineralisation is structurally controlled by two major groups of fault trends, namely, the NE–SW and NW–SE; the N–S and E–W groups are mere occurrences that do not contribute to the structural control of the iron ore mineralisation in Akunu.

The upward continuation has a linear feature similar to the principal orientation of the regional faults, while Locations 2 and 3 have relatively high magnetic susceptibility zones; suspected to be iron ore deposits. The depths to the magnetic sources ranged from 25 m to about 250 m.

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

  • [1] Henkel H. (1976): Studies of density and magnetic properties of rocks from northern Sweden: Pure and Applied Geophysics 114 235–249.

  • [2] Puranen R. (1989): Susceptibilities iron and magnetite content of Precambrian rocks in Finland: Tutkimusraportti – GeologianTutkimuskeskus – Report of Investigation – Geological Survey of Finland.

  • [3] Henkel H. (1994): Standard diagrams of magnetic properties and density; a tool for understanding magnetic petrology: Journal of Applied Geophysics 32 43–53.

  • [4] Li Y. Shearer S. Haney M. Dannemiller N. (2004): Comprehensive approaches to the inversion of magnetic data with strong remanent magnetization 74th Ann. Internat. Mtg. Soc. Explor. Geophys. Expanded Abstracts.

  • [5] Telford W. M. Geldart L. P. Sheriff R. G. Keys D. A. (1976): Applied Geophysics: Cambridge University Press Cambridge pp. 7–215 632–692.

  • [6] Medeiros W. E. Silva J. B. C. (1995): Simultaneous estimation of total magnetization direction and spatial orientation: Geophysics 50 1365–1377.

  • [7] Helbig K. (1963): Some integrals of magnetic anomalies and their relation to the parameters of the disturbing body: Zeitschrift für Geophysik 29 83–96.

  • [8] Valyashko G. M. Ivanenko A. N. Czerniawski G. E. Lukyanov S. V. (1995): Interpretation procedure of marine magnetic data: topical problems. In: Gorodnitsky A. M. (Ed.): Anomalous Magnetic Field of the World Ocean CRC Press Boca Raton Florida pp. 21–66.

  • [9] Schmidt P. W. Clark D. A. (1997): Directions of magnetization and vector anomalies derived from total field surveys: Preview 70 30–32.

  • [10] Schmidt P. W. Clark D. A. (1998): The calculation of magnetic components and moments from TMI: a case study from the Tuckers igneous complex Queensland: Exploration Geophysics 29 609–614.

  • [11] Phillips J. D. (2005): Can we estimate magnetization directions from aeromagnetic data using Helbig’s integrals? Earth Planets and Space 57 681–689.

  • [12] Carmichael R. S. (1989): Practical Handbook of Physical Properties of Rocks and Minerals: CRC Press Boca Raton Ann Arbor Boston.

  • [13] Thompson R. Oldfield F. (1986): Environmental Magnetism: Allen and Unwin London 227 pp.

  • [14] Lowrie W. (1990): Fundamental of Geophysics Low Price Paper Back Edition: Cambridge University Press Cambridge pp. 229–306.

  • [15] Schon J. H. (1996): Physical properties of rocks: fundamentals and principle of petrophysics. In: Klaus H. Sven T. (Eds): Handbook of Geophysical Exploration Vol. 18 Pergamon Press London 583 p.

  • [16] Mazzullo J. (1996): Investigations into Physical Geology A Laboratory Manual: Saunders College Publishing New York 361 p.

  • [17] Weymouth J. W. (1985): Geophysical Surveying of Archaeological Sites Surveying: Archaeological Geology Yale University Press New Haven and London pp. 191–235.

  • [18] Rahaman M. A. (1976): A Review of the Basement Geology of Southwestern Nigeria: Elizabeth Publishing Co. Nigeria pp. 41–58.

  • [19] Ajayi T. R. (1981): Ground magnetic studies of Ilesa east Southwest Nigeria: African Journal of Environmental Science and Technology 4(3) 122–131.

  • [20] Burke K. C. Dewey J. F. (1972): Orogeny in Africa. In: Dessauvagie T. F. J. Whiteman A. J. (Eds): African Geology University of Ibadan Nigeria pp. 583–608.

  • [21] Black R. Caby R. MonssinePouchkin A. Bayer R. Betrand J. M. Boullier A. M. Fabre J. Lesquer A. (1979): Evidence for late Precambrian plate tectonics in West Africa: Nature 278 223–227.

  • [22] Caby R. Bertrand J. M. Black R. (1981): Pan-African closure and Continental collision in the Hoggar-Iforas segment central Sahara. In: Kroner A. (Ed): Precambrian Plate Tectonics Elsevier Amsterdam pp. 407–434.

  • [23] Terry Chilinger J. S. P. (1955): Chart for visual estimation of percentage of minerals in rocks.

  • [24] Kearey P. Brooks M. Hill I. (2002): An Introduction to Geophysical Exploration 3rd edn. Blackwell Publishing Oxford pp. 155–180.

  • [25] Breiner S. (1999): Application Manual for Portable Magnetometer: Geometrics California USA pp. 1–58.

  • [26] Riddihoug R. P. (1971): Diurnal correction to magnetic survey – an assessment of errors: Geophysical Prospecting 19(4) 551–567.

  • [27] Dobrin M. B. Savit C. H. (1988): Introduction to Geophysical Prospecting. McGraw-Hill Book Co. Inc. New York pp. 152–190 498–578 691–745.

  • [28] Nabighian M. N. Grauch J. S. Hansen R. O. LaFehr T. R. Li Y. Peirce J. W. Phillips J. D. (2005): The historical development of the magnetic method in exploration: Geophysics 70 33ND–61ND.

  • [29] Trompat H. Boschetti F. Hornby P. (2003): Improved downward continuation of potential field data: Exploration Geophysics 34 249–256.

  • [30] Roest W. R. Pilkington M. (1993): Identifying remanent magnetization effects in magnetic data: Geophysics 58 653–659.

  • [31] MontajTM Tutorial. (2004): Two-dimensional frequency domain processing of potential field data.

  • [32] Akingboye A. S. (2014): Geology and Ground Magnetic Investigation over Iron ore deposit Akunu-Akoko Area Southwestern Nigeria. Unpublished (BSc.) project 115 p.

Search
Journal information
Metrics
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 288 117 5
PDF Downloads 209 93 1