1887
Volume 53, Issue 3
  • ISSN: 0812-3985
  • E-ISSN: 1834-7533

Abstract

The airborne Time-domain electromagnetic data acquired over the Ilesha Schist Belt in southwestern Nigeria were filtered, enhanced and analysed to generate ground conductivity responses at different time gates and employed to characterise the subsurface in terms of rock distribution, structural framework as well as evaluate the gold and base metal mineralisation potential of the region. The near-surface sensitive early time gate conductivity responses (EMZ – EMZ) indicate relatively high subsurface conductivity distribution (60–120 mS/m) in amphibole schist and pegmatite terrain in the west while medium to low-conductivity (<5 mS/m) values were recorded in the east underlain by granitic rocks. Major and minor linear/sub-linear conductive features having conductivity in excess of 2 mS/m and trending NE-SW, NNE-SSW, NNW-SSE and ENE-WSW directions were delineated on the mid conductivity time gate responses (EMZ – EMZ). One of which presents geometry and pattern consistent with the well-reported Ifewara – Iwaraja fault system that runs through the entire Ilesha Schist Belt. Very high anomalous conductivity (160–300 mS/m) responses at late conductivity time gates (EMZ – EMZ) with characteristic long decay curves were obtained over isolated zones, especially along fractures and veins suggesting the occurrence of structurally controlled gold and base metal mineralisation.

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2026-01-18

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References

  1. Adelusi, A.O., J.S.Kayode, and A.A.Akinlalu. 2013. Interpretation of aeromagnetic anomalies and electrical resistivity mapping around Iwaraja area southwestern Nigeria. Journal of Geology and Mining Research5, no. 2: 38–57.
     [Google Scholar]
  2. Ajayi, T.1980. On the geochemistry and origin of the amphibolites in Ife-Ilesa area SW Nigeria. Nigerian Journal of Mining and Geology17: 179–96.
     [Google Scholar]
  3. Ajibade, A.C.1976. Provisional classification and correlation of the Schist Belts in northwestern Nigeria. In Geology of Nigeria, ed. C.A.Kogbe, 85–90. Lagos: Elizabeth Publ. Co.
     [Google Scholar]
  4. Akande, S.O., and O.Fakorede. 1988. Gold mineralization in the Nigerian Schist Belts, vol. 88. Melbourne: Bicentennial Gold, pp. 140–2.
  5. Akande, S.O., A.Hoffknecht, and B.D.Erdtmann. 1992. Rank and petrographic composition of selected upper cretaceous and tertiary coals of southern Nigeria. International Journal of Coal Geology20: 209–24.
     [Google Scholar]
  6. Akanmu, T., O.Oshin, and O.S.Ayodele. 2019. Mineralogical characterization of the gold-bearing rocks around okemesi ijero area, southwestern Nigeria. Global Scientific Journals 7, no. 1, 34–76.
     [Google Scholar]
  7. Akinlalu, A.A., A.O.Adelusi, G.M.Olayanju, K.A.N.Adiat, G.O.Omosuyi, A.Y.B.Anifowose, and B.E.Akeredolu. 2018. Aeromagnetic mapping of basement structures and mineralizationcharacterisation of Ilesa Schist belt, southwestern Nigeria. Journal of African Earth Sciences138: 383–91.
     [Google Scholar]
  8. Ako, B., T.Ajayi, and A.Alabi. 1978. A geoelectrical study of the Ifewara area. Journal Mining and Geology15: 84–9.
     [Google Scholar]
  9. Aktarakci, H.K., N.Harthill, and M.W.Blohm. 1997. Time-domain electromagnetic survey for gold exploration, Nevada. Geophysics62, no. 5: 1409–18.
     [Google Scholar]
  10. Bedrosian, P.A., M.K.Burgess, and T.Nishikawa. 2013. Faulting and groundwater in a desert environment: constraining Hydrogeology using time-domain electromagnetic data. Near Surface Geophysics11, no. 5: 545–55.
     [Google Scholar]
  11. Black, R.1980. Precambrian of West Africa. Episodes Journal of International Geoscience3, no. 4: 3–8.
     [Google Scholar]
  12. Christiansen, A.V., E.Auken, and K.Sorensen. 2006. The transient electromagneticmethod, in groundwater geophysics – a tool for hydrogeology, ed. R. kirsch. Berlin: Springer.
  13. Combrinck, M.2017. Using representative synthetic data to analyze effects of filters when processing Full Waveform airborne TEM data. Proceedings of Exploration 17: sixth decennial International Conference on mineral Exploration, eds. V. Tschirhart and M.D. Thomas, 99–111.
  14. Combrinck, M., R.Oortimer, and B.Peters. 2009. Base metal discoveries in Africa and Australia from VTEM data. ASEG Extended Abstracts 35, no. 8: 1563–1573.
     [Google Scholar]
  15. Combrinck, M., and R.Wright. 2016. Achieving accurate interpretation results from full-waveform streamed data AEM surveys: ASEG Expanded Abstracts 2016, 4 p.
  16. Edwards, M.D., and J.A.Webb. 2003. Ground-truthing of a tempest airborne electromagnetic survey in the Salinised Kamarooka catchment, near Bendigo in central Victoria. In Advances in regolith, ed. I.C.Roach, 110–114. Australia: CRC LEME.
     [Google Scholar]
  17. Elueze, A.A.1988. Geology of the Precambrian schist belt in IIesha area, southwestern Nigeria, 77–89. Precambrian geology of Nigeria. Geological Survey of Nigeria.
  18. Fainberg, E.1999. TEM–Fast 48 manual. Amsterdam: Applied Electromagnetic Research.
  19. Fullagar, P.K., and J.E.Reid. 2001. Emax conductivity-depth transformation of airborne TEM data. ASEG 15th Geophysical Conference and Exhibition, August 2001, Brisbane.
     [Google Scholar]
  20. Grant, F.S., and G.F.West. 1965. Interpretation theory in applied geophysics. New York: McGraw-Hill.
  21. Hammack, R.W., E.I.Love, G.A.Veloski, T.E.Ackman, and W.Harbert. 2003a. Using helicopter electromagnetic surveys to identify environmental problems at coal mines. Mine Water and the Environment22: 62–8.
     [Google Scholar]
  22. Hefford, S.W., R.S.Smith, and C.Samson. 2005. Quantifying the effect that changes in the transmitter-receiver geometry have on the capabilities of an airborne electromagnetic survey system with a towed receiver to detect good conductors. Presented at Ontario Prospector’s Association Annual Symposium, Toronto, ON, Dec. 13-14.
  23. Huang, H.P., and J.Rudd. 2008. Conductivity-depth imaging of helicopter borne TEM data based on a pseudolayer half-space model. Geophysics73, no. 3: F115–F120. doi:10.1190/1.2904984.
     https://doi.org/10.1190/1.2904984 [Google Scholar]
  24. Hubbard, F.H.1975. Precambrian crustal development in western Nigeria: indications from Iwo region. Geological Society of America Bulletin86: 548–54.
     [Google Scholar]
  25. Irvine, R.J., and M.J.Smith. 1990. Geophysical exploration for epithermal gold deposits. Journal of Geochemical Exploration36: 375–412.
     [Google Scholar]
  26. Jones, H.A., and R.D.Hockey. 1964. The geology of part of southwestern Nigeria. Geological Survey of Nigeria Bulletin31.
     [Google Scholar]
  27. Kamenetsky, F. M.1997. Electromagnetic geophysical research by the method of transitive processes, 162. Moscow: GEOS.
  28. Kaminski, V., D.Di Massa, and A.Viezzoli. 2016. Joint inversions of two VTEM surveys using quasi-3D TDEM and 3D magnetic inversion algorithms. Exploration Geophysics47, no. 4: 260–8. doi:10.1071/EG16014.
     https://doi.org/10.1071/EG16014 [Google Scholar]
  29. Kaufman, A., and G.V.Keller. 1993. Frequency and Transient sounding, 685. Amsterdam: Elsevier.
  30. Kayode, J.S.2006. Ground magnetic study of Jeda-Iloko Area, Southwestern Nigeria and its geologic implications. Unpublished M. Tech. Thesis Fed. Univ. Technol., Akure, Nigeria.
  31. Klemm, D.D., W.Schneider, and B.Wagner. 1984. The Precambrian metavolcano-sedimentary sequence east of Ife and IIesha/SW Nigeria. A Nigerian ‘greenstone belt'?Journal of African Earth Sciences2, no. 2: 161–76.
     [Google Scholar]
  32. Knight, R.J., and A.L.Endres. 1990. A new concept in modeling the dielectric response of sandstones: defining a wetted rock and bulk water system. Geophysics55: 586–94.
     [Google Scholar]
  33. Lane, R., A.Green, C.Golding, M.Owers, P.Pik, C.Plunkett, D.Sattel, and B.Thorn. 2000. An example of 3D conductivity mapping using the TEMPEST208 airborne electromagnetic system. Exploration Geophysics31: 162–72.
     [Google Scholar]
  34. Legault, J.M., G.Plastow, S.Zhao, N.Bournas, A.Prikhodko, and M.Orta. 2015. ZTEM and VTEM airborne EM and magnetic results over the Lalorcopper-gold volcanogenic massive sulfide deposit region, near Snow Lake, Manitoba. Interpretation 3, no. 2: SL83–SL94.
     [Google Scholar]
  35. Macnae, J., A.King, N.Stolz, A.Osmakoff, and A.Blaha. 1998. Fast AEM data processing and inversion. Exploration Geophysics29, no. 1–2: 163–9. doi:10.1071/EG998163.
     https://doi.org/10.1071/EG998163 [Google Scholar]
  36. Macnae, J., and Y.Lamontagne. 1987. Imaging quasi-layered conductive structures by simple processing of transient electromagnetic data. Geophysics52: 545–54.
     [Google Scholar]
  37. Macnae, J.C., R.Smith, B.D.Polzer, Y.Lamontagne, and P.S.Klinkert. 1991. Conductivity-depth imaging of airborne electromagnetic step-response data. Geophysics56: 102–14.
     [Google Scholar]
  38. McCracken, K.G., M.L.Oristaglio, and G.W.Hohmann. 1986. Minimization of noise in electromagnetic exploration systems. Geophysics51: 819–32.
     [Google Scholar]
  39. McCurry, P.1973. Geology of degree sheet 21, Zaria, Nigeria. Overseas geology and mineral resources. London, 45.
  40. McCurry, P.1976. The geology of the Precambrian to lower Paleozoic rocks of northern Nigeria – a review. In Geology of Nigeria, ed. C.A.Kogbe, 15–39. Lagos: Elizabeth Publ.
     [Google Scholar]
  41. Meju, M.1998. A simple method of transient electromagnetic data analysis. Geophysics63: 405–10.
     [Google Scholar]
  42. Mulè, S., R.Miller, H.Carey, and R.Lockwood. 2019. Review of three airborne EM systems. 22nd International Geophysical Conference and Exhibition, 26-29 February 2012 - Brisbane, Australia. ASEG. doi: 10.1071/ASEG2012ab352.
     https://doi.org/10.1071/ASEG2012ab352
  43. Munday, T., Y.Ley-Cooper, S.Johnson, and I.Tyler. 2013. A regional scale fixed-wing TDEM survey of the palaeo-Proterozoic Bryah Basin, Western Australia: providing insights into a setting highly prospective for VMS Cu-Au and mesothermal Au systems. ASEG Extended Abstracts2013, no. 1: 1–4.
     [Google Scholar]
  44. Nabighian, M., and J.Macnae. 1991. Time domain electromagnetic prospecting methods, Chapter 6 in Electromagnetic methods in applied geophysics, Volume 2, M. Nabighian Ed., Society of Exploration Geophysicists.
  45. Nekut, A.G.1987. Direct inversion of time-domain electromagnetic data. Geophysics52: 1431–5.
     [Google Scholar]
  46. NGSA. 2006. Nigeria Geological Survey Agency Geological map of Southwestern Nigeria.
  47. Obaje, N.G.2009. Geology and mineral resources of Nigeria. Springer: Springer-Verlag Berlin Heidelberg.
  48. Olobaniyi, S.B.1997. Geological and geochemical studies of the basement rocks and associated iron-formations of Isanlu Area in the Egbe-Isanlu Schist Belt, Southwest Nigeria. Unpublish PhD. thesis. University of Ilorin, Ilorin, Nigeria.
  49. Olobaniyi, S.B., and A.Mücke. 2011. Chemical composition of chromite and intergrown chlorite in metamorphosed ultramafic rocks (serpentinite and talc schist) of theEgbe-Isanlu schist belt, southwest Nigeria: genetic implications. Journal of Mining and Geological47: 115–34.
     [Google Scholar]
  50. Osinowo, O.O., A.K.Usman, and A.A.Omitoogun. 2020. Application of electrical resistivity tomography for mapping gold mineralization potential in Iperindo, Ilesha Schist Belt, southwestern Nigeria. International Journal of Advanced Geosciences8, no. 2: 146–52.
     [Google Scholar]
  51. Oyawoye, M.O.1972. The basement complex of Nigeria. In African geology. Ibadan University Press, ed. T.F.J.Dessauvagie, and A.J.Whiteman, 67–11/3. Ibadan: Ibadan University Press.
     [Google Scholar]
  52. Oyinloye, A.O.2011. Geology and geotectonic setting of the Basement Complex rocks in southwestern Nigeria: Implications on provenance and evolution. In Earth and Environmental Sciences, ed. I.A. Dar, chapter 5. Rijeka: InTech.
     [Google Scholar]
  53. Oyinloye, A.O., and G.M.Steed. 1996. Geology and geochemistry of the Iperindo primary gold deposits Ilesha schist belt southwestern Nigeria. inferences from stable carbon isotope studies. Africa Journal of Science and Technology8, no. 1: 16–9.
     [Google Scholar]
  54. Palacky, G.J.1976. Use of decay patterns for the classification of anomalies in time-domain AEM measurements. Geophysics41: 1031–41.
     [Google Scholar]
  55. Palacky, G.J.1993. Use of airborne electromagnetic methods for resource mapping. Advances in Space Research13, no. 11: 5–14.
     [Google Scholar]
  56. Pavlov, D.A., and M.S.Zhdanov. 2001. Analysis and interpretation of anomalous conductivity and magnetic permeability effects in time domain electromagnetic data. Journal of Applied Geophysics46, no. 4: 217–33. doi:10.1016/s0926‑9851(01)00040‑4.
     https://doi.org/10.1016/s0926-9851(01)00040-4 [Google Scholar]
  57. pbEncom. 2012. EM flow user guide.
  58. Peters, G., G.Street, I.Kahimise, and D.Hutchins. 2015. Regional TEMPEST survey in north-east Namibia. Exploration Geophysics46, no. 1: 27. doi:10.1071/eg14022.
     https://doi.org/10.1071/eg14022 [Google Scholar]
  59. Pfaffhuber, A.A., S.Monstad, and J.Rudd. 2009. Airborne electromagnetic hydrocarbon mapping in Mozambique. Exploration Geophysics40: 1–9.
     [Google Scholar]
  60. Rahaman, M.A.1976. Review of the basement Geology of southwestern Nigeria. In Geology of Nigeria, ed. C.A.Kogbe, 41–58. Lagos: Elizabethan Publ.Co.
     [Google Scholar]
  61. Rahaman, M.A.1988. Recent advances in the study of the basement complex of Nigeria. In Geological Survey of Nigeria, ed. P.O.Oluyide, W.C.Mbonu, A.E.Ogezi, I.G.Egbuniwe, A.C.Ajibade, and A.C.Umeji. Precambrian Geology of Nigeria, 11–43. Nigeria: Geological Survey of Nigeria.
     [Google Scholar]
  62. Ranieri, G.2000. TEM-fast: A useful tool for hydrogeologists and environmental engineers. Annali di Geofisica43: 1147–58.
     [Google Scholar]
  63. Ranieri, G., T.Haile, and T.Alemayehu. 2005. TEM-Fast Small-Loop Soundings to map underground tunnels and galleries connecting the rock-hewn churches of Lalibela, Ethiopia. Geoarchaeology20, no. 5: 433–48.
     [Google Scholar]
  64. Reninger, P.A., G.Martelet, E.Lasseur, L.Beccaletto, J.Deparis, J.Perrin, and Y.Chen. 2014. Geological environment of karst within chalk using airborne time domain electromagnetic data cross-interpreted with boreholes. Journal of Applied Geophysics106: 173–86. doi:10.1016/j.jappgeo.2014.04.020.
     https://doi.org/10.1016/j.jappgeo.2014.04.020 [Google Scholar]
  65. Russ, W.1957. The geology of parts of Niger, Zaria and Sokoto provinces, with special references to the occurrence of gold. Bulletin Geological Survey of Nigeria 27.
  66. Sapia, V., G.A.Oldenborger, A.Viezzoli, and M.Marchetti. 2014. Incorporating ancillary data into the inversion of airborne time-domain electromagnetic data for hydrogeological applications. Journal of Applied Geophysics104: 35–43.
     [Google Scholar]
  67. Sattel, D.2006. A brief discussion of helicopter time-domain EM system. SEG annual meeting, New Orleans.
  68. Sengpiel, K.P.1988. Approximate inversion of airborne electromagnetic data from a multilayered ground. Geophysical Prospecting36: 446–59.
     [Google Scholar]
  69. Sharma, P.V.1997. Environmental and engineering geophysics. Cambridge: Cambridge University Press.
  70. Silic, J., and T.Ballantyne. 2004. Discoveries through innovation in applications of airborne and ground TDEM in very conductive environment. ASEG Extended Abstracts2004, no. 1: 1–7. doi:10.1071/ASEG2004ab131.
     https://doi.org/10.1071/ASEG2004ab131 [Google Scholar]
  71. Slattery, S.R., and L.D.Andriashek. 2012a. Overview of Airborne-Electromagnetic and Magnetic Geophysical Survey Data Collection Using GEOTEM® over North of Calgary, Alberta. ERCB/AGS Open File Report 2012-09.
  72. Slattery, S.R., and L.D.Andriashek. 2012b. Overview of Airborne-Electromagnetic and Magnetic Geophysical Survey Data Collection Using the TEMPEST® Survey near Edmonton, Alberta. ERCB/AGS Open File Report 2012-11.
  73. Smiarowski, A., J.Macnae, and R.C.Bailey. 2010. Predictive filter calculation of primary fields in a fixed-wing time-domain AEM system. Geophysics75, no. 4: F97–F106.
     [Google Scholar]
  74. Smith, R.S.2001a. On removing the primary field from fixed-wing time-domain airborne electromagnetic data: some consequences for quantitative modelling, estimating bird position and detecting perfect conductors. Geophysical Prospecting49: 405–16.
     [Google Scholar]
  75. Telford, W.M., L.P.Geldart, and R.E.Sheriff. 2004. Applied geophysics. 2nd ed. Cambridge: Cambridge Univ. Press. pp. 356.
  76. Turner, D.C.1983. Upper Proterozoic schist belts in the Nigerian sector of the Pan- African province of West Africa. Precambrian Research21: 55–79.
     [Google Scholar]
  77. Ward, S.H.1967. The electromagnetic method. Mining Geophysics, Society of Exploration Geophysics2: 250–3.
     [Google Scholar]
  78. Webb, M., and B.Rohrlach. 1992. The Walford creek prospect – an exploration overview. Exploration Geophysics23: 407–12.
     [Google Scholar]
  79. West, G.F., and J.C.Mcnae. 1991. Physics of the electromagnetic induction exploration method. In Electromagnetic methods in applied geophysics v. 2: applications, part A: SEG, ed. M. N.Nabighian, 5–45. Tulsa: Society of Exploration Geophysicists.
     [Google Scholar]
  80. Woakes, M., C.A.Ajibade, and M.A.Rahaman. 1987. Some metallogenic features of the Nigerian basement. Journal of Africa Earth Sciences5: 655–64.
     [Google Scholar]
  81. Wright, J.B.1985. Geology and mineral resources of West Africa. London: George Allen & Unwin.
  82. Zhang, Q., C.Peng, Y.Lu, H.Wang, and K.Zhu. 2018. Airborne electromagnetic data levelling using principal component analysis based on flight line difference. Journal of Applied Geophysics151: 290–7. doi:10.1016/j.jappgeo.2018.02.023.
     https://doi.org/10.1016/j.jappgeo.2018.02.023 [Google Scholar]
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Structural mapping and gold mineralisation potential evaluation from airborne time – domain electromagnetic (TDEM) data of Ilesha Schist Belt, southwestern Nigeria
Exploration Geophysics 53, 237 (2022); https://doi.org/10.1080/08123985.2021.1922275
/content/journals/10.1080/08123985.2021.1922275
/content/journals/10.1080/08123985.2021.1922275
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  • Article Type: Research Article
Keyword(s): Airborne electromagnetics; mineral geophysics; processing; time-domain

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