Magnetic rocks distribution and depth to basement analysis on an old Quarry Site, Abeokuta, SW Nigeria

Subject Areas : Mineralogy

Akintayo  Ojo ¹ (Department of Science Laboratory Technology, School of Engineering and Sciences, D.S. Adegbenro ICT Polytechnic, Itori-Ewekoro, Ogun State, Nigeria)
Mubor  Adeloye ² (Department of Science Laboratory Technology, School of Engineering and Sciences, D.S. Adegbenro ICT Polytechnic, Itori-Ewekoro, Ogun State, Nigeria)
Ismail  Egbedele ³ (Department of Science Laboratory Technology, School of Engineering and Sciences, D.S. Adegbenro ICT Polytechnic, Itori-Ewekoro, Ogun State, Nigeria)
Feyisayo  Akinwande ⁴ (Department of Science Laboratory Technology, School of Engineering and Sciences, D.S. Adegbenro ICT Polytechnic, Itori-Ewekoro, Ogun State, Nigeria)

Received: 2019-12-05 Accepted : 2020-03-01 Published : 2020-07-01

Keywords: Mineral Rocks, Geomagnetic, Distribution, Susceptibility, depth,

Abstract :

Geomagnetic study was carried out to investigate the distribution and depth of formations of different magnetic rocks on an old quarry site, Abeokuta, Southwestern, Nigeria. Eight ground magnetic profiles were established with 10 m spacing intervals orientated in West-East and North-South directions, and ranged between 110 and 190 m. A total of 223 data sets were acquired and corrected for all forms of magnetic variations. The resulting residual anomalies were plotted against distance using Microsoft Excel tool. Also, these anomalies were modeled into 2D and 3D contour sections using Surfer 10. The depth to basement analysis was carried out using Peter’s half slope graphical method. The resulting profiles and contour sections revealed variable anomalies which indicated contrast in the magnetic distributions of the subsurface. Mineral rocks with average (0-150 nT) magnetic susceptibilities dominated the profiles, and this indicated that the study area is on pegmatite or Quartz vein which probably harbored Beryl, Graphite, Sandstone, Quartz, Tantalite and Mica in both massive and disseminated quantities. Regions with high (150-300 nT) and low (0 to -150 nT) magnetic susceptibilities were also observed across the profiles. Mineral rocks with very thin bodies were observed at depths 3.48-17.42 m, intermediate bodies were buried at depths 2.61-13.06 m, while very thick bodies were located at depths between 2.09 and 10.45 m. The depth of the magnetic sources revealed that the major and minor mineral rock contact in the study area.

References:

1. Adegoke JA, Layade GO (2014) Variation of Structural Index of Peters Half Slope in Determining Magnetic Source-Depth. Archives of Physics Research 5:23-31.


2. Ajayi TR, Ogedengbe O (2003) Opportunities for the exploitation of precious and rare metals in Nigeria. Prospects for investment in Mineral Resources of Southwestern Nigeria, A. A. Elueze (ed), Nigerian Mining and Geosciences Society (NMGS).


3. Biswas A (2016) Interpretation of gravity and magnetic anomaly over thin sheet-type structure using very fast simulated annealing global optimization technique. Model. Earth Syst. Environ. 2:30.


4. Folami SL (1992) Interpretation of Aeromagnetic Anomalies in Iwaraja area, South Western Nigeria. Journal of Mining and Geology 28:391-396.


5. Hrouda F, Chlupacova M, Chadima M (2009) The use of magnetic Susceptibility of Rocks in Geological Exploration. Terraplus Geophysical Equipment Supplier, First Edition.


6. Jones HA, Hockey RD (1964) The geology of South Western Nigeria. Nigerian Geological Survey Bulletin 31:101.


7. Kayode JS, Adelusi AO (2010) Ground Magnetic Data Interpretation of Ijebu-Jesa Area, Southwestern Nigeria, Using Total Component. Research Journal of Applied Sciences, Engineering and Technology 2:703-709.


8. Kayode JS, Adelusi AO, Nyabeze PK (2013) Interpretation of Ground Magnetic Data of Ilesa, Southwestern Nigeria for Potential Mineral Targets. Advances in Applied Science Research 4:163-172.


9. Kogbe CA (1989) Geology of Nigeria (Second Edition) Elizabethan Publishing & Co., Lagos.


10. Mandal A, Mohanty WK, Sharma SP, Biswas A, Sen J, Bhatt AK (2015) Geophysical signatures of uranium mineralization and it’s subsurface validation at Beldih, Purulia District, West Bengal, India: A case study. Geophysical Prospecting 63:713–724.


11. Mariita NO (2007) The Magnetic Method. Presented At Short Course Ii On Surface Exploration For Geothermal Resources, Organized By Unu-Gtp And Ken Gen, At Lake Naivasha, Kenya, 2-17 November.


12. Meri-Liisa A (2015) Geophysical Signatures of Mineral Deposit Types – Synopsis. Geophysical Signatures of Mineral Deposit Types in Finland, edited By Meri-Liisa Airogeological Survey of Finland, Special Paper 58:9-70.


13. Nabighian MN, Grauch JS, Hansen RO, LaFehr TR, Li Y, Peirce JW, Phillips JD (2005) The istorical development of the magnetic method in exploration. Geophysics 70:33ND-61ND.


14. Nwosu OB, Umego MN, Onuba LN (2015) Comparison of Magnetic Basement Depth Values from Spectral Technique, SPITH and Slope Techniques using HRAM. Journal of Geology and Geophysics 4:232.


15. Ojo Akintayo O (2013) Geomagnetic and Geoelectric Investigation of Mineral Rocks at Awo, Osun State, Southwest Nigeria. International Journal of Physical Research 1:60-74.


16. Ojo Akintayo O, Omotoso Toyin O, Adekanle Olorunyomi J (2014) Determination of Location and Depth of Mineral Rocks at Olode Village in Ibadan, Oyo State, Nigeria Using Geophysical Methods. International Journal of Geophysics, Article ID 306862, 13 pages.


17. Ojo AO, Popoola OI (2014) Geomagnetic of Mineral Rocks at Awo, Osun State, Southwest Nigeria. International Journal of Advanced Geosciences 2:20-30.


18. Okpoli C, Akingboye A (2016) Reconstruction and appraisal of Akunu–Akoko area iron ore deposits using geological and magnetic approaches. RMZ-M&G 63:19-38.


19. Okunlola OA (2005) Metallogeny of Tantalum-Niobium Mineralization of Precambrian Pegmatite of Nigeria. Mineral Wealth 104:38-50.


20. Okunlola OA, Adeigbe OC, Oluwatoke OO (2009) Compositional and petrogenetic features of schistose rocks of Ibadan area, southwestern Nigeria. Earth Sciences Research Journals 13:29-43.


21. Okunlola OA, Jimba S (2006) Compositional trends in relation to Ta-Nb Mineralization in Precambrian Pegmatite of Aramoko-Ara-Ijero Area, South Western Nigeria. Journal of Mining and Geology 42:113-126.


22. Okunlola OA, Ofonime BE (2006) Geological setting, petrographical features and age of Rare Metal (Ta-Nb) Mineralization of Pegmatite of Komu area, Southwestern Nigeria. African Journal of Science and Tech. (AJST); Science and Engineering Series 7:96-110.


23. Omatsola ME, Adegoke OS (1981) Tectonic Evolution and Cretaceous Stratigraphy of the Dahomey Basin. Journal of Mining Geology 8:130-137.


24. Oyawoye MO (1964) The geology of the basement complex. Journal of Nigeria Mining, Geology and Metallurgy 1:87-102.


25. Peters LJ (1949) The direct approach to magnetic interpretation and its practical application. Geophysics 14:290-320.


26. Rahaman MA (1976) Review of the basement geology of southwestern Nigeria In Kogbe, C.A. (Ed); Geology of Nigeria. Elizabethan publishing Co, Lagos.


27. Reynolds JM (1997) An introduction to Applied and Environmental Geophysics (Second Edition). Reynold Geo-Sciences Limited.


28. Roger S (2008) Magnetic Susceptibility as a Tool for Investigating Igneous Rocks experience. IODP Expedition 304.


29. Telford WM, Geldart LP, Sheriff RA (1990) Applied geophysics. Cambridge University Press.


30. Umego MN, Ojo SB (1995) A magnetic depth to basement analysis in the Sokoto basin, North Western Nigeria. Journal of Mining and Geology 31:161-167.