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  • Fadele, Jatau, Patrick / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.1143-1153Geophysical Engineering Investigation Around Makiyaye Village, Shika Area Within The Basement Complex Of North-Western Nigeria. FADELE S.I, JATAU B.S AND PATRICK N.O Nasarawa State University, Keffi, NigeriaAbstractGeophysical investigation for engineering studies as septic tanks and sewage channels are plannedwas carried out around Makiyaye village which for the area under study.falls within the Basement Complex of North-Western Nigeria. The study is aimed at (Key words: VES, Top soil, Weathered Basement,evaluating the competence of the near surface Partly weathered or Fractured Basement, Freshformation as foundation materials, and to Basement)unravel the subsurface profile which in turndetermines if there would be any subsurface I. Introductionlithological variation(s) that might lead to The failure statistic of structures such asstructural failure at the site and evaluating the buildings, tarred roads and bridges throughout thegroundwater potential of the site and nation is increasing geometrically. Most of thesedetermining the level of safety of the failures were caused by swelling clays (Blyth andhydrogeologic system. Vertical Electrical Freitas, 1988). In recent times, the collapse of civilSounding (VES) using Schlumberger array was engineering structures has been on the increase forcarried out at eighteen (18) VES stations. ABEM reasons associated with subsurface geologicalterrameter (SAS 300) was used for the data sequence (Omoyoloye et al., 2008). The need foracquisition. The field data obtained have been subsurface geophysical investigation has thereforeanalysed using computer software (IPI2win) become very imperative so as to prevent loss ofwhich gives an automatic interpretation of the valuable properties and lives that always accompanyapparent resistivity. The geoelectric section such a failure. Foundation evaluation of a new site isrevealed three to four lithologic units defined by necessary so as to provide subsurface and aerialthe topsoil, which comprises clayey-sandy and information that normally assist civil engineers,sandy lateritic hard pan; the weathered builders and town planners in the design and sitingbasement; partly weathered/fractured basement of foundations of civil engineering structuresand the fresh basement. The resistivity values (Omoyoloye, et al., 2008). Geophysical methodsrange from 28 - 354Ωm in the topsoil, 70 - such as the Electrical Resistivity (ER), Seismic356Ωm in the weathered basement, 245 - 694Ωm refraction, Electromagnetic (EM), Magnetic andin the fractured basement and 1114 - 3699Ωm in Ground Penetrating Radar (GPR) are used singly orthe fresh basement . Layer thicknesses vary from in combinations for engineering site investigations.0.38 – 2.64m in the topsoil, 0.7 – 37.36m in the The applications of such geophysical investigationweathered layer, 5.86 – 34.2m in the fractured are used for the determination of depth to bedrock,basement. Depth from the surface to structural mapping and evaluation of subsoilbedrock/fresh basement generally varied competence (Burland, J.B and Burbidge, M.Cbetween 2.64 and 44.11m. Based on the resistivity 1981). The engineering geophysical investigationvalues, it is concluded that the subsurface was carried out around Makiyaye village, Zaria,material up to the depth greater than 20m is Kaduna State, North-Western Nigeria, aimed atcompetent and has high load-bearing capacity. determining the depth to the competent stratum inHowever, resistivity values less than 100Ωm at the subsurface, delineation of areas that are prone todepths of 10 - 15m indicate high porosity, high subsidence or some form of instability, evaluatingclayey sand content and high degree of saturation the groundwater potential of the site andwhich are indications of soil conditions requiring determining the level of safety of the hydrogeologicserious consideration in the design of massive system in the study area.engineering structures. The hydrogeologic systemat the site is vulnerable to contamination. Hence, II. Location and Topography of thethe result reasonably provide a basis for which Study areagroundwater potential zones are appraised for The study area lies between Latitudes 110safety in case potential sources of groundwater 10’ 09”N - 110 11’00’’N and Longitudes 70contamination sites such 1143 | P a g e
  • Fadele, Jatau, Patrick / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.1143-115335’50”E - 70 38’ 40” E. The site is situated along northwest trend. They have a pronounced effect onthe Sokoto road, North West of Zaria (Fig. 1). The the drainage pattern of the state.topography is that of high plain (flat terrain) ofHausa land. The site is located within the tropical IV. Methodologyclimatic belt with Sudan Savannah vegetation. The Vertical Electrical Soundings (VES) usingenvironment is Savannah type with distinct wet and Schlumberger array were carried out at eighteendry season. The rainfall regime is simple but with (18) stations. A regular direction of N-S azimuthslight variation which consists of wet season lasting was maintained in the orientation of the profiles.from May to September and characterized by heavy Overburden in the basement area is not as thick as todown pour at the start and end of the rainy season. warrant large current electrode spacing for deeperThe annual rainfall varies between 800 mm to 1090 penetration (Oseji, et al., 2005; Okolie, et al., 2005),mm while the mean annual temperature ranges therefore the largest Current electrode spacing ABbetween 240C to 310C reaching a maximum of about used was 200m, that is, 1/2AB=100m. The360C around April (Hore,1970; Goh Cheng Leong principal instrument used for this survey is theand Adeleke, 1978). ABEM (Signal Averaging System, (SAS 300) Terrameter. The resistance readings at every VESIII. Geology of Study Area point were automatically displayed on the digital The study area is laid on undifferentiated readout screen and then written down on paper.basement. Though there were no rock out-cropswithin the site, observation however revealed that V. Results and Discussionthe weathered bedrock in some existing hand-dug The geometric factor, K, was firstwells within the site and environs indicates the calculated for all the electrode spacings using theoccurrence of granitic rocks within the site which formula; K= π (L2/2b – b/2), for Schlumberger arrayare porphiritic in texture. The study area falls within with MN=2b and 1/2AB=L. The values obtained,the Metasediments of the Basement Complex were then multiplied with the resistance values to(McCurry, 1970). The Basement Complex in obtain the apparent resistivity, ρa, values. Then theKaduna state was affected by an Orogeny, which apparent resistivity, ρa, values were plotted againstpredated the emplacement of the Older Granite. the electrode spacings (1/2AB) on a log-log scale toDuring this event, deformation of the basement obtain the VES sounding curves using anproduced north-south trending basins of appropriate computer software IPI2win in theMetasediment in the form of Synclinoria. Tertiary present study. Some soundingearth movements tilted the Metasediments to northand warped the basement along the axis of the upliftpass through the present Kaduna state having 1144 | P a g e
  • Fadele, Jatau, Patrick / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.1143-1153 Study Area Figure 1: Location Map Showing the Study Area (From Northern Nigerian Survey Map) 1145 | P a g e
  • Fadele, Jatau, Patrick / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.1143-1153curves and their models are shown in Fig 2. structural features have some geological, physicalSimilarly, geoelectric sections are shown in Figs. 3 and near-surface engineering significance.and 4.Three resistivity sounding curve types wereobtained from the studied area and these are the H Profile A-A’(ρ1>ρ2<ρ3), A (ρ1< ρ2<ρ3) and KH (ρ1>ρ2< ρ3>ρ4) Profile A-A’ geoelectric section suggeststype curves. The results of the interpreted VES that the site is characterized by lateritic hard pan atcurves are shown in Table 1 and 2. The modeling different consolidation levels within shallowof the VES measurements carried out at eighteen depths, while gneiss and granites mainly,(18) stations has been used to derive the geoelectric characterize the basements. The fresh basementssections for the various profiles (Figs. 4 and 5). have synclinal structure which cut across theThese have revealed that there are mostly four and profile (fig. 4). The weathered/fractured basementsthree geologic layers beneath each VES station. have sharp dipping layers along VES 5, 6, 7 and 8.The geologic sequence beneath the study area is The probable feature that may cause buildingcomposed of top soil, weathered basement, partly failure could be geologic feature like dippingweathered/fractured basement, and fresh basement. bedrock or synclinal structure. This is becauseThe topsoil is composed of clayey-sandy and while overburden materials fill the synclinalsandy-lateritic hard crust with resistivity values structure, their columns undergo ground movementranging from 28Ωm to 354Ωm and thickness by subsidence and thereby could amount to unevenvarying from 0.38m to 2.64m, thinnest at VES 12 settlement at the foundation depths of buildings. Inand thickest at VES 6, 11 and 14. It is however, other words, uneven stress distribution may occurobserved from the geoelectric sections that VES 2, at the foundation depths of subsurface, that is one3, 4, 9, 10, 11, 12, 13, 14 and 15 are characterized side of building structure may have a strongerwith low resistivity values varying between 26Ωm support than the other adjacent of it. Anotherto 53Ωm suggesting the clayey nature of the topsoil factor that could contribute to structural defect ofin these areas and possibly high moisture content. building is the seasonal variation in the saturationThe second layer is the weathered basement with of clay which causes ground movement and isresistivity values varying from 70Ωm to 356Ωm caused by clay swells and shrinkages which areand thickness ranges between 0.7m to 37.36m, occasioned by alternate wet and dry seasons. Thethinnest at VES 1and thickest at VES 6. The third area is characterized by clay soils with lateriticlayer is the partly weathered and fractured patches at shallow depths with their thicknessbasement with resistivity and thickness values ranging between 1.37m and 2.64m, which arevarying between 245Ωm to 694Ωm and 5.86m to considerably thin and are resting on the shallow34.2m respectively. The layer is extensive and weathered/fractured basement.thickest at VES 18 and thinnest at VES 16. Thefourth layer is presumably fresh basement whoseresistivity values vary from 1114Ωm to 3699Ωmwith an infinite depth. Though the thickness of thebedrock is assumed to be infinite, the depth fromthe earth’s surface to the bedrock surface variesbetween 2.64m to 44.11m. Quite a few of theprofiles dipping and a negligible number of themshow synclinal and fractured structure. These 1146 | P a g e
  • Fadele, Jatau, Patrick / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.1143-1153 Table 1: The results of the interpreted VEScurves VES Thickness (m) Layer resistivity Remarks Curve types Numb of layersStations (Ωm) 1.23 152 TP 1 0.70 113 WB KH 4 9.69 426 PWB - 1329 FB 2.29 45 TP 2 12.2 171 WB A 3 - 1765 FB 3 1.71 48 TP 3 11.2 298 WB A - 1198 FB 1.13 48 TP 4 5.96 326 WB KH 4 11.6 433 PWB - 2112 FB 1.23 196 TB 5 0.78 152 WB KH 4 10.2 245 PWB - 1960 FB 2.64 256 TP 6 37.36 114 WB H 3 - 1450 FB 1.87 249 TP 7 12.1 169 WB H 3 - 1365 FB 1.37 154 TP 8 2.14 199 WB KH 4 15.2 565 PWB - 1289 FB 2.09 53 TP 9 7.82 70 WB KH 4 34.2 450 PWB - 1114 FB 1.13 26 TP 10 2.33 316 WB A 3 - 1251 FB 2.64 28 TB 11 8.84 162 WB A 3 - 1410 FB 0.38 27 TP 12 5.10 162 WB A 3 - 3600 FB 1147 | P a g e
  • Fadele, Jatau, Patrick / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.1143-1153 Table 2: The results of the interpreted VES curves VES Thickness (m) Layer resistivity Remarks Curve types Numb of layersStations (Ωm)Apparent resistivity (Ωm) Where, N is the number of layers, ρ is the apperent resistivity, h is the thickness and d is the depth to interface of each layer. Electrode spacing (m) (a) TYPE KH CURVE 1148 | P a g e
  • Fadele, Jatau, Patrick / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.1143-1153Apparent resistivity (Ωm) Where, N is the number of layers, ρ is the apperent resistivity, h is the thickness and d is the depth to interface of each layer. Electrode spacing (m) (b) TYPE A CURVEApparent resistivity (Ωm) Where, N is the layer number, ρ is the apperent resistivity in ohm-metre, h is the layer thickness and d is the depth to interface of each layer Electrode spacing (m) (c) TYPE A CURVE Figure 2: Typical curve types and models obtained from the study area. 1149 | P a g e
  • Fadele, Jatau, Patrick / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.1143-1153 VES 1 VES 2 VES 3 VES 4 VES 5 VES 6 VES 7 VES 8 VES 9 A 1A 52𝜴𝒎 2A 3A 𝟒𝟖𝜴𝒎 4A 𝟒𝟖𝜴𝒎 5A 𝟏𝟗𝟔𝜴𝒎 6A 𝟐𝟓𝟕𝜴𝒎 7A 𝟐𝟒𝟗𝜴𝒎 8A 𝟏𝟓𝟒𝜴𝒎 9A 𝟓𝟎𝜴𝒎 A’ 𝟒𝟓𝜴𝒎 113 𝜴𝒎 𝟏𝟓𝟐𝜴𝒎 𝟏𝟗𝟗𝜴𝒎 𝟐𝟎𝜴𝒎 326𝛺𝑚 𝟏𝟕𝟏𝜴𝒎 𝟐𝟗𝟖𝜴𝒎 10 426 𝜴𝒎 𝟏𝟔𝟗𝜴𝒎 𝟐𝟒𝟓𝜴𝒎 𝟏𝟏𝟒𝜴𝒎 𝟏𝟓𝟐𝜴𝒎 𝟒𝟑𝟑𝜴𝒎 𝟏𝟓𝟑𝜴𝒎 𝟐𝟔𝟒𝟑 𝜴𝒎 𝟏𝟑𝟎𝟗 𝜴𝒎DEPTH (m) 20 𝟏𝟏𝟔𝟓 𝜴𝒎 𝟏𝟗𝟔𝟎 𝜴𝒎 𝟏𝟑𝟎𝟗𝜴𝒎 𝟐𝟏𝟏𝟐 𝜴𝒎 𝟏𝟐𝟖𝟗𝜴𝒎 30 𝟏𝟏𝟒𝟒𝜴𝒎 40 𝟏𝟒𝟏𝟎 𝜴𝒎 Clay/clayey sandy (Top soil) Lateritic hard pan (Top soil) Weathered layer Partly weathered/fractured layer Fresh basement Figure 3: Geoelectric section along profiles A-Ai 1150 | P a g e
  • Fadele, Jatau, Patrick / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.1143-1153 VES 10 VES 11 VES 12 VES 13 VES 14 VES 15 VES 16 VES 17 VES 18 1D 3D 4D 5D 6D 7D 8D 9D B’ B 26 𝜴𝒎 28 𝜴𝒎 30 𝜴𝒎 254 𝜴𝒎 281 𝜴𝒎 256 𝜴𝒎 28 𝜴𝒎 30 𝜴𝒎 316 𝜴𝒎 347 𝜴𝒎 358 𝜴𝒎 356 𝜴𝒎 261 𝜴𝒎 162 𝜴𝒎 199 𝜴𝒎 519 𝜴𝒎 694 𝜴𝒎 302 𝜴𝒎 3699 𝜴𝒎 2593 𝜴𝒎 3307 𝜴𝒎 1270 𝜴𝒎 2935 𝜴𝒎 10 1519 𝜴𝒎 658 𝜴𝒎 1410 𝜴𝒎DEPTH (m) 20 30 1614 𝜴𝒎 40 Clay/clayey sandy (Top soil) Lateritic hard pan (Top soil) 3511 𝜴𝒎 Weathered layer Partly weathered/fractured layer Fresh basement Figure 4: Geoelectric section along profiles B-Bi Profile B-B’ Competence Evaluation The geoelectric section revealed clayey There are no indications of any major sandy topsoil having some lateritic hard crust linear structure such as fracture or faults that could patches (fig. 5). The synclinal structure at VES aid building subsidence. The geologic sequence point 11 is not well pronounced and may not pose beneath the area is composed of thin layer of any serious danger to building foundation. topsoil, thick weathered layer, partly However, there is a deep weathering beneath VES weathered/fractured basement and fresh bedrock. point 17 and 18. The presence of laterite beneath The topsoil constitutes the layer within which small the clayey topsoil which hardly extends beyond civil engineering structures can be constructed. 2.64m reduces the danger posed by clay formation From the table of resistivity values (Table 1), the to large buildings. This area forms a good site for topsoil is composed of sandy clay, clayey sand and the erection of high-rise civil engineering patches of lateritic hard pans. Engineering structures. competence of the subsurface can be qualitatively evaluated from the layer resistivity. The higher the layer resistivity value, the higher the competence of a layer; hence from the point of view of the 1151 | P a g e
  • Fadele, Jatau, Patrick / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.1143-1153resistivity value therefore, laterite is the most areas and possibly high moisture content. Thecompetent of the delineated topsoil, followed by second layer is the weathered basement withclayey sand and sandy clay being the least resistivity values varying from 70Ωm to 356Ωmcompetent. Based on the resistivity values, depths and thickness ranges between 0.7m to 37.36m,of about 10 - 15m can support small to medium thinnest at VES 1 and thickest at VES 6. The thirdsize structures while depth in excess of 25m can layer is the partly weathered and fracturedsupport massive civil engineering structures in the basement with resistivity and thickness valuesstudy area. varying between 245Ωm to 694Ωm and 5.86m to 34.2m respectively. The layer is extensive andGroundwater Potential thickest at VES 18 and thinnest at VES 16. The Even though experience has shown that fourth layer is presumably fresh basement whosethere is no direct relationship between groundwater resistivity values vary from 1114Ωm to 3699Ωmyield and borehole depth in a basement complex with an infinite depth. Though the thickness of theenvironment, studies (Bala and Ike, 2001; Omosuyi bedrock is assumed to be infinite, the depth fromet al., 2008; Ariyo and Osinawo, 2007) revealed the earth’s surface to the bedrock surface variesthat areas with thick overburden cover in such between 2.64m to 44.11m. A-curve type whichbasement complex terrain has high potential for shows a continuous and uniform increase ingroundwater. According to Ariyo and Oguntade resistivity predominates. This curve typifies an area(2009), in a basement complex terrain, areas with showing characteristics of high load-bearingoverburden thickness of 15m and above are good strength. This is followed by HK-curve showingfor groundwater development. The highest that some areas have overburden saturation whichgroundwater yield is often obtained from a recharges the main aquifer units. The rest of theweathered/fractured aquifer, or simply a subsurface curves are minority in number with H-type curvesequence that has a combination of a significantly which has a minimum resistivity intermediate layerthick and sandy weathered layer and fractured underlain and overlain by more resistant materialsaquifer. Where the bedrock is not fractured, a reminiscent of areas promising for groundwaterborehole can be located at a point having a development. Based on the resistivity values of therelatively high layer resistivity greater than 150Ωm different geoelectric layers, the various geologicbut less than 600Ωm (Olorunfemi, 2009). From the units up to depth of 25m are competent and canforegoing two parameters – overburden thickness support massive civil engineering structures. Theand resistivity values, VES 2, 3, 4, 5, 6, 8, 9, 17 presence of laterite beneath the clayey topsoiland 18 can be considered to be productive zones which hardly extends beyond 2.64m reduces thefor groundwater development in the study area. danger posed by clay formation to large buildings.Since the area is generally shallow to the water Other probable causes of foundation defects are theaquifer and groundwater in this area is vulnerable growth of tree roots, organic deposits, sink holes,to pollution, the depth of sewage system should be cavities or ground surface saturation due to<10m to the weathered basement (aquiferrous seepages and this should be taken care of duringzone) in order to avoid groundwater contamination. building project implementation to ensure thatIt is suggested that potential sources of buildings erected at the site stands the test of time.contamination site like sewage channels should be In a basement complex terrain, areas withsited far away from viable aquifer units to ensure overburden thickness of 15m and above are goodsafety consumption of groundwater within the area. for groundwater development. The highest groundwater yield is often obtained from aVI. Conclusion weathered/fractured aquifer, or simply a subsurface The VES results revealed heterogeneous sequence that has a combination of a significantlynature of the subsurface geological sequence. thick and sandy weathered layer and fracturedThough the geoelectric section showed complexity aquifer. Where the bedrock is not fractured, ain the Subsurface lithology, there is however, no borehole can be located at a point having aindication of any major fracture or fault that could relatively high layer resistivity greater than 150Ωmaid subsidence. The geologic sequence beneath the but less than 600Ωm (Olorunfemi, 2009). From thestudy area is composed of topsoil, weathered layer, foregoing two parameters – overburden thicknesspartly weathered/fractured basement, and fresh and resistivity values, VES 2, 3, 4, 5, 6, 8, 9, 17basement. The topsoil is composed of clayey-sandy and 18 can be considered to be productive zonesand sandy-lateritic hard crust with resistivity values for groundwater development in the study area. Toranging from 26Ωm to 391Ωm and thickness ensure safety appraisal of groundwatervarying from 0.38m to 2.64m, however, observed consumption in the area, potential sources offrom the geoelectric sections that VES 2, 3, 4, 10, contamination site should be sited far away from11, 12, 13, 14 and 15 are characterized with low viable aquifer units to ensure safety consumption ofresistivity values varying between 26Ωm to 53Ωm groundwater within the study area.suggesting the clayey nature of the topsoil in these 1152 | P a g e
  • Fadele, Jatau, Patrick / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.1143-1153References 14. Nigerian Association of Hydrogeologists. 1. Ariyo, S.O. and Oguntade, A.K. (2009). Special Publication Series 1, pp. 1-20. Geophysical Investigation for 15. Omoyoloye, N.A., Oladapo, M.I. and Groundwater Potential in Mamu Area, Adeoye, O.O., (2008). Engineering Southwestern Nigeria. Medwell Online Geophysical Study of Adagbakuja Journal of Earth Sciences, Vol.3, no.1, Newtown Development, Southwestern pp.10-13. Nigeria. Medwell Online Journal of Earth 2. Ariyo, S.O. and Osinawo, O.O. (2007). Science; Vol. 2(2); pp. 55-63 Hydrogeophysical Evaluation of 16. Oseji, J.O., Atakpo, E. and Okolie, E.C. Groundwater Potentials of (2005). Geoelectric Investigation of the Atan/Odosenbora. Vol.9, no.1, pp. 50-65. Aquifer Characteristics and Groundwater 3. Bala, A.E. and Ike, E.C. (2001). The Potential in Kwale, Delta State. Nigerian Aquifer of the Crystalline Basement Journal of Applied Sciences and Complex Area of Africa. Quarterly Environmental Management, Vol.9, pp. Journal of Engineering Geology, Vol.18, 157-1600. pp. 35-36.Burger, R.H (1992), ‘Exploration Geophysics of the Shallow Subsurface’. prentice Hall, U.S.A. pp. 30- 56 4. Blyth, F.G.H and de Freitas, M.D., (1988).A Geology for Engineers’, Butler and Tannar Ltd, Frome and London. Pp. 292-293. 5. Geology for Engineers. Butler and Tannar Ltd, Frome and London. Pp. 292-293. 6. Burland, J.B and Burbidge, M.C (1981). Settlement of Foundations on Sand and Gravel Proceedings of the Institution of Civil Engineers, 78(1), pp. 1325- 1381. 7. Goh, C.L., and Adeleke, B.O., (1978). Certificate Physical and Human Geography’ Oxford University Press, Ibadan,pp78-150. 8. Hore, P.N (1970). Weather and Climate of Zaria and its Region .(Ed.) By M.J. Mortimore, Department of Geography, Occasional Paper No4. A.B.U. Zaria. pp. 41-54 9. McCurry, P. O. (1970). The Geology of Zaria Sheet 102 S.W and its Region in Mortimore, M.J. (Ed). Department of Geography occasional paper No.4, 10. Ahmadu Bello University, Zaria. pp. 1-3. 11. Omosuyi, G.O., Ojo, J.S. and Enikanoselu, P.A. (2003). Geophysical Investigation for Groundwater around Obanla-Obakekere in Akure Area within the Basement Complex of South-western Nigeria. Journal of Mining and Geology, Vol.39, no.2, pp. 109-116. 12. Okolie, E.C., Osemeikhian, J.E.A., Oseji, J.O. and Atakpo, E. (2005). Geophysical Investigation of the Source of River Ethiope in Ukwuani Local Government Area of Delta State. Nigerian Institute of Physics, Vol.17, pp.30-45. 13. Olorunfemi M.O. (2009). Water resources, Groundwater Exploration, Borehole site selection, and Optimum Drill Depth in Basement Complex Terrain: Journal of the 1153 | P a g e