Applied Geophysics
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Applied Geophysics
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Item Determination of Depth to Buried Magnetic Rocks under the Lower Sokoto Basin, Nigeria Using Aeromagnetic Data. Nigerian Journal of Physics N.J.P. Vol 19 No.2 Pp 275 - 283.(Nigerian Journal of Physics N.J.P., 2007-08) ADETONA, Adebayo Abbass, Udensi E.E. and A.G Agelaga (2007).The Total Aeromagnetic Data covering the study area was subjected to First Vertical Derivative, Spectral Depth Amalysis and Source Parameter Imaging. The result from the First Vertical Derivative shows the Northern part of the area is covered by the young biotite granite of precambrian origin, and the western edge is covered by the old granite, gneisses and migmatite of Western Nigeria, while the remaining area are covered by the cretaceous sedimentary deposits. The entire area was divided into forty eight sections Spectral Depth Analysis was run for each of these forty eight sections, the result shows that a maximum depth above 7 km was obtained within the cretaceous sediments of Idah, and Ankpa, and bellow Udegi at the middle of the study area. Minimum depth estimate between 188.0 to 452 meters were observe around the basement regions. Result from Source Parameter Imaging shows a minimum depth of 76.983 meters and a maximum thickness of sedimentation of 9.847 km, which also occur within Idah, Ankpa and Udegi axis. The disparity observes in depth obtained by each method is discussed base on the merit and demerit of each method, and the depth obtained were compared with result from previous researchers. Geophysical implication of the result to oil and gas exploration in the area is briefly discussed.Item The Delineation and Hydrothermal Alteration zones in Gitata Sheet, North Central Nigeria(. Kada journal of Physics, 2019-03) ADETONA, Adebayo Abbass, Mam D,T, Emmanuel E, U and Usman D. AThis research presents a summary of the research carried out within Talata_Mafara (31) and Kaura_Namoda (32) sheets in Zamfara State, and is bounded by the longitude 6°00´E and 7°00 E and latitude 12°30´N and 13°00´N using Aero-magnetic and Aero radiometric data. The structural deformation to the basement rocks interpreted as faults, fractures, dykes, joints and geological boundaries were delineated. From the radiometric data, regions that has suffered hydrothermal alterations due to potassium enrichment and Thorium depreciation were mapped and interpreted as regions of orogenic gold mineralization. Majority of the fault lines were identified and some subsistent fracture lines denoted as fs. A major fault line trending NE-SW, cut the study area into two runs diagonally for about 70 km. Regions of hydrothermal alteration were evaluated from K/Th ratio, K-deviation and F-parameter. Combination of these grid results obtained from the three methods stated above was used to build a ternary map, where K/Th is red, k-deviation is blue and F-Parameter as green. Analysis and interpretation of the ternary image indicate that regions where high K/Th values (0.19 – 0.25) %/ppm, high k-deviation values (0.63 – 1.20) and high F-Parameter values (0.43 – 0.67) appears as white on the colour aggregate, an indication of high hydrothermal altered zone. Area with grey colour indicating moderately altered zone. Regions that appears as dark colour indicate low values of K/Th, K-deviation and F-Parameter this occurs within the sedimentary formation of Bida Basin sand stone, located at the Northern end and South Eastern corner of the study area. A comprehensive analysis of these results delineated region of hydrothermal altered zones in white and grey colour that coincides with areas within the faulted and fractured basement. Delineated structures from the magnetic data that coincide with regions of potassium alterd hydrothermal zones are marked as regions of orogenic gold mineralisation haloes. Most of the features that are solid mineral hosts can be found within this vein and in the adjacent, highly deformed host rock located around Tagangani, Kwashebawa, Gyeranya, Yanbuki and Zurmi. The deformation appears to principally comprise of quartz schist, amphibolites schist, undifferentiated schist, mica schist, granite gneiss, porphyritic granite, migmatite, along medium grained granite.Item Geoelectrical Investigation on Road Failure of part of London Road Minna, Nigeria(Dutse Journal of Pure and Applied Sciences (DUJOPAS), 2020) ADETONA, Adebayo Abbass, 31 Ndanusa H. H, Rafiu A. A, Salako K.A, Alhassan U,D,An electrical resistivity method involving Wenner technique was carried out at part of London Road Minna, Niger State. The aim of the study was to investigate the causes of road failure. Two profiles parallel to the road of the study area of 300 m in length were investigated using Wenner array electrical configuration method. The electrode spacing was at equal interval of 7.5 m and current was sent into the ground using both current electrodes while potential electrodes received the signal which is display by the terrameters in resistivity. A total of 42 electrodes were probed. The calculated apparent resistivity pseudo section of profile A shows low resistivity. At the distance between 205 - 250 m the material is of low resistivity which can also lead to failure of the road. Profile B shows some anomalies between the distances of 45-60 m which is likely to be clay.Item Determination of sedimentation thickness within the Eastern part of Benue Trough, Nigeria from high resolution aeromagnetic data(Zimbabwe Journal of Science & Technology, 2018) ADETONA, Adebayo Abbass.The estimation of basement depth within the eastern part of Lower Benue Basin was based on both Source Parameter Imaging and Spectral method of analysis of the high resolution Aeromagnetic data covering the study area. The total area covered is 18,150 km2 which include Markudi, Gboko, Otukpo Agena, Akwana, and Katsina-Ala, all in Benue state of Nigeria. The areais bounded by latitude 70 .00' and 80 .00' and longitude 8 0 .00’and 90.50’. The aeromagnetic data was subjected to Vertical derivative, Analytical signal, Source parameter imaging SPI) and spectral depth analysis. These derivatives help demarcate regions of relatively thick sedimentation and regions of basement rock outcrop and intrusions into sedimentary formations at shallow depth. Maximum depth of sedimentation from SPI method is 4.146 Km which is located at the Eastern edge below Akwana, depth in the range of 3 Km were also obtain at the Western edge below Gboko, Makurdi and around Agena. Shallow sedimentations were observed at the South Eastern and North Eastern corner of the study area. Result from the spectral depth analysis give depth values that varies from 2.36 Km to 5.42 Km. Results from these two methods correlate in location and value. Regions with depth estimate above 4 Km could be explored for hydrocarbon and gas exploration. The South-Eastern corner and the North-Eastern corner of the study area which depict consolidated lithology at relatively shallow depths can serve as locations for water reservoirs at the height of rainy seasons to avoid flooding.Item Assessment of Geothermal Potentials In Some Parts of Upper Benue Trough Northeast Nigeria Using Aeromagnetic Data(Journal of Geoscience, Engineering, Environment, and Technology, 2019) ADETONA, Adebayo Abbass, Abdulwahab Mohammed, Taiwo Adewumi, Salako A.Kazeem, Rafiu AbdulwaheedAbstract The assessment of geothermal potentials over part of the upper Benue trough corresponding to Kaltungo, Guyok, Lau and Dong areas, North Eastern Nigeria using spectral depth analysis of aeromagnetic data has been carried out. The study area is bounded by latitudes 9o o o oThis research work is necessitated by the need forrenewable and alternative sources of energy for use in Nigeria. Regional/residual separation was carried out on the total magneticfield using polynomial fitting method of order one. The residual map was divided into nine overlapping blocks for the spectral analysis. The centroid depths and depth to top of basement were obtained from the plot of log of power spectrum against wavenumber. These two parameters were used to estimate the Curie point depth using 𝑍𝑏 = 2𝑍𝑜 − 𝑍𝑡 , where 𝑍𝑏, 𝑍𝑜 and 𝑍𝑡 are Curie depth, centroid depth and depth to top of basement respectively. The results from the spectral analysis suggested that in the parts of the Upper Benue trough, the basement is deepest at the south western portion towards the Lau area and varies between 0.55 and 3.8 km, while the centroid depth varies from 7.26 to 18.00 km. From the same portion of the trough, the Curiepoint depths vary between 12.43 and 33.91 km and the corresponding geothermal gradient and heat flow values varying from 17.10 to 46.66 0C/km with an average of 30.75 0 C/km and 42.75 to 116.65 mW/m2 with an average of 75.91 mW/m2 respectively. The maximum heat flow is found around the south western portion of the study area (Lau). The entire study area with high heat flow values might probably be good sources for geothermal and thereby recommended for both geothermal exploration and exploitation.Item Geoelectrical investigation of groundwater potential, at Nigerian Union of Teachers Housing estate, Paggo, Minna, Nigeria(Applied Water Science, 2019) ADETONA, Adebayo Abbass, Bello H. I. • U. D. Alhassan • K. A. Salako, • A. A. RafiuAbstract Vertical electrical sounding (VES) was carried out to evaluate the groundwater potentials of Nigerian Union of Teachers Housing estate, Paggo, Minna. The ABEM Terrameter model SAS 4000 was used to collect the subsurface data for the evaluation of groundwater potentials. Six profles with ten VES stations on each profle were sounded with intervals of 100 m apart. It has a maximum current electrode separation (AB/2) of 100 m. Three and four geoelectric layers were obtained which include: topsoil, weathered layer, fractured layer and fresh basement layer. The stratigraphy of the subsurface shows: topsoil (67.5–835.1 Ωm), weathered layer (108.0–939.7 Ωm), fractured layer (118.9–242.0 Ωm) and the fresh basement layer (1041.0–9704.0 Ωm). Sixteen VES points were recommended as groundwater potentials of the area having weathered/ fractured layer resistivity varying between 65.84 and 454 Ωm, depths range from 10.61 to 26.37 m, and thickness varies between 9.255 and 24.69 m. The observed frequencies in curve types include 58.33% of H, 26.67% of A, 10% of HA and 5% of AA. A correlation of the borehole log data with the VES was made and is in agreement. Viable boreholes for good portable water should be sited at VES stations A10 and D9 with a reasonable thickness of 21.2 and 10.68 m, respectivelyItem Application of Aeromagnetic Data to Assess the Structures and Solid Mineral Potentials in Part of North Central Nigeria(Journal of Geography, Environment and Earth Science International, 2020) ADETONA, Adebayo Abbass. 15. M.D. Tawey, D.U. AlhassanAssessment of the structures and solid minerals was carryout to investigate subsurface structural characteristics and mineralization potential zones within part of north-central Nigeria. The residual magnetic intensity data of the area was reduced to magnetic pole after which several source edge detection/interpretation with depth determination techniques including, analytic signal; tilt derivative; first and second vertical derivatives and Euler deconvolution were applied to the aeromagnetic data. From the analytic signal map, three magnetic zones were delineated. These are: low to relatively low magnetic zone (LM) with amplitude range from 0.003 to 0.009, moderate magnetic zone (MM) with amplitude 0.009 to 0.106 and those with amplitudes above 0.106 were products of later magmatic intrusions into host with fractures, faults and joints. Tilt derivative helped in delineating location and extent of edges of causative sources while Euler deconvolution helps in determination of boundary, depth and geometry of the structures. From first vertical derivative mapstructures were found to have high lineament density around the central portion of the area and span toward the western end of the map were delineated. The lineaments mapped trending in the ENE-WSW followed by WNW-ESE with some NE-SW, NNE-SSW and NNW-SSE trends. The second vertical derivative (SVD) map also helped in delineating structures and possible mineralization zones that are pronounced within the study area, around high analytic signal zones. Delineated possible and favorable mineralization zones from second vertical derivative map correlate with portion of the study area with rocks showing high analytic signal amplitude suggesting the rocks to be of later magmatic intrusions where mineralization fluids solidify within the host rocks.Item Structural Analysis and Interpretation of High Resolution Aeromagnetic data over the Southern Bida basin, North Central, Nigeria(Zuma Journal of Pure and Applied Sciences, 2020) ADETONA, Adebayo Abbass, Okwokwo O.IThis study focuses on the analysis and interpretation of high resolution aeromagnetic data over the southern part of Bida basin. The study covers an area of 24,200 km2 located between latitude 80 30′N and 90 30′N and longitudes 50 00′E and 70 00′E. Aeromagnetic data in grid format containing eight sheets in 1/2o by 1/2o (55 x 55 km) were analyzed and interpreted. This study employed several magnetic filtering methods to investigate lineaments and other structural features. The filtering methods used are: reduction to the magnetic equator, horizontal derivatives, vertical derivatives, analytical signal, and Centre for exploration targeting grid analysis. The reduced to magnetic equator shows variation in magnetic signatures ranging from-58.65nT-131.44nT. The results from first vertical derivative, second vertical derivative, horizontal derivatives and center for exploration targeting maps reveal that the major structures delineated, trend in NE –SW and NW-SE direction. Since minerals are structurally controlled, these structures delineated might host the economic mineralsin the study area. The second vertical derivative shows a major fault line cutting the area into two parts which is an extension of the Romanche fault. The CET grid analysis map reveals the geologic boundaries and fault lines within the basement rock.Item GEOELECTRICAL INVESTIGATION OF ROAD FAILURE ALONG MINNA-BIDA ROAD, NIGER STATE, NIGERIA(FUW Trends in Science & Technology Journal, 2020) ADETONA, Adebayo Abbass, 10. Rafiu A.A., T.A Adesete, Salako K. A., Alhassan U.D, Shehu JThe study is meant to reveal the horizontal and vertical geological discontinuities on the said road that has suffered repairs in the past. Probable zones of untimely failure along the road are then investigated by variation in resistivity. The resistivity values for profiles A, B, C, D and F range between 0.10 and 30.4 Ωm; indicating failed segments which are typical of fractured or fissured zone, as a result of clayey nature of the topsoil/sub-grade soil on which the road pavement is founded. The stable segment which is characterized by high ranging resistivity (16.4 – 4628 Ωm) shows no evidence of any major geologic feature such as fault and fractured zone that could have precipitated failure. The range of values characteristically places the regions in a basement complex area with the presence of clay-sandstone intercalation. The causes of road pavement failure on the studied road was found to be majorly as a result of a combination of clayey topsoil/sub grade soils, water-logged sands with characteristically low resistivity values and thin pavement unable to withstand pressure exerted on the roadItem Interpretation of Airborne Radiometric data for possible hydrocarbon presence over Bornu basin and its environs, Northeast Nigeria using Thorium normalisation method(Iranian Journal of Earth Sciences, 2021) ADETONA, Adebayo Abbass, Taiwo Adewuyi, Kazeem Adeyinka Salako, Usman Defyan AlhassanA new exploration technique called Thorium Normalisation Method has been applied on the airborne radiometric data of the Bornu basin and its environs to delineate favourable zones for hydrocarbon accumulations within the study area. This method is significant because it indicates the probable presence of hydrocarbon in a sedimentary basin. Separation of the radiospectrometric measurements over each lithologic unit and the estimation of the characteristic statistics of these units were carried out. The statistical treatment applied on the radioelements (K, eTh and eU) of the study area shows a relatively low coefficient of variability (CV%) value for K, eTh and eU signifying their high degree of homogeneity. The mean value of the radioelements (K ranging from 0.6 to 2.0 %; Th ranging from 9.6 to 15.9 ppm and U ranging from 2.2 to 3.8 ppm) obtained from the statistical analysis correlates with the mean of natural radioelement (K ranging from 0.1 to 2.7 %; Th ranging from 0.4 to 11.2 ppm and U ranging from 0.1 to 3.7 ppm) content of sedimentary rocks which corresponds to shale, the main source rock for hydrocarbon accumulation in the study area. The DRAD (delineation of radioactive anomalies) result ranges from -0.77 to 1.83. The positive values are indicators of favourable zones for the presence of hydrocarbon accumulations. These results suggest that the preliminary information obtained from the use of the thorium normalisation method will guide the exploration of hydrocarbon in the study area.