Applied Geophysics
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Applied Geophysics
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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 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, respectively