Lawal, Taofeeq Olanrewaju
@portal.unilorin.edu.ng
,
,
University of Ilorin, Ilorin
RESEARCH, TEACHING, or OTHER INTERESTS
Environmental Science, Physics and Astronomy, Geophysics, Atmospheric Science
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
K.S. Ishola, A.A. Fatoyinbo, A.I. Hamid-Mosaku, C.J. Okolie, O.E. Daramola, and T.O. Lawal
Elsevier BV
A. A. Fatoyinbo, T. O. Lawal, A. Yussuf and O. Fawale
Yarmouk University
Abstract: An integrated geophysical survey involving three different techniques; namely, VLF-EM, Seismic Refraction and Vertical Electrical Sounding (VES) has been carried out in parts of Eruwa, Ibarapa East LGA, Oyo State with a view of determining the structural characteristics of the subsurface geology and identifying suitable sites where viable borehole could be sited to reduce the problem associated with acute shortage of groundwater in the area. The area lies within the crystalline basement rock terrain of South-Western Nigeria and bounded by Latitude 7° 32' 59"N and Longitude 3° 25' 59"E. The VES results reveal that the area is made up of four major lithologic layers with the topmost layer being majorly laterites, the second layer being sandy clay, the third is weathered basement, while the fourth layer is fractured basement. The aquifer in the study area is mostly confined with curve responses of HA- and HKH-types. The 2-D pseudosection also showed that the fresh basement is very extensive laterally with undulating topography. The result of VLF-EM revealed high-amplitude anomalies. These anomalies are indicative of high conductive zones within the basement bedrock of the study area. The results of the seismic inversion reveals three lithologic layers; namely, the topmost layer / topsoil which is sandy (moderately loose) with an average velocity of 500 m/s, the middle layer can be sandy clay/laterite/caked clay with an average velocity of 1,149.33 m/s and the third layer can be said to be the beginning of the weathered/fresh basement with a velocity of 2,719 m/s. In conclusion, the three geophysical techniques have shown that the area is a hard-rock terrain with complicated geology with aquifers confined and the water bearing formation with low total longitudinal conductance. Keywords: Basement terrain, Granitic masses, Aquifer, Topography, Curve types.
T.O. Lawal, D.M. Omar, M.K. Salami, T. Adewumi, J.A. Sunday, and O. Fawale
IOP Publishing
Abstract Magnetic data of part of Osun State and its Environs, Southwestern Nigeria has been studied with the aim of identifying structures concealing mineral deposits through some enhancement techniques. These techniques are Analytic signal, Euler deconvolution, Center for exploration targeting and porphyry analysis. In this work we were have applied Analytic signal to identify edges and distribution of magnetic sources that are equivalent to concealed mineral deposits, Euler deconvolution was used to identify and estimate depth to various magnetic source geometries using prescribed structural indices of 0.0, 1.0 and 2.0 respectively and lastly, the center for exploration targeting and porphyry analysis was used to obtain magnetic lineaments and porphrytic intrusives that may serve as structures concealing mineral deposits. From this study, we were able to identify several volcanic intrusions which appeared beyond surface exposure and at the same time of Cenozoic era. These intrusions resulted from the high magnetic content which serves as a contributing factor for the presence of positive magnetic anomalies in the area. In conclusion, we have been able use magnetic data of Osun State and its environs to delineate structures concealing mineral deposits.
Taofeeq Olanrewaju Lawal
Springer Science and Business Media LLC
M. M. Orosun, A. B. Alabi, A. O Olawepo, R. O. Orosun, T. O. Lawal, and S. O Ige
IOP Publishing
Water samples from Hadejia River in the north eastern part of Nigeria were studied in order to ascertain the suitability and radiological safety of water from the river for human consumption. Radioactive measurements, using a lead shielded sodium iodide detector coupled to a multichannel analyzer were used to estimate eight radiological parameters of water samples from Hadejia River. The results show that the values of all the parameters fall within the minimum universal standard, indicating that consuming the water pose no serious radiological hazard, especially for adults. The values of the Absorbed Dose Rate (50.10511 nGyh-1) and AEDE (12.458 mSvy-1) for the infant however portend that infant consumer could be susceptible to radiation hazard on consuming water from the River. It is however recommended that activities that are capable of enhancing the radiological content of the River be avoided within the area.
T.O. Lawal, J. A. Sunday, L.I. Nwankwo, M.M. Orosun, K. A. Yusuf, and S. O. Ige
IOP Publishing
Depth to magnetic basement and mapping of source geometries were estimated from High Resolution Aeromagnetic (HRAM) data of Benisheikh using wavelet transformation technique. This technique was chosen because it has been proven to be a powerful and efficient tool in interpreting potential field data. In this work, a non-orthogonal wavelet function with a good symmetry and higher vanishing moment, Morlet was chosen as the analyzing wavelet. Wavelet power spectrums of the aeromagnetic anomalies were obtained using the scaled normalized analyzing wavelet in order to estimate the depth to the magnetic basement. Also, the square of the absolute value of the wavelet coefficient were plotted against the period in other to identify and map variations of pronounced and least energy values which can be regarded as magnetic source geometric features found from the HRAM data profiles. The results obtained from the analysis have shown the ability of wavelet transform as a tool in depth estimation and mapping of geological features of HRAM data of this part of Nigeria.
T. O. Lawal and L. I. Nwankwo
Springer Science and Business Media LLC