Application of aeromagnetic data to map subsurface structural features in Ewekoro, Southwestern Nigeria

Abstract. In the Pitoa-Figuil area (Northern Cameroon), an interpretation of aeromagnetic data was conducted. The aim of this investigation was first to emphasize lineaments hidden under geological formations and secondly to propose two 2.75D models of the subsurface structures. Different magnetic data processing techniques were used, notably horizontal gradient magnitude, analytic signal, and Euler deconvolution. These techniques in combination with the 2.75D modelling to the aeromagnetic anomaly reduced to the equator permit to understand the stratification of the deep and near surface structures, which are sources of the observed anomalies. We managed to put in evidence and characterize 18 faults and some intrusive bodies. According to Euler's solutions, anomaly sources go up to a depth of 5.3 km.

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Interpretation of aeromagnetic data over Abeokuta and its environs, Southwest Nigeria, using spectral analysis (Fourier transform technique)

Materials and Geoenvironment ◽

10.1515/rmzmag-2016-0018 ◽

2016 ◽

Vol 63 (4) ◽

pp. 199-212 ◽

Cited By ~ 2

Author(s):

Oluwaseun T. Olurin ◽

Saheed A. Ganiyu ◽

Olaide S. Hammed ◽

Taiwo J. Aluko

Keyword(s):

Spectral Analysis ◽

Fourier Transform ◽

Ground Level ◽

Magnetic Data ◽

Depth Range ◽

Aeromagnetic Data ◽

Southwestern Nigeria ◽

Southwest Nigeria ◽

Below Ground ◽

Magnetic Basement

AbstractThis study presents the results of spectral analysis of magnetic data over Abeokuta area, Southwestern Nigeria, using fast Fourier transform (FFT) in Microsoft Excel. The study deals with the quantitative interpretation of airborne magnetic data (Sheet No. 260), which was conducted by the Nigerian Geological Survey Agency in 2009. In order to minimise aliasing error, the aeromagnetic data was gridded at spacing of 1 km. Spectral analysis technique was used to estimate the magnetic basement depth distributed at two levels. The result of the interpretation shows that the magnetic sources are mainly distributed at two levels. The shallow sources (minimum depth) range in depth from 0.103 to 0.278 km below ground level and are inferred to be due to intrusions within the region. The deeper sources (maximum depth) range in depth from 2.739 to 3.325 km below ground and are attributed to the underlying basement.

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Reconnaissance geochemical and geophysical exploration for gold at Iri gold field, north central Nigeria

Scientia Bruneiana ◽

10.46537/scibru.v18i2.93 ◽

2020 ◽

Vol 18 (2) ◽

pp. 19-31

Author(s):

Ahmed Sidi Aliyu ◽

Nuhu Musa Waziri ◽

Hadiza Liman Mohammad ◽

Mohammed Abubakar Mohammed ◽

Apeh Aromeh Gideon

Keyword(s):

Gold Mineralization ◽

Structural Features ◽

Parent Material ◽

Geological Mapping ◽

Magnetic Data ◽

Geochemical Data ◽

Aeromagnetic Data ◽

Geophysical Exploration ◽

Rock Types ◽

Soils And Sediments

Reconnaissance geochemical and geophysical exploration for gold was carried out at IRI Gold field. Geological mapping was conducted and rocks, soils and sediments samples were collected. The outcome revealed rocks of the basement complex of Nigeria made up of mainly, Migmatite Gneiss, Older Granite and the Schist. The major lithology in the area is silicified sheared rocks and large quartz vein. Isolated occurrence of undifferentiated schist was found as parent material on which quartzite intruded possibly during a major geological activity. Shattering of the rocks left boulders and rubbles of quartzite all around two major ridges within the study area. The rocks have shown weak geochemical anomaly except in two locations were positive anomalies were observed and identified as target for further exploration. Gold veins are prominent in the area suggesting potential gold mineralization. Interpretation of the aeromagnetic data give the orientations of the structural features, the major structural trend in the area is NE-SW. The lineaments extracted from the magnetic data range in length from 46.43m to about 1251.66m. Most of the lineaments extracted from the area are subsurface within the quartz-mica and migmatites while some of them have surface expressions even though not clearly defined. These magnetic lineaments could be the contacts between two rock types of contrasting magnetic susceptibility or edges of structures that could be faults or intrusive bodies. Interpreted satellite data show several subsurface structures which could be hosts to gold mineralization in the area. Results of the geochemical analysis of rocks, soils and sediments were super imposed on the interpreted aeromagnetic data and similar geochemical and geophysical signatures were established. Index Terms: Gold mineralization, aeromagnetic data, geochemical data, schist belt, Nigeria

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Structural analysis of subsurface stability using aeromagnetic data: a case of Ibadan, southwestern Nigeria

Journal of Physics Conference Series ◽

10.1088/1742-6596/1299/1/012083 ◽

2019 ◽

Vol 1299 ◽

pp. 012083 ◽

Cited By ~ 1

Author(s):

O.P. Oladejo ◽

T.A. Adagunodo ◽

L.A. Sunmonu ◽

M.A. Adabanija ◽

M. Omeje ◽

...

Keyword(s):

Structural Analysis ◽

Aeromagnetic Data ◽

Southwestern Nigeria

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Exploration for limestone deposit at Onigbedu, South–Western Nigeria

Materials and Geoenvironment ◽

10.1515/rmzmag-2016-0013 ◽

2016 ◽

Vol 63 (3) ◽

pp. 139-150

Author(s):

Kayode F. Oyedele ◽

Sunday Oladele ◽

Charles A. Emakpor

Keyword(s):

Structural Features ◽

Economic Importance ◽

Vertical Electrical Sounding ◽

Aeromagnetic Data ◽

Overburden Thickness ◽

Electrical Sounding ◽

Schlumberger Array ◽

Lithological Unit

Abstract The Onigbedu limestone deposit was investigated using the aeromagnetic data, resistivity soundings and borings with the aim of characterizing the limestone deposit and estimating its reserves. The subsurface structural features and depth to basement were identified with the analysis of aeromagnetic data. Twenty nine boreholes were drilled for subsurface appraisal and correlation of the limestone deposit. Eighty nine Vertical Electrical Sounding (VES) were acquired using the Schlumberger array. The results showed NE-SW trending lineaments that segmented the limestone. Depth to basement varied from 144.2 m to 1090 m. The VES results showed four to six layers indicating the topsoil (7-315 Ωm), clay (2-25 Ωm), shale (6-31 Ωm), limestone (20-223 Ωm), sandstone (>200 Ωm) and sandy materials. The VES results correlated well with the lithological unit delineated from the borehole. The overburden thickness ranged from 3.3 m to 28 m, while the limestone thickness varies between 18.1 m and 48.3 m. The limestone reserve was estimated at 1.9 × 109 t. This study concluded that the study area had vast occurrence of the limestone deposits, which would be of economic importance, if exploited.

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Linear feature analysis for aeromagnetic data

Geophysics ◽

10.1190/1.2357831 ◽

2006 ◽

Vol 71 (6) ◽

pp. L61-L67 ◽

Cited By ~ 42

Author(s):

R. O. Hansen ◽

Eduard deRidder

Keyword(s):

New York ◽

Principal Curvature ◽

New York State ◽

Synthetic Data ◽

Depth Estimation ◽

Structural Features ◽

Horizontal Gradient ◽

Aeromagnetic Data ◽

Linear Feature ◽

Total Gradient

This paper presents a new approach to detecting and two approaches to displaying lineaments associated with high-angle magnetic contacts, based on analysis of the curvature of the total horizontal gradient of the total magnetic field reduced to the pole. The first display is a contour or color plot of minus the principal curvature of largest absolute value. The second is a point plot of the local maxima of minus the largest principal curvature in regions where this curvature is negative. The paper also develops a depth-estimation technique for magnetic contacts based on the ratio of the curvature of the total gradient to the total gradient itself. Tests on synthetic data yield excellent results in detecting and delineating magnetic contact edges, and reasonable performance in producing depth estimates for the magnetic contacts. Results obtained using aeromagnetic data from the Finger Lakes region of New York State show good correlation with known structural features.

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