Mapping of subsurface structural features in some parts of Anambra Basin, Nigeria, using aeromagnetic data

Data transformation, regional-residual separation, trend analysis, and Analytic Signal (AS) depth estimation were applied to aeromagnetic data covering the Anambra Basin, which is a major depocentre in the Benue Trough, southeast Nigeria with the primary objectives of accentuating attributes of magnetic sources and determining if sufficient sediment thickness exists for hydrocarbon generation, maturation, and expulsion. The application of data transformation techniques (such as map projection, merging, and reduction-to-pole) and regional-residual ensured the computation of a crustal magnetic field that would be suitable for magnetic analyses. Results indicate that the magnetic basement in the basin forms an undulating surface overlain by sediments with average thickness ranging between 4 km and 7.5 km, while maximum thickness reaches 8 km in some areas. This depth range suggests promising prospect for source-facies maturation and expulsion. We expect that areas in the study area with these appreciable sediment thicknesses, good preservation of graben-fill, and suitable areal closures or fault structures would be favorable for hydrocarbon prospectivity.

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Structural features derived from a Multiscale Analysis and 2.75D Modelling of Aeromagnetic Data over the Pitoa-Figuil Area (Northern Cameroon)

10.5194/se-2020-135 ◽

2020 ◽

Author(s):

Voltaire Souga Kassia ◽

Theophile Ndougsa-Mbarga ◽

Arsène Meying ◽

Jean Daniel Ngoh ◽

Steve Ngoa Embeng

Keyword(s):

Multiscale Analysis ◽

Structural Features ◽

Magnetic Data ◽

Horizontal Gradient ◽

Aeromagnetic Data ◽

Near Surface ◽

Subsurface Structures ◽

Northern Cameroon ◽

Processing Techniques ◽

Geological Formations

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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EFFECT OF CONTINUATION AND DERIVATIVE FILTERS ON A HIGH RESOLUTION AEROMAGNETIC DATA COVERING PARTS OF LOWER BENUE TROUGH AND ANAMBRA BASIN.

International Journal of Advanced Research ◽

10.21474/ijar01/6303 ◽

2018 ◽

Vol 6 (1) ◽

pp. 938-950

Author(s):

OfohaC C ◽

◽

Bello R ◽

Keyword(s):

High Resolution ◽

Aeromagnetic Data ◽

Benue Trough ◽

Anambra Basin ◽

Lower Benue Trough

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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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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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Geological Interpretation of the High Resolution Aeromagnetic Data over Okigwe-Udi Area, Anambra Basin, Nigeria, Using 3-D Euler Deconvolution and 2-D Spectral Inversion Methods

Journal of Geography Environment and Earth Science International ◽

10.9734/jgeesi/2017/30741 ◽

2017 ◽

Vol 10 (1) ◽

pp. 1-22

Author(s):

R Onyewuchi ◽

S Ugwu

Keyword(s):

High Resolution ◽

Aeromagnetic Data ◽

Euler Deconvolution ◽

Geological Interpretation ◽

Spectral Inversion ◽

Inversion Methods ◽

Anambra Basin

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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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