Spectral analysis and Hilbert transform of aeromagnetic data over the upper Benue trough, Nigeria.

Nur, A.; Ofoegbu, O.C.; Onuoha, K. Mosto

doi:10.4314/gjgs.v1i2.18662

Cited by 7 publications

(7 citation statements)

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“…Profile two shows the thickest sedimentary cover in the Nkalagu area (cells 4, 5 and 6 of Table 1). This result closely agrees with the results from other aeromagnetic works which had indicated depth (sedimentary thickness) of 1.5 to 4 km in Nkalagu (Nur et al, 1994;Obi et al, 2010). The range of the average profile depths implies a nearly evenly distributed sedimentary thickness within the study area and ranges between 3.5 and 4.2 km.…”

Section: Discussionsupporting

confidence: 93%

Spectral depth analysis for determining the depth to basement of magnetic source rocks over Nkalagu and Igumale areas of the Lower Benue Trough, Nigeria

Joachims¹,

Ugwu²,

Asielue³

2017

Int. J. Phys. Sci.

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Structural interpretation of aeromagnetic data over Nkalagu-Igumale area of the Lower Benue Trough of Nigeria was carried out to determine the depth to magnetic basement and delineate the basement morphology and the structural features associated with the basin and their trends. The aeromagnetic data were subjected to series of computer based image and data enhancement techniques before spectral analysis. Results of the 2-D spectral analysis revealed two depths source models with the depth model (D1) for deep magnetic source bodies which are associated with intra-basement discontinuities and faults ranging from 2.15 to 5.25 km while the depth model (D2) of the shallow magnetic source bodies range from 0.35 to 0.99 km. From an economic viewpoint, the results indicate possible mineralization and existence of a reasonable Cretaceous sedimentary thickness in the area which is deep enough for hydrocarbon accumulation. The average sedimentary thickness obtained in the area is 3.75 km.

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Section: Discussionsupporting

confidence: 93%

Spectral depth analysis for determining the depth to basement of magnetic source rocks over Nkalagu and Igumale areas of the Lower Benue Trough, Nigeria

Joachims¹,

Ugwu²,

Asielue³

2017

Int. J. Phys. Sci.

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“…The resultant filtered magnetic data was then used to generate a residual magnetic intensity map of the study area ( Figure 5). The application of spectral analysis to the interpretation of magnetic data allows the estimation of depth to the top of magnetic sources that produced the observed anomalies in magnetic maps [9,10]. The approach of plotting the computed radially average power spectrum of the Fourier transform magnetic data against the wave number [11] was employed in this study.…”

Section: Ground Magnetic Surveymentioning

confidence: 99%

Geophysical prospecting for iron ore deposit around Tajimi village, Lokoja, North–Central Nigeria

Bayowa

Ogungbesan

Majolagbe³

et al. 2016

Materials and Geoenvironment

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Ground magnetic and electrical resistivity survey were undertaken to investigate the occurrence and geometry of iron ore deposit around Tajimi village, Lokoja, North-Central Nigeria. The generated residual map of the ground-magnetic data acquired at 250 stations along 15 traverses revealed numerous prominent anomalies, mostly trending in the N-S direction. The radial power spectrum revealed the depth to magnetic sources between 6 m to 20 m. The interpreted VES data characterized the area into three subsurface layers: top soil, presumably iron ore layer and weathered/fresh basement. The result of vertical electrical sounding curves showed a sudden drop in resistivity (42-241 Ωm) over high magnetic response. The geo-electric section revealed that the study area is generally characterized with thin overburden (0.5-1.7 m) and the thickness of the second layer (presumed to be the iron ore layer) ranged between 6.2-25.1 m. The study concluded that areas of high magnetic intensity showed a sudden drop in resistivity value for the VES points, which give an indication of the presence of an electrically conductive structure presumed to be iron ore deposits.

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“…The MAGMAP 2D-FFT program of the geophysical interpretation platform was used to enhance, extract derivatives, compute analytical signals and estimate depth-to-source of anomalies of the gridded airborne magnetic data based on the power spectra analyses of the geophysical data. Application of spectral method is effective in solving geologic structural problems and map depth-to-bedrock (or magnetic basement) (Hassan and Peirce, 2007;Onyedim et al, 2006b;Onyedim et al, 2006a;Tanaka, et al, 1999;Nur et al, 1994;).…”

Section: Geophysical Data Inversionmentioning

confidence: 99%

Geophysical mapping of the inland extension of Deep Ocean Fault zones, south-western Nigeria

Olayanju¹

2015

ESR

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Research activities close to the south western edge of the coastal line has shown inland extension of deep oceanic features identified as regional fault zones. This research work focused on mapping of inland extension of Chain Fault zones into the south-western part of Nigeria using both satellite images and aeromagnetic intensity map over a 55 km by 55 km Ifon Basement-Sedimentary area. The area is a transition zone between the south-western basement complex and sedimentary basin of the south-western Nigeria. Interpretations of magnetic field over the area revealed intra-sedimentary features identified as fault zone which form an alignment and inland extension pattern with the offshore Chain fault zone. On the account of the qualitative and quantitative interpretation of the acquired aeromagnetic data, the Landsat-ETM+ multi-spectral bands and Digital Elevation Model (DEM) of the topography of the area, the evidence of inter-sedimentary tectonic events are recorded in the geomorphic characteristics of the study area's terrain in relation to the underlying influence of geology and structural trends revealed by extracted lineaments. From geophysical and geomorphologic interpretations, the observed geomorphic characteristics show three physiographical areas: the northern uplifted block (connection of a series of hills cut by deep-sided valleys), the central SW-NE trending subsided block (or graben) and the southern uplifted block. This geomorphic pattern of a series of flat and highly undulating terrain broken by a series of deep valleys and hills is believed to be related to rifting arising from the influence of the transform fault zones, which subdivide the area into smaller units. The rift valleys in the area are long, deep valleys bounded by parallel faults, or fractures. In addition, the predominant SW/NE, SE/NW and E-W trending linear structures mapped as fracture/faults cut the basement and penetrated the overlying Cretaceous and Tertiary sediments in the study area.

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Spectral analysis and Hilbert transform of aeromagnetic data over the upper Benue trough, Nigeria.

Cited by 7 publications

References 0 publications

Spectral depth analysis for determining the depth to basement of magnetic source rocks over Nkalagu and Igumale areas of the Lower Benue Trough, Nigeria

Spectral depth analysis for determining the depth to basement of magnetic source rocks over Nkalagu and Igumale areas of the Lower Benue Trough, Nigeria

Geophysical prospecting for iron ore deposit around Tajimi village, Lokoja, North–Central Nigeria

Geophysical mapping of the inland extension of Deep Ocean Fault zones, south-western Nigeria

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