Magnetic source basement depth determination of Ikogosi Warm Water Spring South Western Nigeria and the environ using aeromagnetic data

After interpreting aeromagnetic data on a worldwide basis for more than 20 years without recourse to any ancillary data, subsequent basement drilling showed an accuracy of ±7.5 percent for the contoured maps, not individual depth values, of the bottom of new sedimentary basins. The fields were resolved into intrabasement, suprabasement, and intrasedimentary anomalies, and depths were computed to their sources of thick prisms and thin plates with two universally applied coefficients. More than once, intrasedimentary volcanics were handled routinely. The author’s statement in paragraph three of his Introduction is not correct.

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ANALYSIS OF HIGH RESOLUTION AEROMAGNETIC DATA OF SOME PARTS OF BENUE TROUGH, NIGERIA

FUDMA Journal of Sciences ◽

10.33003/fjs-2020-0402-148 ◽

2020 ◽

Vol 4 (2) ◽

pp. 76-85

Author(s):

Nuraddeen Usman ◽

Ibrahim Jibril

Keyword(s):

Spectral Analysis ◽

Magnetic Anomalies ◽

Aeromagnetic Data ◽

Benue Trough ◽

First Order ◽

Qualitative Interpretation ◽

Maximum Value ◽

Magnetic Source ◽

Analysis Technique ◽

Basement Depth

This work is aimed to determine the depth to basement of some magnetic sources in the study area. Four aeromagnetic sheets were acquired from the Nigerian Geological Survey Agency which includes (Bajoga, 131, Gulani, 132, Gombe, 152 and Wuyo, 153). The study area covers an estimated area of about 12100km2 between latitude 90N-110N and longitude 110E-130E. The total magnetic field of the study area have been evaluated. In order to determine the basement depth, spectral analysis technique was applied. Detailed analysis of the aeromagnetic data for the study area was performed. The procedure involved in the analysis include reduction to equator to remove the effect of inclination, contouring of the total magnetic intensity, separation of the regional and residual anomalies using polynomial fitting of first order, qualitative interpretation and quantitative interpretation. The residual field of the study area composes of low magnetic anomalies reaching a minimum value of -158.6nT as observed in the northern and southern parts and high magnetic anomalies reaching a maximum value of 178.1nT as observed in the western part of the study area. The result from the spectral analysis for each block shows that the depths to the magnetic source are 5.20Km for block 1, 5.74Km for block 2, 7.59Km for block 3 and 3.56Km for block 4. The average depth to magnetic source in the study area was found to be 5.52Km. Based on the computed average sedimentary thickness obtained in this study area, hydrocarbon accumulation in the study area is feasible.

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Discussions of “An Evaluation of Basement Depth Determination from Airborne Magnetometer Data,” by Peter Jacobsen, Jr.

Geophysics ◽

10.1190/1.1486538 ◽

1961 ◽

Vol 26 (3) ◽

pp. 317-319 ◽

Cited By ~ 3

Author(s):

R. J. Bean ◽

Walter R. Fillippone ◽

Norman R. Paterson ◽

Isidore Zietz

Keyword(s):

Quantitative Analysis ◽

Sedimentary Basins ◽

Depth Determination ◽

Magnetometer Data ◽

Local Relief ◽

Basement Depth ◽

Basement Surface

In his discussion of the magnetic interpretations, Mr. Jacobsen rightly distinguishes between the determination of basement depth and configuration by analysis of anomalies originating from magnetization contrast within the basement and the delineation of local relief or faulting at the basement surface by analysis of smaller anomaly trends. It cannot be emphasized too strongly that the principal purpose of conducting aeromagnetic surveys is to outline the extent and depth of sedimentary basins, and the calculation of depth to basement by quantitative analysis of anomalies has progressed to the point where reliable results can be obtained by skilled interpreters.

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The straight‐slope method for basement depth determination revisited

Geophysics ◽

10.1190/1.1443442 ◽

1993 ◽

Vol 58 (4) ◽

pp. 593-595 ◽

Cited By ~ 4

Author(s):

Jan Reidar Skilbrei

Keyword(s):

Magnetic Anomaly ◽

Inflection Point ◽

Horizontal Projection ◽

Slope Method ◽

Source Estimation ◽

Magnetic Source ◽

Straight Line ◽

Depth Determination ◽

Basement Depth ◽

General Reliability

The straight‐slope method is still popular for depth to magnetic source estimation due to its simplicity and general reliability in manual interpretation (e.g., Nettleton, 1976). Other commonly used manual slope methods are Peters rule (Peters, 1949) and Sokolov rule (Åm, 1972). The straight‐slope method uses the horizontal projection of the straightline part of the magnetic anomaly curve at the inflection point as the depth estimator (see Figure 1). Because no straight line exists mathematically, the rule is purely empirical, even though visually a certain part of a curve will appear to be straight.

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AEROMAGNETIC DATA ESTIMATE MAGNETIC SOURCE DEPTHS BENEATH LAKE SUPERIOR

10.1130/abs/2018am-322262 ◽

2018 ◽

Author(s):

Eric D. Anderson ◽

◽

V.J.S. Grauch

Keyword(s):

Lake Superior ◽

Aeromagnetic Data ◽

Magnetic Source

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Core depth determination of a slightly buried Si-wire waveguide with a reduced bend loss

Japanese Journal of Applied Physics ◽

10.35848/1347-4065/ac06b4 ◽

2021 ◽

Author(s):

Tatsuya Aso ◽

Takehiro Ishiguro ◽

Junji Yamauchi ◽

Hisamatsu Nakano

Keyword(s):

Depth Determination ◽

Core Depth

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Analytic Signal Depth from High Resolution Aeromagnetic Data over the Gongola Basin Upper Benue Trough Northeastern Nigeria

Journal of Applied Sciences and Environmental Management ◽

10.4314/jasem.v25i4.15 ◽

2021 ◽

Vol 25 (4) ◽

pp. 585-590

Author(s):

H. Musa ◽

N.E. Bassey ◽

R. Bello

Keyword(s):

High Resolution ◽

Magnetic Structure ◽

Horizontal Cylinder ◽

Analytic Signal ◽

Aeromagnetic Data ◽

Polynomial Fitting ◽

Benue Trough ◽

Local Maxima ◽

Depth Determination ◽

Programming Software

The study of high-resolution aeromagnetic data was carried out over the Gongola basin, upper Benue trough, northeastern Nigeria, for analytic signal depth determination. Total intensity magnetic map obtained from the data using the Oasis Montaj TM programming software was used to get the residual map by polynomial fitting, from where the analytic signal was obtained with the use of anomaly width at half the amplitude (X1/2). This was used to carry out depth estimations over the study area. The results showed that it peaks over the magnetic structure with local maxima over its edges (boundaries or contact), and the amplitude is simply related to magnetization, likewise results also showed that the depth estimates were in the range of 1.2 to 5.9 km and were calculated for contact, dyke/sill and horizontal cylinder respectively. The lowest values are from DD profiles, while the highs are from AA profiles. This work is important in identifying dykes, contacts and intrusives over an area.

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