Depth of magnetic basement in Iran based on fractal spectral analysis of aeromagnetic data

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.

Download Full-text

Estimation of The Structural Pattern and Sedimentary Thickness Over Part Of Anambra Basin, Nigeria Using Aeromagnetic Data

Pakistan Journal of Geology ◽

10.2478/pjg-2021-0002 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Priscilla E. Ikioda ◽

Charles O. Ofoegbu ◽

Etim D. Uko ◽

Olatunji S. Ayanninuola

Keyword(s):

Spectral Analysis ◽

Analytical Techniques ◽

Average Depth ◽

Intensity Data ◽

Aeromagnetic Data ◽

Structural Pattern ◽

Near Surface ◽

Anambra Basin ◽

Potential Depth ◽

Magnetic Basement

AbstractAeromagnetic data acquired over part of the Anambra Basin is analyzed to determine the structural pattern and sedimentary thickness of the basin. The study area is covered by high resolution aeromagnetic data on sheets 301 (Udi), 302 (Nkalagu), 312 (Okigwe) and 313 (Afikpo), and lies between latitudes 5o30’0’‘-6o30’0’‘ and longitudes 7o0’0”-8o0’0”. The whole area was divided into 25 overlapping blocks of 37.2km2 each and a 2D energy spectral analysis was carried out. Total magnetic intensity data was subjected to filtering and analytical techniques to determine the structural pattern, mineralization potential, depth to the basement, variation in the sedimentary thickness. The structural map generated using the vertical derivatives shows that the major structural orientation of the area is in the ENE-WSW trend and the minor trend is the NW to SE direction widespread all over the area. These structures are as a result of the various near-surface magnetic intrusion within the study area. The spectral analysis result shows two depth layers, the deep and the shallow depth, the depth to magnetic basement for the deep anomalous source ranges from 3.3km to 4.8 4km with an average depth of 3.99km, while the depth to shallow magnetic sources ranges between 0.46km to 0.67km and an average of 0.56km within the area. The mineralization pattern in this area follows the ENE-WSW direction.

Download Full-text

Estimation of Curie-point depths, geothermal gradients and near-surface heat flow from spectral analysis of aeromagnetic data in the Loum – Minta area (Centre-East Cameroon)

Egyptian Journal of Petroleum ◽

10.1016/j.ejpe.2018.07.002 ◽

2018 ◽

Vol 27 (4) ◽

pp. 1291-1299

Author(s):

Jean Aimé Mono ◽

Théophile Ndougsa-Mbarga ◽

Yara Tarek ◽

Jean Daniel Ngoh ◽

Olivier Ulrich Igor Owono Amougou

Keyword(s):

Spectral Analysis ◽

Heat Flow ◽

Curie Point ◽

Surface Heat ◽

Aeromagnetic Data ◽

Near Surface ◽

Geothermal Gradients ◽

Surface Heat Flow

Download Full-text

Three‐dimensional model of the Koyna area of Maharashtra State (India) based on the spectral analysis of aeromagnetic data

Geophysics ◽

10.1190/1.1441522 ◽

1983 ◽

Vol 48 (7) ◽

pp. 964-974 ◽

Cited By ~ 26

Author(s):

J. G. Negi ◽

P. K. Agrawal ◽

K. N. N. Rao

Keyword(s):

Spectral Analysis ◽

Case History ◽

Three Dimensional ◽

Aeromagnetic Data ◽

Dimensional Model ◽

Three Dimensional Model ◽

Block Model ◽

Deccan Volcanism ◽

Geophysical Investigations

The estimation of thickness of trap rocks in the earthquake‐affected Koyna area is an important parameter for revealing the topography that existed before the Deccan volcanism. In the present work, a case history is presented delineating a three‐dimensional block model for the Koyna area by the spectral analysis of aeromagnetic data. The thickness in the area was found to vary from 700 to 2200 m, which correlates well with the results of other geophysical investigations.

Download Full-text

Depth to magnetic basement in the Anambra Basin, Benue Trough of Nigeria from aeromagnetic data: A prelude for hydrocarbon exploration

Interpretation ◽

10.1190/int-2021-0014.1 ◽

2021 ◽

pp. 1-57

Author(s):

Olatunbosun O. Olagundoye ◽

Chiedu S. Okereke ◽

Aniekan E. Edet ◽

Dominic Obi ◽

Aniediobong Ukpong

Keyword(s):

Depth Estimation ◽

Data Transformation ◽

Hydrocarbon Exploration ◽

Hydrocarbon Generation ◽

Depth Range ◽

Aeromagnetic Data ◽

Benue Trough ◽

Anambra Basin ◽

Magnetic Basement ◽

Fault Structures

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.

Download Full-text

3D Magnetic Basement Derived from Power Spectrum of Aeromagnetic Data of Parts of Lower Benue Trough, Nigeria

80th EAGE Conference and Exhibition 2018 ◽

10.3997/2214-4609.201801694 ◽

2018 ◽

Author(s):

M. Abdullahi ◽

U. Singh ◽

R. Prajapati ◽

M. ASIF

Keyword(s):

Power Spectrum ◽

Aeromagnetic Data ◽

Benue Trough ◽

Lower Benue Trough ◽

Magnetic Basement

Download Full-text

Spectral analysis of aeromagnetic data for geothermal investigation of Wikki warm Spring, north-east Nigeria

Geothermics ◽

10.1016/j.geothermics.2014.05.016 ◽

2015 ◽

Vol 55 ◽

pp. 207-208 ◽

Cited By ~ 1

Author(s):

Levi I. Nwankwo

Keyword(s):

Spectral Analysis ◽

Aeromagnetic Data ◽

Warm Spring ◽

North East

Download Full-text

THE INTERPRETATION OF AEROMAGNETIC SURVEYS FOR HYDROCARBON EXPLORATION

The APPEA Journal ◽

10.1071/aj98030 ◽

1999 ◽

Vol 39 (1) ◽

pp. 494

Author(s):

I. Kivior ◽

D. Boyd

Keyword(s):

Spectral Analysis ◽

Sedimentary Basins ◽

Hydrocarbon Exploration ◽

Petroleum Exploration ◽

Magnetic Data ◽

Curve Matching ◽

Aeromagnetic Data ◽

Profile Data ◽

Aeromagnetic Survey ◽

New Approach

Aeromagnetic surveys have been generally regarded in petroleum exploration as a reconnaissance tool for major structures. They were used commonly in the early stages of exploration to delineate the shape and depth of the sedimentary basin by detecting the strong magnetic contrast between the sediments and the underlying metamorphic basement. Recent developments in the application of computer technology to the study of the earth's magnetic field have significantly extended the scope of aeromagnetic surveys as a tool in the exploration for hydrocarbons. In this paper the two principal methods used in the analysis and interpretation of aeromagnetic data over sedimentary basins are: 1) energy spectral analysis applied to gridded data; and, 2) automatic curve matching applied to profile data. It is important to establish the magnetic character of sedimentary and basement rocks, and to determine the regional magnetic character of the area by applying energy spectral analysis. Application of automatic curve matching to profile data can provide results from the sedimentary section and deeper parts of a basin. High quality magnetic data from an experimental aeromagnetic survey flown over part of the Eromanga/Cooper Basin has recently been interpreted using this new approach. From this survey it is possible to detect major structures such as highs and troughs in the weakly magnetic basement, as well as pick out faults, and magnetic layers in the sedimentary section. The results are consistent with interpretation from seismic and demonstrate that aeromagnetic data can be used to assist seismic interpretation, for example to interpolate between widely spaced seismic lines and sometimes to locate structures which can not be detected from seismic surveys. This new approach to the interpretation of aeromagnetic data can provide a complementary tool for hydrocarbon exploration, which is ideal for logistically difficult terrain and environmentally sensitive areas.

Download Full-text