Curie depth and geothermal gradient from spectral analysis of aeromagnetic data over Upper Anambra and Lower Benue Basin, Nigeria.

2017 ◽  
Vol 12 (2) ◽  
pp. 20
Author(s):  
A. A. Adetona ◽  
K. A. Salako ◽  
A. A. Rafiu
2021 ◽  
Author(s):  
Elshalom Omokpariola ◽  
Emmanuel Anakwuba

Abstract In tackling energy-related challenges in Nigeria; the exploration of an alternative source of energy (Geothermal Energy) comes to the limelight as it is generated below the earth subsurface. This work focuses on the delineation of geothermal energy potentials in parts of Calabar Flank, in southeastern Nigeria using Aeromagnetic Data. The aim is to understand the geothermal energy potentials and structural of parts of the Calabar flank by studying the various geothermal, geological, and structural parameters using Aeromagnetic Data. The methodologies applied are quantitative for structural analysis and qualitative using spectral analysis and 3D Euler Deconvolution. The study area lies between within Latitude 5°30ʹ00ʺ N - 6°30ʹ00ʺN and Longitude 7°30ʹ00ʺE - 8°30ʹ0ʺE respectively. Results from the 3D Euler analysis revealed the depth range of 0.25 Km to 4.018 Km. the spectral Analysis revealed a depth range of Magnetic source (Zt) is (-)0.564 Km to (-)0.828 Km, the Zo is (-)4.261 Km to (-)5.999Km and the average depth to basement thickness is (-)4.825 Km. The Curie Point Depth, Geothermal Gradient, and Heat flow yield an average depth of (-)9.452 Km, a value of 61.893CKm-1, and 154.983 mWm-2 from the Spectral Analysis. Some structural features such as trending faults, and fractured basements was observed at the NE-SW of the study area and this correlated to the relatively high heat flow and geothermal gradient at the NNE-SSW part is associated with thermal structures, mineralogical and tectonic history from the NE-SW trending fault in the study area is suitable for geothermal energy exploitation.


2020 ◽  
Vol 4 (2) ◽  
pp. 627-638
Author(s):  
Idena Odidi ◽  
A. Mallam ◽  
N. Nasir

The current study deals with an estimate of the Curie point depth, heat flow and geothermal gradient from spectral analysis of aeromagnetic data covering an area located approximately between latitude 7.5o N to 11.5o N and longitude 7.5o E to 10.5o E, which corresponds to parts of the Benue trough (lower part of the Upper Benue trough, the entire middle Benue trough, and upper part of the Lower Benue trough), lower part of the Gongola and Yola Basins, the Precambrian Basement, the Jurassic Younger Granites and two prominent hot Springs, Wiki hot spring in Bauchi state (in the north-eastern part) and Akiri hot spring in Nasarawa state (in the south-western part) of central and north-eastern Nigeria. Radially power spectrum was applied to the aeromagnetic data of the study area divided into 48 square blocks and each block analysed using the spectral centroid method to obtain depth to the top, centroid and bottom of magnetic sources. The depth values were subsequently used to evaluate the Curie-point depth (CPD), geothermal gradient and near-surface heat flow in the study area. The values of the curie point depths (Zb), range from 7.6341 km to 34.5158 km, with a mean value of 14.7928km, geothermal gradient, range from 16.8039 0C km-1 to 75.97490C km-1, with mean value of 45.7021 0C km-1 and heat flow (q), range from 42.0097 mWm-2 to 189.9372mWm-2, with a mean value of 114.2554mWm-2. Which reveals that, there might probably be good sources for geothermal and thereby further recommended for detailed geothermal exploration.


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

2021 ◽  
Vol 23 (1) ◽  
pp. 195-211
Author(s):  
I.M. Okiyi ◽  
S.I. Ibeneme ◽  
E.Y. Obiora ◽  
S.O. Onyekuru ◽  
A.I. Selemo ◽  
...  

Residual aeromagnetic data of parts of Southeastern Nigerian sedimentary basin were reduced to the equator and subjected to magnetic vector inversion and spectral analysis. Average depths of source ensembles from spectral analysis were used to compute depth to magnetic tops (Z), base of the magnetic layer (Curie Point t Depth (CPD)), and estimate geothermal gradient and heat flow required for the evaluation of the geothermal resources of the study area. Results from spectral analysis showed depths to the top of the magnetic source ranging between 0.45 km and 1.90 km; centroid depths of 4 km - 7.87 km and CPD of between 6.15 km and 14.19 km. The CPD were used to estimate geothermal gradients which ranged from 20.3°C/km to 50.0°C/km 2 2 and corresponding heat flow values of 34.9 mW/m to 105 mW/m , utilizing an average thermal conductivity -1 -1 of 2.15 Wm k . Ezzagu (Ogboji), Amanator-Isu, Azuinyaba, Nkalagu, Amagunze, Nta-Nselle, Nnam, Akorfornor environs are situated within regions of high geothermal gradients (>38°C/Km) with models delineated beneath these regions using 3D Magnetic Vector Inversion, having dominant NW-SE and NE-SW trends at shallow and greater depths of <1km to >7 km bsl. Based on VES and 2D imaging models the geothermal system in Alok can be classified as Hot Dry Rock (HDR) type, which may likely have emanated from fracture systems. There is prospect for the development of geothermal energy in the study area. Keywords: Airborne Magnetics, Magnetic Vector Inversion, Geothermal Gradient, Heat Flow, Curie Point Depth, Geothermal Energy.


Geophysics ◽  
1983 ◽  
Vol 48 (7) ◽  
pp. 964-974 ◽  
Author(s):  
J. G. Negi ◽  
P. K. Agrawal ◽  
K. N. N. Rao

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.


1999 ◽  
Vol 39 (1) ◽  
pp. 494
Author(s):  
I. Kivior ◽  
D. Boyd

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.


2014 ◽  
Vol 53 (1) ◽  
pp. 5-16 ◽  
Author(s):  
Théophile Ndougsa-Mbarga ◽  
Donatus Yufenyiu Layu ◽  
Charles Tabod Tabod ◽  
Joseph Quentin Yene-Atangana

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