Curie point depth and heat flow deduced from spectral analysis of magnetic data over Adamawa volcanic region (Northern Cameroon): geothermal implications

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.

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INVESTIGATION OF SUBSURFACE STRUCTURES WITHIN PARTS OF NIGER DELTA, NIGERIA, VIA AEROMAGNETIC DATA

Geological Behavior ◽

10.26480/gbr.02.2020.78.83 ◽

2020 ◽

Vol 4 (2) ◽

pp. 78-83

Author(s):

Ekpa, Moses M. M ◽

Ibuot, Johnson C. ◽

Okeke, Francisca N. ◽

Obiora, Daniel N.

Keyword(s):

Spectral Analysis ◽

Heat Flow ◽

Curie Point ◽

Niger Delta ◽

Research Work ◽

Geothermal Gradient ◽

Future Research ◽

Curie Point Depth ◽

Magnetic Intensity ◽

Subsurface Structures

Geophysical study involving aeromagnetic method was carried out to investigate parts of Niger Delta in Nigeria, aimed at investigating the cause and nature of anomalous bodies within the study area. Spectral analysis technique was employed in quantitative interpretation to determine depth/thickness of the sedimentary basin, basement topography, structural trends, curie point depth, thermal gradient and heat flow in the area. The total magnetic intensity (TMI) anomalies had values of between -53.7nT and 119.5nT while the residual magnetic intensity ranged from -52.5 to 58.0nT. The spectral analysis revealed the depth to magnetic sources varying from 2.5 to 5.5km while the shallow magnetic sources varied from 0.89 to 1.47km. The geothermal analysis revealed the curie point depth between 11.782 and 18.048km while the calculated geothermal gradient ranged lie between 32.137 and 49.231o𝐶𝑘𝑚−1. The heat flow values ranged from 80.343 to 123.080𝑚𝑊𝑚−2. The results from this study have thrown more light to the understanding of the variation of subsurface structures in the study area. These will enhance the development of the resources and will be of economic benefit to the country if well harnessed. However, possible future research work on this active area is proposed for more robust results.

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Curie point depth and heat flow maps deduced from magnetic data of Gonghe Basin, China

10.5194/egusphere-egu21-4140 ◽

2021 ◽

Author(s):

Zhuo Wang ◽

Zhaofa Zeng

Keyword(s):

Magnetic Susceptibility ◽

Heat Flow ◽

Curie Point ◽

Magnetic Data ◽

Inversion Method ◽

Adjacent Area ◽

Curie Point Depth ◽

Actual Measurement ◽

New Energy ◽

Gonghe Basin

Most recently, energy consumption around the world steps into a new situation divided by petroleum, natural gas, coal and new energy. Fossil fuels are disputed for pollution and CO2 emission, and geothermal energy is popular as a clean, ecofriendly and renewable new energy, which can be used for power generation or direct application (e.g. bathing, building heating).Gonghe Basin, located in the western part of China, has been thought as a potential geothermal field since 1989. To investigate geothermal distribution in Gonghe Basin and adjacent area, magnetic data is used in this paper. Firstly, we proposed an improved magnetic interface inversion method based on traditional Park-Oldenburg method. This improved method introduces dual geological interfaces instead of one interface, variable magnetic susceptibility instead of constant magnetic susceptibility and upward continuation in a form equivalent to inversion iteration in the Fourier domain instead of the divergent, downward continuation term, to improve suitability and precision of the inversion method. Then Curie point depth (CPD) map and heat flow map could be deduced from magnetic data through the improved Park-Oldenburg method.The CPDs range from 16 to 25.5 km and heat flow values range from 61 to 91 mW/m2. What's more, we take faults and seismic activities into account, we find that study area has greater geothermal potential in eastern part with shallower CPD, higher heat flow values and more active subsurface structure. Considering with known geothermal value in actual measurement, the results indicate high heat flow value in Gonghe Basin is coaction of high thermal background, radiogenic heat and partial geothermal anomalous heat source.&#160;

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