Curie Point Depth, Geothermal Gradient and Heat-Flow Estimation and Geothermal Anomaly Exploration from Integrated Analysis of Aeromagnetic and Gravity Data on the Sabalan Area, NW Iran

2016 ◽  
Vol 174 (3) ◽  
pp. 1133-1152 ◽  
Author(s):  
A. Afshar ◽  
G. H. Norouzi ◽  
A. Moradzadeh ◽  
M. A. Riahi ◽  
S. Porkhial
Author(s):  
B. C. Udochukwu ◽  
M. Akiishi ◽  
A. A. Tyovenda

The aeromagnetic data of Monguno area northeastern Nigeria have been used to estimate Curie point depth, geothermal gradients and heat flow using spectral analysis. These geothermal parameters were subsequently employed to identify areas of geothermal resources. First order polynomial fitting was applied in Regional-residual separation. The Curie point depth obtained in this area ranges from 10.318 to 24.476 km with an average of 13.387 km, the geothermal gradient of the area varies from 23.697 to 56.212°C /km, with an average of 46.195°C /km, while the heat flow ranges from 59.242 to 136.176 mWm-2, with an average value of about 112.364 mWm-2. It was also observed that the deepest Curie depth in the area is identified in the south, while the shallow depth is located in the northeast and spread toward the southwest. On the other hand, the highest geothermal gradient in the area is identified in the northern part of Moguno, while in the south,                    the lowest, geothermal gradient is located. The highest heat flow in the area is seen in the south-west and north-east, while the lowest heat flow is observed in the south. The high heat flow and geothermal gradient in the area show that geothermal energy could be found in Monguno region of the northeastern Nigeria.


Geophysics ◽  
1985 ◽  
Vol 50 (3) ◽  
pp. 481-494 ◽  
Author(s):  
Y. Okubo ◽  
R. J. Graf ◽  
R. O. Hansen ◽  
K. Ogawa ◽  
H. Tsu

As part of a comprehensive, nationwide evaluation of geothermal resources for Japan, the first of the Curie point depth maps, covering the island of Kyushu, has been prepared. The map was created by inverting gridded, regional aeromagnetic data. Two satisfactory algorithms were developed to invert the gridded data based upon a distribution of point dipoles. The first algorithm estimates [Formula: see text],[Formula: see text], and [Formula: see text], the coordinates of the centroid of the distribution, by computing a least‐squares fit to the radial frequency of the Fourier transform; the second algorithm estimates centroid depth only by computing a least‐squares fit to the squared amplitude of the frequency estimates. The average depth to the top, [Formula: see text] of the collection of point dipoles, was estimated by a variation of the second algorithm. The depth to the bottom of the dipoles, inferred Curie point depth, is [Formula: see text]. The depth estimates are hand contoured to produce the final map. The Curie point depth map is then compared to regional geology and heat flow data, and to a limited set of gravity data. Good correlations are found between the Curie point depths and the heat flow and regional geology. A spatial correlation observed between gravity and Curie point depths is considered a secondary, structural effect. Locations of the currently operating geothermal power plants correspond to the shallowest Curie point depths. Based on these comparisons, we conclude that the methods provide geologically reasonable results which are usable in a nationwide geothermal assessment program.


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 91 ◽  
pp. 620-629 ◽  
Author(s):  
S. Elbarbary ◽  
M. Abdel Zaher ◽  
H. Mesbah ◽  
A. El-Shahat ◽  
A. Embaby

2020 ◽  
Vol 4 (2) ◽  
pp. 86-89
Author(s):  
J. A. Yakubu ◽  
J. C. Agbedo ◽  
N.M. Ossai

This work presents the interpretation of the aeromagnetic data over Soko and Ankpa area using spectral analysis method. The study area was divided into eight (8) equal spectral blocks in order to estimate the depth to the top boundary, centroid, Curie point depth, heat flow and geothermal gradient of the study area. The result of the analysis shows the range of the depths to the top boundary and centroid varies between 1.085 to 1.984 km and 6.151 to 8.730 km respectively. The Curie temperature isotherm ranges between 11.112 km and 15.476 km and the geothermal gradients associated with it ranges from 39.967 and 52.196 0 𝐶⁄𝑘𝑚. The corresponding values of heat flow ranges from 93.697 𝑚𝑊𝑚􀀀 and 130. 49􀀁 𝑚𝑊𝑚􀀀. From this analysis, it was observed that areas with high geothermal gradient correspond to high heat flow and an inverse relationship exists between the heat flow and the Curie point depth. With the high geothermal gradient especially at the southeastern part of the study area, there is a possibility of enough geothermal energy for exploration in order to boost and generate clean energy for electricity.


2020 ◽  
Vol 4 (2) ◽  
pp. 78-83
Author(s):  
Ekpa, Moses M. M ◽  
Ibuot, Johnson C. ◽  
Okeke, Francisca N. ◽  
Obiora, Daniel N.

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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