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In this study, an interactive analysis combined measurements of surface radiogenic heat production (RHP) and sub-surface heat flow data to predict the crustal thermal regime of the area. The radioactive decay of 40 K, 232Th and 238U radionuclides in combination with other processes generate a significant quantity of heat within the earth's crust which can be utilized to produce green energy. Statistical analysis involving a box–whisker plot was used to optimize the generated RHP data with median RHP value of each lithologic unit presented as 3.2 µW m−3 (diorite), 2.9 µW m−3 (granodiorite), 3.1 µW m−3 (granite) and 2.7 µW m−3 (quartzdiorite). The results are in tandem with similar studies around the globe and are in near approximation to measurements that depict high heat production character. Heat generation predictions were extrapolated from the RHP values and displayed in percentile plots. The study showed that quartzdiorite presented the largest variation (from 5.2740 to 8.7185 HGU) in the region, followed by granite (from 6.1127 to 8.7445 HGU), then diorite (from 6.499 to 8.8975 HGU) and granodiorite (from 5.9870 to 8.3762 HGU). Heat flow measurements in 12 site holes within the granitoid emplacement showed averaged values of 48.5, 40.9, 48.5 and 28.9 mW m−2 for diorite, granodiorite, granite and quartzdiorite plutons, respectively. The analyzed thermal properties in this study suggest that the surface plutons are not deep-seated. An explanation for the high thermal condition of the deep-seated crustal rocks was adduced to tectonic events that distributed radioelements into reactivated inter-rift crustal blocks. [ABSTRACT FROM AUTHOR]

Both aeromagnetic and radiometric data were used to evaluate the Curie point depth and radiogenic heat production (RHP) of the young granitic regions of the Jos Plateau. An area of 55 by 110 square kilometers is bounded by latitude 9°30' to 10°00' N and longitude 8°30' to 9°30' E in central Nigeria. The magnetic data was subjected to spectral analysis to obtain the Curie depth, which was subsequently used to evaluate the geothermal gradient and heat flow for the area. Also, the concentration of radioelements (potassium, thorium and uranium) and the average density of the in-situ rock were used to estimate the radiogenic heat production at each point where the Curie point was evaluated. The heat flow in the study area ranges from 10 to 165.5 mW/m² with an average value of 111.00 mW/m². The regions with anomalous heat flow of 165.5 mW/m² are located around Bowon Dodo, Dan Tsofo, Kadunu, Gimi, Kaura and Zankan in plateau state. The geothermal gradient values range from 5 to 68 °C/Km with an average of 26.16 °C/Km. The radiometric data analysis resulted in radiogenic heat values ranging  from 0.4 µWm3   to 6 µW/m³ with an average radiogenic heat value of 3.36 µW/m³. Both analyses revealed that regions such as Ataka, Gimi, Jimjim and Pari could be investigated for geothermal energy potential. The high concentration of uranium, thorium and potassium associated with the study area is likely due to the weathering of the in-situ granitic basement rocks. [ABSTRACT FROM AUTHOR]

The occurrence and manifestation of warm and hot springs gives a hint to the availability and abundance of geothermal resources in Nigeria. So for the first time we estimated and quantify the geothermal energy resource potentials in Ikogosi Warm Spring area (IKGWS) and environs using geophysical and Numerical methods. The results from heat flow computation from aeromagnetic investigations and volumetric estimation confirmed there are zones in the IKGWS with anomalous heat flow and great prospects of geothermal energy for direct and indirect applications. The heat flow estimated for the IKGWS and environs ranged from 75 to 127 mW/m2 with an average value of 100 mW/m2 while temperature gradient varied from 28 to 48 °C/Km with a mean value of 38 °C/Km. Also the Curie point depth (CPD) estimated ranged from 12 to 21 km with a mean value of 16 km. The power output of 2 MWe can be produced with 90% confidence and production greater than or equal to 3.7 MW with 5% confidence. The IKGWS isolated will produce 0.9 MWe if the recoverable heat is used for 25 years. The outcomes implied that IKGWS can primarily sustain a 0.9 MW power plant for a period of 25 years and likely extension will be subjected to further well-defined drilling and site data performance availability. The simulation results show that an estimated stored heat in-place of 0.65–1.95 × 10 J can be expected from the inferred resource areas at 90% probability. This figure is equivalent to electric power generation potential of 3.2–9.6 MWe or annual electricity generation of 25–76 GWh at the same probability rate. Therefore Nigeria may appear on the global geothermal map by generating power and direct utilization of geothermal energy in IKGWS. [ABSTRACT FROM AUTHOR]

Curie point depth, geothermal gradient, and heat flow values of part of the Mid-Niger Basin, Nigeria were estimated using high-resolution aeromagnetic data of the study area. Spectral inversion of highresolution aeromagnetic data was used to estimate the top and centroid depths of the magnetic sources which were further applied to calculate the Curie point depths of the magnetic sources. Top depths to the magnetic sources across the area are of the range of 1.865 km to 4.264 km with a mean of 2.723 km whereas the centroid depths of the magnetic sources are of the range of 13.26 km - 17.12 km with a mean value of 14.78 km. The range of values for the Curie point depth values are from 24.21 km to 32.26 km with an average value of 26.83 km. The geothermal gradient values were estimated to be of the range of 17.98 - 23.95o C/km with an average value of 21.62oC/km. Finally, the heat flow values range from 44.95 mWm-2 to 59.89 mWm-2 with an average value of 54.04mWm-2. It was observed that the range of estimated geothermal conditions in the study area point to the fact that the area is not a volcanic or thermally active region and therefore has no potential geothermal energy reservoirs. Finally, the estimated geothermal gradient in this study may not be enough to cause thermal maturation of the available source rocks in the area. [ABSTRACT FROM AUTHOR]

Geothermal gradients and heat flow variations were evaluated for about fifteen wells in the Shallow Offshore of the Niger Delta using corrected bottom-hole temperatures and other relevant data. Thermal gradients in the shallow offshore vary between 14.6° to 22.4°C/Km with an average of 19.4°C/Km. Heat flow values that range from 30.5 mW/m² - 48 mW/m² (0.87 - 1.13 HFU) with an average of 41.3 mW/m² (0.99 HFU) were calculated using the Petro Mod 1-D modelling software and calibrated against the measured temperature values. Geothermal gradients variations in the Shallow Offshore are analogous heat flow variations in the area. Geothermal gradients and heat flow values are higher at the K field in the east and lower in the J field in the central parts from where it increases southwestwards. These variations in geothermal gradients, subsurface temperatures and heat flow are caused by lithological variations, fault patterns, overpressure and different scales of fluid migrations. [ABSTRACT FROM AUTHOR]

The investigation of geothermal energy resources potential in this study involves delineating targets areas of the earth's crust where geologic processes have raised temperatures near the surface, such that the heat contained can be utilised. A high-resolution aeromagnetic (HRAM) data of part of south-western Nigeria on longitude 3.5° to 5.5° and latitude 7.0° to 9.0° consisting of 16 half degree sheet was used for this research work. Spectral analysis was applied in processing HRAM data, which transforms the spatial data into the frequency domain, and provides a relationship between the two-dimensional spectrum of the magnetic anomalies. Results indicates that the average Curie point depth (CPD) within the study area is 8.5 km followed by the average geothermal gradient of 42.5Ckm-1 and an average heat flow 55 mWm-2. The equitable promising geological results useful for geothermal exploitation is within longitude 4.2° to 4.6° and latitude7.8° to 8.2°, where the lowest CPD (5.5km), highest geothermal gradient (75&#176Ckm-1) and highest heat flow (190mWm-2) bounded by Oshogbo and Ogbomosho as indicated on the maps. The paper suggests that such an area can be considered for geothermal energy exploitation since the demagnetized of magnetic rocks confirms a hot rock who's temperature of about 580°C. [ABSTRACT FROM AUTHOR]

Given the daunting energy challenges currently bedeviling Nigeria, with demand for electrical power exceeding availability, alternative energy sources (preferentially renewable) are vigorously considered. This is the first study to examine geothermal energy prospects in southeastern Nigeria with the ultimate aim of locating and mapping regions of shallow Curie point depths (CPDs), crustal thickness, and geologic structures supportive of a geothermal system. We estimated CPD using the spectral analysis technique on magnetic field anomalies. Gravity anomalies were subjected to a series of procedures to assess geological structures. Result reveals deeper CPDs within central and southern regions of Okposi, Afikpo and Biase towns in an approximate range of 18.4 to 19.3 km. Shallow CPDs (9.8–17.4 km) have also been obtained within Obubra and Abakaliki regions. Estimated crustal thickness (Moho) ranges between 26.5 and 35.8 km. Part of the region with shallow CPD correlates with regions of shallow Moho depths, particularly in Abakaliki, and deeper Moho depths coincide with deeper CPD estimates at the Afikpo location. The estimated geothermal gradient and heat flow values range between 29.0 and 45.0 ºC and 52.2–101.5 mW/m2, respectively, and fall within values evaluated from deep wells drilled for oil exploration within the adjoining Anambra Basin region. This study recommends the regions with shallow depths for possible geothermal power plant location. Gravity data evaluations also reveal significant subsurface intrusions within Ugbodo, Obubra and Abakaliki locations. Overall, this study is a step forward toward a better evaluation of the geothermal energy resources potential of southeastern Nigeria. [ABSTRACT FROM AUTHOR]

An evaluation of Curie-point depths, geothermal gradients and near-surface heat flow has been carried out from the spectral analysis of the recently acquired high resolution aeromagnetic (HRAM) data of the entire Sokoto Basin in northwestern Nigeria. The HRAM data was divided into twenty two (22) overlapping blocks and each block analyzed 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 result shows that the CPD varies between 11.13 and 27.83 km with an average of 18.57 km, the geothermal gradient varies between 20.84 and 52.11 °C/km with an average of 33.99 °C/km, and the resulting heat flow varies between 52.11 and 130.28 mW m − 2 with an average of 84.97 mW m − 2 . Such heat flow values are suggestive of anomalous geothermal conditions and are recommended for detailed geothermal exploration in the basin. [ABSTRACT FROM AUTHOR]

Highlights: [•] Determines the thermal structure of the crust across the Wikki Warm Spring. [•] Determines approximate temperature gradient. [•] Determines approximate heat flow at shallower depths. [•] Provides CPD and heat flow maps for the study area. [•] Provides information for geothermal exploration and exploitation of the area. [Copyright &y& Elsevier]

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