Determination of the Curie point Depth of Anambra Basin and Its Environs Using High Resolution Airborne Magnetic Data

Authors

Christopher Aigbogun & Kuforijimi Olorunsola
Department of Physics, Faculty of Physical Science, University of Benin, Benin City.

Abstract

The subsurface of Anambra basin was assessed for geothermal energy source which is a renewable energy using airborne magnetic data. Gridded data of digitized twelve (12) airborne magnetic maps of high resolution were acquired from the Nigerian Geological Survey Agency, Abuja for this research. The data were combined to form a composite map – total magnetic intensity (TMI) anomaly map. Regional-residual separation of the total magnetic intensity data was performed using Polynomial Fitting method. The filtered residual data was Fourier transformed after dividing the whole area into Thirty-five (35) overlapping cells for spectral analysis. The subsurface geology of the study area was delineated into shallow and deeper sources. Spectral analysis for crustal magnetization was used for the determination of the depth to magnetic sources giving rise to magnetic anomalies for the determination of; curie point depth and geothermal heat flow supply. Conclusively, the results show that the study area has good sedimentary thickness with the highest value of 3.86 km, Curie point highest value was 38.62 km and geothermal heat flow highest value was 99.02 mWm-2 around Aimeke, Enugu, Mbashere, Ankpa and Ogobia. Due to the moderate to low Curie point depths, there was no anomalous geothermal heat flow in the study area, thus, the basin has a likelihood of geothermal heat flow prospect.