Geothermal Gradient, Curie Point Depth and Heat Flow Determination of Some Parts of Lower Benue Trough and Anambra Basin, Nigeria, Using High Resolution Aeromagnetic Data

Background and Objective: This study, which is bounded within Latitude 6° 00’-6° 30’N and Longitude 7°00’ 7° 30’E with an approximate area of about 3025 km2 within parts of lower Benue trough and Anambra basin of Nigeria, aims at outlining the regional temperature distribution and delineating areas that are geo thermally responsive by determining: the heat change per unit distance, the heat flowing from the earth’s interior to the outer surface and the deepest depth at which the minerals loss their magnetic properties within the study area without any heat data. Materials and Methods: For the aim to be achieved, the data was subjected to quantitative analysis with the aid of the WingLink, ArcGIS, Origin Pro 8, Ms Excel and sulfer 10 software’s. Regional-residual was applied on the total magnetic intensity map and thereafter the residual divided into sixteen (16) overlapping windows. Spectral depth analysis was performed upon the overlapping windows and this revealed depth due to low frequency and high frequency components. The depths due to the low frequency components exemplify the Curie depth point (CPD).

Results: The average sedimentary thickness or the average depth due to the low frequency part was ascertained to be -5 km while the geothermal and heat flow varies from -25.2°C km-2 to -38.9°C km-2 and from -64.4 mWm-2 to -97.3 mWm-2 but with average values of -32.1°C km-2 and -80.1 mWm-2 respectively.

Conclusion: These results suggest alternative geothermal energy resource to be plausible within windows 2, 4, 8, 10, 12, 15 and 16 and presence of some amount of sedimentary thickness within the area of study.