Evaluation of the Thermal Regime of the Southern Bida and Northern Anambra Basins, Nigeria: Insights from Aeromagnetic and Remote Sensing Data

Abstract

The Bida and Anambra Basins are major inland sedimentary basins located in the central and southern part of Nigeria with possible hydrocarbon potential but lack exploratory data. The present study aims at providing base line information on the thermal regime of the sedimentary basins, which would significantly contribute to its hydrocarbon prospect, investment opportunity and exploitation. The spectral analysis of the aeromagnetic anomaly data from the southern Bida Basin, northern Anambra Basin and adjacent basement complex terrain reveals the Curie point depth (CPD), geothermal gradient and heat flow in the region. The data reveals a CPD that varies between 19 and 30 km while the geothermal gradient is from 23 to more than 44 °C/km with heat flow values ranging from 50 to 109 mW/m² in the southern Bida Basin. In the northern Anambra Basin, the CPD values range from 6.8 to 20 km and the heat flow values vary between 59 mWm² and 109 mWm², with a localized shallow CPD value of less than 6.8 km and associated high heat flow of 109 mWm² in the central part of the basin. The delineated thermal patterns in the Bida and Anambra Basins are interpreted to be associated with the intrusions and the presence of deep-seated rift. The interpretation of the aeromagnetic data shows good agreement with the land surface temperature obtained from remote sensing data of the study area. The distribution of heat patterns in the southern Bida and northern Anambra Basins have implications for geothermal, source rock maturation and hydrocarbon generation evaluation of the basins.