Geophysical Assessment of Curie Point Depth and Thermal Structure Over the Pb-Zn Bearing Region in the Lower Benue Trough, Nigeria Using Aeromagnetic Data

The Pb-Zn mineralization in the lower Benue Trough (LBT) is associated with the continental rifting which accompanies very high geothermal gradients. The origins of Pb-Zn deposits are often linked with intrusions and its ore formation has been related to regional processes having a temperature range of 90 – 2000C. An essential parameter to understand the thermal history of a region is the Curie point depth (CPD). Several studies have been done in LBT, but none, as far as we know, has used CPD to delineate thermal characteristics of the Pb-Zn bearing regions despite geochemical reports on the thermal attributes of the mineralization zones. In this work, the CPD, geothermal gradient, and heat flow of the LBT were determined. It was noted that while the area of greater depth to the top has a higher surface elevation. The CPD value in the area where currently Pb-Zn deposits are being mined in the LBT region shows that the ore is generated in a low shrinking encased high-temperature region that extends beyond the active mining regions. This implies a possibility of occurrence of Pb-Zn in the extension. The zone trends in the NE direction and goes as far as Abakaliki which is a low thermal area. The outcomes show that such mining locations also experience considerable geothermal gradients and heat flow.