ESTIMATION OF CURIE POINT DEPTH, HEAT FLOW AND GEOTHERMAL GRADIENT INFERED FROM AEROMAGNETIC DATA OVER JALINGO AND ENVIRONS NORTH – EASTERN NIGERIA

Abstract

The purpose of the study is to estimate the Curie point depth, Heat flow and geothermal gradient from spectral analysis of aeromagnetic data over Jalingo and Environs, North-Eastern part of Nigeria. The area covered is approximately 48,400 Km² and bounded by latitudes 7^o 00' and 9^o 00' N and longitudes 10^o 00' and 12^o 00' E. The Aeromagnetic maps were digitized at an equal interval of 2 km and the regional value removed using plane surface polynomial. The resulting residual data were subsequently divided into 16 overlapping blocks for the purpose of this study. The results of Curie point depth obtained varies between 24 and 28km, geothermal gradient varies between 21 and 23 ^OCkm^-1, while the heat flow varies between 53 and 61 mWm^-2. A plot of Curie point depths versus heat flow values revealed an inverse linear relationship between heat flow and Curie depths. This relationship indicates that, heat flow increases with decrease in Curie point depth in the study area. These results are consistent with the prevailing geotectonic regime in the study area. However, this study illustrates that surface magnetic data can be used to produce Curie point depth estimate even for region with paucity of heat flow and geothermal gradient data.