Curie-Temperature Depth, Geothermal Gradient and Heat Flow Deduce from Spectral Analysis of Gravity Data of Chad Basin Northeast Nigeria

The purpose of the study is to estimate the curie-point depth, geothermal gradient, and heat flow in the Chad basin, which is deduced from spectral analysis of gravity data of Chad basin, Northeast Nigeria. The area is bounded by latitudes 9.50N ? 11.00N and longitudes 9.50E - 12.50E in the Northeastern part of Nigeria. It covers a total land area of 230, 000km2. The qualitative and quantitative interpretations of the Bouguer anomaly map were carried out using spectral analysis. The Bouger gravity anomaly ranges from -55.5 to 26.4mgal with northeast to southwest trend. Therefore, the graben in the basin is connected with low heat flow and low negative Bouguer gravity anomaly. The study disclosed that a decrease in heat flow is noticed with an increasing sedimentary thickness. The result shows that the Curie point depths, range from 5.77km to 13km, with a mean value of 9.21km, geothermal gradient, range from 44.62 0C km-1 to 107.210C km-1, with a mean value of 75.92 0C km-1 and heat flow, range from 111.55mWm-2 to 268.03mWm-2, with a mean value of 189.79mWm-2. This result is excellent for utilization for exploration of an alternative source of geothermal energy. Therefore, the spectral depth analysis data in coexistence with heat flow information disclosed an almost linear relationship between heat flow and Curie-point depths.