Depth-To-Basement Mapping Using Fractal Technique: Application To The Chad Basin, Northeastern Nigeria

Abstract

Fractals are being recently used to describe many geophysical processes and rock properties. The estimation of crystalline basement depths from power spectra of magnetic data presumes some knowledge of the basement magnetization behaviour. Replacing the common assumption of non correlation of magnetization with a fractal description leads to a reduction in these estimates, producing more realistic results. The fractal method requires the knowledge of the scaling exponent at source level. It is shown in this work that the scaling exponent varies with depth in a linear form, and can thus be obtained at source level. Application to aeromagnetic data from the Chad basin north eastern Nigeria produced a basement relief which range from depths of 2.47 km to 5.40 km with an average of 3.92 +- 0.66 km.

Keywords: Fractal, depth, basement, spectra, aeromagnetic

Nigerian Journal of Physics Vol. 19 (1) 2007: pp. 75-88