Power spectral depth from residual magnetic field of Calabar flank, southeastern, Nigeria. – A. A. Okiwelu, E. E. Okwueze and C. S. Okereke
The study area lies in the rainforest belt of sourtheastern Nigeria, an area of about 15, 600Km2, devastated by acute Fourier transformation of aeromagnetic anomaly data of Calabar Flank from space domain to frequency domain yielded a method for source depth determination. From the analysis of the magnetic data, progressively deeper sources correspond to the lower frequency components while the shallower sources are indicated by higher frequency components. The power spectrum analysis gave a two-depth source model with the deeper sources (intra basement sources) indicating a depth of 5.8km while the shallower sources (sedimentary section) gave a value of 3.11km. These source depths are compatible with earlier results obtained from gravity surveys within and adjacent to the flank.