ABSTRACT
Aeromagnetic data of Nsukka and Udi areas were analyzed qualitatively and quantitatively. The study was aimed at mapping mineral deposits in a sedimentary basin, delineating susceptibility of rocks in the area, dip, plunge and type of body causing the magnetic anomaly and their trends as well as estimating the depth to magnetic source bodies. Spectral Analysis, Source Parameter Imaging (SPI), and Forward and Inverse modelling methods were used in the quantitative interpretation. Regional- residual separation was applied to a total aeromagnetic intensity contour map to produce a residual aeromagnetic intensity contour map. Depth results from the spectral analysis revealed two depth sources with the shallower magnetic sources varying from 314 to 1061 m with an average depth value of 632.3 m, whereas the depth of the deeper magnetic sources vary from 1465.9 to 5888.7 m with an average depth value of 3260.4 m. The SPI estimated depth ranges from 472.3 m (shallower magnetic bodies) to 6051.8 m (deeper magnetic bodies). The estimated depths from the forward and inverse modelling method are 6415 m, 2917 m, 3749 m, 1306 m, 4449 m and 2561 m for profiles 1 - 6 respectively, with respective susceptibility values of 0.0037, 0.0061, 0.0100, 0.0033, 0.0061 and 0.0100. These indicate the presence of sedimentary intrusions (shales), Quartzite, Hematite, Calcite and Quartz, which are typically sandstones and ironstones or oxides of iron that are magnetic in nature. The sedimentary cover in the area was generally high, thus will likely favour hydrocarbon generation.
