Spectral Analysis Determination of Depth to Basement in Parts of Nigerian Sector of Chad Basin using Aeromagnetic Data

High resolution aeromagnetic data covering parts of Nigerian sector of Chad basin (latitude 12 ° 00' to13 00' North and longitude 12° 30' to 14° 00' East) have been interpreted qualitatively and quantitatively. Residual-regional separation was carried out by applying polynomial fitting (first order), which was fitted by least square method. First order was used because it is the best regional fit for the data as it reflected the available geological information of the area. The residual magnetic anomaly values obtained were used to produce residual magnetic anomaly map while the regional magnetic anomaly values were used to produce regional magnetic anomaly map. Depth to basement was obtained using spectral analysis. The result indicates that deep depth (D1) varies between 6.568 and 2.644 km, with an average depth value of about 4.043 km, while shallow depth (D2) lies between 1.393 and 0,869 km, with an average depth value of 1.065 km. The deeper magnetic anomalies could be due to deep magnetic bodies, while the shallow magnetic sources might be as a result of near surface magnetic bodies, which intruded the area. The average depth to deeper magnetic bodies (D1) of 4.043 km indicates that the area has the potential for hydrocarbon accumulation; therefore it is recommended that oil (crude) company should be sited in the area, this will provide employment opportunity for the masses.