Characterisation of lithology a case study of the Precambrian basement complex

Abstract

Some parts of the Precambrian basement complex of North Central Nigeria was analysed using aeromagnetic data in order to characterise the various rock types. Having subjected the data to filtering algorithm and enhancement procedures such as shaded relief enhancement, elemental concentration enhancement using Geosoft Oasis Montaj Software, Golden Software Surfer was then used to characterise the revealed lithological units. Three different types of lithologies were delineated; the granitoids, the metasediments and the metavolcanics. The high magnetic intensity areas within the metavolcanic formation could be as a result of the presence of magnetic minerals such as magnetite and pyrrhotite and the granitoids are seen to record high magnetic values. The metasediments are seen in the central portion in the area with relatively low magnetic values. The inferences in this study have shown that lithological mapping of an area is feasible even without the actual visitation to the area.

Keywords: Aeromagnetic Data, Precambrian basement complex, Lithological Units, Metasediments, Metavolcanics, Igneous Granitoid