Assessment of Magnetic Susceptibility of Some Selected Rock Samples from Karu Area, Northcentral Nigeria

Magnetic susceptibility is a very sensitive indicator of magnetic minerals present in rock because any slight variation in magnetic mineralogy is usually reflected by a profound change of susceptibility. However, the knowledge of its mineral composition does not provide adequate information about the rock and mineral composition of rock and properties such as magnetic susceptibility determines the property of rock. Six samples of the rocks were obtained at different two quarries site each located at Nyanya and Karu for the assessment of magnetic susceptibility which were measured with an instrument called magnetic susceptibility meter EM2S+. The results obtained shows that limestone has low magnetic susceptibility compared to other rock samples such as pegmatite, quartzite, gneiss, granite, granite gneiss, sand stone in both site and pegmatite has the low magnetic susceptibility compared to other rock samples in Karu. The average magnetic susceptibility of the rock samples from Nyanya and Karu are 4.11 x 10-4 (SI) and 4.99 x 10-4(SI) respectively. In conclusion, the selected rock samples show that granite gneiss > laterite > sand stone > granite > gneiss > quartzite > pegmatite > limestone. Which indicate that limestone has the low magnetic susceptibility than other rock samples, show the present of Felsic materials while granite gneiss has a very high magnetic susceptibility, as a result of the present of large amount of iron and magnesium in it.