Utilization of Landsat and Field Data in Geological Mapping of Vom-Kuru Area, North-central Nigeria

Abstract

The study area is a part of the Jos-Bukuru younger granite ring complex of North-central, Nigeria. It is very difficult to carry out geological mapping due to its rugged terrain as well as difficulty in accessing several outcrops due to communal conflicts. In view of this, the study integrated Landsat and field data to precisely map out the geology of the area. Five (5) land cover elements i.e. soil minerals, drainage pattern, surface water bodies, vegetations and rock outcrops were successfully mapped out from Landsat data. Thus, mafic and granitic rocks were observed and classified as rock units. One hundred and twenty-four (124) lineaments were automatically extracted in PCI Geomatica software and analyses show that they trend majorly in a North-south direction. Seventeen (17) rock samples were obtained in the field; they were studied and analyzed, and was observed that four (4) basic rocks units occurred in the area: basalt, biotite microgranite, biotite granite and undifferentiated older (porphyry) granite. Furthermore, five (5) groundwater samples were analyzed for major cations and anions elements using Atomic Absorption Spectrometer (AAS) and the result indicated the presence Ca2+, Mg2+, Na+, K+, HC03 -, S04 2-and Cl- where the concentration of Na+/K+ ions are greater than Ca2+/Mg2+ while which HC03 - is greater than Cl-/S04 2- and as such the alkali-bicarbonate dominated the composition of the groundwater. This result proved valid that the geology of the study area is composed predominantly of rocks that are mainly alkaline in nature and this also correlated with the result of the geology obtained from remotely sensed data as well as from fieldwork. Therefore, the study has shown that the area is composed of basically two (2) main rock types: mafic rocks (basalts), felsic rocks (biotite microgranite, biotite granite and undifferentiated older porphyry granite).