Determination of density and porosity of rock units in Afikpo area, south of the Benue trough, Nigeria. – A. O. I. Selemo, J. O. Cainye and C.Z. Akaolisa
Over 200 rock samples representing the major sedimentary, metamorphic and igneous rock units in Afikpo area were collected and various laboratory tests were carried out on them in order to determine their densities and porosities. The objectives are to provide reference materials to researchers who may run gravity traverses within this area and also to intimate hydrogeologists about the aquifereous units within this study area. The results obtained are quite comparable with results of similar rock types from other places like England and (New Zealand). The lowest density of 2.27g/cm3 has been calculated for Uwana siltstone while the highest value of 3.23g/cm3 is obtained for the dolerite sill. The porosity range is from 0.03 to 0.11 with the Afikpo sandstone and siltstone having the highest. These results would be valuable materials in gravity data analysis where density contrast of these rock units are needed. Also in groundwater exploration, rocks with high porosities should be the targets.