Aspects of the Geology and Hydrogeology around Awe Town, Nigeria

Abstract

Awe Town, Nigeria is popular for the occurrence of brine, the brine is mined for salt production and is the major economic activity going on in the town. The occurrence of brine has however always posed a problem for domestic water supply. To avoid the salty water, public water supply scheme provided by the government is situated about 8km away from the settlement thus access to fresh water is quite difficult. The present study was initiated to study at a smaller scale, aspects of the geology and hydrogeology of the area with a view to understanding the ‘limit' of the brine issuing Awe Formation and in so doing, suggest aquiferous zones with less saline water. Geological and hydro geological mapping of the area around the town was done, which led to the production of a geological map and also a groundwater elevation contour map. In addition to this, borehole samples from four boreholes were analysed. Major ion concentration in groundwater samples was determined from XRF analysis. The main findings of the present study are that: three of the six sedimentary successions in the Benue Trough are exposed in the study area viz: Awe, Keana and Ezeaku Formations. The brine as already established by previous researchers is restricted to the Awe Formation which itself is only exposed at the core of the anticline; aquifers containing non-saline groundwater are present in sandy units of Keana and Ezeaku Formations. Groundwater in the saline region is of sodium chloride type while that in the non-saline region is of calcium bicarbonate type.