GEOPHYSICAL STUDY OF BRINE DEPOSITS USING ELECTRICAL RESISTIVITY TECHNIQUE IN AWE, AWE LOCAL GOVERNMENT AREA OF NASARAWA STATE IN NIGERIA

Résumé

Forty-five (45) Vertical electrical sounding (VES) were carried out in Awe brine field Awe LGA, Nasarawa State, with the aim of providing valuable information on the geology of the area, and delineating the brine deposits and their subsurface configuration. The VES result(curves) obtained showed a dominant trend of decreasing resistivity with depth which indicates increase in salinity with depth. The result also revealed four distinct geoelectric layers. The first layer which constitutes the top soil showed resistivity values ranging
between 4.2 Ωm and 282.5 Ωm; and the thickness ranging from 0.276 m to 19m; the second layer has resistivity values which vary between 11 Ωm and 650Ωm with the thickness ranging from 0.502m to 22.47m. The third geoelectric layer is interpreted as the brine zone. The resistivity of this layer is generally low at most locations. Its values vary from 0.12Ωm to 97Ωm with thickness ranges between 0.210 m to 21.56m. The low resistivity of the layer confirmed the presence of brine deposit within it. The geoelectric section revealed the occurrence of brine deposit between the depth interval of 4 and 38m in the study area. The fourth layer show resistivity values which vary between 15 Ωm and 34568 Ωm and thickness between 5.34 m to 44.78m. The layer revealed very high resistivity in most VES locations however, some points showed low resistivity which may be because of infiltration of brine from the upper layer