Geochemistry and Structural Control of Brines in the Middle Benue Trough, Nigeria

Brine occurrence in the Middle Benue Trough, Nigeria, is strongly influenced by the region’s structural and stratigraphic framework. This study integrates geological mapping, geophysical interpretation and hydro-chemical analysis investigations to assess structural control on brine migration. Field observations reveal that NE–SW and NW–SE trending basement-rooted faults, particularly at intersections and terminations, are the principal pathways for the vertical ascent of mineralized fluids. Aeromagnetic and Source Parameter Imaging (SPI) data confirm the presence of deep fault corridors coinciding with brine-rich localities. Hydro-chemical analyses show extremely high salinity, predominantly Na–Cl facies, and elevated potassium, calcium, and trace metal concentrations, suggesting evaporite dissolution and prolonged water–rock interaction. These evidences, supports a model of structurally focused brine migration and stratigraphic confinement within permeable sandstones such as the Keana Formation. The findings have dual implications: (1) exploration targeting should prioritize fault intersections, anticline closures, and structurally confined porous units for economically valuable brines; and (2) environmental management should focus on monitoring and protecting shallow aquifers in structurally active zones. This multidisciplinary approach provides a robust framework for both resource development and groundwater protection in tectonically complex basins.