Gravity Survey for Structural Mapping in the Bida Basin, North Central Nigeria

The Bida Basin in North Central Nigeria is an intracratonic sedimentary basin that has received limited modern geophysical investigation despite its potential for hydrocarbon and mineral resources. This study undertakes a ground gravity survey to map subsurface structural features and estimate sediment thickness within a selected portion of the basin in Niger State. Bouguer anomaly data were acquired at 45 gravity stations using a LaCoste-Romberg gravimeter calibrated at the Nigerian Geological Survey benchmark network. Corrections for latitude, free-air, Bouguer slab, and terrain effects were applied following standard processing protocols. Regional-residual separation was performed using upward continuation to isolate residual gravity signatures associated with basin structures. Two-dimensional forward modelling was carried out along three profiles to estimate the geometry of the basin floor and the thickness of overlying sedimentary sequences. Modelled sediment thicknesses range from approximately 400 metres at basin margins to over 1,800 metres at the depocenter, consistent with earlier basin analysis studies. A series of NE-SW trending gravity lows are interpreted as half-graben structures possibly associated with rifting episodes in the Late Cretaceous. The study enhances the structural database of the Bida Basin and provides primary geophysical constraints for future hydrocarbon exploration and mineral prospecting campaigns. Keywords: gravity survey, Bida Basin, Bouguer anomaly, sediment thickness, structural mapping