An Original Geophysical-Tectonic Model for the Origin and Termination of the Benue Trough: Constraints from New Seismological and Potential Field Evidence

The origin of the Benue Trough as either a failed rift arm, a pull-apart basin on a transform fault, or a product of lithospheric folding during compression remains one of the most contested problems in Nigerian tectonics, and none of the existing models has been tested against a complete set of geophysical constraints spanning all relevant length and time scales from near-surface basin geometry to lithospheric thickness and mantle structure. This research develops an original geophysical-tectonic model for the Benue Trough by synthesising new seismological, potential field, magnetotelluric, and geodetic evidence acquired specifically for this investigation. Forty-two months of broadband seismic recordings from a new 28-station temporary network provide P and S wave arrivals from 312 teleseismic events used in a multi-parameter finite-frequency tomographic inversion that images the mantle down to 400 kilometres. New gravity and magnetic satellite data from GOCE and SWARM missions provide lithospheric-scale constraints on crustal thickness and bulk magnetisation that complement the seismic tomography. GPS velocity vectors from 14 continuous GNSS stations straddle the trough and are analysed for differential tectonic movement. MT data from 36 stations image the deep electrical structure. The synthesis of these multi-physics datasets within a self-consistent tectonic modelling framework produces an original model that identifies the Benue Trough as a product of oblique rifting along a pre-existing Neoproterozoic suture zone, with episodic shortening inversions driven by far-field Atlantic plate boundary forces. Keywords: Benue Trough, tectonic model, seismic tomography, potential field, mantle structure