Integrated Gravity and Magnetic Modelling of Crustal Structure Beneath the Jos Plateau, North Central Nigeria

The Jos Plateau is a distinctive geomorphological and geological feature in North Central Nigeria whose crustal structure, including the depth and geometry of the Mohorovicic discontinuity and mid-crustal density variations, is incompletely constrained despite its significance for understanding Proterozoic crustal evolution in West Africa. This study constructs an integrated gravity and magnetic crustal model of the Jos Plateau using publicly available Bouguer anomaly and aeromagnetic data. Complete Bouguer anomaly values across the plateau exhibit a pronounced negative anomaly of approximately -120 milligals indicative of crustal thickening beneath the plateau relative to surrounding lowland basement terrain. The anomaly is forward-modelled along two regional profiles using a two-dimensional programme incorporating density-depth relationships derived from global empirical datasets. The preferred crustal model requires a Moho depth of 38 to 42 kilometres beneath the plateau compared to 33 to 35 kilometres at surrounding lowland elevations. An upper crustal mafic intrusion centred beneath the Bukuru younger granite complex is modelled to reconcile the residual short-wavelength Bouguer anomaly. Aeromagnetic modelling constrains the depth extent and magnetic susceptibility of the younger granite ring complexes, indicating emplacement depths of 5 to 15 kilometres. The derived crustal model is compared with receiver function results from recent African seismic network deployments and shows good consistency. The study provides a refined geophysical reference model for the Jos Plateau crust. Keywords: crustal structure, gravity modelling, aeromagnetic, Jos Plateau, Moho depth