Developing a Unified Geophysical Stratigraphy for the Cretaceous Sequences of the Upper Benue Trough: A Multi-Method Approach

The Cretaceous stratigraphy of the Upper Benue Trough in Taraba and Adamawa states is characterised by multiple lithostratigraphic schemes derived from different outcrop-based research programmes that lack geophysical continuity, making subsurface correlation for petroleum and mineral exploration purposes unreliable and hindering regional tectono-sedimentary reconstruction. This research develops a unified geophysical stratigraphy for the Cretaceous sequences of the Upper Benue Trough using the integration of seismic reflection interpretation, borehole geophysical logging, and ground geophysical surveys to establish a continuous subsurface stratigraphic framework. Four existing 2D seismic profiles in the Upper Benue Trough are reprocessed using a modern workflow and integrated with borehole logs from seven exploration and water wells to generate synthetic seismograms that tie geological markers to the seismic data. Gamma-ray and resistivity log signatures are used to define electrofacies units correlatable between wells. Ground gravity surveys along three regional transects constrain the total sediment thickness distribution, providing a basin-scale framework within which the seismic-defined sequences are positioned. Magnetostratigraphic dating of outcrop sections at four key localities in Taraba State is used to assign absolute ages to the geophysically defined stratigraphic units, reducing age assignment ambiguity currently spanning 10 to 15 million years for some sequences. The unified geophysical stratigraphy resolves the conflicting nomenclature of the Pindiga, Yolde, and Jessu formations and provides a reproducible, data-driven stratigraphic framework for the Upper Benue Trough. Keywords: geophysical stratigraphy, Upper Benue Trough, seismic reflection, well logs, Cretaceous