Developing a Tectono-Stratigraphic Framework for the Evolution of the Benue Trough: New Constraints from Geochronology and Structural Analysis

The tectono-stratigraphic evolution of the Benue Trough, Nigeria's most extensively studied intracratonic basin, remains contested owing to inadequate geochronological constraints on deformation phases and sedimentary provenance, leaving the basin's role in the fragmentation of Gondwana incompletely resolved. This study develops a revised tectono-stratigraphic framework for the Benue Trough through systematic integration of new U-Pb zircon geochronology, Ar-Ar biotite thermochronology, structural kinematics, and sedimentary facies analysis across all three sub-basins. Detrital zircon U-Pb ages from thirty-four stratigraphic intervals are used to constrain maximum depositional ages and document provenance shifts through the Cretaceous succession. In-situ magmatic zircon U-Pb dating from syn-rift volcanics provides absolute timing constraints on rift initiation and inversion episodes. Ar-Ar thermochronology on biotite and muscovite from basement inliers constrains cooling histories and their relationship to deformation events. Fault kinematic data from over three hundred measurement stations are inverted for palaeostress tensors using multiple inversion algorithms, enabling a refined chronology of stress rotations. The tectono-stratigraphic framework produced integrates these datasets into a revised basin evolution model that reconciles conflicting interpretations regarding the relative importance of strike-slip versus pure extensional tectonics during rift development. This study makes an original contribution to understanding of South Atlantic rift systematics and has implications for hydrocarbon prospectivity assessment in underexplored portions of the trough. Keywords: Benue Trough, tectono-stratigraphy, U-Pb geochronology, Ar-Ar thermochronology, basin evolution.