Mapping Basement Features and Deep Crustal Structures in the Lower Benue Trough: A 2D Reduction to Pole and Upward Continuation Approach

Abstract

This study focuses on deep-seated magnetic sources in the southern Benue Trough of southeastern Nigeria, using high-resolution aeromagnetic data collected in 2010 by the Nigerian Geological Survey Agency (NGSA). The dataset was processed through reduction to the equator (RTE), and upward continuation at multiple levels (200 m, 1000 m, 5000 m, 20,000 m, and 50,000 m) to distinguish shallow from deep crustal anomalies. The results highlight a clear division of the region into distinct magnetic domains. At deeper levels, upward continuation to 20 km and 50 km isolates major crustal features. A large south-central magnetic body beneath Uzoakali–Bende–Umuahia emerges as the principal deep-seated source, while the Abakaliki axis and Oban Massif are restricted to upper and mid-crustal depths. The central Benue Trough appears as a regional magnetic low, reflecting thick, non-magnetic sedimentary cover above a deep basement depression. The integrated interpretation defines the deep basement framework, maps intrusive complexes, and constrains structural controls on mineralization. These findings provide valuable insights for both mineral exploration and hydrocarbon basin evaluation in southeastern Nigeria