Using High-resolution Aeromagnetic Data to Recognise and Map Intra-Sedimentary Volcanic Rocks and Geological Structures Across the Cretaceous Middle Benue Trough, Nigeria

Abstract

Recently acquired high-resolution aeromagnetic data over the Cretaceous middle Benue Trough of Nigeria have been analysed employing various edge-enhancement (magnetic derivative) methods: vertical derivatives, total horizontal derivative, analytic signal, and total horizontal derivative of tilt derivative. The study was aimed at mapping intra-sedimentary volcanic rocks and their areal extents/distribution as well as delineating geological structures, their structural trends and tectonic implications. The magnetic derivative anomaly maps produced in this project greatly enhanced the high amplitude, short-wavelength (high wavenumber) anomalies associated with the surface/near-surface intra-sedimentary volcanic rocks and associated geological structures. The maps show that volcanic rocks of Late Cretaceous to Palaeocene age are much more widespread than implied by surface geological mapping, with an areal extent of greater than 12,000 km2 in the relatively shallow subsurface. The...