Neotectonic activities around the Benin-Owena basin, Nigeria

Abstract

The topographic break around Ore, Benin City, and Auchi was studied to provide information about the tectonic evolution that can be inferred from the structures, geomorphology and drainage basin morphology. Some morphotectonic analyses utilized are basin elongation ratio, hypsometric integral, drainage basin asymmetry, valley floor width to valley height ratio, longitudinal profiles, stream length gradient index, and mountain front sinuosity. This study focused on the indicators that can be used to provide information on the timing of the fault-related topographic break. The study also reveals a non-uniform state of tectonic activity within this region. The evolutionary influence of river meanders, faceted spurs, sediment deposits, horst and graben structures were also investigated. The analysis of morphotectonic indices in the drainage basins suggests that the architecture is strongly altered by the prevalent regional structures and lithology. The existing tectonic state of some of these structures varies from active in the northern parts and along the topographic break to slightly active in the southern parts with a minor influence of lithology and the impact of climate change.