Work

Origin and evolution of potholes in the northeastern of Brazil

Year: 2026

Type: article

Abstract: Potholes are circular or hemispherical erosional cavities formed by hydraulic abrasion on bedrock surfaces, with the potential to accumulate sediments. Their formation depends on the interaction among three main factors: flow hydrodynamics, lithological resistance of the substrate, and the availability of abrasive sediments. The analysis of these features helps in understanding the relationship between fluvial processes, bed characteristics, and the role of detrital material in shaping the landscape. This study investigated four occurrences in rivers of the Brazilian semiarid region, developed on granite, sandstone, and gneiss. The potholes were characterized through petrographic, mechanical, and morphometric analyses, as well as an assessment of the morphology of the accumulated sediments and anomalies in the channels' longitudinal profiles. The data revealed significant contrasts in rock resistance: microfracturing between 0.73 and 2.37 mm/mm 2 , porosity ranging from 0.96% to 9.84%, and point-load strength varying from 1.693 to 3.669 MPa. Analysis of the longitudinal profile showed that all occurrences are associated with knickpoints, with local slopes between 0.034 and 0.120 m/m. The minimum depth required for process activation ranged from 0.327 m to 1.126 m, indicating that relatively shallow flows are already capable of initiating pothole formation. The results demonstrate that the origin and evolution of potholes arise from the interaction among lithological resistance, sediment grain size, and topographic anomalies, highlighting the integrated role of substrate, hydrodynamics, and grinding sediments in erosional dynamics.

Source: Geomorphology

DOI: 10.1016/j.geomorph.2026.110562

Authors: Davi Henrick Veras Diógenes, Frederico de Holanda Bastos, Lionel L. Siame, Abner Monteiro Nunes Cordeiro, Rubson Pinheiro Maia