Escarpment retreat along an intracontinental divide: evidence of drainage reorganization between the Araguaia and Paraná basins, Central Brazil

Abstract

This study investigates the geomorphological evolution of the Araguaia–Paraná drainage divide in the Brazilian Central Plateau, focusing on the Rio Claro Basin as a key sector of active drainage reorganization. The analysis is based on an integrated geomorphological approach combining DEM-derived morphometric metrics, longitudinal profile analysis, knickpoint mapping, geomorphic mapping, and field validation. The results indicate that this divide does not correspond to a stable landform but rather to a dynamic zone marked by persistent fluvial disequilibrium and asymmetric interactions between adjacent basins. The Araguaia Basin operates at a continental base level significantly lower than that of the Paraná Basin, promoting upstream erosion, high ksn values, and a high density of knickpoints on the Araguaia-facing flank, contrasting with the topographically perched, low-energy profiles of the Paraná network. Structural inheritance plays a fundamental role in the spatial organization of these processes. The Transbrasiliano Lineament controls the orientation of the Serra Dourada escarpment, constrains drainage network geometry, and anchors a substantial portion of the macro-knickpoints, while remaining detached from a massive, upstream-propagating transient wave of incision. Evidence such as elbows of capture, lowered divides, and incised channels indicates that drainage reorganization and headwater starvation are continuous, active processes. Collectively, the results support the interpretation of the Serra Dourada escarpment as an intracontinental analogue of passive-margin escarpments, with an inverted eastward divide migration controlled by internal contrasts in continental base level.