Long-term tectonic controls on landscape evolution of large intraplate catchments: Evidence from a major tributary of the transcontinental Paraná River, Brazil

Intraplate river systems on passive continental margins commonly exhibit complex geomorphic responses to subtle but persistent tectonic forcing, despite low seismicity and limited surface expression of active faults. Drainage networks in these settings may reorganize rapidly once geomorphic thresholds are exceeded, generating knickzones, channel deflections, asymmetric basins and localized incision that record the reactivation of inherited crustal structures. Here we investigate the long-term morphotectonic evolution of the Piquiri River catchment, a major tributary of the Paraná River on the SE–S Brazilian passive margin, integrating drainage morphometrics, χ–Ksn analysis, swath profiles, bulk erosion mapping, brittle structural data, and independent thermochronological constraints. We show that the landscape is organized by two orthogonal strike-slip fault systems trending WNW–ESE and NNE–SSW, which exert first-order control on drainage geometry, knickpoint distribution, basin asymmetry and vertical incision. These structural corridors focus river entrenchment, produce repeated elbow captures and generate fault-aligned knickzones and gorges, particularly in the central sector of the basin. Minimum bulk erosion reaches 4125 km 3 , an anomalously high value for a catchment of this size, and its spatial distribution demonstrates that tectonic segmentation of the Ponta Grossa Arch amplifies erosion far beyond lithologic or climatic controls alone. By combining bulk erosion and vertical incision patterns with U Th/He ages of laterite surfaces, we derive a relative chronology of landscape evolution that identifies two major pulses of drainage reorganization and major river captures at ~25 Ma and ~8 Ma, linking episodes of increased incision to plate-scale stress reorganization transmitted from the Andean margin. Our results demonstrate that passive-margin intraplate landscapes can remain highly sensitive to long-wavelength, low-strain tectonic forcing through threshold-controlled fluvial adjustment along inherited fault networks. The integrated morphometric–structural–geochronologic framework developed here provides a transferable approach for detecting tectonically driven drainage reorganization in continental interiors and passive margins worldwide. • Inherited strike-slip faults govern drainage geometry in the Piquiri river basin. • Ksn and χ analyses delineate fault-bounded blocks and corridors. • Two Cenozoic pulses (~25 and ~8 Ma) record intraplate rejuvenation. • A multi-proxy framework links drainage reorganization to far-field stress. • Episodic tectonic forcing plays a key role in intraplate landscape evolution.