Decoding surface processes from escarpment to watershed: Insights from karst landscapes using cosmogenic nuclides and geochemical data

Tropical karst landscapes are marked by complex sediment dynamics resulting from the interplay between geomorphic processes and sediment transport . In the Vermelho Watershed (Brazilian savanna), we use paired cosmogenic nuclides ( 10 Be and 26 Al) to quantify denudation rates, burial durations, and sediment mixing. The spatial distribution of Al Be ratios reveals rapid erosion and prolonged burial on escarpments , in contrast to the more stable conditions of flatter areas, where erosion is subdued, and sediment residence time is longer. Comparisons with Iraquara and Serra das Mesas emphasize the influence of topography and sediment sources on nuclide inventories. Downstream increases in freshly eroded material point to fluvial mixing, while discrepancies between cosmogenic burial and OSL ages (Tarimba Cave) suggest partial burial and pre-depositional histories. The integration of cosmogenic, geochemical, and geomorphic data underscores the complexity of tropical karst systems, where vertical mixing and uneven erosion are key processes. These results contribute to a broader understanding of landscape evolution and offer a comparative basis for interpreting cosmogenic signals in fluvio-karst environments worldwide. • Cosmogenic nuclides reveal sediment mixing and erosion in tropical karst watersheds. • Flatter terrain erodes slowly with long residence, unlike steep escarpment slopes. • Burial age gaps challenge full burial, stressing pre-depositional process roles.