Deciphering non-steady state denudation and sediment recycling using cosmogenic nuclides across regolith to catchment scales

Understanding the processes of non-steady state denudation and sediment recycling is crucial for interpreting landscape evolution and sedimentary records, yet its quantification remains challenging. This study integrates field observations, cosmogenic nuclide analyses, topographic data, and modeling to unravel these processes from regolith to catchment scales. Depth profile models were used to estimate denudation rates in regolith within non-steady landscapes, revealing that abrupt surface denudation events—such as those driven by climate change, landslides, or human activities—can be recorded by cosmogenic nuclides in regolith. Our findings also show that denudation rates derived from non-steady state region with strong tectonic activity are often overestimated by assuming steady state. Through measurements of both ¹⁰Be and ²⁶Al in riverine sediments, we identified evidence of sediment recycling in the central Tibetan Plateau, with a consistent burial age of 0.54 ± 0.16 Ma. By combining these results and paleoclimate records, we interpret this "Great Burial" as most likely resulting from climate-controlled deglaciation and denudation at the termination of Naynayxungla glaciation during the MIS 13–15 period. This event likely marks the first widespread deglaciation on the Tibetan Plateau.