Understanding erosion rates in the Himalayan orogen: A case study from the Arun Valley

摘要: Understanding the rates and pattern of erosion is a key aspect deciphering impacts climate tectonics on landscape evolution. Denudation derived from terrestrial cosmogenic nuclides (TCNs) are commonly used to quantify bridge tectonic (Myr) climatic (up several kiloyears) time scales. However, how processes in active orogens ultimately reflected 10Be TCN samples remains topic discussion. We investigate this problem Arun Valley eastern Nepal with 34 new 10Be-derived catchment-mean denudation rates. The characterized by steep north-south gradients topography climate. Locally, increase northward, <0.2 mm yr−1 ~1.5 mm yr−1 tributary samples, while main stem appear downstream ~0.2 mm yr−1 at border Tibet 0.91 mm yr−1 foreland. most strongly correlate normalized channel steepness (R2 = 0.67), which has been interpreted indicate activity. Significant decrease concentration suggests that upstream sediment grains fining point they operationally excluded processed sample. This results concentrations do not uniformly represent catchment area. observe strong local, nonfluvial geomorphic processes, such as glaciation landsliding coinciding areas peak rainfall rates, pointing toward modulation predominantly tectonically driven