Impact of glacial erosion on 10 Be concentrations in fluvial sediments of the Marsyandi catchment, central Nepal

Abstract : Several processes contribute to denudation in high-mountain environments. Of these, glacial erosion is particularly difficult to constrain, despite its critical importance in the evolution of many mountain ranges. In this study, we present a new data set of 10Be concentrations in fluvial sediments sampled along the Marsyandi River and its main tributaries in central Nepal. We interpret the 10Be concentrations as being significantly impacted by glacially derived sediments along the Marsyandi River. Such additions complicate conventional interpretations of 10Be-derived catchment-scale denudation rates. Using a simple linear mass-conservation formulation, we invert our data set in order to separate the different denudational contributions to the observed signal, as well as to constrain their magnitude and spatial distribution. Our results suggest significant variations in glacial erosion, both in space and magnitude, within the Marsyandi catchment.