Environmental controls on 10Be-based catchment-averaged denudation rates along the western margin of the Peruvian Andes

Abstract

We present 10Be-based basin-averaged denudation rates for the entire western margin of the Peruvian Andes. Denudation rates range from c. 9 mm ka−1 to 190 mm ka−1 and are related neither to the subduction of the Nazca plate nor to the current seismicity along the Pacific coast and the occurrence of raised Quaternary marine terraces. Therefore, we exclude a tectonic control on denudation on a millennial time-scale. Instead, we explain >60% of the observed denudation rates with a model where erosion rates increase either with mean basin slope angles or with mean annual water discharge. These relationships suggest a strong environmental control on denudation.