Rapid exhumation in the Western Alps driven by slab detachment and glacial erosion

Abstract

Identifying topographic and erosion rate response to tectonic and climatic forcing remains challenging. This is in part because of the difficulty in isolating the respective roles of climate and tectonics. Here we exploit 2500 thermochronometric data points collected over several decades of research, using a new inverse technique, to image the space-time evolution of erosion rate across the European Alps over the past 35 m.y. The most striking feature of our results is a two- to three-fold increase in erosion rate over the past 2 m.y. exclusively within the Western and Central Alps. This increase appears to be controlled by the inferred high rock uplift rate due to the progressive detachment of the European slab under the Western Alps. The similarity in mean elevation between the Western and Eastern Alps indicates a surprisingly low topographic response to this differential tectonic forcing, and points to the role of enhanced glacial erosion in response to surface uplift.