Northward migration of the eastern Himalayan syntaxis revealed by OSL thermochronometry.

Erosion influences the dynamical evolution of mountains. However, evidence for the impact of surface processes on tectonics mostly relies on the circumstantial coincidence of rugged topography, high stream power, erosion, and rock uplift. Using the optically stimulated luminescence (OSL) thermochronometry technique, we quantified the spatial and temporal exhumation of the eastern Himalayan syntaxis. We found increasing exhumation rates within the past million years at the northeast end of the Namche Barwa-Gyala Peri dome. These observations imply headward propagation of erosion in the Parlung River, suggesting that the locus of high exhumation has migrated northward. Although surface processes influence exhumation rates, they do not necessarily engage in a feedback that sets the location of tectonic deformation.