Denudation rate is a key parameter to quantify the evolution of a relief and we show that mass balance at the scale of a catchment-alluvial fan system is a powerful way to determine such rates. This work is focused on the northern side of the Chinese Tian Shan. There, large alluvial fans have been incised at the onset of the Holocene and their basal surface is now visible in the landscape.

Based on these observations, we reconstruct the volume of sediments trapped in the fans and thus, exported from the range during the last 300 000 years. By simple mass-balance considerations, we then convert the volume of sediments into an average denudation rate for the range.

Denudation rates appear to be very limited for such an active range with steep relief. It seems to be the consequence of a limited amount of water in this region for several million years.

Related publications:

• Denudation intensity and control in the Chinese Tian Shan: new constraints from mass balance on catchment-alluvial fan systems, L. Guerit, L. Barrier, M. Jolivet, B. Fu, F. Métivier, Earth Surface Processes and Landforms, 2015 - 41, p.1088-1106.

• Unbalanced sediment budget in the catchment - alluvial fan system of the Kuitun River (northern Tian Shan, China): implications for mass balance estimates and erosion rates in mountain ranges, M. Jolivet, L. Barrier, S. Dominguez, L. Guerit, G. Heilbronn, B. Fu, Geomorphology 2014 - 214, p.168-182.