Impact of rock uplift on bedrock-valley width and channel sinuosity

The last decades have seen major advances in our understanding of the long-profile evolution of bedrock rivers, whereas constraints on the development of bedrock-river planform and the coupled evolution of long-profiles and planform patterns in tectonically active landscapes remain limited. Here, we quantify how bedrock-valley width and channel sinuosity are modulated by changes in rock uplift rates on the million-year timescale. Using field- and remote sensing data as well as models, we explore the links between rock-uplift rate, bedrock-valley widening, and channel meandering in rivers draining the Ordos Block in Northern China. There, rock uplift rates have increased in the past 1 Ma, and rivers drain a generally uniform substrate under well constrained paleoclimate conditions. We show that the steady state width of bedrock valleys scales with uplift rate and channel mobility, as predicted by a recent physics-based model. We also observe a possible tectonic control on bedrock meandering where the sinuosity of channels scales positively with the uplift and incision rate beyond a critical threshold.