A Comparative Analysis of Fluvial Propagation and Divide Migration in the Liqiu River Basin, Eastern Tibet

     The assessment of rock uplift and climatic conditions through channel profiles traditionally relies on the assumption of topographic equilibrium. Nevertheless, there is a growing acknowledgment that landscapes frequently transition away from this equilibrium as a result of shifts in boundary parameters, such as base-level changes, climatic fluctuations, drainage network reconfigurations, or tectonic activities. Notably, the dynamic nature of drainage divides can introduce substantial disequilibrium into the profiles, severing the tight linkage between channel morphology and the spatiotemporal distributions of tectonic uplift, climatic conditions, or lithologic resistance. It is therefore vital to quantify the rates of river network adjustment and drainage divide migration to fully unravel the complex narratives of landscape evolution, as well as evaluate the influence of mobile divide mobility on the interpretation of river profiles in tectonically active settings.

      In the context of this research, we utilized a topographic index alongside ¹⁰Be-derived catchment-wide denudation rates to explore how river channels and drainage divides of the Liqiu River in Eastern Tibet adapt to environmental and tectonic forces. Our discovery reveals a significant temporal lag, with divide migration occurring at a pace roughly tenfold slower than that of river channel adjustments. Despite the continuous movement of divides, the channels' swift morphological response broadly maintains their fidelity as indicators of regional uplift, climatic perturbations, and bedrock characteristics.