Stream-power incision model in non-steady-state mountain ranges: An empirical approach

Stream-power incision model has al- ways been applied to detecting the steady-state situa- tion of ranges. Oblique arc-continent collision occur- ring during the period of Penglai Orogeny caused the Taiwan mountain belt to develop landscape of three evolution stages, namely stages of pre-steady-state (growing ranges in southern Taiwan), steady-state (ranges in central Taiwan) and post-steady-state (decaying ranges in northern Taiwan). In the analysis on streams of the Taiwan mountain belt made by ex- ploring the relationship between the slope of bedrock channel (S) and the catchment area (A), the topog- raphic features of the ranges at these three stages are acquired. The S-A plot of the steady-state ranges is in a linear form, revealing that the riverbed height of bedrock channel does not change over time (dz/dt = 0). The slope and intercept of the straight line S-A are related to evolution time of steady-state topog- raphy and tectonic uplift rate respectively. The S-A plots of the southern and northern ranges of Taiwan mountain belt appear to be in convex and concave forms respectively, implying that the riverbed height of bedrock channel at the two ranges rises (dz/dt > 0) and falls (dz/dt < 0) over time respectively. Their tan- gent intercept can still reflect the tectonic uplift rate. This study develops an empirical stream-power ero- sion model of pre-steady-state and post-steady-state topography.