Test the topographic steady state in an active mountain belt

Abstract

Landscape evolution is the window to the link between deep earth and surface processes. One of the key issues in landscape evolution is to characterize the topographic steady state of mountain belts. The Taiwan mountain belt is an extraordinary case due to its extremely high uplift and denudation rates. The uplift of Taiwan Island is caused by the oblique collision between the Luzon Arc and the East Asian continent. In this case, the mountain building process in the north always occurs earlier than that in the south, which causes the spatial distribution of steady-state regions. The East Central Range receives much research attention with the presence of river basins that mainly distribute along the trajectory of the collision propagation. Normally, based on analyses of geomorphic parameters, the whole Central Range, or at least part of it, should be at a topographic steady state. However, the balance between uplift rates and denudation rates that exist in these regions is seldomly tested. In this contribution, we make a comprehensive literature review on the uplift and denudation rates derived from various approaches, including sediment yields, in-situ cosmogenic nuclide ¹⁰Be, incision of river channels, thermochronology, and GPS observations. This literature review reveals that the topographic steady state may prevail in the northern and middle parts of the East Central Range. However, an obvious inconsistency in denudation rates calculated by different methods prevents us from better constraining the topographic steady state in some regions of this mountain range.