Pleistocene onset of rapid, punctuated exhumation in the eastern Central Range of the Taiwan orogenic belt

The Taiwan orogenic belt is often treated as a steady, southward-propagating orogenic system with an essentially constant erosion rate of 4-6 mm/yr over the past 5 m.y. We present 4 new age-elevation transects from the Central Range based on 19 new and 86 previously published fission track and (U-Th)/He dates of completely reset detrital zircon and apatite grains. The age-elevation curves and thermal models imply slow cooling prior to ca. 2-1.5 Ma (at exhumation rates of ~0.1 mm/yr), an increase in exhumation rates from ca. 2-1.5 Ma to ca. 0.5 Ma (2-4 mm/yr), and possibly a further acceleration in exhumation from ca. 0.5 Ma to present (4-8 mm/yr). Three transects from three different latitudes in the eastern Central Range yield similar results, each showing punctuated exhumation with progressively faster rates.