Rapid topographic growth of the Taiwan orogen since ~1.3-1.5 Ma.

Abstract

We present the first paleotopographic reconstruction of Taiwan by measuring the hydrogen isotope composition of leaf waxes (δ²H_<i>n</i>C29) preserved in 3-Ma and younger sediments of the southern Coastal Range. Plant leaf waxes record the δ²H of precipitation during formation, which is related to elevation. Leaf waxes produced across the orogen are transported and deposited in adjacent sedimentary basins, providing deep-time records of the source elevation of detrital organic matter. δ²H_<i>n</i>C29 exported from the southern Taiwan orogen decreased by more than 40‰ since ~1.3-1.5 Ma, indicating an increase of >2 kilometers in the organic source elevation. The increase in organic source elevation is best explained by rapid surface uplift of the southern Central Range at around ~1.3-1.5 Ma and indicates that this part of the orogen was characterized by maximum elevations of at least 3 km at this time. Further increase in organic source elevation from ~0.85 to ~0.3 Ma indicates continued topographic growth to modern elevations.