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 (δ2HnC29) 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. δ2HnC29 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.