Tectonic geomorphology and patterns of late Quaternary uplift, eastern Central Range, Taiwan

The predictable response of a landscape to changes in rate and style of deformation in a tectonically active environment provides an excellent tool for examining the late Quaternary kinematic history of an active arc-continent collision in eastern Taiwan. In Taiwan, the Luzon Arc on the Philippine Sea plate (Coastal Range) is colliding with and deforming the Asian continental margin (Central Range). The suture between the two terranes lies in the Longitudinal Valley of eastern Taiwan. Geomorphic analysis of the eastern Central Range provides new and unexpected constraints on the kinematic evolution of the collision. Geomorphic segmentation based on drainage basin shape and stream profile characteristics suggests a first-order boundaries in tectonic response in the middle of the Longitudinal Valley as well as at each end of the valley. In that part of the Central Range adjacent to the southern Longitudinal Valley, maximum relative uplift appears to be concentrated toward the crest of the range, with relatively little uplift along the mountain front. However, south of Longitudinal Valley, uplift seems to be more evenly distributed across the range. An older tectonic regime is suggested by inferred valley floor remnants near the mountain front all along the range; these remnants suggest rapid frontal uplift. Thus a shift from frontal uplift to frontal stability is recorded in the geomorphology of the eastern Central Range; it is possible that the shift is due to docking of the Coast Range block.