Date of Completion

1-20-2015

Embargo Period

1-20-2015

Keywords

Taiwan, Structural Geology, Tectonics, Tulungwan Fault, Chaochou Fault

Major Advisor

Timothy B. Byrne

Associate Advisor

William B. Ouimet

Associate Advisor

Jean M. Crespi

Associate Advisor

Jonathan R. Gourley

Associate Advisor

Jonathan C. Lewis

Field of Study

Geological Sciences

Degree

Doctor of Philosophy

Open Access

Open Access

Abstract

Taiwan is an active accretionary wedge resulting from the collision between the Chinese passive margin and the Luzon magmatic arc. This study focus on the southern Central Range of Taiwan as an example to demonstrate the internal deformation of an active accretionary wedge.

Recent leveling survey shows that the uplift rate in southern Taiwan is higher in the core of the wedge and lower on both flanks. We propose that this differential uplift rate is accommodated by major structures that should be recorded in geologic and geomorphic data. In this study, we suggest that one of the structures is the Tulungwan-Chaochou fault system, which separates Miocene slates from unmetamorphosed rocks of the same age.

The study revealed a major structure along the east flank of the range, the Tulungwan-Chaochou fault system, and an associated regional-scale, SSW-plunging antiform composed of slaty cleavage that verges to the NW. The antiform is a post-metamorphic structure and is an active structure based on field data and geodetic survey. The second part of the study demonstrates that landslides are preferentially developed where structural cleavage and hillslopes dip in the same direction, suggesting that the orientation of tectonic fabrics is important in landslide development. The last part of the study compiled the geomorphic indices (river steepness index, ksn, and basin asymmetry factor, AF) and geodetic data. The results suggest that the Tulungwan-Chaochou fault system has been active at a time scale sufficient to influence the evolution of the watersheds in the hanging wall.

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