Erosion rates and orogenic-wedge kinematics in Taiwan inferred from fission-track thermochronometry
- 1Department of Earth and Space Sciences, University of Washington, Seattle, Washington 98125, USA
- 2Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA
- 3Department of Earth and Space Sciences, University of Washington, Seattle, Washington 98125, USA
- 4Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA
- 5Department of Geosciences, National Taiwan University, Taipei 106, Taiwan
Abstract
New apatite and zircon fission-track ages and previously published thermochronometric data are used to evaluate erosion rates and particle paths within the active Taiwan arc-continent collision. We present 20 new apatite fission-track ages and 6 new zircon fission-track ages. Apatite and zircon ages are all reset in the northern and eastern parts of Taiwan, although the region of reset apatite ages is larger. We interpret this pattern as resulting from crustal accretion at the western margin of the orogenic wedge combined with southward propagation of the collision zone. A one-dimensional thermal model including erosion provides prediction of the fission-track ages. The distribution of reset ages is best explained with an erosion rate of 4–6 mm/yr. Given a propagation velocity of 60 mm/yr, this erosion rate implies that nearly 25 km of material has been eroded from northern Taiwan. The lack of reset 40Ar/39Ar ages from muscovite and biotite suggests that rock-particle paths have a large horizontal component, a result consistent with an eroding orogenic-wedge model.
Footnotes
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↵GSA Data Repository item 2003142, Table DR-1 (apatite fission-track age data) and Table DR-2 (zircon fission-track age data), is available online at www.geosociety.org/pubs/ft2003.htm, or on request from editinggeosociety.org or Documents Secretary, GSA, P.O. Box 9140, Boulder, CO 80301–9140, USA.
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- Accepted July 15, 2003.
- Received April 2, 2003.
- Revision received July 10, 2003.
- Geological Society of America
