Simoes, Martine and Avouac, Jean Philippe (2006) Investigating the kinematics of mountain building in Taiwan from the spatiotemporal evolution of the foreland basin and western foothills. Journal of Geophysical Research B, 111 (B10). Art. No. B10401. ISSN 0148-0227 http://resolver.caltech.edu/CaltechAUTHORS:20101116-110335366
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The Taiwanese range has resulted from the collision between the Luzon volcanic arc and the Chinese continental margin, which started about 6.5 Myr ago in the north, and has since propagated southward. The building of the range has been recorded in the spatiotemporal evolution of the foreland basin. We analyze this sedimentary record to place some constraints on the kinematics of crustal deformation. The flexure of the foreland under the load of the growing wedge started with a 1.5 Myr long phase of rapid subsidence and sedimentation, which has migrated southward over the last 3.5 Myr at a rate of 31 +10/−5 mm/yr, reflecting the structural evolution of the range and the growth of the topography during the oblique collision. Isopachs from the Toukoshan (~0 to 1.1 Ma) and Cholan (~1.1 to 3.3 Ma) formations, as well as the sedimentation rates retrieved from a well on the Pakuashan anticline, indicate that the foreland basement has been moving toward the center of mass of the orogen by ~45–50 mm/yr during the development of the basin. From there, we estimate the long-term shortening rate across the range to 39.5–44.5 mm/yr. By considering available data on the thrust faults of the foothills of central Taiwan, we show that most (if not all) the shortening across the range is accommodated by the most frontal structures, with little if any internal shortening within the wedge. The range growth appears therefore to have been essentially sustained by underplating rather than by frontal accretion. In addition, only the upper ~7 to 9 km of the underthrusted crust participates to the growth of the orogen. This requires that a significant amount of the Chinese passive margin crust is subducted beneath the Philippine Sea plate.
|Additional Information:||© 2006 American Geophysical Union. Received 8 December 2005; revised 7 June 2006; accepted 23 June 2006; published 5 October 2006. The authors would like to thank Andrew Tien-Shun Lin (NCU, Taiwan) for discussions on the foreland and for providing the data needed for Figure 4, as well as Meng-Long Hsieh (NTU, Taiwan) for his data on the Holocene subsidence rates in the western Coastal Plain. Also, Typhoon Lee (Academia Sinica, Taiwan) and Chen- Feng You (National Cheng-Kung University, Taiwan), as well as Devendra Lal (UCSD, California) and Ala Aldahan (Uppsala University, Sweden) provided helpful insights into the 10Be technique to derive sedimentation rates. Discussions with J. Suppe (University of Princeton) and J. Malavieille (Université Montpellier 2) helped improve the ideas and discussions presented in this manuscript. This paper also benefited from the comments by two anonymous reviewers. This study was partly funded by the Gordon and Betty Moore Foundation. This is Caltech Tectonics Observatory contribution 42.|
|Group:||Caltech Tectonics Observatory, Caltech Tectonics Observatory. Taiwan Tectonics and Seismicity|
|Subject Keywords:||kinematics; foreland basin; mountain-building|
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|Official Citation:||Simoes, M., and J. P. Avouac (2006), Investigating the kinematics of mountain building in Taiwan from the spatiotemporal evolution of the foreland basin and western foothills, J. Geophys. Res., 111, B10401, doi:10.1029/2005JB004209|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||17 Nov 2010 19:35|
|Last Modified:||26 Dec 2012 12:38|
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