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Communication Dans Un Congrès Année : 2006

Mountain-building in Taiwan: a multidisciplinary and quantitative approach

Résumé

The Taiwan range results from the collision between the Chinese continental margin and the Luzon volcanic arc. It has been key in the development of a popular model of mountain-building, in which a range can be considered as a critical wedge growing by frontal accretion of material. In this case, shortening is expected to be distributed within the whole range to compensate the loss of material due to erosion. However the kinematics of deformation, crucial to test this model, has remained up to now unresolved. To address this issue, we have first conducted morphotectonic investigations on the active faults of the western foothills to assess their contribution to crustal shortening over time scales of ~10s to ~100s kyr. From deformed fluvial terraces and geomorphic markers, dated using OSL and radiocarbon, we derive the slip rates on the Changhua and Chelungpu thrust faults, at the front of the range (Simoes et al, symposium 7). We get that most of (if not all) the shortening is absorbed within the western foothills, leaving little (if any) internal shortening within the range. These findings contradict the model previously proposed for mountain-building in Taiwan. Indeed, shortening localized at the front requires that the range growth is sustained by underplating rather than by frontal accretion. To test this scenario on the longer term, we implement this kinematics into a thermo-kinematic model, which is adjusted to fit available structural, thermometric (RSCM) and low-temperature thermochronological data [FT and (U-TH)/He]. All these geological constraints provide a consistent picture of the kinematics of deformation in Taiwan, and indicate that our previous results also hold over at least the last 2 Myr. The thermal model also allows for quantifying vertical deformation and exhumation rates over the whole range. Our study provides quantitative constraints on mountain-building processes in Taiwan that ought to be considered in future mechanical models.

Domaines

Tectonique
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Dates et versions

insu-00165305 , version 1 (25-07-2007)

Identifiants

  • HAL Id : insu-00165305 , version 1

Citer

Martine Simoes, Jean-Philippe Avouac, Olivier Beyssac, Yue-Gau Chen, Bruno Goffé, et al.. Mountain-building in Taiwan: a multidisciplinary and quantitative approach. Réunion des Sciences de la terre 2006, Dec 2006, Dijon, France. 1 p. ⟨insu-00165305⟩
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