HR: 1340h
AN: T23D-1665    [Abstracts]
TI: Exhumation and shortening distribution in the Taiwan orogen: insights from thermomechanical modeling
AU: * Mouthereau, F
EM: mouther@ccr.jussieu.fr
AF: University Pierre et Marie Curie, T. 45-46, E2, 4, place Jussieu, Paris, 75005, France
AU: Yamato, P
EM: philippe.yamato.rennes1@gmail.com
AF: University Rennes 1, Batiment 15, 1er étage, bureau 128/1 Campus de Beaulieu, Rennes, 35042, France
AU: Burov, E
EM: evgenii.burov@lgs.jussieu.fr
AF: University Pierre et Marie Curie, T. 45-46, E2, 4, place Jussieu, Paris, 75005, France
AB: The Taiwan orogen has long been regarded as a case example for studying exhumation and erosion processes in association with mountain building. In the recent years, the increasing number of thermochronometric data (mainly ZFT and AFT ages) has allowed to better understanding the deep-seated tectonic processes. For instance, using thermomechanical wedge modelling, up to 50% of underplating has been proposed to explain the observed distribution of FT ages. So it would appear that a large amount of materials added to the orogen originated in more deeper and ductile parts of the crust. The nature of this additional flux (velocity, mechanism of deformation) is however poorly constrained in the current thermomechanical model. Our concern is to use a fully- coupled visco-elasto-plastic themomechanical numerical model to reproduce the observed FT ages and long- term distribution of shortening. To this aim we use the numerical code PARA(O)VOZ based on F.L.A.C. (Fast Lagrangian Analysis of Continua) algorithm. Our results show that the particular distribution of shortening across the Taiwan belt as well as the rapid exhumation and thermal conditions in the hinterland are well accounted for by two superimposed flows of upper and lower crustal rocks decoupled from the subducting Eurasian mantle.
DE: 1140 Thermochronology
DE: 1815 Erosion
DE: 8038 Regional crustal structure
DE: 8102 Continental contractional orogenic belts and inversion tectonics
DE: 8175 Tectonics and landscape evolution
SC: Tectonophysics [T]
MN: 2007 Fall Meeting