HR: 10:35h
AN: T42A-02 INVITED    [Abstracts]
TI: Numerical Models of Subduction to Collision in Taiwan.
AU: * Lavier, L L
EM: luc@ig.utexas.edu
AF: Jackson School of Geosciences, University of Texas at Austin, Institute for Geophysics, J.J. Pickle Research Campus, Bldg. 196; 10100 Burnet Road (R2200), Austin, TX 78758-4445, United States
AU: Wu, F T
EM: wu@geol.binghamton.edu
AF: Binghamton University, Department of Geological Sciences and Environmental Studies PO BOX 6000, Bighamton, NY 13902-6000, United States
AU: Okaya, D
EM: okaya@usc.edu
AF: Univ. Southern California, 133 South Science Bldg Los Angeles, CA 90089-0740, Los Angeles, CA 90089-0749, United States
AU: McIntosh, K
EM: kirk@ig.utexas.edu
AF: Jackson School of Geosciences, University of Texas at Austin, Institute for Geophysics, J.J. Pickle Research Campus, Bldg. 196; 10100 Burnet Road (R2200), Austin, TX 78758-4445, United States
AB: The Island of Taiwan is formed by the collision of the Philippine Sea plate with the Eurasian plate. In the south, the Philippine Sea plate overlies a seismically active subduction zone. On the other hand the Central Range is underlain by only crustal seismicity. Does the Asian continent actively subduct into the upper mantle under the Central Range or does it underplate the Luzon arc? Do the resulting large-scale structures provide the dynamic forces to explain the pattern of deformation observed across Taiwan? We study the dynamic evolution of the Taiwanese orogeny using 2D elastic-plastic and viscoelastic numerical models of deformation of the lithosphere. We drive this modeling exercise from the assumption that the present day structure and motion depend on the long-term stress and strain history of the lithosphere. We start the models from the subduction of the Eurasian plate under the Philippine Sea plate and let it evolve to the collision of the Eurasian plate with the Luzon arc. We find that whether or not the Asian crust is dragged in the mantle is dependent on the crustal structure of the South China Sea margin. If the ocean continent transition there is mainly formed of thinned continental crust the accumulated buoyancy of the thickened crust during collision generates forces large enough to tear the subducting slab off the margin. If it consists of accreted oceanic crust the margin is dragged into the upper mantle and the slab stays attached to the Asian plate. Both scenarios lead to predictions on the type of structures and motions that should be observed by future seismic experiments in Taiwan.
DE: 1847 Modeling
DE: 3040 Plate tectonics (8150, 8155, 8157, 8158)
DE: 8100 TECTONOPHYSICS
DE: 8108 Continental tectonics: compressional
DE: 8122 Dynamics: gravity and tectonics
SC: Tectonophysics [T]
MN: 2007 Fall Meeting