HR: 0800h
AN: T11B-0370    [Abstracts]
TI: Lithosphere-Scale Modeling of the Taiwan Orogeny
AU: * Steedman, C E
EM: steedman@usc.edu
AF: University of Southern California, Department of Earth Sciences 3751 Trousdale Ave Zumberge Hall, Rm 117, Los Angeles, CA 90089 United States
AU: Kaus, B J
EM: kaus@usc.edu
AF: University of Southern California, Department of Earth Sciences 3751 Trousdale Ave Zumberge Hall, Rm 117, Los Angeles, CA 90089 United States
AU: Okaya, D
EM: okaya@usc.edu
AF: University of Southern California, Department of Earth Sciences 3751 Trousdale Ave Zumberge Hall, Rm 117, Los Angeles, CA 90089 United States
AU: Becker, T W
EM: twb@usc.edu
AF: University of Southern California, Department of Earth Sciences 3751 Trousdale Ave Zumberge Hall, Rm 117, Los Angeles, CA 90089 United States
AB: We investigate characteristics of the Taiwan plate collision involving the Luzan arc and the Eurasian continental plate and also the``subduction" of the Eurasian plate as evidenced by seismicity and seismic tomography studies. We use a fully coupled, large strain, thermo-mechanical visco-elasto-plastic finite element code (SloMo) to simulate the collision of continental lithosphere with both oceanic lithosphere and an island arc. Taiwan provides an exceptional opportunity to study processes associated with collisional mountain belts, as the collision of the Luzon arc with the southeast China (Eurasian) continental margin is the most active arc-continent collision in the world. This collision, which forms the Taiwan Central Ranges, began in northern Taiwan 4-5 million years ago but is only just starting in the south. Thus, the following questions can be addressed: What is the role of the continental lithosphere in the collision, and does the continental plate subduct? Do both colliding plates experience pervasive deformation? In the case of the collision between a continental plate and an island arc, how is the subduction zone geometry modified after the introduction of continental lithosphere into the collision zone? What are the 3-D rheological and mechanical properties of the crust and the mantle in the orogen and what are the deformation processes involved? Does the orogenic process extend to upper mantle depths of 100-200 km? The Taiwan Integrated Geodynamics Research project (TAIGER) is a multi-national, multi-disciplinary effort which aims to study the lithospheric collision between Eurasia and the Philippine Sea Plates that has produced the island of Taiwan. This project involves passive and active seismology, magnetotellurics and the study of crustal seismic anisotropy and petrophysical properties. A major focus of the TAIGER project is to tie observation data to geodynamical models. We present here some preliminary two-dimensional geodynamical models that approximate initial crustal collision scenarios, with the hope of informing data collection and stimulating discussion. Deformation styles as a function of rheology, initial configuration and collision velocities are described.
DE: 8108 Continental tectonics: compressional
DE: 8120 Dynamics of lithosphere and mantle: general (1213)
DE: 8159 Rheology: crust and lithosphere (8031)
DE: 8170 Subduction zone processes (1031, 3060, 3613, 8413)
SC: Tectonophysics [T]
MN: Fall Meeting 2005