New results from physical modelling of arc-continent collision in Taiwan: evolutionary model

Both the analysis of the geological data and the results from 2D and 3D exp erimental modelling of arc-continent collision in Taiwan reveal the followi ng major stages in this process: (1) failure and thickening of the subducti ng crust of the Chinese continental margin under the frontal part (accretio nary prism) of the Philippine Sea Plate (PSP) since ca, 6-7 Ma: (2) uplift (squeezing) and exhumation of the subducted crustal slice of the Chinese ma rgin and initiation of the Central Range about 5 Ma ago; (3) flexural buckl ing (subsidence) of the Luzon arc/fore-arc under strong horizontal compress ion and sedimentary infilling of this area by the material shed from the gr owing and exhuming Central Range; (4) failure: of the PSP along the west-ve rgent Longitudinal Valley Fault dipping beneath the are and closure of the fore-arc; (5) subduction reversal and stoppage of continental subduction wh ich has already occurred in northern Taiwan and propagates to the south. Th e southward propagation of the collision is not stationary. Currently occur ring initial collision in southern Taiwan and offshore to the south does no t follow the same (described above) evolution as in central and northern Ta iwan. The evolution of the collision in time acid space should be considere d in the framework of a 3D model where the PSP rupture is preparing in the central and northern Taiwan during a long time, passing through a number of evolutionary stages. Once it has occurred, the rupture (Longitudinal Valle y Fault) rapidly propagates to the south into the domain, which did not und ergo the pre-rupture evolution. The rupture front is currently located near 21 degrees 30'N. (C) 2001 Elsevier Science B.V. All rights reserved.