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

Abstract

Both the analysis of the geological data and the results from 2D and 3D experimental modelling of arc–continent collision in Taiwan reveal the following major stages in this process: (1) failure and thickening of the subducting crust of the Chinese continental margin under the frontal part (accretionary prism) of the Philippine Sea Plate (PSP) since ca. 6–7Ma; (2) uplift (squeezing) and exhumation of the subducted crustal slice of the Chinese margin and initiation of the Central Range about 5Ma ago; (3) flexural buckling (subsidence) of the Luzon arc/fore-arc under strong horizontal compression and sedimentary infilling of this area by the material shed from the growing and exhuming Central Range; (4) failure of the PSP along the west-vergent Longitudinal Valley Fault dipping beneath the arc and closure of the fore-arc; (5) subduction reversal and stoppage of continental subduction which has already occurred in northern Taiwan and propagates to the south. The southward propagation of the collision is not stationary. Currently occurring initial collision in southern Taiwan and offshore to the south does not follow the same (described above) evolution as in central and northern Taiwan. The evolution of the collision in time and space should be considered 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 Valley Fault) rapidly propagates to the south into the domain, which did not undergo the pre-rupture evolution. The rupture front is currently located near 21°30′N.