Two-Layer Deformation in Taiwan Reveals Subduction's Role in Mountain Building

The study of mountain building and the underthrusting of continental crust during this process is a topic of ongoing debate in geology. In the case of Taiwan, new three-dimensional seismic anisotropic tomography shows evidence of a two-layer deformation process that is consistent with the presence of two distinct layers of deformation.

The upper crust of Taiwan appears to be dominated by collision-related compressional deformation, while the lower crust, which is mostly composed of the subducted Eurasian plate, is dominated by convergence-parallel shear deformation. This lower crustal shearing is believed to be driven by the continuous sinking of the Eurasian mantle lithosphere when the surface of the subducted plate is coupled with the orogen.

This two-layer deformation process helps to define the role of subduction in the formation of the Taiwan mountain belt. It is an important contribution to our understanding of mountain building and the complex geological processes that shape our planet.