Geometry and Kinematics of the Taiwan Arc-Continent Collision from 3-D Mapping

点击翻译按钮获取中文摘要

In Taiwan two subduction zones come together in a quasi-orthogonal, kinematically stable configuration. Under Taiwan the upper crust of Eurasia is largely decoupled from the rest of the lithosphere by a detachment that forms the main subduction interface between Eurasia (EU) and Philippine Sea plate (PSP). This interface is visible in both seismicity and crustal tomography at shallow depths, and can be followed into the mantle to depths of 450-500 km using global tomography. We plan to address the details of the 3-D configuration of the plates near Taiwan, focusing on the geometry and kinematics of several tectonic elements, in particular the EU/PSP plate boundary with its accretionary wedge/orogen complex, the Luzon volcanic arc, and the lithospheric-scale fold of the Eurasian lithosphere. Our goal is to determine both architecture and kinematics of the Taiwan arc-continent collision. We plan to first map in detail the 3-D geometry of the collision and reversal of subduction polarity and then place age constraints on the kinematics of the system, including changes in convergence velocity between Eurasia and Philippine Sea plate in the last 15 Ma, and show that both Eurasian lithospheric mantle and Eurasian lower crust are actively subducting below Taiwan.The outcome of this project will have a significant impact for both the local structure and tectonics of Taiwan, and for the more general plate tectonics of East Asia, as well as for the understanding of other arc-continent collision systems, past and present, which are considered as analogous to Taiwan.