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

在台湾，两个俯冲带以准正交的、运动学上稳定的构型结合在一起。在台湾之下，欧亚大陆的上地壳与岩石圈的其余部分通过一条拆离带分离开来，该拆离带构成了欧亚大陆(EU)和菲律宾海板块(PSP)之间的主要俯冲界面。这一界面在地震活动和地壳层析成像中都是可见的，利用全球层析成像可以跟踪到450-500公里深的地幔。我们计划处理台湾附近板块三维构型的细节，重点关注几个构造元素的几何和运动学，特别是Eu/PSP板块边界及其增生的楔形/造山带杂岩，吕宋火山弧，以及欧亚岩石圈的岩石圈规模褶皱。我们的目标是确定台湾弧陆碰撞的构造学和运动学。我们计划首先详细绘制碰撞和俯冲极性反转的三维几何图形，然后对该系统的运动学施加年龄限制，包括最近15 Ma欧亚和菲律宾海板块之间会聚速度的变化，并表明欧亚岩石圈地幔和欧亚下地壳都在活跃地俯冲到台湾以下。这一项目的结果将对台湾的局部结构和构造、更广泛的东亚板块构造以及对过去和现在被认为与台湾类似的其他弧陆碰撞系统的认识产生重大影响。

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.