板块初始俯冲的三维物理模拟研究：以九州-帕劳海脊南段为例

板块初始俯冲机制是板块构造理论的核心问题，至今依然存在大量争议。九州-帕劳海脊南段及其邻区蕴含了丰富的初始俯冲相关信息，是研究初始俯冲机制的典型地区。本课题以九州-帕劳海脊南段为研究对象，基于实际地质与地球物理观测资料约束，开展岩石圈尺度地球动力学物理模拟实验，研究不同的潜在因素对古太平洋板块-西菲律宾海板块初始俯冲的影响，同时用粒子图像测速系统（PIV）和三维激光扫描技术定量化分析从初始俯冲到稳定自持性俯冲过程中深部地幔流特征和浅部板块表面的应力、应变场，进而揭示俯冲过程中的壳-幔相互作用。结合实验机理分析和实际观测，揭示古太平洋板块-西菲律宾海板块初始俯冲机制、动力学过程和控制因素，探索九州-帕劳海脊南段及邻区从“初始俯冲-岛弧裂离-弧后伸展”的演化史。

Subduction initiation is the key issue of plate tectonics theory, however, its mechanism is still on controversy. The southern Kyushu-Palau Ridge contains abundant information of subduction initiation, providing a typical natural laboratory for studying the mechanism of subduction initiation. In this study, the southern section of Kyushu-Palau Ridge will be our research object and based on its geological and geophysical constrains, a series of lithosphere-scaled analogue modeling experiments will be conducted to study the mechanism, dynamic processes and controlling factors of Paleo-Pacific Plate- West Philippine Sea Plate subduction initiation. The characteristics of deep mantle flow field as well as superficial strain, stress fields of subducting and overriding plates during the transition of subduction initiation to self-sustaining subduction will be quantitatively analyzed by PIV and three-dimensional laser scanning techniques. And then reveal the interaction of crust-mantle processes during the subduction. Combined the analogue modeling and natural observation, a complete evolution of subduction initiation, island arc splitting and back-arc seafloor spreading is aimed to be constructed.