俯冲板块初始化过程的研究进展

摘要

Subduction initiation is one of the most important processes of tectonic evolution of the Earth.Since the tectonic theory was proposed about five decades ago,studies of subduction initiation have been performed for a long time.In early time,a variety of theoretical models were proposed to describe such a process and evaluate the model controlling parameters.Some of the tectonic phenomena can be explained based on these models.Meanwhile,important physical properties of rocks were measured in laboratory,which provided a series of possible conditions for temperature,pressure and rheological parameters.Based on these preliminary results,numerical simulations were conducted to study the mechanism of subduction initiation.There have been two basic theoretical models proposed for subduction initiation.Numerical simulations investigated parameterization of the theoretical models based on the conservation of mass,momentum and energy equations.Results from numerical models discuss the roles of different controlling parameters in the evolution of subduction initiation,which explain the geological observations to some extent.However,since there are limitations on the numerical simulations and critical hypotheses for the basic models,current results remain obscure for clearly understanding the process.With the increases of geological observations and technical development for numerical simulations,it will be possible to better explain the mechanism of subduction initiation and plate tectonics.This paper is a summary of the advancements for the mechanism of subduction initiation in the last tens of years.Also,the divergent evolutionary processes of subduction initiation resulting from recent numerical simulations are discussed.Finally,possible directions for future studies of subduction initiation are proposed.%俯冲板块初始化是地球构造演化过程中一个重要环节.随着板块构造理论的提出,对于俯冲板块初始化的研究也由来已久.早期对于俯冲初始化的研究主要是提出了各种理论模型,并对模型中主要的参数进行估算,定性地解释一些构造地质现象.同时,实验室中可以测定地质岩石采样的物理性质,并给出初始化过程中一系列可能的温压条件和流变参数.此后在这些基础上,数值模拟研究逐渐开展.基于理论模型所提出的两类基本的俯冲板块初始化模型,数值模型使用物质守恒、能量守恒和动量守恒方程对其进行参数化研究,并探讨了各个控制参数在模型演化中的作用和影响.数值模型的结果可以很好地解释一部分地质观测得到的构造过程.但是由于模拟条件所限并且还涉及较多的未能充分证实的假设,仍然有一部分结果存在较大争议.随着地质记录的增加以及数值模拟条件的进一步完善,将可以更好地解释俯冲板块初始化的形成机制以及板块构造理论的驱动原理.本文总结了过去几十年来关于俯冲板块初始化过程机制的研究结果,同时回顾了近十多年采用计算机进行数值模拟得到的俯冲初始化演化过程,讨论并提出了进一步研究俯冲板块初始化过程所需要的工作.