Plate Motions in 3D Cartesian Convection: The Role of Internal Heating and Plate Reorganization

KingEAR-0207222研究人员记录了在二维和三维移动板块的笛卡尔对流计算中的对流模式，其中板块运动的变化时间尺度可与在地球上观察到的板块重组的时间尺度相媲美。这一建议将进一步加深我们对板幔耦合对流的理解。在过去的几年里，该领域对几何固定的板块和地幔对流的相互作用有了实质性的理解；考虑板块边界随时间演变的计算是适当的。在Lowman，King和Gable的板块重组研究中使用的长宽比、瑞利数和内部热值的一系列计算中，建议使用屈服强度本构定律流变学(2001年提交)。这项提议将解决两个具体问题：当在屈服-强度流变学计算中允许板块边界动态演变时，我们在以前的计算中看到的快速板块重组是否伴随着板块边界的变化？第二，在什么条件下(即，激活能和临界屈服强度)，基于本构的板方法能够在板重组事件期间和之后产生类似板的表面速度？

KingEAR-0207222The investigators have documented a mode of convection in both 2D and 3D Cartesian convection calculations with mobile plates where the plate motion changes on a time scale comparable to the time scales of plate reorganizations observed on Earth. This proposal will further our understanding of coupled plate-mantle convection. Over the past few years, the field has developed a substantial understanding of the interaction of geometrically fixed plates and mantle convection; and it is appropriate to consider calculations where the plate boundaries evolve with time. It is proposed to use a yield-strength constitutive-law rheology in a series of calculations using the aspect ratio, Rayleigh number and internal heating values used in the plate reorganization studies by Lowman, King and Gable (2001, submitted). There are two specific questions that this proposal will address: When plate boundaries are allowed to evolve dynamically in the yield-strength rheology calculations, are the rapid plate reorganizations that we have seen in previous calculations accompanied by changes in plate boundaries? Second, under what conditions (i.e., what activation energies and critical yield-strengths) are the constitutive-based plate methods able to produce plate-like surface velocities during and after a plate reorganization event?