ABR: Mantle Circulation Models: Development and Application to Geophysical and Geochemical Observables

这项拟议的工作将发展和使用地幔流动和对流模型来了解固体地球的状态和演化。这项工作将包括对地幔热柱和热点的研究；热柱为整个地幔深处的地幔流动提供了一个指示器，最近对地幔热柱的地震观测将使人们能够直接比较地幔流动模型与对地幔流动所移动和扭曲的热柱的观测。这些结果对于理解热点轨迹和板块运动以及地幔中的流动也将是重要的。这项工作还将研究地幔中俯冲物质和其他不均质的运动，并将它们与地幔中不均质性的地球化学特征联系起来。这将建立在最近开发的地幔非均质性发展和演化的统计模型的基础上，并将提供一种将观察到的非均质性的地球化学证据与地幔中的动力学过程联系起来的手段。将进一步发展流动和对流模型，以更真实地处理热对流和地幔流变学。为了更好地约束我们的结论，将应用模型反演的最新发展。由于模型预测了一系列地球物理现象(包括大地水准面、板块运动、极地漂移)，模型研究的结果将系统地应用于其他现象。这项工作将把流动和对流的动态过程与新出现的地幔结构的地震图以及地球的地球化学演化联系起来。这将允许在短时间和长时间尺度上更统一地查看地球内部的运行情况。这项工作将包括对研究生的培训，并将开发出可供其他研究人员使用的数值模型。这项工作的结果将对理解地球的动力学和演化具有广泛的影响，并将把地球系统的演化和工作的动力学、构造和地球化学观点联系起来，这是地球科学研究的一个极其活跃的领域。

The proposed work will develop and use models of mantle flow and convection to understand the state and evolution of the solid earth. The work will include studies of mantle plumes and hotspots; plumes provide an indicator of mantle flow throughout the depth of the mantle, and recent seismic observations of plumes will allow a direct comparison of models of mantle flow with observation of plumes that are moved and distorted by mantle flow. These results will also be important for understanding hotspot tracks and plate motions, as well as flow in the mantle. The work will also address the motions of subducted material and other heterogeneities in the mantle, and will relate them to geochemical signatures of heterogeneity in the mantle. This will build upon recently developed statistical models of the development and evolution of mantle heterogeneity, and will provide a means of relating observed geochemical evidence of heterogeneity with dynamical processes in the mantle. Further development of flow and convection models will be done to deal more realistically with thermal convection and mantle rheology. Recent developments for inversion of models will be applied in order to better constrain our conclusions. Since the models predict a range of geophysical phenomena (including the geoid, plate motions, polar wander) the results of the model studies will be systematically applied to these other phenomena.The work will relate the dynamic processes of flow and convection to the emerging seismological pictures of mantle structure, as well as to the geochemical evolution of the Earth. This will allow a more unified view of the workings of the Earth's interior on both short and long time scales. The work will involve the training of graduate students, and will also develop numerical models that will be available to other researchers. The results of the work will have broad implications for understanding the dynamics and evolution of the Earth, and will relate dynamical, tectonic and geochemical views of the evolution and working of the Earth system, which represents an extremely active area of earth science research.