Mantle Circulation Models: Applications to Lithospheric Deformation, Subduction and Plumes

提议的研究是研究过去150年来地幔中的流动和循环（即流动随时间的发展）。这项工作将涉及包含岩石圈板块几何和运动的地球模型，并受到地幔非均质性和观测到的俯冲板块的地震层析模型的限制。该模型还考虑了近150年来板块几何形状和运动的变化，以及内部密度场的演变。这些流动模型以前被用来预测地幔中地幔柱和热点的运动。研究人员将把地幔流模型应用于几种地球物理现象和观测。一个目的是模拟岩石圈板块的牵引力，并建立岩石圈应力和变形的有限元模型。结果将与全球应力观测结果以及板内变形区域进行比较。将研究大陆的流变学和强度非均质性的影响。他们还将计算上地幔的应变场和演化，以便将其与地震各向异性的观测结果进行比较，特别是在太平洋板块之下。流动模型还将用于将预测的流动模式与俯冲板块的方向进行比较。这将为地幔黏度模型和地幔密度非均质性的地震推断提供强有力的约束，并有助于更好地理解板块运动和俯冲的动力学。

O'Connell 0001046 The proposed research is to study flow and circulation (i.e. the development of flow over time) in the mantle over the past 150 My. The work will involve Earth models that incorporate the geometry and motions of lithospheric plates and is constrained by seismic tomographic models of mantle heterogeneity and observed subducted slabs. The changes of plate geometry and motions over the last 150 My, and the evolution of the internal density field are also included in the model. The flow models have previously been used to predict the motions of plumes and hotspots in the mantle. The investigators will apply models of mantle flow to several geophysical phenomena and observations. One aim is to model the tractions on lithospheric plates and to construct finite element models of stress and deformation in the lithosphere. The results will be compared to global stress observations, as well as areas of intraplate deformation. The effects of the rheological and strength heterogeneity of continents will be investigated. They will also calculate the strain field and evolution of the upper mantle in order to compare it with observations of seismic anisotropy, particularly beneath the Pacific plate. The flow models will also be used to compare predicted flow patterns with the orientations of subducted slabs. These should provide strong constraints on mantle viscosity models and seismic inferences of mantle density heterogeneities, and lead to a better understanding of the dynamics of plate motion and subduction.