Integrating Lithospheric Dynamics, Geophysical Observations, and Three-Dimensional Whole Earth Dynamics

整合岩石圈动力学、地球物理观测和三维全地球动力学

• 批准号: 0310193
• 负责人: William Holt
• 金额: --
• 依托单位: SUNY at Stony Brook
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-15 至 2008-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0310193&HistoricalAwards=false
• 关键词: Integrating; Lithospheric; Dynamics; Geophysical; Observations

Principal investigators seek to construct a complete description of both the lithosphere and mantle dynamics on Earth. They propose a joint modeling of the lithosphere (thin sheet) and three-dimensional mantle dynamics. These models will be directly constrained by surface observations of geodesy, gravity, topography, stress measurements from the World Stress Map, crustal structure estimates, earthquake moment tensor solutions, together with mantle tomography solutions and the inferred history of subduction. The new generations of three-dimensional dynamic models can provide new insights into dynamics and rheology of both lithosphere and mantle, especially, (1) lithosphere-mantle coupling, (2) lithosphere dynamics of both continents and oceans, and (3) the role of lateral viscosity variations in the lithosphere and asthenosphere. Their approach is to solve the force-balance equations directly for vertically averaged deviatoric stress in the lithosphere using the complete set of possible forces that are applied to the lithosphere. This procedure is set up as an inverse method in which the forces constitute observations and the deviatoric stresses constitute model parameter estimates. These forces include (1) body forces associated with gravitational potential energy (GPE) differences within the lithosphere (directly inferred from observations of topography, geoid, and seismically defined crustal thicknesses) and (2) basal tractions associated with observationally constrained large-scale mantle circulation. The coupled three-dimensional mantle circulation models, while providing basal tractions at the base of the lithosphere, will also predict surface topography, geoid, and surface motions that are directly compared with the surface observations. Such observationally constrained lithosphereic and mantle circulation models allow us to move a step forward in answering fundamental questions in geodynamics: such as lithosphere-mantle coupling, asthenospheric and lithospheric viscosity and their lateral variations, the role that the actual lithospheric viscosity variations play in affecting mantle flow, basal tractions and plate motion, as well as the relative importance of the various driving forces for plate motion and plate boundary deformation. This proposal has the following broader impacts: its proposed research will contribute toward the International Lithosphere Projects (ILP) Global Strain Rate Map (GSRM) project (http://archive.unavco.ucar.edu/ilp_gsrm) and it will strengthen the research and teaching tool developed in that project by the P.I. in collaboration with UNAVCO facility scientists Dr. Lou Estey and Dr. Chuck Meertens; the proposed research will also provide training for a PhD student and it includes the participation of Dr. Lucy Flesch, a post-doctoral fellow at Department of Terrestrial Magnetism, who is experienced with lithosphere dynamic modeling.

主要研究人员试图构建一个完整的描述岩石圈和地幔动力学在地球上。他们提出了岩石圈（薄片）和三维地幔动力学的联合建模。这些模型将直接受到大地测量、重力、地形、世界应力图的应力测量、地壳结构估计、地震矩张量解、地幔层析成像解和推断的俯冲历史等地面观测的制约。新一代的三维动力学模型可以为岩石圈和地幔的动力学和流变学提供新的认识，特别是（1）岩石圈-地幔耦合，（2）大陆和海洋的岩石圈动力学，（3）岩石圈和软流圈中横向粘度变化的作用。他们的方法是利用施加在岩石圈上的一整套可能的力，直接求解岩石圈中垂直平均偏应力的力平衡方程。这个过程被设置为一个逆方法，其中的力构成观测值和偏应力构成模型参数估计。这些力包括（1）与岩石圈内重力势能（GPE）差异相关的体力（直接从地形、大地水准面和地震定义的地壳厚度的观测中推断）和（2）与观测约束的大尺度地幔环流相关的基底牵引力。耦合的三维地幔环流模型，同时提供在岩石圈底部的基底牵引力，也将预测表面地形，大地水准面和表面运动，直接与表面观测比较。这种观测约束的岩石圈和地幔环流模型使我们能够在回答地球动力学的基本问题方面向前迈进一步：如岩石圈-地幔耦合、软流圈和岩石圈粘度及其横向变化、实际岩石圈粘度变化对地幔流动、基底牵引和板块运动的影响，以及板块运动和板块边界变形的各种驱动力的相对重要性。该提案具有以下更广泛的影响：其拟议的研究将有助于国际岩石圈项目（ILP）全球应变率图（GSRM）项目（http：//archive.unavco.ucar.edu/ilp_gsrm），并将加强P.I.在该项目中开发的研究和教学工具。拟议的研究还将为一名博士生提供培训，地磁学系博士后研究员Lucy Flesch博士也将参加，她在岩石圈动态建模方面经验丰富。