Dynamic Subduction Zone Thermal Modeling

动态俯冲带热模拟

• 批准号: 0408005
• 负责人: Scott King
• 金额: $ 21万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-15 至 2007-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0408005&HistoricalAwards=false
• 关键词: Dynamic; Subduction; Zone; Thermal; Modeling

The pressure-temperature environment of the subducting slab is critical for a variety of research fields. Hence, slab thermal structure calculations are used in seismology, mineral physics, gravity, petrology, and heat flow studies. The work proposed here is a major departure from previous slab thermal structure studies because the plate and slab motion in these models will be calculated dynamically. This will enable the investigators to test the validity of one of the most critical underlying assumptions used in the majority of slab thermal structure calculations: the kinematic slab approximation. Current slab thermal structure models are not able to consider the effect of deformation within the slab. Furthermore, current models are dynamically inconsistent because the density structure of the slab does not feed back into the plate and wedge flow. With the increased resolution of seismic tomography and the ability to predict flow patterns from seismic anisotropy measurements, it appears that the resolution in the observations is reaching a point that serious reconsideration of the slab thermal structure tools is warranted. In addition, there are now much better estimates of slab rheology, both from the lab and from observational constraints, and testable models of slab density structure. In order to use these new constraints to their fullest potential, a new generation of slab thermal models is needed. With a new slab thermal modeling tool, the researchers plan to focus on two specific issues: what is the impact of slab deformation on the thermal structure of the slab; and to what extend are estimates of slab buoyancy inconsistent with the observed motion of the incoming plate and the slab itself?The broader impact of this work will be the development of a tool for calculating a new generation of slab thermal structure models. The investigators envision that this will impact subduction zone researchers in several ways. First, they will be able to quantify a range of temperatures that bound the effect of slab deformation on thermal structure. This will give researchers temperature bounds to place on simple kinematic models. The new tool for generating slab thermal structure models will be significantly more complex and computationally intensive than current tools. However, they will also generate a set series of thermal fields for a variety of geometries approximating the major currently active subduction zones. These would be available for downloading from a website so that other researchers could work with them. In addition, they plan to make the source code for this new tool available to researchers on request and plan to create a reasonably friendly GUI front-end so that non-specialists will be able to work with it.

俯冲板片的压力-温度环境对于各种研究领域都是至关重要的。因此，板片热结构计算被用于地震学、矿物物理学、重力学、岩石学和热流研究。这里提出的工作是从以前的板热结构研究的主要出发，因为在这些模型中的板和板的运动将动态计算。这将使研究人员能够测试在大多数板热结构计算中使用的最关键的基本假设之一的有效性：运动板近似。现有的板热结构模型不能考虑板内变形的影响。此外，目前的模型是动态不一致的，因为板的密度结构不反馈到板和楔流。随着地震层析成像分辨率的提高和从地震各向异性测量中预测流型的能力，看来观测中的分辨率正在达到一个点，即需要认真重新考虑板状热结构工具。此外，现在有更好的估计板流变，无论是从实验室和观测的限制，和可测试的模型板密度结构。为了充分利用这些新的约束条件，需要新一代的板热模型。通过一种新的板热建模工具，研究人员计划重点关注两个具体问题：板变形对板的热结构的影响是什么;以及板浮力的估计在多大程度上与观测到的传入板和板本身的运动不一致？更广泛的影响，这项工作将是一个工具的发展，用于计算新一代的平板热结构模型。研究人员设想，这将在几个方面影响俯冲带研究人员。首先，他们将能够量化限制板变形对热结构影响的温度范围。这将为研究人员提供简单运动学模型的温度范围。用于生成板热结构模型的新工具将比当前工具更加复杂和计算密集。然而，它们也将产生一组系列的热场，用于各种几何形状，近似于目前主要的活跃俯冲带。这些数据可以从网站上下载，以便其他研究人员可以使用。此外，他们计划根据要求向研究人员提供这个新工具的源代码，并计划创建一个相当友好的GUI前端，以便非专业人员能够使用它。