Dynamic Subduction Zone Thermal Modeling

动态俯冲带热模拟

• 批准号: 0749708
• 负责人: Scott King
• 金额: $ 12.76万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-06-22 至 2009-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0749708&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.

俯冲板块的压力-温度环境对各种研究领域都是至关重要的。因此，板坯热结构计算被用于地震学、矿物物理学、重力、岩石学和热流研究。这项工作与以往的板坯热结构研究有很大的不同，因为这些模型中的板坯和板坯运动都是动态计算的。这将使研究人员能够测试在大多数板材热结构计算中使用的最关键的基本假设之一的有效性：运动学板材近似。现有的板坯热结构模型不能考虑板坯内部变形的影响。此外，目前的模型在动态上是不一致的，因为板坯的密度结构不能反馈到板材和楔形流中。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，观测中的分辨率似乎达到了需要认真重新考虑板坯热结构工具的程度。此外，现在有了更好的板坯流变性估计，无论是从实验室还是从观测约束，以及板坯密度结构的可测试模型。为了最大限度地利用这些新的约束条件，需要新一代板坯热模型。有了新的板坯热模拟工具，研究人员计划重点研究两个具体问题：板坯变形对板坯热结构的影响；以及板坯浮力的估计与来料板和板坯本身的观测运动在多大程度上不一致？这项工作的更广泛影响将是开发用于计算新一代板坯热结构模型的工具。调查人员预计，这将在几个方面影响俯冲带研究人员。首先，他们将能够量化板坯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界限。与现有工具相比，用于生成板坯热结构模型的新工具将显著更加复杂和计算密集。然而，它们也将为各种几何形状产生一系列的热场，这些几何形状与目前主要的活动俯冲带相似。这些可以从网站上下载，这样其他研究人员就可以与之合作了。此外，他们计划应研究人员的要求提供这一新工具的源代码，并计划创建一个相当友好的图形用户界面前端，以便非专业人员能够使用它。