CSEDI: Dynamics of Subducted Slabs in the Transition Zone: Compressible Convection with Self-Consistent Equation of State

CSEDI：过渡带俯冲板片动力学：具有自洽状态方程的可压缩对流

• 批准号: 0855446
• 负责人: Scott King
• 金额: $ 25.37万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-10-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0855446&HistoricalAwards=false
• 关键词: CSEDI; Dynamics; Subducted; Slabs; Transition

Seismologists have imaged a variety of geometries fast anomalies beneath subduction zones. These anomalies have been interpreted as deformed subducted oceanic lithosphere lying atop the base of the transition zone at some locations and subducted oceanic lithosphere traversing the transition zone with little apparent resistance at other locations. The investigators will investigate how the equation of state (i.e., density as a function of pressure, temperature, and composition) impacts the dynamics and morphology of subducted oceanic lithosphere. While a number of studies have shown that the morphology of subducted oceanic crust is controlled by the evolution of the plate boundary at the surface, the investigators have shown that the material properties and phase changes in the transition zone also have a significant impact on the morphology of subducted material. This research will bring together laboratory measurements of mineral properties with mantle convection calculations. Most compressible convection calculations currently use a simplified equation of state that is thermodynamically inconsistent and the first-order question that will be addressed is when and whether it is justified to use a simple equation of state. A second question is which parameters (e.g., slab strength, Clapyron slope of the transition zone phase transformations, slab age, plate velocity, trench migration) control the transition from flat lying slabs to penetrating slabs. The third component of this work is to assess which minerals and specific parameters in the thermodynamic database have the most significant effect on the dynamics of subduction. This provides guidance to the mineral physics research community as to which parameter(s) have the most significant influence on the dynamics of subduction. This will provide feedback as to which parameters to focus on improving measurements. This proposal will develop a clearly documented, modular, software package that will provide the thermodynamic properties of a mantle material at a given pressure and temperature. The goal is to enable future researchers to update elements of the thermodynamic database as new information becomes available or to perform parameter study investigations by systematically changing specific elements of the thermodynamic database. This software will be developed to interface with current and future mantle convection codes and will be made available to the research community through the Computational Infrastructure for Geodynamics website.

地震学家们已经在俯冲带下描绘出了各种几何形状的快速异常。 这些异常已被解释为变形俯冲大洋岩石圈位于顶部的过渡带的底部在某些位置和俯冲大洋岩石圈穿越过渡带在其他位置几乎没有明显的阻力。 研究人员将研究状态方程（即，密度作为压力、温度和成分的函数）影响俯冲洋岩石圈的动力学和形态。 虽然一些研究表明，俯冲洋壳的形态受表面板块边界演变的控制，但调查人员表明，过渡区的材料性质和相变也对俯冲材料的形态产生重大影响。这项研究将把矿物性质的实验室测量与地幔对流计算结合起来。 大多数可压缩对流计算目前使用的简化状态方程是热力学不一致的，一阶问题，将解决的是什么时候以及是否有理由使用一个简单的状态方程。 第二个问题是哪些参数（例如，板片强度、过渡带相变的克拉皮龙斜率、板片年龄、板片速度、沟槽迁移）控制着从平放板片到穿透板片的过渡。 这项工作的第三个组成部分是评估热力学数据库中哪些矿物和具体参数对俯冲动力学具有最重要的影响。 这为矿物物理学研究界提供了指导，以确定哪些参数对俯冲动力学具有最重要的影响。 这将提供反馈，说明应重点改进哪些参数。 该提案将开发一个有明确记录的模块化软件包，提供地幔材料在给定压力和温度下的热力学性质。 我们的目标是使未来的研究人员能够更新的热力学数据库的元素，新的信息变得可用或执行参数研究调查，通过系统地改变特定元素的热力学数据库。将开发该软件，以便与当前和未来的地幔对流代码接口，并将通过地球动力学计算基础设施网站提供给研究界。