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Effect of Partial Melting on Elastic Properties of Rocks at Mantle Conditions

地幔条件下部分熔融对岩石弹性特性的影响

基本信息

批准号：
1809165
负责人：
Donald Weidner
金额：
$ 60万
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：
2018
资助国家：
美国
起止时间：
2018-07-01 至 2022-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1809165&HistoricalAwards=false
关键词：
Effect Partial Melting Elastic Properties

项目摘要

The temperature within the Earth is high enough to melt rocks as evidenced by volcanoes and volcanic rocks. It is thereby probable that parts of the Earth's crust and mantle are partially molten even though they are dominantly solid. The goal of this proposal is to improve the understanding of the relationship between the state of partial melting and changes in elastic properties of the media. The focus will be the upper mantle of the Earth. Since elastic properties quantitatively define the speed that seismic waves propagate through the media, the results of this research will enable better associations between maps of seismic speed variations and degrees of partial melting. The approach of this program is to probe the physics and chemistry basics of melting and mechanics yielding a deeper understanding of the underlying principles in order to provide a robust model that can then be applied to a wide variety of environments. While the focus of the proposal is the upper mantle region of the Earth, an improved model will also be relevant to the crust. Indeed, the results could also have applications in defining this relationship in industrial settings in detecting incipient stages of melting of various materials. This program provides a cutting-edge learning experience for students including graduate students in the preparation of their PhD and undergraduate students in the focus of a summer research project. The results will be used throughout the Earth sciences as fundamental information on the behavior of the Earth's interior. The tools that are developed will be made available to other researchers for studying strength related properties of materials. These tools (software and hardware) will immediately become part of the COMPRES-operated synchrotron facility and available to all in the community that wish to use them. The tools developed here will be useful for studying material properties under extreme environments and will be useful to develop better industrial materials.The authors have recently demonstrated that the current models of the mechanical properties of solid/melt combinations are inadequate and have proposed that the interaction between the solid and melt has a significant effect on the elastic properties. The new model, "dynamic melting," changes the predicted effect of melting on the relationship between the bulk modulus and the shear modulus. In the dynamic melting model, the kinetics of melting introduces a change in the frequency dependence of the elastic properties. The current proposal is to carefully test the dynamic melting model by studying a broader range of chemistry of the material and alter the experimental conditions and protocols in order to compare the predicted changes with the experimentally observed changes. The experiments are made possible by new high pressure capabilities on multi-anvil high pressure apparatus installed at synchrotron light sources. These systems enable the generation of pressure and temperature of the upper mantle on samples that can then be axially compressed, with the synchrotron yielding images of the sample with very high precision measurements of length, and diffraction profiles that yield state of stress.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

地球内部的温度高到足以融化岩石，火山和火山岩就是证明。因此，地壳和地幔的部分可能是部分熔融的，尽管它们主要是固体。该提案的目的是提高对部分熔融状态与介质弹性性质变化之间关系的理解。重点将是地球的上地幔。由于弹性性质定量地定义了地震波通过介质传播的速度，因此本研究的结果将使地震速度变化图与部分熔融程度之间有更好的关联。该计划的方法是探索熔化和力学的物理和化学基础知识，从而更深入地了解基本原理，以提供一个强大的模型，然后可以应用于各种环境。虽然该提案的重点是地球的上地幔区域，但改进的模型也将与地壳有关。事实上，这些结果也可以应用于在工业环境中定义这种关系，以检测各种材料熔化的初期阶段。该计划为学生提供了一个前沿的学习经验，包括研究生在准备他们的博士和本科生在夏季研究项目的重点。其结果将作为地球内部行为的基本信息在整个地球科学中使用。开发的工具将提供给其他研究人员，用于研究材料的强度相关性能。这些工具（软件和硬件）将立即成为压缩机操作的同步加速器设施的一部分，并提供给所有希望使用它们的社区。在这里开发的工具将是有用的研究极端环境下的材料性能，将是有用的，以开发更好的工业material.The作者最近证明，目前的固体/熔体组合的力学性能的模型是不够的，并提出了固体和熔体之间的相互作用对弹性性能有显着的影响。新的模型，“动态熔融”，改变了预测的熔融的体积模量和剪切模量之间的关系的影响。在动态熔化模型中，熔化的动力学引入弹性性质的频率依赖性的变化。目前的建议是通过研究更广泛的材料化学性质来仔细测试动态熔化模型，并改变实验条件和方案，以便将预测的变化与实验观察到的变化进行比较。实验是可能的新的高压能力的多砧高压装置安装在同步加速器光源。这些系统能够在样品上产生上地幔的压力和温度，然后可以轴向压缩，同步加速器产生样品的图像，具有非常高的精度测量长度和衍射轮廓，产生应力状态。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。