Collaborative Research: CSEDI--Grand Challenge for Experimental Study of Plastic Deformation Under Deep Earth Conditions

合作研究：CSEDI--深地条件下塑性变形实验研究的重大挑战

• 批准号: 0652894
• 负责人: Pamela Burnley
• 金额: $ 16.81万
• 依托单位: Georgia State University Research Foundation, Inc.
• 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: 2007-05-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0652894&HistoricalAwards=false
• 关键词: Collaborative; Research; CSEDI; Grand; Challenge

One of the most critical experimental data in developing our understanding of dynamics and evolution of Earth and other terrestrial planets are the data on rheological properties of their constituent materials. The physical and chemical conditions in planetary interior are very broad particularly in terms of pressure. The major challenge in the experimental studies on rheological properties is to develop techniques to obtain quantitative data on rheological under the conditions of planetary interiors. Well-accepted rheological data in the previous studies were limited to those obtained at pressure less than 0.5 GPa. In the previous funding period, the investigators have extended this to ~15 GPa and obtained initial results on rheological properties under the transition zone conditions of Earth''s mantle. However, their studies have also underlined several important challenges: (i) even at relatively low pressures (10 GPa) there is a large discrepancy in the experimental results (on olivine) among different laboratories, (ii) water fugacity in the previous experiments were not controlled, and (iii) the maximum pressure of quantitative deformation experiments is still limited and virtually nothing quantitative is known about the rheology of the lower mantle of the Earth. The goals of this new phase of the grand challenge project are: (i) to establish a strategy for quantitative deformation experiments under pressures through improved x-ray diffraction and inter-laboratory comparisons, (ii) to develop new methods of controlling water fugacity under high-pressures, and (iii) to expand the pressure (and temperature) range of these studies. The experimental studies will be conducted as a team effort involving experts in this research area across the country. Post-docs and students will be involved in this group effort and the results will be open to the community both through technical reports and through direct collaborations.The results of this project will provide us with a new tool by which we can determine rheological properties of minerals under a broad range of conditions (under high pressures and controlled water fugacity), and the scientific results that will come out using these techniques will form the basis for geodynamic studies of Earth and planetary interiors.

在发展我们对地球和其他陆地行星的动力学和进化的理解时，最关键的实验数据之一是其组成材料的流变特性的数据。行星内部的物理和化学条件非常广泛，尤其是在压力方面。关于流变学特性的实验研究的主要挑战是开发技术在行星内部条件下获取有关流变学的定量数据。在先前的研究中，经过良好接受的流变数据仅限于在低于0.5 GPA的压力下获得的。在上一个资金期间，研究人员将其扩展到了约15 GPA，并在地球地幔的过渡区条件下获得了关于流变特性的初步结果。但是，他们的研究也强调了一些重要的挑战：（i）即使在相对较低的压力（10 GPA）中，在不同实验室之间的实验结果（橄榄石）中也存在很大的差异，（ii）先前的实验中的水散度也无法控制，并且（iii）（iii）较低的量化实验的最大压力是量身定量的，而在量化方面却是有限的。大挑战项目的这个新阶段的目标是：（i）通过改进的X射线衍射和实验室间比较，建立在压力下进行定量变形实验的策略，（ii）开发在高压下控制水的新方法，以及（iii）以扩大这些研究的压力范围。实验研究将作为团队努力进行，涉及全国这一研究领域的专家。事后和学生将参与这一小组的努力，结果将通过技术报告和直接协作向社区开放。该项目的结果将为我们提供一个新工具，我们可以通过这些工具来确定矿物质在广泛的条件下（在高压和受控水的赋予性和受控的水上赋予）中，以及使用这些技术的基础来形成基础的科学结果。