Experimental studies on plastic deformation of the lower mantle materials

下地幔材料塑性变形的实验研究

• 批准号: 1520006
• 负责人: Shun-ichiro Karato
• 金额: $ 40.5万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-12-01 至 2018-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1520006&HistoricalAwards=false
• 关键词: Experimental; studies; plastic; deformation; lower

In this project, the PI team will study the plastic flow behavior of materials in the lower mantle of the Earth that occupies a large fraction of Earth between the upper mantle and the core. Plastic deformation in this region is an important mechanism of cooling of Earth and it also controls the way in which materials are stirred or mixed. The experimental studies on plastic deformation under the conditions of the lower mantle have been difficult due to the difficulties in generating and measuring stress and strain under these conditions. The team has made various modifications to the deformation apparatus that was developed in their lab to conduct these deformation experiments. The results will provide the first data set to understand the whole Earth thermal and chemical history.Rheological properties of the lower mantle will be investigated using a rotational Drickamer apparatus developed in in the PI's laboratory. This apparatus, after numerous modifications, now allows his team to conduct large strain quantitative deformation experiments (to strain ~100-300%) under shallow lower mantle conditions (P to 28 GPa, T to 2200 K) providing the quantitative results on rheological behavior under these conditions. Not only the flow laws of each mineral, but also the microstructural evolution will be studied to provide the mechanisms of deformation and the nature of lattice-preferred orientation that can be used to interpret seismic anisotropy.

在这个项目中，PI团队将研究地球下层地幔中材料的塑性流动行为，这些材料占地层之间的大部分占地。该区域的塑性变形是地球冷却的重要机制，它还控制着搅拌或混合材料的方式。由于在这些条件下产生和测量应力和应变的困难，因此在较低地幔条件下进行塑性变形的实验研究很困难。该团队对他们实验室中开发的变形设备进行了各种修改，以进行这些变形实验。结果将提供第一个数据集，以了解整个地球的热和化学史。将使用PI实验室中开发的旋转式drickamer设备来研究下地幔的真学特性。经过大量的修饰，该设备现在允许他的团队在浅较低的地幔条件下（P至28 GPA，T至2200 K）进行大型应变定量变形实验（降压约100-300％），从而在这些条件下为流变行为提供定量结果。不仅将研究每个矿物的流量定律，而且还将研究微结构演化，以提供可用于解释地震各向异性的变形机理和晶格偏爱方向的性质。