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团队将研究地球下地幔中物质的塑性流动行为，下地幔占据了上地幔和地核之间的大部分地球。该区域的塑性变形是地球冷却的一个重要机制，它也控制着物质搅拌或混合的方式。由于下地幔条件下应力应变的产生和测量困难，下地幔条件下塑性变形的实验研究一直很困难。该团队对实验室开发的变形装置进行了各种修改，以进行这些变形实验。研究结果将为了解整个地球的热历史和化学历史提供第一个数据集。下地幔的流变特性将使用PI实验室开发的旋转Drickamer装置进行研究。经过多次修改后，该装置现在使他的团队能够在浅层下地幔条件（P至28 GPa，T至2200 K）下进行大应变定量变形实验（应变~100-300%），提供这些条件下流变行为的定量结果。不仅要研究每种矿物的流动规律，还要研究显微构造的演化，以提供变形机制和晶格择优取向的性质，从而可以用来解释地震各向异性。