Elasticity of Iron-bearing Mantle Minerals

调查人员正在对下地幔成分进行速度测量，以便更好地了解高自旋到低自旋（HSLS）电子跃迁对下地幔地震剖面的影响。他们将使用脉冲受激光散射对装载在金刚石砧室中的样品进行速度测量。该团队试图表征由电子构型、铁含量、温度和压力变化引起的铁方镁石速度的衍生物。这些结果将在地球深部地幔的背景下解释，通过进一步的扩展和应用的过渡理论。最终，铁方镁石的弹性常数应在地幔温度超过1000K以及压力的条件下测量。然而，近期的合理目标将是在适度的加热和冷却条件下进行高压研究。在实验可获得的温度条件下对预测进行定量验证将使外推到地幔温度的可信度增加。通过含铁硅酸盐钙钛矿中的HSLS转变成功表征弹性性质仍然是一个长期目标。 挑战包括获得足够质量的样品进行实验。该项目包括培训一名研究生。

The investigators are undertaking velocity measurements on lower mantle constituents in order to better understand the impact of the high-spin to low-spin (HSLS) electronic transition on lower mantle seismic profiles. They will measure velocities using Impulsive Stimulated Light Scattering on samples loaded in diamond anvil cells. The team seeks to characterize derivatives in velocity of ferro-periclase caused by changes in electronic configuration, iron content, temperature and pressure. These results will be interpreted within the context of Earth's deep mantle through further extension and application of the theory for the transition. Ultimately, elastic constants for ferro-periclase should be measured under mantle conditions of temperature in excess of 1000K as well as pressure. However, a reasonable goal in the near term will be to undertake high-pressure studies under modest conditions of heating and cooling. A quantitative validation of predictions under experimentally accessible conditions of temperature would lend confidence in the extrapolation to mantle temperatures. The successful characterization of elastic properties through the HSLS transition in iron-bearing silicate perovskites remains a longer term goal. Challenges include obtaining samples of sufficient quality to undertake the experiments. The project includes training of a graduate student.