Physical Properties of Core and Deep Mantle Constituents

核心和深部地幔成分的物理性质

• 批准号: 0106683
• 负责人: J Brown
• 金额: $ 30万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-06-15 至 2005-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0106683&HistoricalAwards=false
• 关键词: Physical; Properties; Core; Deep; Mantle

Brown 0106683 Seismic studies of Earth's solid inner core indicate that the inner core is elastically anisotropic and inhomogeneous, and that the apparent axis of inner core anisotropy may rotate differentially from Earth's mantle. In order to fully interpret these data, information is needed on shear wave propagation through dense, high-pressure metals, particularly iron. For most candidate lower mantle constituents the bulk moduli, as functions of pressure, are reasonably well constrained by experiment; less, however, is known about the behavior of the shear modulus. Efforts to understand both radial and lateral variation of seismic velocities in the lower mantle are limited by the remaining uncertainty in the pressure and temperature dependence of the shear elastic constants. Using the technique of Impulsive Stimulated Scattering, interfacial waves can be generated between the suface of an opaque sample in the high-pressure diamond-anvil cell and the surrounding pressure medium. The velocities of these waves, which are particularly sensitive to the shear elastic constants, are then determined. Specific goals include: (1) determination of full tensorial elastic and thermal properties of iron, iron alloys, and other metals at high pressures and (2) determination of isotropic elastic shear moduli at very high pressure of synthesized, polycrystalline, lower mantle phases.

Brown 0106683对地球固体内核的地震研究表明，内核是弹性各向异性和不均匀性的，并且内核各向异性的明显轴可能会与地球地幔差异化。为了充分解释这些数据，需要通过致密的高压金属（尤其是铁）进行剪切波传播的信息。对于大多数候选者而言，较低的地幔成分作为压力的函数，大量模量受到实验的限制。然而，关于剪切模量的行为知之甚少。了解下地幔中地震速度的径向变化和横向变化的努力受到剪切弹性常数的压力和温度依赖性的剩余不确定性的限制。 使用脉冲刺激散射的技术，可以在高压钻石 - 洋维池细胞中不透明样品的Suface和周围压力介质之间产生界面波。然后确定对剪切弹性常数特别敏感的这些波的速度。具体目标包括：（1）在高压下铁，铁合金和其他金属的全张力弹性和热性能，以及（2）在非常高的合成，多晶，多晶，较低地面阶段的高压下确定各向同性弹性剪切模量。