Sound Velocities and Elastic Moduli of Minerals Mantle Pressures and Temperatures with Laser Heating

激光加热下矿物地幔压力和温度的声速和弹性模量

• 批准号: 0003383
• 负责人: Jay Bass
• 金额: $ 46.39万
• 依托单位: University of Illinois at Urbana-Champaign
• 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: 2001-02-01 至 2007-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0003383&HistoricalAwards=false
• 关键词: Sound; Velocities; Elastic; Moduli; Minerals

BassEAR-0003383The focus of this project is laboratory measurements of sound velocities and elastic moduli of oxide minerals under the actual pressure and temperature (P and T) conditions of the Earth's deep interior. This project involves several related activities: 1) The development of an apparatus to measure sound velocities at ultra-high P-T conditions. The apparatus will be based on CO2 laser heating of samples while they are pressurized in a diamond anvil cell. Sound velocities will be measured by Brillouin scattering. Our goal is to measure the velocities of minerals up to T=2500 K and P=50 GPa, which spans the P-T conditions to a depth of ~1300 km. 2) Velocity measurements at high pressure only, at high temperature only, and at simultaneous P-T conditions using a resistively-heated diamond-anvil cell (where the temperature is moderate but accurately known). This will identify the separate effects of P and T on velocities, and help characterize conditions under laser heating. 3) Thermal expansion measurements using synchrotron x-radiation. Initial experiments will involve MgO, a lower mantle constituent. We will assess the precision and accuracy of the measurements, thermal stresses, and deviatoric stresses in the pressure medium. We will then study likely constituents of the Earth's mantle, chosen from: olivine and its high pressure polymorphs beta- and gamma-(Mg,Fe)2SiO4, majorite-garnet solid solutions, pyroxenes, magnesium-silicate perovskites, and hydrous phases. Comparisons of our results with seismologically-determined velocities for the Earth will be used to improve our understanding of the chemical and thermal state of the Earth's interior.

Bassear-0003383该项目的重点是实验室测量在地球深内部的实际压力和温度（P和T）条件下的氧化物矿物质的声速和弹性模量。该项目涉及几个相关活动：1）在超高P-T条件下测量声音速度的设备的开发。该设备将基于样品对样品的加热，同时将它们加压在钻石砧细胞中。声速将通过布里鲁因散射来测量。我们的目标是测量矿物质的速度，最大为T = 2500 K和P = 50 GPA，该矿物质跨度跨度为p-t条件，深度约为1300 km。 2）仅在高温下，仅在高温下，以及使用电阻加热的钻石 - anvil电池（温度中等但准确知道的）同时的P-T条件下的速度测量。这将确定P和T对速度的单独影响，并有助于表征激光加热下的条件。 3）使用Synchrotron X辐射的热膨胀测量。最初的实验将涉及MGO，较低的地幔成分。我们将评估压力培养基中测量，热应力和偏离应力的精度和准确性。然后，我们将研究地球地幔的可能成分，从：橄榄石及其高压多晶型物β和γ-（MG，FE）2SIO4，Mavilite-Garnet固体溶液，辉石，镁，镁硅酸盐 - 硅化硅酸盐钙化溶液和液压相。我们的结果与地球上确定的速度的比较将用于提高我们对地球内部化学和热状态的理解。