Measurements of Thermal Conductivity of Deep Earth Minerals

地球深部矿物热导率的测量

• 批准号: 0510914
• 负责人: Abby Kavner
• 金额: $ 21.58万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0510914&HistoricalAwards=false
• 关键词: Measurements; Thermal; Conductivity; Deep; Earth

The heat transport across the core/mantle boundary places the largest constraint on the whole-Earth heat budget, with ramifications for behavior extending well beyond the physical boundary itself-including generation and power of the dynamo-generated magnetic field, timing of inner-core formation, the driving force and style of whole-mantle convection including the surface manifestation of plate tectonics. This experimental study will take advantage of new precision in temperature measurements in the laser heated diamond cell laboratory at UCLA to measure the pressure and temperature dependence of thermal conductivity of important Earth materials (including iron and alloys, silicates and oxides) at temperatures and pressures mirroring the conditions of Earth's deep interior. In the first approach, temperature gradients will be measured for a series samples at high pressures, and best-fit thermal conductivity models will be chosen from diamond cell heat flow models. A second, more "frontiers" approach, will provide a measurement of temperature gradient in two dimensions, which will be used to measure anisotropic thermal diffusivity in natural and engineered laminar composites. Intellectual Merit: The results will be used to help address key scientific questions regarding heat transport in the Earth's deep interior, including (1) What is the heat flow through the core/mantle boundary? (2) Does the Earth's core require an internal source of heating? and (3) Can chemical heterogeneities in the Earth's lowermost mantle contribute to the style of convection through differences in heat flow mechanisms? Broader Impacts: This experimental system is the focal point of a laboratory-based state of the art research and research-training program in mineral physics at UCLA. The measurements performed by this study are a necessary first step required to calibrate and test the PI's laser heating system's ability to accurately and reproducibly measure temperature and associated gradients. The PI is an active member of the NSF-sponsored COnsortium for Mineral Physics Research at High Pressure (COMPRES) community, and innovations in temperature measurement at UCLA will be presented and exported to community facilities where feasible. In addition, the PI is actively involved in formal and informal science education spanning the pre-school through postdoctoral levels.

通过地核/地幔边界的热传输是整个地球热量收支的最大约束，其影响远远超出了物理边界本身，包括发电机产生的磁场的产生和功率，内核形成的时间，全地幔对流的驱动力和风格，包括板块构造的表面表现。这项实验研究将利用加州大学洛杉矶分校激光加热钻石细胞实验室最新的精密温度测量技术，在反映地球深部条件的温度和压力下，测量重要地球材料（包括铁和合金、硅酸盐和氧化物）的导热性对压力和温度的依赖。在第一种方法中，将测量高压下一系列样品的温度梯度，并从金刚石细胞热流模型中选择最合适的导热模型。第二种，更“前沿”的方法，将提供二维温度梯度的测量，这将用于测量天然和工程层状复合材料的各向异性热扩散系数。智力价值：研究结果将用于帮助解决有关地球深层内部热传输的关键科学问题，包括(1)通过地核/地幔边界的热流是什么？地核需要内部热源吗？(3)地球最下层地幔的化学非均质性能否通过热流机制的差异影响对流的类型？更广泛的影响：这个实验系统是加州大学洛杉矶分校矿物物理学的一个以实验室为基础的最先进的研究和研究培训项目的焦点。本研究进行的测量是校准和测试PI激光加热系统准确、可重复地测量温度和相关梯度的能力所必需的第一步。PI是nsf赞助的高压矿物物理研究联盟（COMPRES）社区的活跃成员，加州大学洛杉矶分校的温度测量创新将在可行的情况下展示并输出到社区设施。此外，PI还积极参与从学前到博士后阶段的正规和非正规科学教育。