Measurement of Thermal conductivity of mantle and core materials and implications for the thermal history of the Earth

地幔和核心材料热导率的测量及其对地球热史的影响

• 批准号: 1522560
• 负责人: Abby Kavner
• 金额: $ 39万
• 依托单位: University of California-Los Angeles
• 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: 2015-07-01 至 2020-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1522560&HistoricalAwards=false
• 关键词: Measurement; Thermal; conductivity; mantle; core

The major goal of this research program is to understand the thermal evolution of the whole Earth, especially its mantle, which helps govern the heat flow driving convection and ultimately generates plate tectonics, earthquakes, and volcanism activity on the Earth's surface. The mineral property of thermal conductivity helps govern the amount of heat that can escape the core and is ultimately transferred to the Earth's surface, where it escapes mostly through volcanism. However, thermal conductivity is not well known for the materials at the high pressures and temperatures inside the Earth. The goal of this research program is to measure the thermal conductivity of important Earth materials at high pressures and temperatures, and then use the measured values to understand how the Earth cools down throughout geological time.Using a diamond anvil cell laser-heating technique, the PI will measure how the thermal conductivity of oxides, silicates, and iron-based alloys vary with temperature, pressure, and composition. These measurements will help determine the thermal conductivity of the inner core and outer core as a function of time, and help constrain dynamo behavior and the role of the inner core in helping to determine the magnetic field. The second outcome is a measure of the effect of chemical change and phase change on the thermal conductivity of oxides, silicates, and iron alloys at deep Earth conditions. This will help assess temporal and spatial variations of thermal conductivity of the deep Earth. The third outcome is a measure of near infrared optical absorption properties of mantle oxides and silicates directly at the relevant high pressures and temperatures. This will constrain place bounds on the radiative contribution to deep Earth thermal conductivity. The outcome of the work proposed here contributes to the broader goal of a three-dimensional time-dependent portrait of the thermal properties of the Earth, both temperature and heat flow, from the surface to the core.

该研究计划的主要目标是了解整个地球的热演化，特别是地幔的热演化，它有助于控制驱动对流的热流，并最终在地球表面产生板块构造、地震和火山活动。矿物的导热性有助于控制从地核逸出并最终转移到地球表面的热量，热量主要通过火山活动逸出。然而，对于地球内部高压和高温下的材料的导热性尚不清楚。该研究计划的目标是测量重要地球材料在高压和高温下的热导率，然后利用测量值来了解地球在整个地质时期如何冷却。PI 将使用金刚石砧单元激光加热技术来测量氧化物、硅酸盐和铁基合金的热导率如何随温度、压力和成分变化。这些测量将有助于确定内核和外核的热导率随时间的变化，并有助于约束发电机行为和内核在帮助确定磁场方面的作用。第二个结果是测量化学变化和相变对地球深处条件下氧化物、硅酸盐和铁合金导热系数的影响。这将有助于评估地球深处热导率的时间和空间变化。第三个结果是直接在相关高压和高温下测量地幔氧化物和硅酸盐的近红外光学吸收特性。这将限制辐射对地球深层热导率的贡献的界限。这里提出的工作成果有助于实现地球热特性（从表面到核心的温度和热流）的三维时间相关肖像的更广泛目标。