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

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，这有助于控制热流驱动对流，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的热量，并最终转移到地球表面，在那里它主要通过火山活动逸出。然而，在地球内部的高压和高温下，材料的热导率并不为人所知。该研究项目的目标是测量地球上重要物质在高温高压下的导热系数，并利用测量值了解地球在整个地质时期是如何冷却的。PI将使用金刚石砧激光加热技术测量氧化物、硅酸盐和铁基合金的导热系数如何随温度、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作为时间的函数，并有助于限制发电机的行为和内核在帮助确定磁场中的作用。第二个成果是测量在地球深部条件下化学变化和相变对氧化物、硅酸盐和铁合金热导率的影响。这将有助于评估地球深部热导率的时间和空间变化。第三个成果是直接在相关的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部热导率的贡献。这里提出的工作成果有助于实现一个更广泛的目标，即对地球从地表到地核的温度和热流的热特性进行三维随时间变化的描述。

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.