Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC, USA.
Sci Rep. 2013;3:2400. doi: 10.1038/srep02400.
Thermal conductivity of mantle materials controlling the heat balance and thermal evolution of the Earth remains poorly constrained as the available experimental and theoretical techniques are limited in probing minerals under the relevant conditions. We report measurements of thermal conductivity of MgO at high pressure up to 60 GPa and 300 K via diamond anvil cells using the time-domain thermoreflectance technique. These measurements are complemented by model calculations which take into account the effect of temperature and mass disorder of materials within the Earth. Our model calculations agree with the experimental pressure dependencies at 300 and 2000 K for MgO. Furthermore, they predict substantially smaller pressure dependence for mass disordered materials as the mechanism of scattering changes. The calculated thermal conductivity at the core-mantle boundary is smaller than the majority of previous predictions resulting in an estimated total heat flux of 10.4 TW, which is consistent with modern geomodeling estimates.
地幔物质的热导率控制着地球的热平衡和热演化，但由于可用的实验和理论技术在探测相关条件下地幔矿物方面存在局限性，因此其热导率仍然难以确定。我们通过金刚石对顶砧装置利用时域热反射技术报告了在高达 60 GPa 和 300 K 压力下 MgO 的热导率测量结果。这些测量结果由模型计算补充，该模型计算考虑了地球物质中温度和质量无序的影响。我们的模型计算与 300 和 2000 K 时 MgO 的实验压力依赖性一致。此外，由于散射机制发生变化，它们预测质量无序物质的压力依赖性要小得多。在核心-地幔边界处计算出的热导率小于大多数先前的预测值，导致估计的总热通量为 10.4 TW，这与现代地球建模估计值一致。
