The Thermal Conductivity of Lower Mantle Minerals

下地幔矿物的热导率

• 批准号: NE/H007636/1
• 负责人: John Brodholt
• 金额: $ 52.6万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2010
• 资助国家: 英国
• 起止时间: 2010 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FH007636%2F1
• 关键词: Thermal; Conductivity; Lower; Mantle; Minerals

The thermal conductivity of mantle minerals affects a wide range of fundamental Earth processes. It controls the heat transferred from the core to the mantle. This in turn determines the cooling of the core, the age of the inner core and the generation of the Earth's magnetic field. Thermal conductivity determines how quickly subducting slabs warm up as they are subducted into the lower mantle. This then affects how visible they are to seismic waves, and more importantly, how much they contribute to plate-driving forces and mantle convection in general. The balance between conduction and convection determines the size and stability of thermal upwellings in the mantle, with implications for plumes and other large igneous events. Yet, despite the importance of thermal conductivity in controlling many Earth processes, thermal conductivities of mantle minerals are very poorly known. MgSiO3 perovksite is the most abundant mineral phase on the Earth and yet there is only one set of experiments measuring its conductivity. These were made at room pressure (10 MPa) and a maximum temperature of 340 K. The pressures and temperatures of the mantle reach 136 GPa and 4000 K, and so a huge extrapolation is required. Moreover, the conductivity was only measured on the pure MgSiO3 perovksite, whereas mantle perovskites contain Fe2+, Fe3+ and Al3+. We propose to use a combination of ab initio molecular dynamics simulations with new experimental techniques to provide a comprehensive set of accurate thermal conductivites for the three main lower mantle minerals. We will do this for all appropriate pressure and temperature conditions and appropriate chemical compositions.

地幔矿物的热导率影响着广泛的地球基本过程。它控制着从地核到地幔的热量传递。这反过来又决定了地核的冷却、内核的年龄和地球磁场的产生。热导率决定了俯冲板块在俯冲到下地幔时升温的速度。这会影响它们对地震波的可见度，更重要的是，它们对板块驱动力和地幔对流的贡献有多大。传导和对流之间的平衡决定了地幔中热上升的大小和稳定性，并对羽流和其他大型火成岩事件产生影响。然而，尽管热导率在控制许多地球过程中的重要性，地幔矿物的热导率知之甚少。MgSiO3钙钛矿是地球上最丰富的矿物相，但只有一组实验测量其电导率。这些是在室温（10 MPa）和最高温度340 K下制备的。地幔的压力和温度达到136 GPa和4000 K，因此需要大量的外推。此外，电导率仅在纯MgSiO3钙钛矿上测量，而地幔钙钛矿含有Fe 2+，Fe 3+和Al 3+。我们建议使用从头算分子动力学模拟与新的实验技术相结合，提供一套全面的准确的热导率的三个主要下地幔矿物。我们将在所有适当的压力和温度条件以及适当的化学成分下这样做。

项目成果

Variation of thermal conductivity and heat flux at the Earth's core mantle boundary

• DOI: 10.1016/j.epsl.2014.01.009
• 发表时间: 2014-03-15
• 期刊: EARTH AND PLANETARY SCIENCE LETTERS
• 影响因子: 5.3
• 作者: Ammann, Michael W.;Walker, Andrew M.;Dobson, David P.
• 通讯作者: Dobson, David P.

Habitable Planets: Interior Dynamics and Long-Term Evolution

宜居行星：内部动力学和长期演化

• DOI: 10.1017/s1743921313013136
• 发表时间: 2014
• 期刊: Proceedings of the International Astronomical Union
• 作者: Tackley P

Mantle dynamics in super-Earths: Post-perovskite rheology and self-regulation of viscosity

超级地球中的地幔动力学：后钙钛矿流变学和粘度的自我调节

• DOI: 10.1016/j.icarus.2013.03.013
• 发表时间: 2013
• 期刊: Icarus
• 影响因子: 3.2
• 作者: Tackley P