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arXiv · 2005.08289

Thermal Conductivity of CaSiO$_3$ Perovskite at Lower Mantle Conditions

Zhen Zhang·Dong-Bo Zhang·Kotaro Onga·Akira Hasegawa·Kenji Ohta·Kei Hirose·Renata M. Wentzcovitch
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Abstract

Thermal conductivity ($\kappa$) of mantle minerals is a fundamental property in geodynamic modeling. It controls the style of mantle convection and the time scale of the mantle and core cooling. Cubic CaSiO$_3$ perovskite (CaPv) is the third most abundant mineral in the lower mantle (LM) (7 vol%). However, despite its importance, no theoretical or experimental estimate of CaPv's $\kappa$ exists. Theoretical investigations of its properties are challenging because of its strong anharmonicity. Experimental measurements at relevant high pressures and temperatures are equally challenging. Here we present $ab$ $initio$ results for CaPv's $\kappa$ obtained using an established phonon quasiparticle approach that can address its strong anharmonicity. We also offer experimental measurements of $\kappa$. Predictions and measurements are in good agreement and reveal a surprisingly large $\kappa$ for cubic CaPv. Despite its relatively low abundance, CaPv's $\kappa$ might increase the lower mantle $\kappa$ by approximately 10%, if accounted for. $\kappa$ of mantle regions enriched in crust material will be more strongly impacted.

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Zhen Zhang, Dong-Bo Zhang, Kotaro Onga, Akira Hasegawa, Kenji Ohta, Kei Hirose, Renata M. Wentzcovitch. 2020-05-17. Thermal Conductivity of CaSiO$_3$ Perovskite at Lower Mantle Conditions. https://doi.org/10.1103/physrevb.104.184101

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