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arXiv · 1609.06996

Radiative conductivity and abundance of post-perovskite in the lowermost mantle

Sergey S. Lobanov·Nicholas Holtgrewe·Jung-Fu Lin·Alexander F. Goncharov
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Abstract

Thermal conductivity of the lowermost mantle governs the heat flow out of the core energizing planetary-scale geological processes. Yet, there are no direct experimental measurements of thermal conductivity at relevant pressure-temperature conditions of Earth's core-mantle boundary. Here we determine the radiative conductivity of post-perovskite at near core-mantle boundary conditions by optical absorption measurements in a laser-heated diamond anvil cell. Our results show that the radiative conductivity of Mg0.9Fe0.1SiO3 post-perovskite (< 1.2 W/m/K) is ~ 40% smaller than bridgmanite at the base of the mantle. By combining this result with the present-day core-mantle heat flow and available estimations on the lattice thermal conductivity we conclude that post-perovskite is as abundant as bridgmanite in the lowermost mantle which has profound implications for the dynamics of the deep Earth.

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Sergey S. Lobanov, Nicholas Holtgrewe, Jung-Fu Lin, Alexander F. Goncharov. 2016-09-22. Radiative conductivity and abundance of post-perovskite in the lowermost mantle. https://doi.org/10.1016/j.epsl.2017.09.016

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