Experimental study of thermal conductivity at high pressures: Implications for the deep Earth's interior

Alexander F. Goncharov, Sergey S. Lobanov, Xiaojing Tan, Gregory T. Hohensee, David G. Cahill, Jung Fu Lin, Sylvia Monique Thomas, Takuo Okuchi, Naotaka Tomioka

Research output: Contribution to journalArticlepeer-review

Abstract

Lattice thermal conductivity of ferropericlase and radiative thermal conductivity of iron bearing magnesium silicate perovskite (bridgmanite) - the major mineral of Earth's lower mantle- have been measured at room temperature up to 30 and 46GPa, respectively, using time-domain thermoreflectance and optical spectroscopy techniques in diamond anvil cells. The results provide new constraints for the pressure dependencies of the thermal conductivities of Fe bearing minerals. The lattice thermal conductivity of ferropericlase Mg0.9Fe0.1O is 5.7(6)W/(m*K) at ambient conditions, which is almost 10 times smaller than that of pure MgO; however, it increases with pressure much faster (6.1(7)%/GPa vs 3.6(1)%/GPa). The radiative conductivity of a Mg0.94Fe0.06SiO3 bridgmanite single crystal agrees with previously determined values for powder samples at ambient pressure; it is almost pressure-independent in the investigated pressure range. Our results confirm the reduced radiative conductivity scenario for the Earth's lower mantle, while the assessment of the heat flow through the core-mantle boundary still requires in situ measurements at the relevant pressure-temperature conditions.

Original languageEnglish (US)
Pages (from-to)11-16
Number of pages6
JournalPhysics of the Earth and Planetary Interiors
Volume247
DOIs
StatePublished - Aug 25 2014

Keywords

  • Bridgmanite
  • Deep Earth's minerals
  • Ferropericlase
  • High pressure
  • Lattice thermal conductivity
  • Lower mantle
  • Optical properties
  • Radiative conductivity
  • Thermal conductivity

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Geophysics
  • Physics and Astronomy (miscellaneous)
  • Space and Planetary Science

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