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The thermal conductivity of Earth's lower mantle
Author(s) -
Tang Xiaoli,
Ntam Moses C.,
Dong Jianjun,
Rainey Emma S. G.,
Kavner Abby
Publication year - 2014
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2014gl059385
Subject(s) - silicate perovskite , thermal conductivity , mantle (geology) , core–mantle boundary , geology , thermodynamics , thermal conduction , mineralogy , materials science , geophysics , radiative transfer , physics , optics
We assess the thermal conductivity of the Earth's lower mantle anchored on our first‐principles calculations of lattice thermal conductivity of MgSiO 3 perovskite. Our calculations agree with measurements of iron‐free perovskite at ambient conditions and show a lower pressure dependence compared with other recent calculations. In addition, we show that the effect of iron on the lattice thermal conductivity of silicate perovskite is likely to be small at high temperatures. To provide an assessment of thermal conductivity throughout the lower mantle, we reevaluate existing high‐pressure optical absorption data to constrain an upper bound radiative contribution to diffusive heat transfer and examine a composite model for combining thermal conductivity of oxide and perovskite phases in the lower mantle. We find that the overall thermal conductivity of the lower mantle is approximately constant between 2.5 and 3.5 W/m/K. These values imply that the mantle has a blanketing effect on heat flow across the core‐mantle boundary.