The thermal diffusivity (κ) of perovskite and post-perovskite CaIrO3 has been measured, at elevated pressure and temperatures up to 600 °C, using the X-radiographic Ångström method. At high temperatures we find that the thermal diffusivity of post-perovskite is slightly below twice that of isochemical perovskite over the temperature range investigated. Assuming a similar effect occurs in MgSiO3 post-perovskite, the effect of the contrasting thermal transport properties between perovskite and post-perovskite on mantle dynamics has been investigated using simple two-dimensional convection models. These show a reduction in extent and increase in depth of post-perovskite lenses, as well as increased core–mantle-boundary heat-flux, broader upwellings and more vigorous downwellings when compared to the reference, constant a, case.
|Translated title of the contribution||On the increase in thermal diffusivity caused by the perovskite to post-perovskite phase transition and its implications for mantle dynamics|
|Pages (from-to)||96 - 105|
|Number of pages||10|
|Journal||Earth and Planetary Science Letters|
|Publication status||Published - Jan 2012|