On the increase in thermal diffusivity caused by the perovskite to post-perovskite phase transition and its implications for mantle dynamics

详细信息	查看全文 | 推荐本文 |

• 作者：Simon A. Hunt^a ; ^b ; ^c ; ^{simon.hunt@ucl.ac.uk} ; D. Rhodri Davies^d ; Andrew M. Walker^e ; Richard J. McCormack^a ; Andrew S. Wills^c ; David P. Dobson^a ; Li Li^b
• 关键词：D double-prime (D&Prime ; ) ; Thermal diffusivity ; Å ; ngstr&ouml ; m method ; CaIrO3 ; Post-perovskite ; Perovskite
• 刊名：Earth and Planetary Science Letters
• 出版年：2012
• 期刊代码：18_0012821x
• 类别：ph
• 出版时间：15 February, 2012
• 卷：319-320
• 期：Complete
• 页码：96-103
• 文件大小：790 K

摘要

The thermal diffusivity (魏) of perovskite and post-perovskite CaIrO₃ has been measured, at elevated pressure and temperatures up to 600 掳C, using the X-radiographic 脜ngstr枚m 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.