2015年12月
Elasticity of Ferropericlase across the Spin Crossover in the Earth's Lower Mantle
SCIENTIFIC REPORTS
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- 巻
- 5
- 号
- 開始ページ
- 17188
- 終了ページ
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1038/srep17188
- 出版者・発行元
- NATURE PUBLISHING GROUP
Knowing the elasticity of ferropericlase across the spin transition can help explain seismic and mineralogical models of the lower-mantle including the origin of seismic heterogeneities in the middle to lowermost parts of the lower mantle(1-4). However, the effects of spin transition on full elastic constants of ferropericlase remain experimentally controversial due to technical challenges in directly measuring sound velocities under lower-mantle conditions(1-5). Here we have reliably measured both V-P and V-S of a single-crystal ferropericlase ((Mg-0.92, Fe-0.08)O) using complementary Brillouin Light Scattering and Impulsive Stimulated Light Scattering coupled with a diamond anvil cell up to 96 GPa. The derived elastic constants show drastically softened C-11 and C-12 within the spin transition at 40-60 GPa while C-44 is not affected. The spin transition is associated with a significant reduction of the aggregate V-P/V-S via the aggregate V-P softening because V-S softening does not visibly occur within the transition. Based on thermoelastic modelling along an expected geotherm, the spin crossover in ferropericlase can contribute to 2% reduction in V-P/V-S in a pyrolite mineralogical model in mid lower-mantle. Our results imply that the middle to lowermost parts of the lower-mantle would exhibit enhanced seismic heterogeneities due to the occurrence of the mixed-spin and low-spin ferropericlase.
- リンク情報
- ID情報
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- DOI : 10.1038/srep17188
- ISSN : 2045-2322
- ORCIDのPut Code : 25091102
- Web of Science ID : WOS:000365478400001
- ORCIDで取得されたその他外部ID : a:1:{i:0;a:1:{s:8:"other-id";s:19:"WOS:000365478400001";}}