Elastic Shear Anisotropy of Ferropericlase in Earth's Lower Mantle

被引：115

作者：

Marquardt, Hauke ^{[1
]}

Speziale, Sergio ^{[1
]}

Reichmann, Hans J. ^{[1
]}

Frost, Daniel J. ^{[2
]}

Schilling, Frank R. ^{[1
]}

Garnero, Edward J. ^{[3
]}

机构：

[1] GFZ German Res Ctr Geosci, D-14473 Potsdam, Germany

[2] Univ Bayreuth, Bayer Geoinst, D-95440 Bayreuth, Germany

[3] Arizona State Univ, Sch Earth & Space Explorat, Tempe, AZ 85287 USA

来源：

SCIENCE | 2009年 / 324卷 / 5924期

关键词：

POST-PEROVSKITE PHASE; SPIN TRANSITION; SEISMIC ANISOTROPY; GPA; IRON; MGO; (MG; FE)O; DEFORMATION; SYSTEMATICS; OXIDES;

D O I：

10.1126/science.1169365

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

Seismic shear anisotropy in the lowermost mantle most likely results from elastic shear anisotropy and lattice preferred orientation of its constituent minerals, including perovskite, post-perovskite, and ferropericlase. Measurements of the elastic shear anisotropy of single-crystal (Mg0.9Fe0.1)O up to 69 gigapascals (GPa) show that it increased considerably across the pressure-induced spin transition of iron between 40 and 60 GPa. Increasing iron content further enhances the anisotropy. This leads to at least 50% stronger elastic shear anisotropy of (Mg, Fe) O in the lowermost mantle compared to MgO, which is typically used in geodynamic modeling. Our results imply that ferropericlase is the dominant cause of seismic shear anisotropy in the lower mantle.

引用

页码：224 / 226

页数：3

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