Modeling lower mantle anisotropy development in a subducting slab

H. R. Wenk, S. Speziale, A. K. McNamara, Edward Garnero

Research output: Contribution to journalArticle

44 Citations (Scopus)

Abstract

A model is presented that simulates anisotropy development in a subducting slab from the upper-lower mantle boundary (661 km) to the core-mantle boundary (2891 km). Two phases are considered: orthorhombic MgSiO3-perovskite and cubic magnesiowuestite (Mg,Fe)O. Single crystal elastic properties at mantle conditions are obtained from existing density functional theory calculations and quasiharmonic approximation. It is assumed that deformation is accommodated by slip. A polycrystal plasticity model predicts strong texture development for perovskite and weaker texture for magnesiowuestite. When averaging single crystal elastic properties with the orientation distribution this results for both phases in weak P-wave anisotropy and shear wave splitting in the upper part of the lower mantle but pronounced anisotropy near the core-mantle boundary (up to 4% for Vp and 7% for Vs). The anisotropy pattern is complex and asymmetric and local heterogeneity is expected. These predictions are consistent with seismic observations.

Original languageEnglish (US)
Pages (from-to)302-314
Number of pages13
JournalEarth and Planetary Science Letters
Volume245
Issue number1-2
DOIs
StatePublished - May 15 2006

Fingerprint

lower mantle
slab
Earth mantle
slabs
Anisotropy
anisotropy
core-mantle boundary
elastic property
perovskite
modeling
textures
elastic properties
Textures
texture
Single crystals
crystal
wave splitting
Shear waves
single crystals
Polycrystals

Keywords

  • anisotropy
  • elasticity
  • lower mantle
  • magnesiowuestite
  • perovskite
  • texture

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)

Cite this

Modeling lower mantle anisotropy development in a subducting slab. / Wenk, H. R.; Speziale, S.; McNamara, A. K.; Garnero, Edward.

In: Earth and Planetary Science Letters, Vol. 245, No. 1-2, 15.05.2006, p. 302-314.

Research output: Contribution to journalArticle

Wenk, H. R. ; Speziale, S. ; McNamara, A. K. ; Garnero, Edward. / Modeling lower mantle anisotropy development in a subducting slab. In: Earth and Planetary Science Letters. 2006 ; Vol. 245, No. 1-2. pp. 302-314.
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