Discovery of post-perovskitephase transition and implications for the nature of the D" layer of the mantle

Kei Hirose, Katsuyuki Kawamura

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

MgSiO3is a principal mineral in the upper part of the lower mantle, but its stability and possible phase transition at greater depths have long been uncertain. Recently, a new high-pressure MgSiO3 polymorph called "post-perovskite" was discovered above 125 GPa and 2500 K on the basis of X-ray diffraction measurements in a laser-heated diamond anvil cell (LH-DAC). Crystal structure of post-perovskite was first determined to be orthorhombic (space group: Cmcm) by molecular dynamics (MD) calculations. The first-principles theoretical calculations also confirmed the stability of this new phase. These results suggest that MgSiO3-rich post-perovskite is a predominant mineral below 2500-2700 km depth near the base of the mantle. The D" layer has long been the most enigmatic region in Earth's interior. The post-perovskite phase can account for the large seismic anomalies observed in the D" region, such as D" discontinuity, polarization anisotropy, and anticorrelation between S-wave and bulk sound velocities. The long-term enigma may be explained with this newly discovered crystal.

Original languageEnglish
Pages (from-to)37-46
Number of pages10
JournalSpecial Paper of the Geological Society of America
Volume421
DOIs
Publication statusPublished - 2007
Externally publishedYes

Fingerprint

perovskite
mantle
sound velocity
diamond anvil cell
lower mantle
mineral
phase transition
crystal structure
S-wave
discontinuity
anisotropy
polarization
laser
X-ray diffraction
crystal
anomaly
calculation

Keywords

  • Core-mantle boundary
  • D layer
  • Perovskite
  • Phase transition
  • Post-perovskite

ASJC Scopus subject areas

  • Geology

Cite this

Discovery of post-perovskitephase transition and implications for the nature of the D" layer of the mantle. / Hirose, Kei; Kawamura, Katsuyuki.

In: Special Paper of the Geological Society of America, Vol. 421, 2007, p. 37-46.

Research output: Contribution to journalArticle

@article{bf7877c9f0604f0f96f34353e75a68cd,
title = "Discovery of post-perovskitephase transition and implications for the nature of the D{"} layer of the mantle",
abstract = "MgSiO3is a principal mineral in the upper part of the lower mantle, but its stability and possible phase transition at greater depths have long been uncertain. Recently, a new high-pressure MgSiO3 polymorph called {"}post-perovskite{"} was discovered above 125 GPa and 2500 K on the basis of X-ray diffraction measurements in a laser-heated diamond anvil cell (LH-DAC). Crystal structure of post-perovskite was first determined to be orthorhombic (space group: Cmcm) by molecular dynamics (MD) calculations. The first-principles theoretical calculations also confirmed the stability of this new phase. These results suggest that MgSiO3-rich post-perovskite is a predominant mineral below 2500-2700 km depth near the base of the mantle. The D{"} layer has long been the most enigmatic region in Earth's interior. The post-perovskite phase can account for the large seismic anomalies observed in the D{"} region, such as D{"} discontinuity, polarization anisotropy, and anticorrelation between S-wave and bulk sound velocities. The long-term enigma may be explained with this newly discovered crystal.",
keywords = "Core-mantle boundary, D layer, Perovskite, Phase transition, Post-perovskite",
author = "Kei Hirose and Katsuyuki Kawamura",
year = "2007",
doi = "10.1130/2007.2421(03)",
language = "English",
volume = "421",
pages = "37--46",
journal = "Special Paper of the Geological Society of America",
issn = "0072-1077",
publisher = "Geological Society of America",

}

TY - JOUR

T1 - Discovery of post-perovskitephase transition and implications for the nature of the D" layer of the mantle

AU - Hirose, Kei

AU - Kawamura, Katsuyuki

PY - 2007

Y1 - 2007

N2 - MgSiO3is a principal mineral in the upper part of the lower mantle, but its stability and possible phase transition at greater depths have long been uncertain. Recently, a new high-pressure MgSiO3 polymorph called "post-perovskite" was discovered above 125 GPa and 2500 K on the basis of X-ray diffraction measurements in a laser-heated diamond anvil cell (LH-DAC). Crystal structure of post-perovskite was first determined to be orthorhombic (space group: Cmcm) by molecular dynamics (MD) calculations. The first-principles theoretical calculations also confirmed the stability of this new phase. These results suggest that MgSiO3-rich post-perovskite is a predominant mineral below 2500-2700 km depth near the base of the mantle. The D" layer has long been the most enigmatic region in Earth's interior. The post-perovskite phase can account for the large seismic anomalies observed in the D" region, such as D" discontinuity, polarization anisotropy, and anticorrelation between S-wave and bulk sound velocities. The long-term enigma may be explained with this newly discovered crystal.

AB - MgSiO3is a principal mineral in the upper part of the lower mantle, but its stability and possible phase transition at greater depths have long been uncertain. Recently, a new high-pressure MgSiO3 polymorph called "post-perovskite" was discovered above 125 GPa and 2500 K on the basis of X-ray diffraction measurements in a laser-heated diamond anvil cell (LH-DAC). Crystal structure of post-perovskite was first determined to be orthorhombic (space group: Cmcm) by molecular dynamics (MD) calculations. The first-principles theoretical calculations also confirmed the stability of this new phase. These results suggest that MgSiO3-rich post-perovskite is a predominant mineral below 2500-2700 km depth near the base of the mantle. The D" layer has long been the most enigmatic region in Earth's interior. The post-perovskite phase can account for the large seismic anomalies observed in the D" region, such as D" discontinuity, polarization anisotropy, and anticorrelation between S-wave and bulk sound velocities. The long-term enigma may be explained with this newly discovered crystal.

KW - Core-mantle boundary

KW - D layer

KW - Perovskite

KW - Phase transition

KW - Post-perovskite

UR - http://www.scopus.com/inward/record.url?scp=75749141971&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=75749141971&partnerID=8YFLogxK

U2 - 10.1130/2007.2421(03)

DO - 10.1130/2007.2421(03)

M3 - Article

VL - 421

SP - 37

EP - 46

JO - Special Paper of the Geological Society of America

JF - Special Paper of the Geological Society of America

SN - 0072-1077

ER -