Crystal structure and thermoelastic properties of (Mg0.91Fe 0.09)SiO3 postperovskite up to 135 GPa and 2,700 K

Sang-Heon Shim, Krystle Catalli, Justin Hustoft, Atsushi Kubo, Vitali B. Prakapenka, Wendel A. Caldwell, Martin Kunz

Research output: Contribution to journalArticle

44 Citations (Scopus)

Abstract

Intriguing seismic observations have been made for the bottom 400 km of Earth's mantle (the D″ region) over the past few decades, yet the origin of these seismic structures has not been well understood. Recent theoretical calculations have predicted many unusual changes in physical properties across the postperovskite transition, perovskite (Pv) → postperovskite (PPv), that may provide explanations for the seismic observations. Here, we report measurements of the crystal structure of (Mg0.91Fe 0.09)SiO3-PPv under quasi-hydrostatic conditions up to the pressure (P)-temperature (T) conditions expected for the core-mantle boundary (CMB). The measured crystal structure is in excellent agreement with the first-principles calculations. We found that bulk sound speed (V Φ) decreases by 2.4 ± 1.4% across the PPv transition. Combined with the predicted shear-wave velocity (VS) increase, our measurements indicate that lateral variations in mineralogy between Pv and PPv may result in the anticorrelation between the VΦ and VS anomalies at the D″ region. Also, density increases by 1.6 ± 0.4% and Grüneisen parameter decreases by 21 ± 15% across the PPv transition, which will dynamically stabilize the PPv lenses observed in recent seismic studies.

Original languageEnglish (US)
Pages (from-to)7382-7386
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume105
Issue number21
DOIs
StatePublished - May 27 2008
Externally publishedYes

Fingerprint

Lenses
Pressure
Temperature
perovskite

Keywords

  • Bulk sound speed
  • Equation of state
  • Grüneisen parameter
  • Mantle
  • Phase transition

ASJC Scopus subject areas

  • Genetics
  • General

Cite this

Crystal structure and thermoelastic properties of (Mg0.91Fe 0.09)SiO3 postperovskite up to 135 GPa and 2,700 K. / Shim, Sang-Heon; Catalli, Krystle; Hustoft, Justin; Kubo, Atsushi; Prakapenka, Vitali B.; Caldwell, Wendel A.; Kunz, Martin.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 105, No. 21, 27.05.2008, p. 7382-7386.

Research output: Contribution to journalArticle

Shim, Sang-Heon ; Catalli, Krystle ; Hustoft, Justin ; Kubo, Atsushi ; Prakapenka, Vitali B. ; Caldwell, Wendel A. ; Kunz, Martin. / Crystal structure and thermoelastic properties of (Mg0.91Fe 0.09)SiO3 postperovskite up to 135 GPa and 2,700 K. In: Proceedings of the National Academy of Sciences of the United States of America. 2008 ; Vol. 105, No. 21. pp. 7382-7386.
@article{416775b8236642a5bc33a7afaaaa8e24,
title = "Crystal structure and thermoelastic properties of (Mg0.91Fe 0.09)SiO3 postperovskite up to 135 GPa and 2,700 K",
abstract = "Intriguing seismic observations have been made for the bottom 400 km of Earth's mantle (the D″ region) over the past few decades, yet the origin of these seismic structures has not been well understood. Recent theoretical calculations have predicted many unusual changes in physical properties across the postperovskite transition, perovskite (Pv) → postperovskite (PPv), that may provide explanations for the seismic observations. Here, we report measurements of the crystal structure of (Mg0.91Fe 0.09)SiO3-PPv under quasi-hydrostatic conditions up to the pressure (P)-temperature (T) conditions expected for the core-mantle boundary (CMB). The measured crystal structure is in excellent agreement with the first-principles calculations. We found that bulk sound speed (V Φ) decreases by 2.4 ± 1.4{\%} across the PPv transition. Combined with the predicted shear-wave velocity (VS) increase, our measurements indicate that lateral variations in mineralogy between Pv and PPv may result in the anticorrelation between the VΦ and VS anomalies at the D″ region. Also, density increases by 1.6 ± 0.4{\%} and Gr{\"u}neisen parameter decreases by 21 ± 15{\%} across the PPv transition, which will dynamically stabilize the PPv lenses observed in recent seismic studies.",
keywords = "Bulk sound speed, Equation of state, Gr{\"u}neisen parameter, Mantle, Phase transition",
author = "Sang-Heon Shim and Krystle Catalli and Justin Hustoft and Atsushi Kubo and Prakapenka, {Vitali B.} and Caldwell, {Wendel A.} and Martin Kunz",
year = "2008",
month = "5",
day = "27",
doi = "10.1073/pnas.0711174105",
language = "English (US)",
volume = "105",
pages = "7382--7386",
journal = "Proceedings of the National Academy of Sciences of the United States of America",
issn = "0027-8424",
number = "21",

}

TY - JOUR

T1 - Crystal structure and thermoelastic properties of (Mg0.91Fe 0.09)SiO3 postperovskite up to 135 GPa and 2,700 K

AU - Shim, Sang-Heon

AU - Catalli, Krystle

AU - Hustoft, Justin

AU - Kubo, Atsushi

AU - Prakapenka, Vitali B.

AU - Caldwell, Wendel A.

AU - Kunz, Martin

PY - 2008/5/27

Y1 - 2008/5/27

N2 - Intriguing seismic observations have been made for the bottom 400 km of Earth's mantle (the D″ region) over the past few decades, yet the origin of these seismic structures has not been well understood. Recent theoretical calculations have predicted many unusual changes in physical properties across the postperovskite transition, perovskite (Pv) → postperovskite (PPv), that may provide explanations for the seismic observations. Here, we report measurements of the crystal structure of (Mg0.91Fe 0.09)SiO3-PPv under quasi-hydrostatic conditions up to the pressure (P)-temperature (T) conditions expected for the core-mantle boundary (CMB). The measured crystal structure is in excellent agreement with the first-principles calculations. We found that bulk sound speed (V Φ) decreases by 2.4 ± 1.4% across the PPv transition. Combined with the predicted shear-wave velocity (VS) increase, our measurements indicate that lateral variations in mineralogy between Pv and PPv may result in the anticorrelation between the VΦ and VS anomalies at the D″ region. Also, density increases by 1.6 ± 0.4% and Grüneisen parameter decreases by 21 ± 15% across the PPv transition, which will dynamically stabilize the PPv lenses observed in recent seismic studies.

AB - Intriguing seismic observations have been made for the bottom 400 km of Earth's mantle (the D″ region) over the past few decades, yet the origin of these seismic structures has not been well understood. Recent theoretical calculations have predicted many unusual changes in physical properties across the postperovskite transition, perovskite (Pv) → postperovskite (PPv), that may provide explanations for the seismic observations. Here, we report measurements of the crystal structure of (Mg0.91Fe 0.09)SiO3-PPv under quasi-hydrostatic conditions up to the pressure (P)-temperature (T) conditions expected for the core-mantle boundary (CMB). The measured crystal structure is in excellent agreement with the first-principles calculations. We found that bulk sound speed (V Φ) decreases by 2.4 ± 1.4% across the PPv transition. Combined with the predicted shear-wave velocity (VS) increase, our measurements indicate that lateral variations in mineralogy between Pv and PPv may result in the anticorrelation between the VΦ and VS anomalies at the D″ region. Also, density increases by 1.6 ± 0.4% and Grüneisen parameter decreases by 21 ± 15% across the PPv transition, which will dynamically stabilize the PPv lenses observed in recent seismic studies.

KW - Bulk sound speed

KW - Equation of state

KW - Grüneisen parameter

KW - Mantle

KW - Phase transition

UR - http://www.scopus.com/inward/record.url?scp=45149116913&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=45149116913&partnerID=8YFLogxK

U2 - 10.1073/pnas.0711174105

DO - 10.1073/pnas.0711174105

M3 - Article

C2 - 18495922

AN - SCOPUS:45149116913

VL - 105

SP - 7382

EP - 7386

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

SN - 0027-8424

IS - 21

ER -