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Title: X-ray Raman scattering study of MgSiO₃ glass at high pressure: Implication for triclustered MgSiO₃ melt in Earth's mantle

Abstract

Silicate melts at the top of the transition zone and the core-mantle boundary have significant influences on the dynamics and properties of Earth's interior. MgSiO 3-rich silicate melts were among the primary components of the magma ocean and thus played essential roles in the chemical differentiation of the early Earth. Diverse macroscopic properties of silicate melts in Earth's interior, such as density, viscosity, and crystal-melt partitioning, depend on their electronic and short-range local structures at high pressures and temperatures. Despite essential roles of silicate melts in many geophysical and geodynamic problems, little is known about their nature under the conditions of Earth's interior, including the densification mechanisms and the atomistic origins of the macroscopic properties at high pressures. Here, we have probed local electronic structures of MgSiO 3 glass (as a precursor to Mg-silicate melts), using high-pressure x-ray Raman spectroscopy up to 39 GPa, in which high-pressure oxygen K-edge features suggest the formation of tricluster oxygens (oxygen coordinated with three Si frameworks; [3]O) between 12 and 20 GPa. Our results indicate that the densification in MgSiO 3 melt is thus likely to be accompanied with the formation of triculster, in addition to a reduction in nonbridging oxygens. The pressure-induced increasemore » in the fraction of oxygen triclusters >20 GPa would result in enhanced density, viscosity, and crystal-melt partitioning, and reduced element diffusivity in the MgSiO 3 melt toward deeper part of the Earth's lower mantle.« less

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ;  [1];  [2];  [2];  [2];  [2] more »;  [2];  [2];  [2];  [2] « less
  1. SNU
  2. (
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
DOE - BASIC ENERGY SCIENCESDOE - OTHER
OSTI Identifier:
1169993
Resource Type:
Journal Article
Resource Relation:
Journal Name: Proc. Natl. Acad. Sci. USA; Journal Volume: 105; Journal Issue: (23) ; 06, 2008
Country of Publication:
United States
Language:
ENGLISH

Citation Formats

Lee, Sung Keun, Lin, Jung-Fu, Cai, Yong Q., Hiraoka, Nozomu, Eng, Peter J., Okuchi, Takuo, Mao, Ho-kwang, Meng, Yue, Hu, Michael Y., Chow, Paul, Shu, Jinfu, Li, Baosheng, Fukui, Hiroshi, Lee, Bum Han, Kim, Hyun Na, Yoo, Choong-Shik, LLNL), NSRRC), Okayama), UC), CIW), Wash State U), Nagoya), and SBU). X-ray Raman scattering study of MgSiO₃ glass at high pressure: Implication for triclustered MgSiO₃ melt in Earth's mantle. United States: N. p., 2015. Web. doi:10.1073/pnas.0802667105.
Lee, Sung Keun, Lin, Jung-Fu, Cai, Yong Q., Hiraoka, Nozomu, Eng, Peter J., Okuchi, Takuo, Mao, Ho-kwang, Meng, Yue, Hu, Michael Y., Chow, Paul, Shu, Jinfu, Li, Baosheng, Fukui, Hiroshi, Lee, Bum Han, Kim, Hyun Na, Yoo, Choong-Shik, LLNL), NSRRC), Okayama), UC), CIW), Wash State U), Nagoya), & SBU). X-ray Raman scattering study of MgSiO₃ glass at high pressure: Implication for triclustered MgSiO₃ melt in Earth's mantle. United States. doi:10.1073/pnas.0802667105.
Lee, Sung Keun, Lin, Jung-Fu, Cai, Yong Q., Hiraoka, Nozomu, Eng, Peter J., Okuchi, Takuo, Mao, Ho-kwang, Meng, Yue, Hu, Michael Y., Chow, Paul, Shu, Jinfu, Li, Baosheng, Fukui, Hiroshi, Lee, Bum Han, Kim, Hyun Na, Yoo, Choong-Shik, LLNL), NSRRC), Okayama), UC), CIW), Wash State U), Nagoya), and SBU). Mon . "X-ray Raman scattering study of MgSiO₃ glass at high pressure: Implication for triclustered MgSiO₃ melt in Earth's mantle". United States. doi:10.1073/pnas.0802667105.
@article{osti_1169993,
title = {X-ray Raman scattering study of MgSiO₃ glass at high pressure: Implication for triclustered MgSiO₃ melt in Earth's mantle},
author = {Lee, Sung Keun and Lin, Jung-Fu and Cai, Yong Q. and Hiraoka, Nozomu and Eng, Peter J. and Okuchi, Takuo and Mao, Ho-kwang and Meng, Yue and Hu, Michael Y. and Chow, Paul and Shu, Jinfu and Li, Baosheng and Fukui, Hiroshi and Lee, Bum Han and Kim, Hyun Na and Yoo, Choong-Shik and LLNL) and NSRRC) and Okayama) and UC) and CIW) and Wash State U) and Nagoya) and SBU)},
abstractNote = {Silicate melts at the top of the transition zone and the core-mantle boundary have significant influences on the dynamics and properties of Earth's interior. MgSiO3-rich silicate melts were among the primary components of the magma ocean and thus played essential roles in the chemical differentiation of the early Earth. Diverse macroscopic properties of silicate melts in Earth's interior, such as density, viscosity, and crystal-melt partitioning, depend on their electronic and short-range local structures at high pressures and temperatures. Despite essential roles of silicate melts in many geophysical and geodynamic problems, little is known about their nature under the conditions of Earth's interior, including the densification mechanisms and the atomistic origins of the macroscopic properties at high pressures. Here, we have probed local electronic structures of MgSiO3 glass (as a precursor to Mg-silicate melts), using high-pressure x-ray Raman spectroscopy up to 39 GPa, in which high-pressure oxygen K-edge features suggest the formation of tricluster oxygens (oxygen coordinated with three Si frameworks; [3]O) between 12 and 20 GPa. Our results indicate that the densification in MgSiO3 melt is thus likely to be accompanied with the formation of triculster, in addition to a reduction in nonbridging oxygens. The pressure-induced increase in the fraction of oxygen triclusters >20 GPa would result in enhanced density, viscosity, and crystal-melt partitioning, and reduced element diffusivity in the MgSiO3 melt toward deeper part of the Earth's lower mantle.},
doi = {10.1073/pnas.0802667105},
journal = {Proc. Natl. Acad. Sci. USA},
number = (23) ; 06, 2008,
volume = 105,
place = {United States},
year = {Mon Feb 09 00:00:00 EST 2015},
month = {Mon Feb 09 00:00:00 EST 2015}
}