Compositional dependence of structural transition pressures in amorphous phases with mantle-related compositions

Sang Heon Shim, Krystle Catalli

Research output: Contribution to journalArticle

27 Scopus citations

Abstract

Properties of silicate melts are key to understanding the evolution of the mantles of the Earth and terrestrial planets. Although remarkable progress has been made in first-principle calculations for melts in recent years, structural measurements of silicate melts at in situ high P-T remain one of the most challenging tasks. The study of glasses, kinetically frozen melts, at high pressure can provide valuable insights into related melts in the mantle. We report Raman scattering of MgSiO3 glass revealing a structural transition at 19-38 GPa, which is associated with increases in the Si{single bond}O coordination number, and another transition at 65-70 GPa. However, in CaSiO3 and Mg2SiO4 glasses, the former transition occurs at higher pressures by 5-10 GPa and the latter transition is not observed to our maximum pressure (80 GPa), indicating that a less polymerized Si{single bond}O network increases the transition pressures. Our results suggest that the pressure for the structural transitions in these glasses is influenced strongly by the concentration of network former cations and the ionic size of the network modifiers. This observation may have important implications for compositional differentiation in the early magma ocean and the present-day mantle.

Original languageEnglish (US)
Pages (from-to)174-180
Number of pages7
JournalEarth and Planetary Science Letters
Volume283
Issue number1-4
DOIs
StatePublished - Jun 15 2009
Externally publishedYes

Keywords

  • Raman spectroscopy
  • compositional sensitivity
  • mantle differentiation
  • silicate glasses
  • structural transition

ASJC Scopus subject areas

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

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