High-pressure behavior of anorthite: Compression and amorphization

Isabelle Daniel, Philippe Gillet, Paul F. McMillan, George Wolf, Mary A. Verhelst

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

We present the results of a detailed study of the high-pressure behavior of anorthite (CaAl2Si2O8) between ambient pressure and 30 GPa under static conditions, using in situ Raman spectroscopy and energy-dispersive X ray diffraction. On increasing pressure under hydrostatic conditions, the PĪ- 71 transition occurs first at 2.6 GPa. At 10 GPa, a reversible polymorphic transition is observed which transforms the I1̄ polymorph into a phase of higher symmetry. With further pressure increase, large changes occur in the Raman and X ray spectra between 14 and 16 GPa, premonitory to the onset of pressure-induced amorphization. Above 16 GPa, anorthite is fully amorphous. However, only samples pressurized to above 22 GPa remain amorphous on recovery to ambient conditions. The high-pressure behavior of anorthite is highly sensitive to deviatoric stresses. Under less hydrostatic conditions, the 10-GPa transition described above occurs below 9 GPa, amorphization begins below 11.2 GPa, and samples decompressed from peak pressures as low as 17 GPa are fully amorphous. We have also carried out a thermodynamic analysis of the pressure-induced amorphization of anorthite, using a two state model for the equation of state (EOS) of CaAl2Si2O8 glass in order to account for the increase in Al coordination. With this EOS, we calculate that the free energies of the crystalline and amorphous materials are equal at about 30 GPa, or slightly lower when effects of structural relaxation in the glass are taken into account, well above the observed crystalline-amorphous transition at 16 GPa.

Original languageEnglish (US)
Article number97JB00398
Pages (from-to)10313-10325
Number of pages13
JournalJournal of Geophysical Research B: Solid Earth
Volume102
Issue numberB5
StatePublished - 1997

Fingerprint

anorthite
Amorphization
Compaction
compression
hydrostatics
equation of state
equations of state
glass
Equations of state
amorphous materials
Raman spectroscopy
Crystalline materials
Glass
Structural relaxation
symmetry
energy
rays
x rays
transform
thermodynamics

ASJC Scopus subject areas

  • Oceanography
  • Astronomy and Astrophysics
  • Atmospheric Science
  • Space and Planetary Science
  • Earth and Planetary Sciences (miscellaneous)
  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences(all)
  • Environmental Science(all)

Cite this

Daniel, I., Gillet, P., McMillan, P. F., Wolf, G., & Verhelst, M. A. (1997). High-pressure behavior of anorthite: Compression and amorphization. Journal of Geophysical Research B: Solid Earth, 102(B5), 10313-10325. [97JB00398].

High-pressure behavior of anorthite : Compression and amorphization. / Daniel, Isabelle; Gillet, Philippe; McMillan, Paul F.; Wolf, George; Verhelst, Mary A.

In: Journal of Geophysical Research B: Solid Earth, Vol. 102, No. B5, 97JB00398, 1997, p. 10313-10325.

Research output: Contribution to journalArticle

Daniel, I, Gillet, P, McMillan, PF, Wolf, G & Verhelst, MA 1997, 'High-pressure behavior of anorthite: Compression and amorphization', Journal of Geophysical Research B: Solid Earth, vol. 102, no. B5, 97JB00398, pp. 10313-10325.
Daniel I, Gillet P, McMillan PF, Wolf G, Verhelst MA. High-pressure behavior of anorthite: Compression and amorphization. Journal of Geophysical Research B: Solid Earth. 1997;102(B5):10313-10325. 97JB00398.
Daniel, Isabelle ; Gillet, Philippe ; McMillan, Paul F. ; Wolf, George ; Verhelst, Mary A. / High-pressure behavior of anorthite : Compression and amorphization. In: Journal of Geophysical Research B: Solid Earth. 1997 ; Vol. 102, No. B5. pp. 10313-10325.
@article{127019418526478f8e82896d6faa4625,
title = "High-pressure behavior of anorthite: Compression and amorphization",
abstract = "We present the results of a detailed study of the high-pressure behavior of anorthite (CaAl2Si2O8) between ambient pressure and 30 GPa under static conditions, using in situ Raman spectroscopy and energy-dispersive X ray diffraction. On increasing pressure under hydrostatic conditions, the PĪ- 71 transition occurs first at 2.6 GPa. At 10 GPa, a reversible polymorphic transition is observed which transforms the I1̄ polymorph into a phase of higher symmetry. With further pressure increase, large changes occur in the Raman and X ray spectra between 14 and 16 GPa, premonitory to the onset of pressure-induced amorphization. Above 16 GPa, anorthite is fully amorphous. However, only samples pressurized to above 22 GPa remain amorphous on recovery to ambient conditions. The high-pressure behavior of anorthite is highly sensitive to deviatoric stresses. Under less hydrostatic conditions, the 10-GPa transition described above occurs below 9 GPa, amorphization begins below 11.2 GPa, and samples decompressed from peak pressures as low as 17 GPa are fully amorphous. We have also carried out a thermodynamic analysis of the pressure-induced amorphization of anorthite, using a two state model for the equation of state (EOS) of CaAl2Si2O8 glass in order to account for the increase in Al coordination. With this EOS, we calculate that the free energies of the crystalline and amorphous materials are equal at about 30 GPa, or slightly lower when effects of structural relaxation in the glass are taken into account, well above the observed crystalline-amorphous transition at 16 GPa.",
author = "Isabelle Daniel and Philippe Gillet and McMillan, {Paul F.} and George Wolf and Verhelst, {Mary A.}",
year = "1997",
language = "English (US)",
volume = "102",
pages = "10313--10325",
journal = "Journal of Geophysical Research: Atmospheres",
issn = "2169-897X",
publisher = "Wiley-Blackwell",
number = "B5",

}

TY - JOUR

T1 - High-pressure behavior of anorthite

T2 - Compression and amorphization

AU - Daniel, Isabelle

AU - Gillet, Philippe

AU - McMillan, Paul F.

AU - Wolf, George

AU - Verhelst, Mary A.

PY - 1997

Y1 - 1997

N2 - We present the results of a detailed study of the high-pressure behavior of anorthite (CaAl2Si2O8) between ambient pressure and 30 GPa under static conditions, using in situ Raman spectroscopy and energy-dispersive X ray diffraction. On increasing pressure under hydrostatic conditions, the PĪ- 71 transition occurs first at 2.6 GPa. At 10 GPa, a reversible polymorphic transition is observed which transforms the I1̄ polymorph into a phase of higher symmetry. With further pressure increase, large changes occur in the Raman and X ray spectra between 14 and 16 GPa, premonitory to the onset of pressure-induced amorphization. Above 16 GPa, anorthite is fully amorphous. However, only samples pressurized to above 22 GPa remain amorphous on recovery to ambient conditions. The high-pressure behavior of anorthite is highly sensitive to deviatoric stresses. Under less hydrostatic conditions, the 10-GPa transition described above occurs below 9 GPa, amorphization begins below 11.2 GPa, and samples decompressed from peak pressures as low as 17 GPa are fully amorphous. We have also carried out a thermodynamic analysis of the pressure-induced amorphization of anorthite, using a two state model for the equation of state (EOS) of CaAl2Si2O8 glass in order to account for the increase in Al coordination. With this EOS, we calculate that the free energies of the crystalline and amorphous materials are equal at about 30 GPa, or slightly lower when effects of structural relaxation in the glass are taken into account, well above the observed crystalline-amorphous transition at 16 GPa.

AB - We present the results of a detailed study of the high-pressure behavior of anorthite (CaAl2Si2O8) between ambient pressure and 30 GPa under static conditions, using in situ Raman spectroscopy and energy-dispersive X ray diffraction. On increasing pressure under hydrostatic conditions, the PĪ- 71 transition occurs first at 2.6 GPa. At 10 GPa, a reversible polymorphic transition is observed which transforms the I1̄ polymorph into a phase of higher symmetry. With further pressure increase, large changes occur in the Raman and X ray spectra between 14 and 16 GPa, premonitory to the onset of pressure-induced amorphization. Above 16 GPa, anorthite is fully amorphous. However, only samples pressurized to above 22 GPa remain amorphous on recovery to ambient conditions. The high-pressure behavior of anorthite is highly sensitive to deviatoric stresses. Under less hydrostatic conditions, the 10-GPa transition described above occurs below 9 GPa, amorphization begins below 11.2 GPa, and samples decompressed from peak pressures as low as 17 GPa are fully amorphous. We have also carried out a thermodynamic analysis of the pressure-induced amorphization of anorthite, using a two state model for the equation of state (EOS) of CaAl2Si2O8 glass in order to account for the increase in Al coordination. With this EOS, we calculate that the free energies of the crystalline and amorphous materials are equal at about 30 GPa, or slightly lower when effects of structural relaxation in the glass are taken into account, well above the observed crystalline-amorphous transition at 16 GPa.

UR - http://www.scopus.com/inward/record.url?scp=0031466143&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0031466143&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0031466143

VL - 102

SP - 10313

EP - 10325

JO - Journal of Geophysical Research: Atmospheres

JF - Journal of Geophysical Research: Atmospheres

SN - 2169-897X

IS - B5

M1 - 97JB00398

ER -