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The stability and Raman spectra of ikaite, CaCO3??6H2O, at high pressure and temperature

American Mineralogist

By:
, , , , and
DOI: 10.2138/am.2005.1783

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Abstract

Raman analyses of single crystals of ikaite, CaCO3??6H2O, synthesized in a diamond-anvil cell at ambient temperature yield spectra from 0.14 to 4.08 GPa; the most intense peaks are at 228 and 1081 cm-1 corresponding to Eg (external) and A1g (internal) modes of vibrations in CO32- ions, respectively. These are in good agreement with Raman spectra previously published for ikaite in powder form at ambient temperature and pressure. Visual observations of a sample consisting initially of a mixture of calcite + water in a hydrothermal diamond-anvil cell yielded a P-T phase diagram up to 2 GPa and 120 ??C; the boundary for the reaction ikaite ??? aragonite + water has a positive slope and is curved convexly toward the aragonite + water field similar to typical melt curves. This curvature can be explained in terms of the Clapeyron equation for a boundary between a solid phase and a more compressible liquid phase or largely liquid phase assemblage.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
The stability and Raman spectra of ikaite, CaCO3??6H2O, at high pressure and temperature
Series title:
American Mineralogist
DOI:
10.2138/am.2005.1783
Volume
90
Issue:
11-12
Year Published:
2005
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
American Mineralogist
First page:
1835
Last page:
1839
Number of Pages:
5