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

American Mineralogist
By: , and 

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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 CO2− 3 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
Publisher Mineralogical Society of America
Description 5 p.
First page 1835
Last page 1839
Online Only (Y/N) N
Additional Online Files (Y/N) N