Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (7) Citing Articles via Google Scholar Google Scholar Articles by Kurka, A. Articles by Ingrin, J. Search for Related Content GeoRef GeoRef Citation

Kinetics of hydrogen extraction and deuteration in grossular

A. Kurka, M. Blanchard and J. Ingrin^*

LMTG, CNRS, UMR 5563, Minéralogie, 14 Av. Edouard Belin, 31400 Toulouse, France

^* E-mail: ingrin{at}lmtg.obs-mip.fr

The kinetics of hydrogen mobility in grossular with a chemically homogeneous composition of Gr83.2 And14.3 Py2.2 were studied by sequential annealing experiments monitored by Fourier transform infrared spectroscopy. Slices of single crystals <0.5 mm thick were annealed at temperatures in the range 1073–1323 K at ambient pressure in air and in gas mixtures of Ar_(90%)/D_2(10%) and Ar_(90%)/H_2(10%). The change of total infrared (IR) absorbance in the OH-stretching region (3700–3500 cm^–1) and the OD-stretching region (2750–2580 cm^–1) was used to calculate the diffusion coefficients. The law for diffusion of deuterium is given by D = D₀ exp[–102±45 kJ mol^–1/RT] with log D₀ (m²/s) = –7.6. For hydrogen extraction in air the diffusion law is expressed by D = D₀ exp[–323±46 kJ mol^–1/RT] with log D₀ (m²/s) = 1.0. This activation energy agrees with the values found for Dora Maira pyrope and for other pyropes from mantle xenoliths, but the diffusivity is slower for the grossular. A detailed investigation of the decrease in individual OH bands during hydrogen extraction in air revealed two different kinds of kinetics behaviour, suggesting that at least two different types of OH defects are present in this grossular.

KEYWORDS: grossular, hydrogen, diffusion, deuteration, FTIR spectroscopy, water in minerals

This article has been cited by other articles:

				J. A. O'Leary, G. R. Rossman, and J. M. Eiler Hydrogen analysis in minerals by continuous-flow mass spectrometry American Mineralogist, November 1, 2007; 92(11-12): 1990 - 1997. [Abstract] [Full Text] [PDF]

				J. Ingrin and M. Blanchard Diffusion of Hydrogen in Minerals Reviews in Mineralogy and Geochemistry, January 1, 2006; 62(1): 291 - 320. [Full Text] [PDF]

				B. Hertweck and J. Ingrin Hydrogen incorporation in a ringwoodite analogue: Mg2GeO4 spinel Mineralogical Magazine, June 1, 2005; 69(3): 337 - 343. [Abstract] [Full Text] [PDF]