OH concentrations in natural titanites determined by FTIR spectroscopy and nuclear reaction analysis
Hammer, Vera M.F.; Beran, Anton; Endisch, Denis; Rauch, Friedrich
European Journal of Mineralogy Volume 8 Number 2 (1996), p. 281 - 288
published: Apr 26, 1996
manuscript accepted: Oct 3, 1995
manuscript received: Sep 14, 1994
ArtNo. ESP147050802003, Price: 29.00 €
Abstract The OH content of titanite single crystals from different geological occurrences was studied by FTIR microspectroscopy and by nuclear reaction analysis (NRA). Calibrating the OH absorption band at 3485 cm-1 against the OH content determined by NRA, the integral molar absorptivity εi amounts to 67001 * mole-1 * cm-2. The H2O contents of the studied low-(Al,Fe) titanites range from 0.09 to 0.36 wt.%. The structural incorporation of OH is not correlated with the minor element content. Variable OH concentrations of single crystals from alpine fissures indicate fluctuations of the activity of hydrous components during crystallization. Titanite can be regarded as an essential "hydrous" mineral phase of magmatic rocks.