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Published December 1997 | public
Journal Article

An IR absorption calibration for water in minerals

Abstract

Using IR absorption data from polarized measurements on single-crystal minerals with stoichiometric water contents (in the form of H_(2)O or OH groups in the structure), a linear calibration curve (r^2 nearly equal 0.98) for water in minerals is established in the form: epsilon i , (the integrated molar absorption coefficient in units of cm^(-2) per mol H_(2)O/L) = 246.6(3753 - upsilon ) (upsilon = the mean wavenumber of the OH stretching band [in cm^(-1)]). The investigated minerals include hydrogrossular, analcime, hemimorphite and its dehydrated phase, lawsonite, goethite, diaspore, manganite, mozartite, and pectolite. The influence of hydrogen bonding, leading to increased absorption values with lower OH stretching band energies, is confirmed. It is further shown that only the use of integrated absorbance values (band areas) results in a linear correlation with water content, whereas linear absorption data (peak heights) are not correlated. The calibration agrees with previously published quantitative IR data on staurolite and trace H in pyroxenes. It is also close to the frequently used trend of Paterson (1982). However, some of the previous calibrations of trace H in nominally anhydrous minerals, e.g., kyanite and pyrope, differ appreciably from the correlation derived from stoichiometrically hydrous minerals.

Additional Information

© 1997 Mineralogical Society of America. Manuscript received March 19, 1997; manuscript accepted July 15, 1997. E.L. appreciates financial support from the "Fonds zur Förderung der wissenschaftlichen Forschung, Austria" during an Erwin-Schrödinger fellowship, project J01098-GEO. G.R.R. acknowledges financial support from the National Science Foundation, grant EAR-9218980. The constructive comments of J.-L. Robert, H. Keppler, and an anonymous referee helped to improve the quality of the manuscript.

Additional details

Created:
September 14, 2023
Modified:
October 23, 2023