OH point defects in olivine from Pakistan
- Author(s)
- Jürgen Gose, Esther Schmädicke, Anton Beran
- Abstract
The IR (IR) spectra of gem-quality olivine crystals from Pakistan, formed in serpentinized dunitic rocks, are characterised by strongly pleochroic absorption bands at 3,613, 3,597, 3,580 and 3,566 cm-1. These bands are assigned to O-H stretching vibrations of OH point defects corresponding to H2O concns. of about 35 wt ppm. Unlike other olivine spectra, the dominating bands are strongly polarised parallel to the b-axis. The unusual spectra type, excludes the presence of planar defects. This finding is supported by transmission electron microscopy. The 3,613 cm-1 band is related to vacant Si sites, the slightly lower energetic bands preferentially to vacant M2 sites. The exclusive presence of these bands is not only a characteristic feature of olivines treated under high P,T conditions equiv. to mantle environment, the presence of these bands in untreated natural olivine also indicates formation conditions equiv. to crustal rocks.
- Organisation(s)
- Department of Mineralogy and Crystallography
- External organisation(s)
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
- Journal
- Mineralogy and Petrology
- Volume
- 99
- Pages
- 105-111
- No. of pages
- 7
- ISSN
- 0930-0708
- Publication date
- 2010
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 1030 Physics, Astronomy, 1051 Geology, Mineralogy
- Portal url
- https://ucris.univie.ac.at/portal/en/publications/oh-point-defects-in-olivine-from-pakistan(48608743-f06a-4506-a336-d7ea633d00c4).html