Abstract
Polarized FTIR spectra of near endmember forsterite single crystals from Pamir, Tadzikistan show the existence of sharp strongly pleochroic absorption bands in the region of the OH stretching fundamental. Bands centered at 3674/3624, 3647/3598 and 3640/ 3592 cm-1 are attributed to OH dipoles oriented parallel to [100]. An OH band doublet at 3570/3535 cm-1 shows both, a strong absorption parallel to [100] and a strong component parallel to [001]. On the basis of the pleochroic scheme and under the assumption of vacancies on Si- and M-sites it is proposed that O1 is partially replaced by OH defects pointing to the vacant Si-site. O3 is donator oxygen of OH dipoles lying near the O3-O1 tetrahedral edge or roughly pointing to a vacant M2-site. Also O2 can act as donator oxygen of an OH group oriented along the O2-O3 edge of a vacant M1 octahedron. The splitting of the bands is explained by the presence of Fe2+ in cation sites surrounding the OH defects.
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References
Bai Qu, Kohlstedt DL (1993) Effects of chemical environment on the solubility and incorporation mechanism for hydrogen in olivine. Phys Chem Minerals 19:460–471
Bauerhansl P, Beran A (1993) OH-Defekte in Chrysoberyll (Al2BeO4). Ber Dtsch Miner Ges, Beih 1, Eur J Mineral 5:198
Bell DR, Rossman GR (1992) Water in Earth's mantle: The role of nominally anhydrous minerals. Science 255:1391–1397
Beran A (1969) Über OH-Gruppen in Olivin. Österr. Akad Wiss, math naturw Kl Anzeiger: 73–74
Beran A, Putnis A (1983) A model of the OH positions in olivine, derived from infrared-spectroscopic investigations. Phys Chem Minerals 9:57–60
Freund F, Oberheuser G (1986) Water dissolved in olivine: A single-crystal infrared study. J Geophys Res 91:745–761
Karato S (1990) The role of hydrogen in the electrical conductivity of the upper mantle. Nature 347:272–273
Kitamura M, Kondoh S, Morimoto N, Miller GH, Rossman GR, Putnis A (1987) Planar OH-bearing defects in mantle olivine. Nature 328:143–145
Libowitzky E, Beran A (1994) OH-Defekte in Forsterit. Mitt Österr Miner Ges 139:331–333
Mackwell SJ, Kohlstedt DL, Paterson MS (1985) The role of water in the deformation of olivine single crystals. J Geophys Res 90:11, 319–11, 333
Miller GH, Rossman GR, Harlow GE (1987) The natural occurrence of hydroxide in olivine. Phys Chem Minerals 14:461–472
Sciuto PF (1994) On the presence of OH- groups in Zabargad olivine gems. N Jb Miner Mh 1994:145–156
Strens RGJ, Mao HK, Bell PM (1982) Quantitative spectra and optics of some meteoritic and terrestrial titanian clinopyroxenes. In: Saxena SK (ed) Advances in physical geochemistry, Vol 2. Springer, New York Heidelberg Berlin, pp 327–346
Sykes D, Rossman GR, Veblen DR, Grew ES (1994) Enhanced H and F incorporation in borian olivine. Am Mineral 79:904–908
Thompson AB (1992) Water in the Earth's upper mantle. Nature 358:295–302
Young TE, Green HW II, Hofmeister AM, Walker D (1993) Infrared spectroscopic investigation of hydroxyl in β-(Mg,Fe)2SiO4 and coexisting olivine: Implications for mantle evolution and dynamics. Phys Chem Minerals 19:409–422
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Libowitzky, E., Beran, A. OH defects in forsterite. Phys Chem Minerals 22, 387–392 (1995). https://doi.org/10.1007/BF00213336
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DOI: https://doi.org/10.1007/BF00213336