Hostname: page-component-cd9895bd7-lnqnp Total loading time: 0 Render date: 2024-12-24T13:41:41.487Z Has data issue: false hasContentIssue false
  • English
  • Français

Oskarssonite, AlF3, a new fumarolic mineral from Eldfell volcano, Heimaey, Iceland

Published online by Cambridge University Press:  05 July 2018

M. J. Jacobsen ,
T. Balić -Žunić ,
D. Mitolo ,
A. Katerinopoulou ,
A. Garavelli  and
S. P. Jakobsson
M. J. Jacobsen
Affiliation:
Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, DK-1350, Copenhagen K, Denmark
T. Balić -Žunić*
Affiliation:
Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, DK-1350, Copenhagen K, Denmark
D. Mitolo
Affiliation:
Dipartimento di Scienze della Terra e Geoambientali, Università di Bari, via E. Orabona 4, I-70125 Bari, Italy
A. Katerinopoulou
Affiliation:
Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, DK-1350, Copenhagen K, Denmark
A. Garavelli
Affiliation:
Dipartimento di Scienze della Terra e Geoambientali, Università di Bari, via E. Orabona 4, I-70125 Bari, Italy
S. P. Jakobsson
Affiliation:
Icelandic Institute of Natural History, Urridaholtsstraeti 6-8, IS-212 Gardabaer, Iceland
*
*E-mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

The new mineral oskarssonite (IMA2012-088), with ideal formula AlF3, was found in August 2009 at the surface of fumaroles on the Eldfell volcano, Heimaey Island, Iceland (GPS coordinates 63°25′58.9″N 20°14′50.3″W). It occurs as sub-micron-sized crystals forming a white powder in association with anhydrite, bassanite, gypsum, jarosite, anatase, hematite, opal, ralstonite, jakobssonite and meniaylovite. Chemical analyses by energy-dispersive spectrometry with a scanning electronmicroscope produced the following mean elemental composition: Al, 31.70; F, 58.41; O, 9.22; total 99.33 wt.%. The empirical chemical formula is AlF2.6(OH)0.5 which suggests partial substitution of F by OH. Oskarssonite is rhombohedral, space group Rc, with ah = 4.9817(4) Å, c = 12.387(1) Å, Vuc = 266.23(5) Å3, Z = 6. The five strongest lines in the powder diffraction diagram [d in Å(I) (hkl)] are as follows: 3.54 (100) (012), 2.131 (13) (113), 1.771 (20) (024), 1.59 (15) (116), 1.574 (10) (122). Rietveld refinement confirms the identity of oskarssonite with the synthetic rhombohedral form of AlF3. Its structure can be described as a rhombohedral deformation of the idealized cubic perovskitetype octahedral framework of corner-sharing AlF6 groups. Oskarssonite appears in the surface part of the fumaroles where fluorides are abundant. At greater depths (below 10 cm) sulfates dominate among the fumarolic minerals. In accordance with its occurrence, we surmise that oskarssonite forms in the later stages of the fumarolic activity in an environment poor in alkalies and Mg. Ralstonite (NaxMgxAl1−xF3(H2O)y), which, unlike oskarssonite, contains Na and Mg as important constituents, dominated in the first-formed fumaroles, but now, 41 years after the eruption of Eldfell, is only a minor phase. The new mineral is named after the Icelandic volcanologist Niels Oskarsson.

Keywords

oskarssonitenew mineralfumarolessublimatesfluorideEldfellIceland
Type
Research Article
Information
Mineralogical Magazine , Volume 78 , Issue 1 , February 2014 , pp. 215 - 222
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2014

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

†

present address: FL Smidth R & D Center, Daniavej 49, Assens, Denmark

‡

present address: Haldor Topsøe A/S, Nymøllevej 55, DK-2800 Lyngby, Denmark

References

Acquafredda, P. and Paglionico, A. (2004) SEM-EDS microanalyses of microphenocrysts of Mediterranean obsidians: a preliminary approach to source discrimination. European Journal of Mineralogy, 16, 419–429.CrossRefGoogle Scholar
Balić-Žunić, T., Garavelli, A., Acquafredda, P., Leonardsen, E. and Jakobsson, S.P. (2009) Eldfellite, NaFe(SO4)2, a new fumarolic mineral from Eldfell volcano, Iceland. Mineralogical Magazine, 73, 51–57.CrossRefGoogle Scholar
Balić-Žunić, T., Garavelli, A., Mitolo, D., Acquafredda, P. and Leonardsen, E. (2012) Jakobssonite, CaAlF5, a new mineral from fumaroles at the Eldfell and Hekla volcanoes, Iceland. Mineralogical Magazine, 76, 751–760.CrossRefGoogle Scholar
Daniel, Ph., Bulout, A., Rousseaut, M., Nouett, J., Fourquet, J.L., Leblanc, M. and Burriel, R. (1990) A study of the structural phase transitions in AlF3: X-ray powder diffraction, DSC and Raman scattering investigations of the lattice dynamics and phonon spectrum. Journal of Physics: Condensed Matter, 2, 5663–5677.Google Scholar
Effenberger, H. and Kluger, F. (1984) Ralstonit: ein Beitrag zur Kenntnis von Zusammensetzung und Kristallstruktur. Neues Jahrbuch für Mineralogie, Monatshefte, 1984, 97–108.Google Scholar
Herron, N., Thorn, D.L., Harlow, R.L., Jones, G.A., Parise, J.B., Fernandez-Baca, J.A. and Vogtl, T. (1995) Preparation and structural characterization of two new phases of aluminum trifluoride. Chemistry of Materials 7, 75–83.CrossRefGoogle Scholar
Hoppe, R. and Kissel, D. (1984) Zur Kenntnis von AlF3 und InF3 . Journal of Fluorine Chemistry, 24, 327–340.CrossRefGoogle Scholar
Jakobsson, S.P., Leonardsen, E.S., Balić-Žunić, T. and Jonsson, S.S. (2008) Encrustations from three recent volcanic eruptions in Iceland: The 1963–1967.Google Scholar
Surtsey, , the 1973 Eldfell and the 1991 Hekla eruptions. Fjölrit Náttúrufraedistofnunar, 52, 1–65.Google Scholar
Le Bail, A. and Calvayrac, F. (2006) Hypothetical AlF3 crystal structures. Journal of Solid State Chemistry, 179, 3159–3166.CrossRefGoogle Scholar
Le Bail, A., Fourquet, J.L. and Bentrup, U. (1992) t-AIF3: Crystal structure determination from X-ray powder diffraction data. A new MX3, corner-sharing octahedral 3D network. Journal of Solid State Chemistry, 100, 151–159.CrossRefGoogle Scholar
Le Bail, A., Jacoboni, C., Leblanc, M., De Pape, R., Duroy, H. and Fourquet, J.L. (1988) Crystal structure of the metastable form of aluminum trifluoride b-AlF3 and the gallium and indium homologs. Journal of Solid State Chemistry, 77, 96–101.CrossRefGoogle Scholar
Mitolo, D., Garavelli, A., Balić-Žunić, T., Acquafredda, P. and Jakobsson, S.P. (2013) Leonardsenite, MgAlF5(H2O)2, a new fumarolic mineral from Eldfell and Hekla volcanoes, Iceland. The Canadian Mineralogist, 51, 377–386.CrossRefGoogle Scholar
Oskarsson, N. (1981) The chemistry of Icelandic lava incrustations and the latest stages of degassing. Journal of Volcanology and Geothermal Research, 10, 93–111.CrossRefGoogle Scholar
Rosenberg, P.E. (1988) Aluminum fluoride hydrates, volcanogenic salts from Mount Erebus, Antarctica. American Mineralogist, 73, 855–860.Google Scholar
Rosenberg, P.E. (1992) The hydroxylation of fluorite under hydrothermal conditions. The Canadian Mineralogist, 30, 457–462.Google Scholar
Rosenberg, P.E. (2006) Stability relations of aluminium hydroxy-fluoride hydrate, a ralstonite-like mineral, in the system AlF3−Al2O3−H2O−HF. The Canadian Mineralogist. 44, 125–134.CrossRefGoogle Scholar
Ruste, J. (1979) X-ray spectrometry. Pp 215–267 in: Microanalysis and Scanning Electron Microscopy, Summer School St-Martin-d’Hè res, France, September 11-16, 1978 (F. Maurice, L. Meny and R. Tixier, editors). Les Editions de Physique, Orsay, France.Google Scholar
Smith, D.G.W. and Nickel, E.H. (2007) A system of codification for unnamed minerals: report of the Subcommittee for Unnamed Minerals of the IMA Commission on New Minerals, Nomenclature and Classification. The Canadian Mineralogist, 45, 983–1055.CrossRefGoogle Scholar
Staritzky, E. and Asprey, L.B. (1957) Aluminum trifluoride, AIF3. Analytical Chemistry, 29, 984.CrossRefGoogle Scholar