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Zirkelite from the Sebl'yavr carbonatite complex, Kola Peninsula, Russia: an X-ray and electron microprobe study of a partially metamict mineral

Published online by Cambridge University Press:  05 July 2018

A. G. Bulakh ,
A. R. Nesterov ,
C. T. Williams  and
I. S. Anisimov
A. G. Bulakh
Affiliation:
Mineralogy Department, St. Petersburg State Universit y, 199034 St-Petersburg, Russia
A. R. Nesterov
Affiliation:
Mineralogy Department, St. Petersburg State Universit y, 199034 St-Petersburg, Russia
C. T. Williams
Affiliation:
Department of Mineralogy, Natural History Museum, Cromwell Road, London SW7 5BD, UK
I. S. Anisimov
Affiliation:
Mineralogy Department, St. Petersburg State Universit y, 199034 St-Petersburg, Russia
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Abstract

Zirkelite, a cubic mineral of general formula (Ti,Ca,Zr)O2−x occurs as an accessory mineral in phoscorites, carbonatites and associated rocks in the Sebl'yavr complex. After pyrochlore, it is the main mineral concentrating niobium in these rocks. Zirkelite forms platy crystals comprising polysynthetic octahedral twins, often having a complex skeletal internal structure within a cuboctahedral external morphology. The mineral is largely metamict, but after heating to 800°C it produces a cubic crystalline structure with ao = 5.157 ±0.006 Å. It is black to brownish-black in colour, VHN = 760−780 kg.mm−2, density = 4.27 g.cm−3, and reflectance = 12.5%.

Chemically, zirkelite is relatively enriched in Nb2O5 (up to 14.5 wt.%) and ThO2 (up to 7.7 wt.%), and it displays four compositionally-distinct zones which probably formed during primary crystallisation processes. It is patchily altered where it is associated with an unidentified Ba, Ti, Nb, Zr silicate phase which partly replaces and pseudomorphs it. Under the current IMA-approved nomenclature scheme, non-crystalline (metamict) minerals of the composition described here would normally be given the general species name zirconolite, with the name zirkelite confined to the cubic mineral. However, at Sebl'yavr, the name zirkelite is used because the mineral displays a well-defined cubic crystal morphology and has a cubic structure after heating.

Keywords

zirkelitezirconoliteSebl'yavrKola Peninsulacarbonatite
Type
Research Article
Information
Mineralogical Magazine , Volume 62 , Issue 6 , December 1998 , pp. 837 - 846
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1998

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References

Anastasenko, G.F., Bulakh, A.G., Vaganov, P.A. and Bulnaev, A.J. (1978) On the mineralogy and geochemistry of Ta in phoscorites and carbonatites of the Turiy peninsula (Murmansk District). In Minerals and Paragenesis of Minerals. Nauka Press, Leningrad (in Russian), 38–46.Google Scholar
Bayliss, P., Mazzi, F., Munno, R. and White, T.J. (1989) Mineral nomenclature: zirconolite. Mineral. Mag., 53, 565-9.CrossRefGoogle Scholar
Berzelius, J.J. (1824). Undersökning af några mineralier. Kungl. Svenska Vetenskap. Handl., 334–58.Google Scholar
Bulakh, A.G. (1963) On zirkelite and zirconolite from carbonatites at the Kola Peninsula. Zap. Vses. Mineral. Obshch., 92, 746–8. (in Russian).Google Scholar
Bulakh, A.G. and Ivanikov, V.V. (1984) On Problems of Mineralogy and Petrology of Carbonatites. Leningrad University Printing House, Leningrad, (in Russian), 230 pp.Google Scholar
Bulakh, A.G. and Shevaleevsky, I.D. (1962) On mineralogy and crystallomorphology of calzirtite from alkaline rocks and carbonatites. Zap. Vses. Mineral. Obshch., 91, 14–29. (in Russian).Google Scholar
Bulakh, A.G., Il'inskii, G.A. and Kukharenko, A.A. (1960) Zirkelite from Kola Peninsula deposits. Zap. Vses. Mineral. Obshch., 89, 261–73. (in Russian).Google Scholar
Gieré, R. and Williams, C.T. (1992). REE-bearing minerals in a Ti-rich vein from the Adamello contact aureole (Italy). Contrib. Mineral. Petrol., 112, 83–100.CrossRefGoogle Scholar
Hussak, F. and Prior, G.T. (1895) Lewisite and zirkelite, two new Brazilian minerals. Mineral. Mag., 11, 80–8.Google Scholar
Kogarko, L.N., Kononova, V.A., Orlova, M.P. and Woolley, A.R. (1995) Alkaline Rocks and Carbonatites of the World Part 2: Former USSR. Chapman & Hall, London, 226 pp.Google Scholar
Komkov, A.I. (1959) On minerals of the euxenite-polycrase and priorite-blomstrandine series. Dokl. An SSSR, 126, 641–4. (in Russian).Google Scholar
Konev, A.A., Uschapovskaya, S.F., Kashaev, A.A. and Lebedeva, V.S. (1969) Tazheranite–a new calcium-tita nium-zirconium mineral. Dokl. AN SSSR, 186, 917–20. (in Russian).Google Scholar
Nickel, E.H. (1995) Definition of a mineral. J. Russell Soc., 6, 56–7.Google Scholar
Pudovkina, Z.V. and Pjatenko, J.A. (1964) Rentogenographic investigation of zirconolite and its sythetic analogue. Rentogenografia mineralnogo syrja. Nedra Press, Moscow, Issue 4. (in Russian).Google Scholar
Williams, C.T. (1996) The occurrence of niobian zirconolite, pyrochlore and baddeleyite in the Kovdor carbonatite complex, Kola Peninsula, Russia. Mineral. Mag., 60, 639–46.CrossRefGoogle Scholar
Williams, C.T. and Gieré, R. (1996) Zirconolite: a review of localities worldwide, and a compilation of its chemical composition. Bull. Nat. Hist. Mus. Lond. (Geol.), 52, 1–24.Google Scholar
Yakovlevskaya, T.A. (1967) Group of zirkelite. Zirkelite, polymignite, kobeite. In Mineraly Handbook, Nauka Press, Moscow, Vol. II, Issue 3 (in Russian), 181–91.Google Scholar