Hostname: page-component-78c5997874-ndw9j Total loading time: 0 Render date: 2024-11-03T00:20:45.832Z Has data issue: false hasContentIssue false

Zr-rich garnet and Zr- and Th-rich perovskite from the Polino carbonatite, Italy

Published online by Cambridge University Press:  05 July 2018

L. Lupini
Affiliation:
Dipartimento di Scienze della Terra, Universita di Perugia, Piazza Universita, 06100 Perugia, Italy
C. T. Williams
Affiliation:
Department of Mineralogy, The Natural History Museum, Cromwell Road, London SW7 5BD, U.K.
A. R. Woolley
Affiliation:
Department of Mineralogy, The Natural History Museum, Cromwell Road, London SW7 5BD, U.K.

Abstract

Th- and Zr-bearing perovskite and Zr-rich Ti garnet are described from the Polino calcite carbonatite, Italy. The garnets contain 6.05-7.50 wt.% ZrO2 in cores and up to 15.80 wt.% in rims. Silicon is low in these garnets and substantial Al and Fe 3+ has been assigned to the tetrahedral sites. A strong correlation of Si with Zr from published data suggests the possibility that some Zr may also be tetrahedrally coordinated. However, the chemistry alone does not constrain the site distribution of Fe, Ti, Zr and Mg unambiguously. The perovskites are very unusual in containing 2.81-3.27 wt.% ZrO2 and 1.48-1.71 wt.% ThO2. For comparison, new analyses are presented of the zirconium garnet kimzeyite and coexisting perovskite from the type locality at Magnet Cove.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1992

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.)

References

Borodin, L. S. and Bykova, A. V. (1963) Zirconian schorlomite. DokL Acad. Sci. USSR, 141, 1301–2.Google Scholar
Borodin, L. S. and Bykova, A. V. and Kazakova, M. E. (1954) Irinite—a new mineral of the perovskite group. Dokl. Acad. Sci. USSR, 97, 725-8.Google Scholar
Deer, W. A., Howie, R. A., and Zussman, J. (1982) Rock-forming Minerals, 2nd ed., vol. 1A: Orthosilicates, Longman, 617-41.Google Scholar
Dowty, E. (1971) Crystal chemistry of titanium and zirconium garnet: I. Review and spectral studies. Am. Mineral., 56, 19832009.Google Scholar
Hauser, O. (1909) He Uhligite Cornu. Zeit. anorg. Chem., 63, 240.CrossRefGoogle Scholar
Howie, R. A. and Woolley, A. R. (1968) The role of titanium and the effect of TiO2 on the cell-size, refractive index, and specific gravity in the andradite-melanite-schorlomite series. Mineral. Mag. 36, 775–90.Google Scholar
Huggins, F. E., Virgo, D. and Huckenholz, H. G. (1977a) Titanium-containing silicate garnets. I. The ditribution of Al, Fe3+, and Ti4+ between octahedral and tetrahedral sites. Am. Mineral., 62, 475–90.Google Scholar
Huggins, F. E., Virgo, D. and Huckenholz, H. G. (1977b) Titanium-containing silicate garnets. II. The crystal chemistry of melanites and schorlomites. Am. Mineral., 62, 646–65.Google Scholar
Koritnig, S., Rosch, H., Schneider, A. and Seifert, F. (1978) Der Titan-Zirkon-Granat aus den Kalksilikat-fels-Einschlussen des Gabbro im Radautal, Harz, Bundesrepublik Deutschland. Tseherm. Min. Petr. Mitt., 25, 305–13.CrossRefGoogle Scholar
Kukharenko, A. A., Orlova, M. P., Bulakh, A. G., Bagdasarov, E. A., Rimskaya-Korsakova, O. M., Nephedov, E. I., llinsky, G. A., Sergeev, A. S. and Abakumova, N. B. (1965) The Caledonian complex of ultrabasic alkaline rocks and carbonatites of the Kola Peninsula. Nedra, Moscow. 772 pp.Google Scholar
Lapin, A. V., and Kazakova, M. Ye. (1966) Titanium lueshite from the Kovdor massif and isomorphism in the perovskite group. Dokl. Acad. Sci. USSR, 171, 160–3.Google Scholar
Lupini, L. and Stoppa, F. (1990) Occurrence of ultra-alkaline magmatism in Umbria (Italy): an outline of mineralogical and petrographic characteristics. Abstract: Int. Volcanological Conf. IAVCE, Mainz. Google Scholar
Lupini, L. and Stoppa, F. (1991) The Polino carbonatite: regional set ting and petrology. Abstract: EUG V1, Strasbourg. Google Scholar
Milton, C., Ingrain, B. L., and Blade, L. V. (1961) Kimzeyite, a zirconium garnet from Magnet Cove, Arkansas. Am. Mineral., 46, 533–48.Google Scholar
Munno, R., Rossi, G., and Tadini, C. (1980) Crystal chemistry of kimzeyite from Stromboli, Aeolian Islands, Italy. Ibid., 65, 188-91.Google Scholar
Nickel, E. H. (1960) A zirconium-bearing garnet from Oka, Quebec. Can. Mineral., 6, 549-50.Google Scholar
Platt, R. G. and Mitchell. R. H. (1979) The Marathon dykes, i: Zirconium-rich titanian garnets and manga-noan magnesian ulvéspine[-magnetite spinels. Alct. Mineral,, 64, 546–50.Google Scholar
Stoppa, F. and Lavecchia, G. (in press) Late Pleisto-cene ultra-alkaline magmatic activity in the Umbria-Latium region (Italy): an overview. J. Voleanol. Geotherm. Res. Google Scholar
Stoppa, F. and Lavecchia, G. and Lupini, L. (1991) Ultra-alkaline magma tism in the Umbria-Latium district: petrological and geological features. Plinius, 4, 92–4.Google Scholar
Vlasov, K. A. (ed.) (1966) Geochemistry and mineralogy of rare elements and genetic types of their deposits. H. Mineralogy of rare elements. Israel Program for Scientific Translations, Jerusalem. 945 pp.Google Scholar