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Sb-rich titanite in the manganese concentrations at St. Marcel-Praborna, Aosta Valley, Italy: petrography and crystal-chemistry

Published online by Cambridge University Press:  05 July 2018

Elena-Adriana Perseil  and
David C. Smith
Elena-Adriana Perseil
Affiliation:
Muséum National d'Histoire Naturelle, Laboratoire de Minéralogie, France CNRS, Unité de Recherche Associée no 736, 61 Rue Buffon, 75005 Paris, France
David C. Smith
Affiliation:
Muséum National d'Histoire Naturelle, Laboratoire de Minéralogie, France
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Abstract

Titanites rich in antimony (up to 12.59 wt.% Sb2O5; equal to 0.165 Sb5+ per Si4+ = 1.000) arc described for the first time. They coexist with various greenschist-facies minerals in three different petrographical environments in the manganese concentrations at St. Marcel-Praborna in the Aosta Valley, Italy. These titanites are chemically zoned, the Sb-richest parts generally occurring alongside grain boundaries, microfractures, pores or inclusions. Moderately-good positive correlations exist between the Sb, Al and Fe contents, with negative correlations of each of these elements with Ti. Cr has perturbed the Al and Fe contents since a better negative correlation with Ti is obtained with [Al + Cr + Mn + Fe]. The Sr, Ba, Mn and F contents are rather small and vary irregularly. Several crystal-chemical hypotheses are presented concerning the method of structural formula calculation and the valencies and site distributions of Sb and the companion additional minor elements. The favoured interpretation is to place: Sr2+, Ba2+, Mn2+, Fe2+ and possibly also Sb3+ in the viiCa2+ site; Sb5+, Cr3+, Al3+, Sb3+, Fe3+ and possibly also Mn3+ in the viTi4+ site; and Al3+ in the ivSi4+ site; this indicates the existence of a natural silicate containing not only both trivalent and pentavalent Sb, but also both valencies in the same site. The principal ionic substitution is believed to be: 2 viTi4+ = vi[Al3+ + Cr3+ + Mn3+ + Fe3+] + viSb5+ accompanied by a substantial minor proportion of: 2 viTi4+ = viSb3+ + viSb5, or possibly = 2 viSb4+ The data indicate a very late stage penetration of pre-existing titanites by mobilized Sb, Al, Cr, Mn, Fe, F and presumably also (OH) at this locality, whereas Sr and Ba were mobile at an earlier stage. Manganese, which existed in the sedimentary protoliths, did not enter the titanite structure in very significant quantities.

Keywords

antimonytitanitecrystal-chemistrypetrographySt. Marcel-PrabornaItaly
Type
Mineralogy
Information
Mineralogical Magazine , Volume 59 , Issue 397 , December 1995 , pp. 717 - 734
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1995

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References

Bernau, R. and Franz, G. (1987) Crystal-chemistry and genesis of Nb-, V-, and Al-rich metamorphic titanite from Egypt and Greece. Canad. Mineral,, 25, 695–705.Google Scholar
Cerny, P. and Povondra, P. (1972) An Al,F-rich metamict titanite from Czechoslovakia. Neues Jahrb. Mineral, Mh., 400-6.Google Scholar
Clark, A.M. (1974) A tantalum-rich variety of sphene. Mineral. Mag. 39, 605–7.CrossRefGoogle Scholar
Colomba, L. (1910) Rhodonite cristallizzata di St. Marcel (Valle d'Aosta). Atti R. Ace. Sc. Torino, 39, 664–68.Google Scholar
Deer, W.A., Howie, R.A. and Zussman, J. (1982) Orthosilicates. Rock-forming Minerals, 1A, Longman, London, 919 pp.Google Scholar
Dufrenoy, A. (1847) Traite de mineralogie. Paris, 3, 669–71.Google Scholar
Fermor, L.L. (1908) The manganese deposits of India. Mem. Geol. Survey India, 37, 1–1158.Google Scholar
Gibert, F., Moine, B. and Gibert, P. (1990) Titanites (sphenes) alumineuses formees a basse/moyenne pression dans les gneiss a silicates calciques de la Montagne Noire. Comptes Rendus Acad. ScL, Paris, Serie II, 311, 657–63.Google Scholar
Groat, L.A., Carter, R.T., Hawthorne, F.C. and Ercit, T.S. (1985) Tantalian niobian titanite from the Irgon Claim, Southeastern Manitoba. Canad. Mineral., 23, 569–71.Google Scholar
Heslop, R.B. and Robinson, P.L. (1963) Inorganic Chemistry: a guide to advanced study. Elsevier, Amsterdam, 591 pp.Google Scholar
Kienast, J.-R., Smith, D.C. and Martin, S. (1982) Jadeite-acmite solution and the behaviour of manganese in the HP-LT pyroxenes at Praborna, Val d'Aosta, Italy. Terra Cognita, 2(3), 332-3.Google Scholar
Lorn de, B. (1843) La decouverte de la greenovite et de la romeine. Feuilles d'annonces d'Aoste, 3.Google Scholar
Martin, S. and Kienast, J.-R. (1987) The HP-LT manganiferous quartzites of Praborna, Piemont ophiolite nappe, Italian Western Alps. Schweiz. Mineral. Petrogr. Mitt., 67, 339–60.Google Scholar
Martin-Vernizzi, S. (1982) La mine de Praborna (Val d'Aoste, Italie): une serie manganesifere metamor-phisee dans le facies eclogite. These ieme cycle, Univ. Paris VI, 215 pp.Google Scholar
Maury, R., Perseil, E.A., Berbeleac, I. and Tanasescu, I. (1993) L'alabandite (MnS), ses associations, ses parageneses complexes: cas des Hautes Pyrenees (France) et des Monts Metalliferes (Transylvanie-Roumanie). Romanian J. Mineral., 76, 63–9.Google Scholar
Millosevich, F. (1906) Sopra alcuni minerali di Val d'Aosta. Rend. R. Ace. Lincei, Roma, 15, 317–21.Google Scholar
Mottana, A. (1986) Blueschist-facies metamorphism of manganiferous cherts: A review of the alpine occurrences. Ceol. Soc. Amer. Memoir, 164, 267–99.Google Scholar
Mottana, A. and Griffin, W.L. (1979) Pink titanite (greenovite) from St. Marcel, Valle d'Aosta, Italy. Rend. Soc. Ital. Mineral. Petrol., 35, 135–43.Google Scholar
Mottana, A., Rossi, G., Kracher, A. and Kurat, G. (1979) Violan revisited: Mn-bearing omphacite and diopside. Tschermaks Min. Petr. Mitt., 26, 187–201.CrossRefGoogle Scholar
Oberti, R., Smith, D.C, Rossi, G. and Caucia, F. (1991) The crystal-chemistry of high-aluminium titanites. Euro. J. Mineral., 3, 777–92.CrossRefGoogle Scholar
Pascal, P. (1958) Nouveau Traite de Chimie Minerale: Tome XI: arsenic-antimoine-bismuth. Masson, Paris.Google Scholar
Paul, B.J., Cerny, P. and Chapman, R. (1981) Niobian titanite from the Huron Claim pegmatite, Southeastern Manitoba. Canad. Mineral., 19, 549–52.Google Scholar
Perseil, E.-A. (1985) Quelques caracteristiques des facies a oxydes de manganese dans le gisement de St. Marcel-Praborna (Val d'Aoste, Italie). Mineral. Deposita, 20, 271–6.CrossRefGoogle Scholar
Perseil, E.-A. (1987) Particularites des pidmontites de Saint-Marcel-Praborna (Italie): Spectres I.R. Actes du 112e Congres National Societes Savantes, Lyon, Section Sciences, Fascicule I, 209-15.Google Scholar
Perseil, E.-A. (1988) La presence du strontium dans les oxydes manganesiferes du gisement de St. Marcel-Praborna (Val d'Aoste, Italie). Mineral. Deposita, 23, 306–8.CrossRefGoogle Scholar
Perseil, E.-A. (1991) La presence de Sb-rutile dans les concentrations manganesiferes de St. Marcel-Praborna (Val d'Aoste, Italie). Schweiz. Mineral. Petrog. Mitt., 71, 341–7.Google Scholar
Post, J.E. and Bish, D.L. (1989) Rietveld refinement of the coronadite structure. Amer. Mineral., 74, 913–7.Google Scholar
Ribbe, P.H. (1980) Titanite (sphene). Ch. 6 in Orthosilicates, (Ribbe, P.H., ed.), Reviews in Mineralogy, 5, 137–54.Google Scholar
Rota, J.C. and Hausen, D.M. (1991) Geology of the Gold Quarry mine. Ore Geol. Rev., 6, 83–105.CrossRefGoogle Scholar
Russell, J.K., Groat, L.A. and Halleran, A.A.D. (1994) LREE-rich niobian titanite from Mount Bisson, British Columbia: chemistry and exchange mechanisms. Canad. Mineral., 32, 575–87.Google Scholar
Sahama, Th.G. (1946) On the chemistry of the mineral titanite. C. R. Soc. Geol. Finlande, 19 (138), 88–120.Google Scholar
Shannon, R.D. (1976) Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides. Ada Cryst., A32, 751–67.Google Scholar
Smith, D.C. (1981) The pressure and temperature dependence of Al-solubility in sphene in the system Ti-Al-Ca-Si-O-F. Progress Experiment. Petrol. NERC Pub. London, Series D18, 193–7.Google Scholar
Smith, D.C. (1988) A review of the peculiar mineralogy of the ‘Norwegian Coesite-Eclogite Province', with crystal-chemical, petrological, geochemical and geodynamical notes and an extensive bibliography. Pp. 1-206 in Eclogites and Eclogite-Facies Rocks, (Smith, D.C., ed.), Developments in Petrology, 12, Elsevier, Amsterdam, 524 pp.Google Scholar
Smith, D.C. and Perseil, E.-A. (in prep.) Pentavalent antimony in Sb-rich rutile from St. Marcel-Praborana, Aosta Valley, Italy.Google Scholar
Zachariasen, W.H. (1930) The crystal structure of titanite. Zeit. Krist., 73, 7–16.Google Scholar