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GEOREF RECORD

Eltyubyuite, Ca (sub 12) Fe (super 3+) (sub 10) Si (sub 4) O (sub 32) Cl (sub 6) ; the Fe (super 3+) analogue of wadalite; a new mineral from the Northern Caucasus, Kabardino-Balkaria, Russia

Evgeny V. Galuskin, Irina O. Galuskina, Radu Bailau, Krystian Prusik, Viktor M. Gazeev, Aleksandr E. Zadov, Nikolai N. Pertsev, Lidia Jezak, Anatoly G. Gurbanov and Leonid Dubrovinsky
Eltyubyuite, Ca (sub 12) Fe (super 3+) (sub 10) Si (sub 4) O (sub 32) Cl (sub 6) ; the Fe (super 3+) analogue of wadalite; a new mineral from the Northern Caucasus, Kabardino-Balkaria, Russia
European Journal of Mineralogy (February 2013) 25 (2): 221-229

Abstract

Eltyubyuite (IMA2011-022), ideally Ca (sub 12) Fe (super 3+) (sub 10) Si (sub 4) O (sub 32) Cl (sub 6) i.e. the Fe (super 3+) analogue of wadalite, Ca (sub 12) Al (sub 10) Si (sub 4) O (sub 32) Cl (sub 6) , was discovered in altered silicate-carbonate xenoliths in the diatreme facies of ignimbrites in the Upper Chegem caldera, Kabardino-Balkaria, Northern Caucasus, Russia. Eltyubyuite forms light-brown or yellow crystals with tetrahedral habit up to 10 mu m across in rondorfite or larnite grains and commonly overgrows wadalite. Associated minerals are hydroxylellestadite, edgrewite-hydroxyledgrewite, chegemite-fluorchegemite, cuspidine, lakargiite, perovskite, kerimasite, srebrodolskite and dovyrenite. Eltyubyuite formed by contact metamorphism of calcareous sediments under sanidinite-facies conditions (T > 800 degrees C, P <1-2 kbar). Electron microprobe analysis (mean of 9 points) gave in weight% (s.d.): SiO (sub 2) 9.57(0.32), TiO (sub 2) 0.48(0.27), Al (sub 2) O (sub 3) 3.45(1.81), MgO 0.08(0.07), CaO 36.84(0.91), Fe (sub 2) O (sub 3) , Cl 9.60(0.48); O = Cl -2.13, Sum 98.26, and an empirical formula based on 26 cations, Ca (sub 12.12) Mg (sub 0.04) Ti (sub 0.11) Fe (sub 9.41) Al (sub 1.26) Si (sub 2.98) O (sub 31.89) Cl (sub 5.0 4) , which simplifies to Ca (sub 12) (Fe (super 3+) , Al) (sub 11) Si (sub 3) O (sub 32) Cl (sub 5) . Electron-back-scattered diffraction yields isometric symmetry, space group I4d (no. 220), a = 12.20(3) Aa, V = 1815.85(9) Aa (super 3) , Z = 2. Calculated density and refractive index are 3.349 g/cm (super 3) and 1.85, respectively. The main bands in Raman spectra of eltyubyuite are attributed to [Fe (super 3+) O (sub 4) ] (super 5-) : 700-710 cm (super -1) (stretching vibrations), 460-470 cm (super -1) (bending vibrations), whereas bands <400 cm (super -1) are assigned to Ca-O and Ca-[Fe (super 3+) O (sub 4) ] (super 5-) vibrations. The mineral is named for the Balkarian village Eltyubyu, which is situated near the type locality. Eltyubyuite has subsequently been found in altered xenoliths within volcanic rocks of Eifel, Germany and Kel' Highland (volcano Shadil-Khokh), Southern Ossetia.


ISSN: 0935-1221
EISSN: 1617-4011
Serial Title: European Journal of Mineralogy
Serial Volume: 25
Serial Issue: 2
Title: Eltyubyuite, Ca (sub 12) Fe (super 3+) (sub 10) Si (sub 4) O (sub 32) Cl (sub 6) ; the Fe (super 3+) analogue of wadalite; a new mineral from the Northern Caucasus, Kabardino-Balkaria, Russia
Affiliation: University of Silesia, Department of Geochemistry, Mineralogy and Petrography, Sosnowiec, Poland
Pages: 221-229
Published: 201302
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Germany
References: 37
Accession Number: 2013-046200
Categories: Mineralogy of silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table
N43°16'60" - N43°16'60", E43°06'00" - E43°06'00"
Secondary Affiliation: Russian Academy of Sciences, Institute of the Geology of Ore Deposits, Petrography, Mineralogy and Geochemistry, RUS, Russian FederationOOO Science Research Centre, RUS, Russian FederationUniversity of Warsaw, POL, PolandUniversitaet Bayreuth, DEU, Germany
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, copyright, Schweizerbart'sche Verlagsbuchhandlung. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201329
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