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Alumoåkermanite, (Ca,Na)2(Al,Mg,Fe2+)(Si2O7), a new mineral from the active carbonatite-nephelinite-phonolite volcano Oldoinyo Lengai, northern Tanzania

Published online by Cambridge University Press:  05 July 2018

D. Wiedenmann ,
A. N. Zaitsev ,
S. N. Britvin ,
S. V. Krivovichev  and
J. Keller
D. Wiedenmann*
Affiliation:
Department of Geoscience, University of Fribourg, Perolles, 1700 Fribourg, Switzerland EMPA, Swiss Federal Laboratories for Material Testing and Research, Hydrogen and Energy, Ueberlandstrasse 129, Duebendorf 8600, Switzerland
A. N. Zaitsev
Affiliation:
Department of Mineralogy, Faculty of Geology, St. Petersburg State University, Universitetskaya nab. 7/9, St. Petersburg 199034, Russia
S. N. Britvin
Affiliation:
Department of Crystallography, Faculty of Geology, St. Petersburg State University, Universitetskaya nab. 7/9, St. Petersburg 199034, Russia
S. V. Krivovichev
Affiliation:
Department of Crystallography, Faculty of Geology, St. Petersburg State University, Universitetskaya nab. 7/9, St. Petersburg 199034, Russia
J. Keller
Affiliation:
Institut für Geowissenschaften, Mineralogie-Geochemie, Universität Freiburg, Albertstrasse 23b, 79104 Freiburg, Germany
*
* E-mail: [email protected]
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Abstract

Alumoåkermanite, (Ca,Na)2(Al,Mg,Fe2+)(Si2O7), is a new mineral member of the melilite group from the active carbonatite-nephelinite-phonolite volcano Oldoinyo Lengai, Tanzania. The mineral occurs as tabular phenocrysts and microphenocrysts in melilite-nephelinitic ashes and lapilli-tuffs. Alumoåkermanite is light brown in colour; it is transparent, with a vitreous lustre and the streak is white. Cleavages or partings are not observed. The mineral is brittle with an uneven fracture. The measured density is 2.96(2) g/cm3. The Mohs hardness is ~4.5–6. Alumoåkermanite is uniaxial (–) with ω = 1.635(1) and ε = 1.624–1.626(1). In a 30 mm thin section (+N), the mineral has a yellow to orange interference colour, straight extinction and positive elongation, and is nonpleochroic. The average chemical formula of the mineral derived from electron microprobe analyses is: (Ca1.48Na0.50Sr0.02 K0.01)(Si1.99Al0.01O7). Alumoåkermanite is tetragonal, space group P421m with a = 7.7661(4) Å, c = 5.0297(4) Å, V = 303.4(1) Å3 and Z = 2. The five strongest powder-diffraction lines [d in Å, (I/Io), hkl] are: 3.712, (13), (111); 3.075, (25), (201); 2.859, (100), (211); 2.456, (32), (311); 1.757, (19), (312). Single-crystal structure refinement (R1 = 0.018) revealed structure topology typical of the melilite-group minerals, i.e. tetrahedral [(Al,Mg)(Si2O7)] sheets interleaved with layers of (CaNa) cations. The name reflects the chemical composition of the mineral.

Keywords

alumoåkermaniteåkermanitemelilitenew mineralvolcanic rockchemical composition, crystal structureOldoinyo LengaiTanzania.
Type
Research Article
Information
Mineralogical Magazine , Volume 73 , Issue 3 , June 2009 , pp. 373 - 384
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2009

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References

Akasaka, M. and Ohashi, H. (1985) 57Fe Mössbauer study of synthetic Fe3+-melilites. Physics and Chemistry of Minerals, 12, 13 — 18.Google Scholar
Akasaka, M., Nagashima, M., Makino, K. and Ohashi, H. (2005) Distribution of Fe3+ in a synthetic (Ca,Na)2(Mg,Fe3+)Si2O7-melilite: 57Fe Mössbauer and X-ray Rietveld studies. Journal of Mineralogical and Petrological Sciences, 100, 229—236. di Battistini, G., Montanini, A., Vernia, L., Venturelli, G. and Tonarini, S. (2001) Petrology of melilite- bearing rocks from the Montefiascone Volcanic Complex (Roman Magmatic Province): new insights into the ultrapotassic volcanism of Central Italy. Lithos, 59, 1—24.CrossRefGoogle Scholar
Bell, K., Dunworth, E.A., Bulakh, A.G. and Ivanikov, V.V. (1996) Alkaline rocks of the Turiy Peninsula, Russia, including type-locality turjaite and turjite: a review. The Canadian Mineralogist, 34, 265—280.Google Scholar
Berman, H. (1929) Composition of the melilite group. American Mineralogist, 14, 389—407.Google Scholar
Berman, H. (1937) Constitution and classification of the natural silicates. American Mineralogist, 22, 342—408.Google Scholar
Bindi, L. and Bonazzi, P. (2003) Low-temperature study of natural melilite (Ca1.89Sr0.01Na0.08K0.02) (Mg0.92Al0.08)(Si1.97Al0.03)O7: towards a commensurate value of the q vector. Physics and Chemistry ofMinerals, 30, 523—526.Google Scholar
Bindi, L. and Bonazzi, P. (2005) Incommensuratenormal phase transition in natural melilite: an in situ high-temperature X-ray single-crystal study. Physics and Chemistry of Minerals, 32, 89—96.CrossRefGoogle Scholar
Bindi, L., Bonazzi, P. and Fitton, J.G. (2001) Crystal chemistry of strontian soda melilite from nephelinite lava of Mt. Etinde, Cameroon. European Journal of Mineralogy, 13, 121 — 125.CrossRefGoogle Scholar
Bulakh, A.G. and Ivanikov, V.V. (1984) Problems of the Mineralogy and Petrology of Carbonatites. Leningrad State University, Leningrad, Russia, 244 pp. (in Russian).Google Scholar
Chakhmouradian, A.R. and Zaitsev, A.N. (2004) Afrikanda: an association of ultramafic, alkaline and alkali-silica-rich carbonatitic rocks from mantle- derived melts. Pp. 247—291 in: Phoscorites and Carbonatites from Mantle to Mine: the Key Example of the Kola Alkaline Province (F. Wall and A.N. Zaitsev, editors). Mineralogical Society Series, 10. Mineralogical Society, London.Google Scholar
Dawson, J.B. (1998) Peralkaline nephelinite-natrocarbo- natite relationships at Oldoinyo Lengai, Tanzania. Journal ofPetrology, 39, 2077—2094.Google Scholar
Dawson, J.B., Smith, J.V. and Jones, A.P. (1985) A comparative study of bulk rock and mineral chemistry of olivine melilitites and associated rocks from East and South Africa. Neues Jahrbuch für Mineralogie Abhandlungen, 152, 143—175.Google Scholar
Dawson, J.B., Smith, J.V. and Steele, I.M. (1989) Combeite (Na2.33Ca1.74others0.12)Si3O9 from Oldoinyo Lengai, Tanzania. Journal of Geology, 97, 365—372.CrossRefGoogle Scholar
Dawson, J.B., Smith, J.V. and Steele, I.M. (1992). 1966 ash eruption of the carbonatite volcano Oldoinyo Lengai: mineralogy of lapilli and mixing of silicate and carbonate magmas. Mineralogical Magazine, 56, 1—16.Google Scholar
Dawson, J.B., Pyle, D.M. and Pinkerton, H. (1996) Evolution of natrocarbonatite from a wollastonite nephelinite parent: evidence from the June 1993 Eruption of Oldoinyo Lengai, Tanzania. Journal of Geology, 104, 41—54.CrossRefGoogle Scholar
Deer, W.A., Howie, R.A. and Zussman, J. (1997). RockForming Minerals. Disilicates and Ring Silicates. Volume 1B. 2nd Edition. The Geological Society, London, 629 pp.Google Scholar
Donaldson, C.H. and Dawson, J.B. (1978) Skeletal crystallization and residual glass compositions in a cellular alkalic pyroxenite nodule from Oldoinyo Lengai. Contribution to Mineralogy and Petrology, 67, 139—149.CrossRefGoogle Scholar
Donaldson, C.H., Dawson, J.B., Kanaris-Sotiriou, R., Batchelor, R.A. and Walsh J.N. (1987) The silicate lavas of Oldoinyo Lengai, Tanzania. Neues Jahrbuch für Mineralogie Abhandlungen, 156, 246—279.Google Scholar
Droop, G.T. (1987) A general equation for estimating Fe3+ concentrations in ferromagnesian silicates and oxides from microprobe analyses, using stoichiometric criteria. Mineralogical Magazine, 51, 431-435 .CrossRefGoogle Scholar
Dunworth, E.A. and Bell, K. (2003) The Turiy Massif, Kola Peninsula, Russia: mineral chemistry of an ultramafic-alkaline-carbonatite intrusion. Mineralogical Magazine, 67, 423-451 .CrossRefGoogle Scholar
Dunworth, E.A. and Wilson, M. (1998) Olivine melilitites of the SW German Tertiary Volcanic Province: mineralogy and petrogenesis. Journal of Petrology, 39, 1805-1836 .CrossRefGoogle Scholar
Edgar, A.D. (1965) Lattice parameters of melilite solid solutions and a reconnaissance of phase relations in the system Ca2Al2SiO7 (gehlenite)-Ca2MgSi2O7 (akermanite)-NaCaAlSi2O7 (soda melilite) at 1000 kg/cm2 water vapor pressure. Canadian Journal of Earth Sciences, 2, 596-621 .CrossRefGoogle Scholar
Egorov, L.S. (1969) Melilitic Rocks from Maimecha- Kotui Province. Nedra, Leningrad, Russia, 247 pp. (in Russian).Google Scholar
Egorov, L.S. (1991) Ijolite-Carbonatite Plutonism. Nedra, Leningrad, Russia, 260 pp. (in Russian).Google Scholar
Flack, H.D. (1983) On enantiomorph-polarity estimation. Acta Crystallographica A, 39, 876-881 .CrossRefGoogle Scholar
Hatert, F. and Burke, E.A. (2008) The IMA-CNMNC dominant-constituent rule revisited and extended. The Canadian Mineralogist, 46, 717-728 .CrossRefGoogle Scholar
Hay, R.L. (1978) Melilitite-carbonatite tuffs in the Laetolil beds of Tanzania. Contributions to Mineralogy and Petrology, 67, 357-367 .CrossRefGoogle Scholar
Hemingway, B.S., Evans, H.T.Jr, Nord, G.L.Jr., Haselton, H.T.Jr., Robie, R.A. and McGee, J.J. (1986) Åkermanite: phase transitions in heat capacity and thermal expansion, and revised thermodynamic data. The Canadian Mineralogist, 24, 425-434 .Google Scholar
Ivanikov, V.V., Rukhlov, A.S. and Bell, K. (1998) Magmatic evolution of the melilite-carbonatite- nephelinite dyke series of the Turiy peninsula (Kandalaksha Bay, White See, Russia). Journal of Petrology, 39, 2043-2059 .CrossRefGoogle Scholar
Keller, J. and Krafft, M. (1990) Effusive natrocarbona- tite activity of Oldoinyo Lengai, June 1988. Bulletin of Volcanology, 52, 629-645 .CrossRefGoogle Scholar
Keller, J., Zaitsev, A.N. and Wiedenmann, D. (2006) Primary magmas at Oldoinyo Lengai: The role of olivine melilitites. Lithos, 91, 150-172 .CrossRefGoogle Scholar
Klaudius, J. and Keller, J. (2006) Peralkaline silicate lavas at Oldoinyo Lengai, Tanzania. Lithos, 91, 173-190 .CrossRefGoogle Scholar
Kukharenko, A.A., Orlova, M.P., Bulakh, A.G., Bagdasarov, E.A., Rimskaya-Korsakova, O.M., Nefedov, E.I., Ilinskii, G.A., Sergeev, A.S. and Abakumova, N.B. (1965) The Caledonian Complex of Ultrabasic Alkaline Rocks and Carbonatites of the Kola Peninsula and Northern Karelia. Nedra, Leningrad, Russia, 772 pp. (in Russian).Google Scholar
Kusaka, K., Hagiya, K., Ohmasa, M., Okano, Y., Mukai, M., Iishi, K. and Haga, N. (2001) Determination of structures of Ca2CoSi2O7, Ca2MgSi2O7, and Ca2(Mg0.55Fe0.45)Si2O7 in incommensurate and normal phases and observation of diffuse streaks at high temperature. Physics and Chemistry of Minerals, 28, 150-166 .CrossRefGoogle Scholar
Liebau, F. (1985) Structural Chemistry of Silicates. Structure, Bonding and Classification. Springer- Verlag, Heidelberg, New York, 347 pp.CrossRefGoogle Scholar
Louisnathan, S.J. (1970) The crystal structure of synthetic soda melilite, CaNaAlSi207. Zeitschrift für Kristallographie, 131, 314-321 .CrossRefGoogle Scholar
Merlini, M., Gemmi, M. and Artioli, G. (2006) Low temperature SR-XRPD study of åkermanite-gehle- nite solid solution. Zeitschrift für Kristallographie, Supplement 23, 419-424.CrossRefGoogle Scholar
Merlini, M., Gemmi, M., Cruciani, G. and Artioli, G. (2008) High-temperature behaviour of melilite: in situ X-ray diffraction study of gehlenite-akermanite- Na melilite solid solution. Physics and Chemistry of Minerals, 35, 147-155 .CrossRefGoogle Scholar
Mitchell, R.H. and Dawson, J.B. (2007) The 24th September 2007 ash eruption of the carbonatite volcano Oldoinyo Lengai, Tanzania: mineralogy of the ash and implications of a new hybrid magma type. Mineralogical Magazine, 71, 483-492 .CrossRefGoogle Scholar
Mokeeva, V.I. and Makarov, E.S. (1979) Isomorphism in melilites: refining of crystal structure of akermanite and intermediate melilite. Geokhimiya, 10, 1541-1544 . (in Russian).Google Scholar
Nielsen, T.F.D (1980) The petrology of a melilitolite, melteigite, carbonatite and syenite ring dike system, in the Gardiner complex, East Greenland. Lithos, 13, 181-197 .CrossRefGoogle Scholar
Petibon, C.M., Kjarsgaard, D.A., Jenner, G.A. and Jackson, S.E. (1998) Phase relationships of a silicate-bearing natrocarbonatite from Oldoinyo Lengai at 20 and 100 MPa. Journal of Petrology, 39, 2137-2151 .CrossRefGoogle Scholar
Platz, T., Foley, S.F. and André, L. (2004) Low-pressure fractionation of the Nyiragongo volcanic rocks, Virunga Province D.R. Congo. Journal of Volcanology and Geothermal Research, 136, 269-295 .CrossRefGoogle Scholar
Rass, I.T. (1986) Paragenetic Analysis of Zoned Minerals. Nauka, Moscow, 144 pp. (in Russian).Google Scholar
Smith, J.V. (1953) Reexamination of the crystal structure of melilite. American Mineralogist, 38, 643-661 .Google Scholar
Sheldrick, G.M. (1997) SHELXL97, Program for the Refinement of Crystal Structures. University of Göttingen, Germany.Google Scholar
Swainson, I.P., Dove, M.T., Schmahl, W.W. and Putnis, A. (1992) Neutron powder diffraction study of the åkermanite-gehlenite solid solution series. Physics and Chemistry of Minerals, 19, 185 — 195.CrossRefGoogle Scholar
Vasilieva, V.A. and Evdokimov, M.D. (2002) Geologic- petrographical characteristics of melilite-bearing rocks of Turiy peninsula (Kola Peninsula). Proceedings of the Russian Mineralogical Society, 131(1), 19—28. (in Russian).Google Scholar
Watkinson, D.H. (1972) Electron microprobe analysis of melilite and garnet from the Oka complex, Quebec. The Canadian Mineralogist, 11, 457—463.Google Scholar
Wiedenmann, D. (2004) Vulkanologische Stellung und petrologische Interpretation der Biotit-Pyroxen- Olivin-Tuffe am Oldoinyo Lengai, Tansania. Diploma thesis, Freiburg Universitat, Freiburg, 89 pp.Google Scholar
Yakubona, V.V. (1972) Melilite group. Pp. 540—560 in: Minerals (F.V. Chukhrov, editor). Nauka, Moscow. (in Russian).Google Scholar
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