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Substitution of ‘small’ divalent cations (e.g. Mg) for Si and Al in the nepheline tetrahedral framework: 2. The occurrence of Mg-rich nepheline and kalsilite

Published online by Cambridge University Press:  14 March 2022

Ítalo Lopes de Oliveira Open the ORCID record for Ítalo Lopes de Oliveira [Opens in a new window]  and
C. Michael B. Henderson Open the ORCID record for C. Michael B. Henderson [Opens in a new window]
Ítalo Lopes de Oliveira
Affiliation:
Instituto de Geociências, Universidade de Brasília, Campus Universitário Darcy Ribeiro, Brasília, DF, 70910-900, Brazil
C. Michael B. Henderson*
Affiliation:
School of Earth and Environmental Sciences, University of Manchester, Manchester M13 9PL, UK Consultant, Science and Technology Funding Council, Daresbury Laboratory, Warrington WA4 4AD, UK
*
*Author for correspondence: C. Michael B. Henderson, Email: michael.henderson@manchester.ac.uk
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Abstract

Natural nepheline usually contains very small amounts of MgO (<0.1 wt.%), although these examples are mainly from Mg-poor alkaline igneous rocks such as nepheline syenites. However, this work shows that nepheline and kalsilite with much higher MgO concentrations can occur in the groundmass of strongly SiO2-undersaturated, feldspar-free, mafic volcanic rocks (i.e. olivine-rich foidites). Furthermore, a strong positive correlation is evident between their Mg and Fe contents. The occurrence of Mg-rich nepheline and kalsilite seems to be related to their derivation from Mg-rich magmas when compared to most of the host rocks investigated to date. Additionally, the physicochemical conditions of crystallisation seem to have an important role in the incorporation of ‘small’ divalent cations by these minerals. The prevalence of Mg-rich nepheline and kalsilite as late magmatic phases and the divergent Mg and Fe relationships for phenocrysts and ‘quenched’ groundmass crystals support this hypothesis. The positive correlation between Mg and Fe contents reflects their strong geochemical affinity and the entrance of Fe3+, Fe2+ and Mg2+ cations into the same crystallographic site of nepheline and kalsilite structures. The calculation of atomic formulae and stoichiometry parameters for nepheline-group minerals where data for the T2+ cations (e.g. Mg2+) are incorporated gives more reliable compositional parameters (see Paper 1). Calculated excess silica values (Si′) are affected significantly when the coupled substitution 2Al3+ = Mg2+ + Si4+ is considered. Thus, specific analyses of ‘small’ divalent cations are essential to obtain more realistic values of excess Si′, in particular, for nepheline and kalsilite that crystallised from Mg-rich, Si-poor, mafic–ultramafic alkaline lavas.

Keywords

nepheline-group mineralsstoichiometry calculationsmafic volcanic rocksminor elementsFe valence
Type
Article
Information
Mineralogical Magazine , Volume 86 , Issue 2 , April 2022 , pp. 254 - 262
Copyright
Copyright © The Author(s), 2022. Published by Cambridge University Press on behalf of The Mineralogical Society of Great Britain and Ireland

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Footnotes

Associate Editor: G. Diego Gatta

References

Andersen, T., Elburg, M. and Erambert, M. (2012) Petrology of combeite- and götzenite-bearing nephelinite at Nyiragongo, Virunga Volcanic Province in the East African Rift. Lithos, 152, 105–121.10.1016/j.lithos.2012.04.018CrossRefGoogle Scholar
Andersen, T., Elburg, M. and Erambert, M. (2014) Extreme peralkalinity in delhayelite- and andremeyerite-bearing nephelinite from Nyiragongo volcano, East African Rift. Lithos, 206–207, 164–178.10.1016/j.lithos.2014.07.025CrossRefGoogle Scholar
Antao, S.M. and Hovis, G.L. (2021) Structural variations across the nepheline (NaAlSiO4) – kalsilite (KAlSiO4) series. American Mineralogist, 106, 801–811.10.2138/am-2021-7484CrossRefGoogle Scholar
Bannister, F.A. and Hey, M.H. (1931) A chemical, optical and X-ray study of nepheline and kaliophilite. Mineralogical Magazine, 22, 569–608.10.1180/minmag.1931.022.134.03CrossRefGoogle Scholar
Bannister, F.A. and Hey, M.H. (1942) Kalsilite, a polymorph of KAlSiO4, from Uganda. Mineralogical Magazine, 26, 218–224.CrossRefGoogle Scholar
Barth, T.F.W. (1963) The composition of nepheline. Schweizerische mineralogische und petrographische Mitteilungen, 43, 153–164.Google Scholar
Baudouin, C. (2016) Volcanisme alcalin associé à l'initiation de la rupture continentale: Rift East Africain, Tanzanie, bassin de Manyara. PhD dissertation, Université Montpellier, France [available at https://tel.archives-ouvertes.fr/tel-01563231v2].Google Scholar
Baudouin, C. and Parat, F. (2020) Phlogopite-olivine nephelinites erupted during early stage rifting, North Tanzanian Divergence. Frontiers in Earth Science, 8, 1–22, https://doi.org/10.3389/feart.2020.00277CrossRefGoogle Scholar
Baudouin, C., Parat, F., Denis, C.M. and Mangasini, F. (2016) Nephelinite lavas at early stage of rift initiation (Hanang volcano, North Tanzanian Divergence). Contributions to Mineralogy and Petrology, 171, 1–20, https://doi.org/10.1007/s00410-016-1273-5CrossRefGoogle Scholar
Blancher, S., D'Arco, P., Fonteilles, M. and Pascal, M.L. (2010) Evolution of nepheline from mafic to highly differentiated members of the alkaline series: the Messum complex, Namibia. Mineralogical Magazine, 74, 415–432.CrossRefGoogle Scholar
Brod, J.A., Barbosa, E.S.R., Junqueira-Brod, T.C., Gaspar, J.C., Diniz-Pinto, H.S., Sgarbi, P.B.A. and Petrinovic, I.A. (2005) The Late-Cretaceous Goiás Alkaline Province (GAP), Central Brazil. Pp. 261–316 in: Mesozoic and Cenozoic Alkaline Magmatism in the Brazilian Platform (Comin-Chiaramonti, P. and Gomes, C.B., editors). EDUSP/FAPESP, São Paulo.Google Scholar
Campbell, L.S., Charnock, J.M., Dyer, A., Hillier, S., Chenery, S., Stoppa, F., Henderson, C.M.B., Walcott, R. and Rumsey, M. (2016) Determination of zeolite-group mineral compositions by electron probe microanalysis. Mineralogical Magazine, 80, 781–807.10.1180/minmag.2016.080.044CrossRefGoogle Scholar
Dawson, J.B. (1998) Peralkaline nephelinite-natrocarbonatite relationships at Oldoinyo Lengai, Tanzania. Journal of Petrology, 39, 2077–2094.CrossRefGoogle Scholar
Deer, W.A., Howie, R.A., Wise, W.S. and Zussman, J. (2004) Rock-Forming Minerals. Volume 4B. Framework Silicates: Silica Minerals, Feldspathoids and the Zeolites. 2nd Edition. The Geological Society, London, 982 pp.Google Scholar
Dollase, W.A. and Thomas, W.M. (1978) The crystal chemistry of silica-rich, alkali-deficient nepheline. Contributions to Mineralogy and Petrology, 66, 311–318.10.1007/BF00373415CrossRefGoogle Scholar
Edgar, A.D. (1984) Chemistry, occurrence and paragenesis of feldspathoids: A review. Pp. 501–532 in: Feldspars and Feldspathoids. Structures, Properties and Occurrences (Brown, W.L., editor). NATO ASI Series C: Mathematical and Physical Sciences, Vol. 137. D. Reidel Publishing Company, Dordrecht, The Netherlands.CrossRefGoogle Scholar
Gallo, F., Giammetti, F., Venturelli, G. and Vernia, L. (1984) The kamafugitic rocks of San Venanzo and Cupaello, Central Italy. Neues Jahrbuch fur Mineralogie Monatshefte, 5, 198–210.Google Scholar
Gurenko, A.A. and Sobolev, A.V. (2018) Can orthopyroxene be present in the source of Toro-Ankole, East African Rift, kamafugites? Journal of Petrology, 59, 1517–1550.CrossRefGoogle Scholar
Hålenius, U., Hatert, F., Pasero, M. and Mills, S.J. (2018) IMA commission on new minerals, nomenclature and classification (CNMNC) – Newsletter 42. Mineralogical Magazine, 82, 445–451.10.1180/mgm.2018.71CrossRefGoogle Scholar
Henderson, C.M.B. (2020) Nepheline solid solution compositions: stoichiometry revisited, reviewed, clarified and rationalised. Mineralogical Magazine, 84, 813–838.CrossRefGoogle Scholar
Henderson, C.M.B. and Gibb, F.G.F. (1983) Felsic mineral crystallization trends in differentiating alkaline basic magmas. Contributions to Mineralogy and Petrology, 84, 355–364.10.1007/BF01160287CrossRefGoogle Scholar
Henderson, C.M.B. and Oliveira, I.L. (2022) Substitution of ‘small’ divalent cations (e.g., Mg) for Si and Al in the nepheline tetrahedral framework: 1. Calculation of atomic formulae and stoichiometry parameters. Mineralogical Magazine, 86, https://doi.org/10.1180/mgm.2022.24CrossRefGoogle Scholar
Isakova, A.T., Panina, Li.I. and Stoppa, F. (2017) Genesis of kalsilite melilitite at Cupaello, Central Italy; Evidence from melt inclusions. Petrology, 25, 443–447.CrossRefGoogle Scholar
Junqueira-Brod, T.C. (1998) Cretaceous Alkaline Igneous Rocks from the Águas Emendadas Region, Goiás, Central Brazil. MSc. theses, Durham University, UK [available at http://etheses.dur.ac.uk/4909/]Google Scholar
Kimura, F., Kojitani, H. and Akaogi, M. (2021) High-pressure and high-temperature phase relations in the systems KAlSiO4-MgAl2O4 and CaAl2O4-MgAl2O4: Stability fields of NAL phases. Physics of the Earth and Planetary Interiors, 310, 106632 https://doi.org/10.1016/j.pepi.2020.106632CrossRefGoogle Scholar
Lloyd, F.E., Huntingdon, A.T., Davies, G.R. and Nixon, P.H. (1991) Phanerozoic volcanism of southwest Uganda: A case for regional K and LILE enrichment of the lithosphere beneath a domed and rifted continental plate. Pp. 23–72 in: Magmatism in Extensional Structural Settings: the Phanerozoic African Plate (Kampunzu, A.B. and Lubala, R.T., editors). Springer-Verlag, Berlin.CrossRefGoogle Scholar
Lustrino, M., Ronca, S., Caracausi, A., Bordenca, C.V., Agostini, S. and Faraone, D.B. (2020) Strongly SiO2-undersaturated, CaO-rich kamafugitic Pleistocene magmatism in Central Italy (San Venanzo volcanic complex) and the role of shallow depth limestone assimilation. Earth-Science Reviews, 208, 103256, https://doi.org/10.1016/j.earscirev.2020.103256CrossRefGoogle Scholar
Miyashiro, A. (1951) The ranges of chemical composition in nepheline and their petrogenetic significance. Geochimica et Cosmochimica Acta, 1, 278–283.10.1016/0016-7037(51)90002-6CrossRefGoogle Scholar
Morgan, G.B. VI and London, D. (2005) Effect of current density on the electron microprobe analysis of alkali aluminosilicate glasses. American Mineralogist, 90, 1131–1138.10.2138/am.2005.1769CrossRefGoogle Scholar
Neuvonen, K.J. (1956) Minerals of the katungite flow. Bulletin de la Commission Géologique de Finlande, 172, 1–8.Google Scholar
Oliveira, I.L., Brod, J.A. and Junqueira-Brod, T.C. (2021) Significance of K-rich nepheline in strongly silica-undersaturated mafic volcanic rocks. Pp. 818 in: 50th Brazilian Congress of Geology, Annals, vol. 2 (P. Barbosa, J.B. Curto Ma and C. Toledo, editors). Sociedade Brasileira de Geologia, Núcleo Brasília [available at https://50cbg.com/anais/#]Google 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
Prelević, D., Foley, S.F., Romer, R.L., Cvetković, V. and Downes, H. (2005) Tertiary ultrapotassic volcanism in Serbia: constraints on petrogenesis and mantle source characteristics. Journal of Petrology, 46, 1443–1487.CrossRefGoogle Scholar
Roedder, E.W. (1951) The system K2O–MgO–SiO2. American Journal of Science, 249, 81–130 and 224–248.10.2475/ajs.249.2.81CrossRefGoogle Scholar
Sahama, Th.G. (1954) Mineralogy of mafurite. Bulletin de la Commission Géologique de Finlande, 166, 21–28.Google Scholar
Smith, J.V. and Sahama, Th.G. (1954) Determination of the composition of natural nephelines by an X-ray method. Mineralogical Magazine, 30, 439–449.CrossRefGoogle Scholar
Tappe, S., Foley, S.F. and Pearson, D.G. (2003) The kamafugites of Uganda: a mineralogical and geochemical comparison with their Italian and Brazilian analogues. Periodico di Mineralogia, 72, 51–77 [Special Issue: Eurocarb].Google Scholar
Thomson, A.R., Kohn, S.C., Bulanova, G.P., Smith, C.B., Araujo, D. and Walter, M.J. (2014) Origin of sub-lithospheric diamonds from the Juina-5 kimberlite (Brazil): constraints from carbon isotopes and inclusion compositions. Contributions to Mineralogy and Petrology, 168, 1–29, https://doi.org/10.1007/s00410-014-1081-8CrossRefGoogle Scholar
Tilley, C.E. (1954) Nepheline-alkali feldspar parageneses. American Journal of Science, 252, 65–75.10.2475/ajs.252.2.65CrossRefGoogle Scholar
Velde, D. and Yoder, H.S. Jr. (1978) Nepheline solid solutions in melilite-bearing eruptive rocks and olivine nephelinites. Carnegie Institute of Washington, Year Book, 77, 761–767.Google Scholar
Walter, M.J., Kohn, S.C., Araujo, D., Bulanova, G.P., Smith, C.B., Gaillou, E., Wang, J., Steele, A. and Shirey, S.B. (2011) Deep mantle cycling of oceanic crust: Evidence from diamonds and their mineral inclusions. Science, 334, 54–57.10.1126/science.1209300CrossRefGoogle ScholarPubMed
Wilkinson, J.F.G. and Hensel, H.D. (1994) Nephelines and analcimes in some alkaline igneous rocks. Contributions to Mineralogy and Petrology, 118, 79–91.CrossRefGoogle Scholar
Zedgenizov, D.A., Kagi, H., Shatsky, V.A. and Ragozin, A.L. (2014) Local variations of carbon isotope composition in diamonds from São-Luis (Brazil): Evidence for heterogenous carbon reservoir in sublithospheric mantle. Chemical Geology, 363, 114–124.10.1016/j.chemgeo.2013.10.033CrossRefGoogle Scholar
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