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Tracing the chemical evolution of primary pyrochlore from plutonic to volcanic carbonatites: the role of fluorine

Published online by Cambridge University Press:  05 July 2018

A. C. J. M. Bambi ,
A. Costanzo ,
A. O. Gonçalves  and
J. C. Melgarejo
A. C. J. M. Bambi
Affiliation:
Departamento de Geologia, Faculdade de Cieˆncias, Universidade Agostinho Neto, Av. 4 de Fevereiro 7, 815 Luanda, Angola
A. Costanzo*
Affiliation:
Earth and Ocean Sciences, School of Natural Sciences National University of Ireland, Galway, University Road, Galway, Ireland
A. O. Gonçalves
Affiliation:
Departamento de Geologia, Faculdade de Cieˆncias, Universidade Agostinho Neto, Av. 4 de Fevereiro 7, 815 Luanda, Angola
J. C. Melgarejo
Affiliation:
Departament de Cristal·lografia, Mineralogía i Dipo` sits Minerals, Universitat de Barcelona, c/Martí i Franque`s s/n, 08028 Barcelona, Catalonia, Spain
*
*E-mail: [email protected]
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Abstract

Three Angolan carbonatites were selected to evaluate the change in composition of pyrochlores during magmatic evolution: the Tchivira carbonatites occur in a plutonic complex, the Bonga carbonatites represent hypabyssal carbonatites and the Catanda carbonatites are volcanic in origin. In Tchivira pyrochlore, zoning is poorly developed; fluorine is dominant at the Y site; chemical zoning may arise as a result of substitutions for Nb in the B site; and the rare earth element (REE), U, Th and large-ion lithophile element (LILE) contents are very low. Pyrochlores from Bonga show oscillatory zonation; the F and Na contents are lower than those in the pyrochlores from Tchivira; and as substitution of Na at the A site increases, the Th, U, REE contents and inferred vacancies also increase. Pyrochlores from Catanda display complex textures. They generally have a rounded corroded core, which is mantled by two or three later generations. The core composition is similar to the Bonga pyrochlores. The rims are enriched in Zr, Ta, Th, Ce and U, but depleted in F and Na. In pyrochlores from the Angolan carbonatites, the F and Na contents decrease from plutonic to volcanic settings and there is enrichment of Th, U and REE in the A site and Ta and Zr in the B site. Zoning may be explained by changes in the activity of F, due to the crystallization of fluorite or apatite in the plutonic and hypabyssal carbonatites, or to volatile exsolution in the volcanic carbonatites.

Keywords

Angolacarbonatitezonation in pyrochlorefluorinehigh field strength elementsHFSEpyrochlorerare earth elementsREEmineral zonation
Type
Research Article
Information
Mineralogical Magazine , Volume 76 , Issue 2 , April 2012 , pp. 377 - 392
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2012

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References

Agangi, A., Kamenetsky, V.S. and McPhie, J. (2010) The role of fluorine in the concentration and transport of lithophile trace elements in felsic magmas: insights from the Gawler Range Volcanics, South Australia. Chemical Geology, 273, 314–325.CrossRefGoogle Scholar
Alberti, A., Castorina, F., Censi, P., Comin-Chiaramoni, P. and Gomes, C.B. (1999) Geochemical characteristics of Cretaceous carbonatites from Angola. Journal of African Earth Sciences, 29, 735–759.CrossRefGoogle Scholar
Atencio, D., Andrade, M.B., Christy, A.G., Giere, R and Kartashov, P.M. (2010) The pyrochlore supergroup of minerals: nomenclature. The Canadian Mineralogist, 48, 673–698.CrossRefGoogle Scholar
Bambi, A.M., Melgarejo, J.C., Gonçalves, A.O., Neto, A.B. and Morais, E.A. (2004) Os maciços carbonatítico-alcalinos de Tchivira-Bonga (Angola): novos dados sobre su estructura. Actas VIII congresso de geoquímica dos paises de Lingua portuguesa 1, 71–74.Google Scholar
Bambi, A.J.M., Costanzo, A., Manuel, J., Alfonso, P., Olimpio, A. and Melgarejo, J.C. (2008) Natrocarbonatite flows and pyroclastic deposits in the Early Cretaceous Catanda carbonatite volcanoes. Publications of the 33rd International Geological Congress, Oslo, Norway. Bonazzi, P., Bindi, L., Zoppi, M., Capitani, G.C. and Olmi, F. (2006) Single-crystal diffraction and transmission electron microscopy studies of “silicified” pyrochlore from Narssârssuk, Julianehaab district, Greenland. American Mineralogist, 91, 794–801.Google Scholar
Carvalho, H. de (1983) Notice explicative préliminaire sur la géologie de L‘Angola. Garcia de Horta/ Instituto de Investigaça˜o Científica Tropical, 6, 15–30.Google Scholar
Carvalho, H. de, Tassinari, C., Alves, P.H., Guimara˜es, F. and Simo˜ es, M.C. (2000) Geochronological review of the Precambrian in western Angola: links with Brazil. Journal of African Earth Sciences, 31, 383–402.CrossRefGoogle Scholar
Chakhmouradian, A.R. (1996) On the development of niobium and rare-earth minerals in monticellite-calcite carbonatite of the Oka Complex, Quebec. The Canadian Mineralogist, 34, 479–484.Google Scholar
Chakhmouradian, A.R. and Mitchell, R.H. (1998) Lueshite, pyrochlore and monazite-(Ce) from apatite–dolomite carbonatite, Lesnaya Varaka complex, Kola peninsula, Russia. Mineralogical Magazine, 62, 769–782.CrossRefGoogle Scholar
Chakhmouradian, A.R. and Zaitsev, A.N. (1999) Calcite–amphibole–clinopyroxene rock from the Afrikanda complex, Kola Peninsula, Russia: mineralogy and a possible link to carbonatites. I. Oxide minerals. The Canadian Mineralogist, 37, 177–198.Google Scholar
Coltorti, M., Alberti, A., Beccaluva, L., Dos Santos, A.B, Mazzucchelli, M., Morais, E., Rivalenti, G. and Siena, F. (1993) The Tchivira-Bonga alkalinecarbonatite complex (Angola): petrological study and comparison with Brazilian analogues. European Journal of Mineralogy, 5, 1001–1024.CrossRefGoogle Scholar
Goodwin, A.M. (1996) Principles of Precambrian Geology. Academic Press, London, 327 pp. Hodgson, N.A and Le Bas, M.J. (1992) The geochemistry and cryptic zonation of pyrochlore from San Vicente, Cape Verde Islands. Mineralogical Magazine, 56, 201–214.Google Scholar
Hogarth, D. (1977) The pyrochlore group. American Mineralogist, 62, 430–410.Google Scholar
Hogarth, D.D. (1989) Pyrochlore, apatite and amphibole: distinctive minerals in carbonatite. Pp. 105–148. in: Carbonatites: Genesis and Evolution (Bell, K., editor). Unwin Hyman, London,.Google Scholar
Hogarth, D.D. and Horne, J.E.T. (1989) Non-metamict uranoan pyrochlore and uranpyrochlore from tuff near Ndale, Fort Portal area, Uganda. Mineralogical Magazine, 53, 257–262.CrossRefGoogle Scholar
Hogarth, D.D., Williams, C.T. and Jones, P. (2000) Primary zoning in pyrochlore group minerals from carbonatites. Mineralogical Magazine, 64, 683–697.CrossRefGoogle Scholar
Issa Filho, A., Dos Santos, A.B.R.M.D., Riffel, B.F., Lapido-Loureiro, F.E.V. and McReath, I. (1991) Aspects of the geology, petrology and chemistry of some Angolan carbonatites. Journal of Geochemical Exploration, 40, 205–26.CrossRefGoogle Scholar
Jago, B.B. and Gittins, J. (1991) The role of fluorine in carbonatite magma evolution. Nature, 349, 56–58.CrossRefGoogle Scholar
Jago, B.C. and Gittins, J. (1993) Pyrochlore crystallization in carbonatites: the role of fluorine. South African Journal Geology, 96, 149–159.Google Scholar
Johan, V. and Johan, Z. (1994) Accessory minerals of the Cinovec (Zinnwald) granite cupola, Czech Republic, part 1: Nb-, Ta and Ti-bearing oxides. Mineralogy and Petrology, 51, 323–343.CrossRefGoogle Scholar
Kapustin, Y.L. (1980) Mineralogy of Carbonatites. Amerind Publishing, New Delhi, India, 259 pp. Kjarsgaard, K.J. and Mitchell, R.H. (2008) Solubility of Ta in the system CaCO3–Ca(OH)2–NaTaO3– NaNbO3-F at 0.1 GPa: implications for the crystallization of pyrochlore-group minerals in carbonatites. The Canadian Mineralogist, 46, 981–990.Google Scholar
Lapido-Loureiro, F.E.V. (1968) Sub-volcanic carbonatite structures of Angola. Proceedings of the International Geological Congress, Report of the twenty-third session, Prague, 2, 147–161.Google Scholar
Lapido-Loureiro, F.E.V. (1973) Carbonatitos de Angola. Memórias e Trabalhos do Instituto de Investigaça˜o Científica de Angola, 11, 1–242.Google Scholar
Le Bas, M.J. (1971) Pre-alkaline volcanism, crustal swelling, and rifting. Nature, 230, 485–487.Google Scholar
Lee, M.J., Garcia, D., Moutte, J., Wall, F., Williams, C.T. and Woolley, A.R. (1999) Pyrochlore and whole rock chemistry of carbonatites and phoscorites at Sokli, Finland. Pp. 651–653. in: Mineral Deposits: Processes to Processing (Stanley, C.J. and 39 others, editors). Proceedings of the 5th biennial meeting of the Society for Geology Applied to Mineral Deposits (SGA) and the 10th Quadrennial Symposium of the International Association on the Genesis of Ore Deposits (IAGOD), 1. Balkema, A.A., Rotterdam, The Netherlands, 802 pp.Google Scholar
Lee, M.J., Lee, J.I., Garcia, D., Moutte, J., Williams, C.T., Wall, F. and Kim, Y. (2006) Pyrochlore chemistry from the Sokli phoscorite-carbonatite complex, Finland: implications for the genesis of phoscorite and carbonatite association. Geochemical Journal, 40, 1–13.Google Scholar
Lottermoser, B.G. and England, B.M. (1988) Compositional variation in pyrochlores from the Mt. Weld carbonatite laterite, Western Australia. Mineralogy and Petrology, 38, 37–51.CrossRefGoogle Scholar
Lumpkin, G.R. and Ewing, R.C. (1985) Natural pyrochlores: analogs for actinide host phases in radioactive waste forms. Pp. 647–654. in: Materials Research Society Symposium Proceedings 44. The Scientific Basis for Nuclear Waste Management (C.M. Jantzen, J.A. Stone and Ewing, R.C., editors). Materials Research Society, Pittsburgh, PA, USA.Google Scholar
Lumpkin, G.R. and Ewing, R.C. (1995) Geochemical alteration of pyrochlore group minerals: pyrochlore subgroup. American Mineralogist, 80, 732–743.CrossRefGoogle Scholar
Lumpkin, G.R. and Mariano, A.N. (1996) Natural occurrence and stability of pyrochlore in carbonatites, related hydrothermal systems, and weathering environments. Pp. 831–838. in: Materials Research Society Symposium Proceedings 412 The Scientific Basis for Nuclear Waste Management XIX (Murphy, W.M. and Knecht, D.A. editors). Materials Research Society, Pittsburgh, PA, USA.Google Scholar
Mariano, A.N. (1989a) Nature of economic mineralization in carbonatites and related rocks. Pp. 149–176. in: Carbonatites: Genesis and Evolution (Bell, K., editor). Unwin Hyman, London,.Google Scholar
Mariano, A.N. (1989b) Economic Geology of Rare Earth Elements. Pp. 309–337. in: Geochemistry and Mineralogy of Rare Earth Elements (Lipin, B.R. and Kay, M., editors). Reviews in Mineralogy, 21. Mineralogical Society of America, Washington D C.CrossRefGoogle Scholar
Matos Alves, C.A. (1968) Estudo geológico e petroló-gico do maciço alcalinocarbonatítico do Quicuco (Angola). Junta de Investigaço˜es do ultramar, 160 pp.Google Scholar
Mitchell, R.H. and Kjarsgaard, B.A. (2004) Solubility of niobium in the system CaCO3-CaF2-NaNbO3 at 0.1 GPa pressure: implications for the crystallization of pyrochlore from carbonatite magma. Contributions to Mineralogy and Petrology, 148, 281–287.CrossRefGoogle Scholar
Montero, P., Floor, P. and Corretgé, G. (1998) The accumulation of rare-earth and high-field-strength elements in peralkaline granitic rocks: the Galineiro orthogneissic complex, northwestern Spain. The Canadian Mineralogist, 36, 683–700.Google Scholar
Nasraoui, M. and Bilal, E. (2000) Pyrochlores from the Lueshe carbonatite complex (Democratic Republic of Congo): a geochemical record of different alteration stages. Journal of Asian Earth Sciences, 18, 237–251.CrossRefGoogle Scholar
Nasraoui, M. and Waerenborgh, J.C. (2001) Fe speciation in weathered pyrochlore-group minerals from the Lueshe and Araxá (Barreriro) carbonatites by 57Fe Mössbauer spectroscopy. The Canadian Mineralogist, 39, 1073–1080.CrossRefGoogle Scholar
Petruk, W. and Owens, D. (1975) Electron microprobe analyses for pyrochlores from Oka, Quebec. The Canadian Mineralogist, 13, 282–285.Google Scholar
Pichou, J.L. and Pichoir, F. (1984) A new model for quantitative X-ray microanalysis.Part I: application to the analysis of homogeneous samples. La Recherche A ´ erospatiale, 3, 13–38.Google Scholar
Seifert, W., Kämpf, H. and Wasternack, J. (2000) Compositional variation in apatite, phlogopite and other accessory minerals of the ultramafic Delitzsch complex, Germany: implication for cooling history of carbonatites. Lithos, 53, 81–100.CrossRefGoogle Scholar
Sharygin, V.V., Sobolev, N.V. and Channer, D.M.R. (2009) Oscillatory-zoned crystals of pyrochloregroup minerals from the Guaniamo kimberlites, Venezuela. Lithos, 112, 976–985.CrossRefGoogle Scholar
Silva, M.V.S. and Pereira, E. (1973) Estrutura Vulcanico-Carbonatitica da Catanda (Angola). Boletim dos Servicos de Geologia e Minas de Angola, 24, 5–14.Google Scholar
Terraconsult (1983) A review of the mineral resources of the People’s Republic of Angola. Zurich, 100 pp. Thompson, R.N., Smith, P.M., Gibson, S.A., Mattey, D.P. and Dickin, A.P. (2002) Ankerite carbonatite from Swartbooisdrif, Namibia: the first evidence for magmatic ferrocarbonatite. Contributions to Mineralogy and Petrology, 143, 377–396.CrossRefGoogle Scholar
Viladkar, S.G. and Ghose, I. (2002) U-rich pyrochlore in carbonatite of Newania, Rajasthan (India). Neues Jahrbuch für Mineralogie-Monatshefte, 3, 97–106.CrossRefGoogle Scholar
Viladkar, S.G. and Bismayer, U. (2010) Compositional variation in pyrochlores of Amba Dongar carbonatite complex, Gujarat. Journal of the Geological Society of India, 75, 495–502.CrossRefGoogle Scholar
Wall, F., Williams, C.T., Woolley, A.R. and Nasraoui, M. (1996) Pyrochlore from weathered carbonatite at Lueshe, Zaire. Mineralogical Magazine, 60, 731–750.CrossRefGoogle Scholar
Williams, C.T. (1996) The occurrence of niobian zirconolite, pyrochlore and baddeleyite in the Kovdor carbonatite complex, Kola Peninsula, Russia. Mineralogical Magazine, 60, 639–646.CrossRefGoogle Scholar
Williams, C.T., Wall, F., Woolley, A.R. and Phillipo, S. (1997) Compositional variation in pyrochlore from the Bingo carbonatite, Zaire. Journal of African Earth Sciences, 25, 137–145.CrossRefGoogle Scholar
Woolley, A.R. (1989) The spatial and temporal distribution of carbonatites. Pp. 15–37. in: Carbonatites: Genesis and Evolution (Bell, K., editor). Unwin Hyman, London,.Google Scholar
Woolley, A.R. (2001) Alkaline rocks and carbonatites of the world.Part 3. Africa. The Geological Society, London, 384 pp. Woolley, A.R. and Kempe, D.R.C. (1989) Carbonatites: nomenclature, average chemical composition and element distribution.Pp. 1–14. in: Carbonatites: Genesis and Evolution (Bell, K., editor). Unwin Hyman, London.Google Scholar
Zaitsev, A.N., Sitnikova, M.A., Subbotin, V.V., Chakhmouradian, A.R., Wall, F. and Kretser, Yu.L. (1999) Nb-Zr ore mineralization in the Sallanlatvi carbonatites, Kola Peninsula, Russia.Pp. 691–694. in: Mineral Deposits: Processes to Processing (Stanley, C.J. and 39 others, editors). Proceedings of the 5th biennial meeting of the Society for Geology Applied to Mineral Deposits (SGA) and the 10th Quadrennial Symposium of the International Association on the Genesis of Ore Deposits (IAGOD), 1.Google Scholar
Balkema, A.A., Rotterdam, The Netherlands, 802 pp.Google Scholar
Zurevinski, S.E. and Mitchell, R.H. (2004) Extreme compositional variation of pyrochlore group minerals at the Oka Carbonatite Complex, Québec: evidence of magma mixing? The Canadian Mineralogist, 42, 1159–1168.CrossRefGoogle Scholar