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The origins of carbonatites and related rocks from the Grønnedal-Íka Nepheline Syenite complex, South Greenland: C-O-Sr isotope evidence

Published online by Cambridge University Press:  05 July 2018

N. J. G. Pearce ,
M. J. Leng ,
C. H. Emeleus  and
C. M. Bedford
N. J. G. Pearce
Affiliation:
Institute of Earth Studies, University of Wales, Aberystwyth, Ceredigion, SY23 3DB, UK
M. J. Leng
Affiliation:
NERC Isotope Geosciences Laboratory, Keyworth, Nottingham, NGI2 5GG, UK
C. H. Emeleus
Affiliation:
Department of Geological Sciences, University of Durham, Durham, DH1 3LE, UK
C. M. Bedford
Affiliation:
Department of Geological Sciences, University of Durham, Durham, DH1 3LE, UK Present address: Radley College, Abingdon, Oxford, OX14 2HR, UK
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Abstract

The Grønnedal-Íka ring complex (1299 ± 17 Ma) in the Gardar province, South Greenland is composed of a range of layered nepheline syenites which were intruded at a late stage by xenolithic syenite and a plug of carbonatite. The complex was subsequently intruded by a variety of basic dykes, including olivine dolerites, kersantites, vogesites, spessartites, camptonites and an alnöite, and then extensively faulted. The nepheline syenite magmas, produced by fractional crystallisation of basic magmas, show a range in δ13C (−3.86 to −7.57‰) and δ18O (8.27 to 15.12‰), distinctly different to the carbonatites which form a tight group with average δ13C = −4.31 + 0.22 ‰, (1 s.d.) and average δ18O = 7.18 ± 0.41‰ (1 s.d.). Initial 87Sr/86Sr isotope ratios (typically 0.703) suggest the syenites and carbonatites have not assimilated crustal rocks, and therefore the C and O isotope variation within each group is a result of isotopic evolution during fractional crystallisation. A suite of lamprophyre dykes (δ13C −3.86 to −7.86‰ and δ18O 9.12 to 10.81‰) form a coherent group whose stable isotope compositions overlap part of the syenite field, and again are distinctly different from the carbonatites. A single alnöite has δ13C = −3.32‰ and δ18O = 12.34‰ C and O isotope ratios are consistent with origins of syenitic and lamprophyric magmas from a similar source. Despite geochemical evidence which suggests a genetic link between nepheline syenites and carbonatites, C and O isotopic evidence shows that they are not related directly by liquid immiscibility. Comparisons are made between similar rock types from Grønnedal-Íka and from the Gardar Igaliko Dyke Swarm. The possible role of F in controlling δ13C and δ18O during crystallisation of calcite from carbonatite magmas is discussed.

Keywords

carbonatitenepheline syeniteGrønnedal-Íka complexGardarGreenland
Type
Intraplate Alkaline Magmatism
Information
Mineralogical Magazine , Volume 61 , Issue 407 , August 1997 , pp. 515 - 529
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1997

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References

Andersen, T. (1987) Mantle and crustal components in a carbonatite complex, and the evolution of carbonatite magma: REE and isotopic evidence from the Fen Complex, Southeast Norway. Chem. Geol. (Isotope Geosci. Sect.), 65, 147-66.CrossRefGoogle Scholar
Andersen, T. (1997) Age and petrogenesis of the Qassiarsuk carbonatite-alkaline silicate volcanic complex in the Gardar rift, South Greenland. Mineral. Mag., 61, 499-513.CrossRefGoogle Scholar
Bedford, C.M. (1989) The mineralogy, geochemistry and petrogenesis of the Grømnedal-Íka complex, south west Greenland. Unpublished PhD thesis, University of Durham.Google Scholar
Berthelesen, A. and Henriksen, N. (1975) Geological map of Greenland. 1:100,000, Ivigtut 61 v. l Syd. The orogenic and cratogenic geology of a Precambrian shield area. Descriptive text, 169 pp. Geological Survey of Greenland, Copenhagen.Google Scholar
Blaxland, A.B., van Breemen, O., Emeleus, C.H., and Anderson, J.G. (1978) Age and origin of the major syenite centres in the Gardar province of south Greenland: Rb-Sr studies. Geol. Soc. Amer. Bull., 89, 231-44.2.0.CO;2>CrossRefGoogle Scholar
Blaxland, A.B., van Breemen, O. and Steenfelt, A. (1975) Age and origin of agpaitic magmatism at Ilímaussaq, south Greenland: a Rb-Sr study. Lithos, 9, 31-8.CrossRefGoogle Scholar
Boynton, W.V. (1984) Geochemistry of the Rare Earth Elements: Meteorite studies. In Rare Earth Element Geochemistry (Henderson, P., ed.). Developments in Geochemistry, 2. Elsevier, Amsterdam.Google Scholar
Clarke, L.B., Le Bas, M.J. and Spiro, B. (1993) Rare Earth, trace elements and stable isotope fractionation of carbonatites at Kruidfontein, Transvaal, South Africa. Proceedings of the Fifth Kimberlite Conference, 1, Kimberlite, related rocks and mantle xenoliths. CPRM, Brasilia, 236-51.Google Scholar
Craig, H. (1957) Isotopic standards for carbon and oxygen and correction factors for mass spectrometric analyses of carbon dioxide. Geochim. Cosmochim. Acta, 12, 133-49.CrossRefGoogle Scholar
Craven, J.A. (1985) The petrogenesis of some ultramafic rocks from the Gardar Province, S. W. Greenland. Unpublished PhD Thesis, University of Edinburgh.Google Scholar
Deines, P. (1970) The carbon and oxygen isotopic composition of carbonates from the Oka carbonatite, Quebec, Canada. Geochim. Cosmochim. Acta, 34, 1199-225.CrossRefGoogle Scholar
Deines, P. (1989) Stable isotope variations in carbonatites. In Carbonatites: Genesis and Evolution (Bell, K., ed.). 301—59. Unwin and Hyman, London.Google Scholar
Des Marias, D.J. and Moore, J.G. (1984) Carbon and its isotopes in mid-oceanic basalt glasses. Earth Planet. Sci. Lett., 69, 43-57.CrossRefGoogle Scholar
Emeleus, C.H. (1964) The Grønnedal-Íka Alkaline Complex, South Greenland. Bull. Grønlands Geol. Unders., 45. (also Meddelelser om Grønland, 172, Nr. 3).Google Scholar
Emeleus, C.H. and Harry, W.T. (1970) The Igaliko Nepheline Syenite Complex: General Description. Bull. Grønlands Geol. Unders., 85. (also Meddelelser om Grønland, 186, Nr. 3)Google Scholar
Emeleus, C.H. and Upton, B.G.J. (1976) The Gardar Period in Southern Greenland. In The Geology of Greenland (Escher, A. and Watt, W.S., eds.). 153-81, GGU, København.Google Scholar
Gill, R.C.O. (1972) The geochemistry of the Grønnedal-Íka alkaline complex, South Greenland. Unpublished PhD thesis, University of Durham.Google Scholar
Hamilton, D.L., Bedson, P., and Esson, J. (1989) The behaviour of trace elements in the evolution of carbonatites. In Carbonatites: Genesis and Evolution (Bell, K., ed.), 405-27. Unwin and Hyman, London.Google Scholar
Hayward, C.L. and Jones, A.P. (1991) Cathodoluminescence petrography of Middle Proterozoic extrusive carbonatite from Qasiarsuk, South Greenland. Mineral. Mag., 55, 591-603.CrossRefGoogle Scholar
Henderson, P. and Williams, C.T. (1981) Application of intrinsic Ge detectors to the instrumental neutron activation analysis for rare earth elements in rocks and minerals. J. of Radioanalytical Chem., 67, 445-452.CrossRefGoogle Scholar
Hodgson, N.A. (1985) Carbonatites and associated rocks from the Cape Verde Islands. Unpublished PhD thesis, University of Leicester.Google Scholar
Kjarsgaard, B.A. and Hamilton, D.L. (1988) Liquid immiscibility and the origin of alkali-poor carbona-tites. Mineral. Mag., 52, 43-55.CrossRefGoogle Scholar
Kjarsgaard, B.A. and Hamilton, D.L. (1989) The genesis of carbonatites by liquid immiscibility. In Carbonatites: Genesis and Evolution (Bell, K., ed.), 388—404. Unwin and Hyman, London.Google Scholar
Knudsen, C. and Buchardt, B. (1991) Carbon and oxygen isotope composition of carbonates from the Qaqarssuk Carbonatite Complex, southern West Greenland. Chem. Geol. (Isotope Geosci. Sect.), 86, 263-74.CrossRefGoogle Scholar
Kyser, T.K., O'Neil, J.R. and Carmichael, I.S.E. (1982) Genetic relations among basic lavas and ultramafic nodules: evidence from oxygen isotope compositions. Contrib. Mineral. Petrol., 81, 88-102.CrossRefGoogle Scholar
LeBas, M.J. (1977) Carbonatite-Nephelinite Volcanism. John Wiley and Son, New York.Google Scholar
McCrea, J.M. (1950) The isotope chemistry of carbonates and palaeotemperature scale. J. Chem. Phys., 18, 849-57.CrossRefGoogle Scholar
Nielsen, T.F.D. and Buchardt, B. (1985) Sr-C-O isotopes in nephelinitic rocks and carbonatites, Gardiner Complex, tertiary of East Greenland. Chem. GeoL, 53, 207-17.CrossRefGoogle Scholar
NorriSh, K. and Hutton, J.T. (1969) An accurate X-ray spectrographic method for the analysis of a wide range of geological samples. Geochim. Cosmochim. Acta, 33, 431-53.CrossRefGoogle Scholar
Patchett, P.L, Bylund, G. and Upton, B.G.J., (1978) Palaeomagnetism and the Grenville Orogeny: new Rb-Sr ages from dolerites in Canada and Greenland. Earth Planet. Sci. Lett., 40, 349-64.CrossRefGoogle Scholar
Pearce, N.J.G. (1988) The petrology and geochemistry of the lgaliko Dyke Swarm, South Greenland. Unpublished PhD thesis, University of Durham.Google Scholar
Pearce, N.J.G. and Leng, M.J. (1996) The origin of carbonatites and related rocks from the Igaliko Dyke Swarm, Gardar Province, South Greenland: field, geochemical and C-O-Sr-Nd isotope evidence. Lithos, 39, 21-40.CrossRefGoogle Scholar
Pearce, N.J.G., Perkins, W.T., Westgate, J.A., Gorton, M.P., Jackson, S.E., Neal C.R. and Chenery, S.P. (1997) A compilation of new and published major and trace element data for NIST SRM 610 and NIST SRM 612 glass reference materials. Geostandards Newsletter, in press.CrossRefGoogle Scholar
Potts, P.J. (1987) A Handbook of Silicate Rock Analysis. Bell and Bain, Glasgow.CrossRefGoogle Scholar
Potts, P.J., Williams-Thorpe, O. and Watson, J.S. (1981) Determination of the rare earth element abundances in 29 international rock standards by instrumental neutron activation analysis: a critical appraisal of calibration errors. Chem. Geol., 34, 331—52.CrossRefGoogle Scholar
Reid, D.L. and Cooper, A.F. (1992) Oxygen and carbon isotope patterns in the Dicker Willem carbonatite complex, southern Namibia. Chem. Geol. (Isotope Geosc. Sect.), 94, 293-305.CrossRefGoogle Scholar
Rock, N.M.S. (1987) The nature and origin of lamprophyres: an overview. In Alkaline Igneous Rocks (Fitton, J.G. and Upton, B.G.J., eds.). Geological Society of London Special Publication 30. Blackwell, Oxford.Google Scholar
Stewart, J.W. (1964) The early Gardar igneous rocks of the Ilímaussaq area, South Greenland. Unpublished PhD thesis, University of Durham.Google Scholar
Stewart, J.W. (1970) Precambrian alkaline - ultramafic/carbonatite volcanism at Qagssiarssuk, South Greenland. Bull. Grønlands Geol. Unders., 84.Google Scholar
Upton, B.J.G. and Emeleus, C.H. (1987) Mid-Proterozoic alkaline magmatism in Southern Greenland: The Gardar Province. In Alkaline Igneous Rocks (Fitton, J.G. and Upton, B.G.S., eds.). Geological Society of London Special Publication 30. Blackwell, Oxford.Google Scholar
Upton, B.G.J and Fitton, J.G. (1985) Gardar dykes north of the Igaliko Syenite Complex, southern Greenland. Rapp. Grønlands Geol. Unders., 127.Google Scholar
von Eckermann, H. (1948) The alkaline district of Alnö Island. Stockholm AB, Kartografiska Institutet (Sveriges Geolog. Unders., 36).Google Scholar
Woolley, A.R. (1982) A discussion of carbonatite evolution and nomenclature and the generation of sodic and potassic fenites. Mineral. Mag., 46, 13-17.CrossRefGoogle Scholar
Woolley, A.R. (1987) Alkaline Rocks and Carbonatites cf the World. Part 1: North and South America. British Museum (Natural History), London. 216 pp.Google Scholar
Woolley, A.R., Bergman, S.C., Edgar, A.D., LeBas, M.J., Mitchell, R.H., Rock, N.M.S. and Scott-Smith, B.H. (1996) Classification of lamprophyres, lam-proites, kimberlites and the kalsilitic, melilitic and leucitic rocks. Canad. Mineral., 34, 175—86.Google Scholar