Hostname: page-component-848d4c4894-ndmmz Total loading time: 0 Render date: 2024-05-10T05:48:27.881Z Has data issue: false hasContentIssue false
  • English
  • Français

Cathodoluminescence Petrography of Middle Proterozoic extrusive carbonatite from Qasiarsuk, South Greenland

Published online by Cambridge University Press:  05 July 2018

Christopher L. Hayward  and
Adrian P. Jones
Christopher L. Hayward
Affiliation:
Department of Geological Sciences, University College London, Gower Street, London WC1E 6BT
Adrian P. Jones
Affiliation:
Department of Geological Sciences, University College London, Gower Street, London WC1E 6BT
Get access Rights & Permissions [Opens in a new window]

Abstract

The amygdaloidal carbonatite lavas at Qasiarsuk have a primary phenocryst assemblage of calcite, fluor-apatite and magnetite set in a groundmass of calcite, apatite and iron oxides, and minor dolomite. Cathodoluminescence reveals a complex history, both for the major minerals which show zonal growth, and for important Nb and REE accessory phases which include pyrochlore and perovskite. The REE reside in fluor/hydrous-carbonates included exclusively in apatite. These REE minerals are similar to synthetic phases from hydrothermal experiments, but probably crystallised in equilibrium with a late-stage volatile-rich carbonate melt. Apart from low-temperature alteration, the rocks have been little disturbed since their extrusion during the earliest phase of development of the Gardar Alkaline Igneous Province.

Keywords

cathodoluminescence petrographycarbonatiteQasiarsuk, Greenland
Type
Petrology and Geochemistry
Information
Mineralogical Magazine , Volume 55 , Issue 381 , December 1991 , pp. 591 - 603
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1991

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Anderson, T. (1986) Model for the evolution of haematite carbonatite based on whole rock major and trace element data from the Fen Complex, SE Norway, Appl. Geochem., 2, 163–80.CrossRefGoogle Scholar
Balashov, Yu, A. and Pozharitskaya, L. K. (1968) Factors governing the behaviour of rare-earth elements in carbonatitic processes. Geochimiya, 3, 285–303.Google Scholar
Chai, H. T. and Mroczowski, S. (1978) Synthesis of rare earth carbonates under hydrothermal conditions. J. Crystal Growth, 44, 84–96.CrossRefGoogle Scholar
Deans, T. and Roberts, B. (1984) Carbonatite tuffs and lava clasts of the Tinderet foothills, Western Kenya: a study of calcined natrocarbonatites. Proc. Geol. Soc. London, 141, 563–80.CrossRefGoogle Scholar
Deans, T. and Seager, A. F. (1978) Stratiform magnetite crystals of abnormal morphology from volcanic carbonatites in Tanzania, Kenya, Greenland and India. Mineral. Mag., 42, 463–75.CrossRefGoogle Scholar
Goldschmidt, V. M. (1958) Geochemistry. Oxford University Press, Oxford.Google Scholar
Jones, A. P. (1985) Carbonatite volcanics and geology of the Qagssiarssuk area, South Greenland: field notes to selected key localities. Unpublished field notes.Google Scholar
Jones, A. P. and Wyllie, P. J. (1985) Solubility of rare earth elements in carbonatite magmas, indicated by the liquidus surface in CaCO3-Ca(OH)2-La(OH)3 at 1 kbar pressure. Appl. Geochem., 1, 95–102.CrossRefGoogle Scholar
Keller, J. (1989) Extrusive carbonatites and their significance. In Carbonatites (Bell, K., ed.). Unwin Hyman, London, 70–88.Google Scholar
Knudsen, D. (1986) Apatite mineralisation in carbonatite and ultramafic intrusions in Greenland. Final report. The Geological Survey of Greenland. 176 pp.Google Scholar
Kosterin, A. V. (1959) Possible modes of transport of the rare earths by hydrothermal solutions. Geochemistry, 4, 381–7.Google Scholar
Mariano, A. N. (1988) Some further geological applications of cathodoluminescence. In Cathodolumi-nescence of Geological Materials (Marshall, D. J., ed.). Unwin and Allen Inc., Oxford. 94–123.Google Scholar
Mariano, A. N. and Ring, P. J. (1975) Europium-activated catho doluminescence in minerals. Geochim. Cosmochim. Acta, 39, 649–60.CrossRefGoogle Scholar
Mariano, A. N. and Roedder, P. L. (1983) Kerimasi: a neglected carbonatite volcano. Geol., 91, 449–55.Google Scholar
Marshall, D. J. (1988) Cathodoluminescence of Geological Materials. Unwin and Allen Inc. Oxford.Google Scholar
Nakamura, N. (1974) Determination of REE, Ba, Fe, Mg, Na and K in carbonaceous chondrites. Geochim. Cosmochim. Acta, 38, 757–75.CrossRefGoogle Scholar
Pierson, B. J. (1981) The control of cathodolumi-nescence in dolomite by iron and manganese. Sedi-mentology, 28, 601–10.CrossRefGoogle Scholar
Stewart, J. N. (1970) Precambrian alkaline-ultramaficl carbonatite volcanism at Qagssiarssuk, South Greenland. Grønlands Geologiske Uder Søgelse. C A. Rietzels Folog. Kopenhagen, Denmark.Google Scholar
Tuttle, O. F. and Gittins, J. (1966) Carbonatites. Wiley, New York. 591 pp.Google Scholar
Upton, B. G. J. and Emeleus, C. H. (1987) Mid-Proterozoic magmatism in Southern Greenland: the Gardar Province. In Alkaline Igneous Rocks. Geol. Soc. Special Publication, 30, 449-71.CrossRefGoogle Scholar
Woolley, A. R. and Kempe, D. R. C. (1989) Carbonatites: nomenclature, average chemical compositions and element distributions. In Carbonatites (Bell, K., ed,). Unwin Hyman, London, 1–14.Google Scholar