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Ferromagnesian silicates in a differentiated alkaline complex: Kûngnât Fjeld, South Greenland

Published online by Cambridge University Press:  05 July 2018

D. Stephenson  and
B. G. J. Upton
D. Stephenson
Affiliation:
Institute of Geological Sciences, Murchison House, Edinburgh EH9 3LA
B. G. J. Upton
Affiliation:
Institute of Geological Sciences, Murchison House, Edinburgh EH9 3LA
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Abstract

Kûngnât Fjeld is an intrusive complex resulting from three intrusive events involving trachyte, mafic trachyte and hawaiite magmas tapped successively from a single magmatic source. In situ differentiation produced gabbroic, syeno-gabbroic, syenitic, and quartz syenitic cumulates showing strong cryptic variation. Layered sequences of syenitic rocks total c. 3500 m. The compositional range is extended by late-stage minor intrusions of microsyenite and peralkaline granite. The principal cumulus minerals are feldspar (Ab40An60 to Or45Ab51An4); olivine (Fo56 to Fo1) and clinopyroxene (Di70Hd27Ac3 to Di6Hd90Ac4 followed by an abrupt change of trend towards Di3Hd78Ac19 in the layered series and nearly pure aegirine in some peralkaline residues). Intercumulus phases are amphibole (hastingsite to ferro-edenite to ferro-actinolite in the layered series with riebeckite to arfvedsonite in some associated granites) and biotite (annite31 to annite98.5).

Type
Research Article
Information
Mineralogical Magazine , Volume 46 , Issue 340 , September 1982 , pp. 283 - 300
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1982

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References

Anderson, J. G. (1974) The geology of Alangorssuaq, Northern Nunarssuit complex, S. Greenland. Unpubl. Ph.D. thesis, Univ. of Aberdeen.Google Scholar
Bailey, D. K. (1969) Am. J. Sei. 267A, 1–16.Google Scholar
Blaxland, A. B. (1976) Geochronology and isotope geochemistry of the Gardar alkaline complexes. Unpubl. Ph.D. thesis, Univ. of Edinburgh.Google Scholar
Blaxland, A. J., van Breemen, O., Emeleus, C. H., and Anderson, J. G. (1978) GeoL Soc. Am. Bull. 89, 231–44.2.0.CO;2>CrossRefGoogle Scholar
Bridgwater, D., and Harry, W. T. (1968) Bull. Gronlands geol. Unders. 77 (Meddels. Gronland 185).Google Scholar
Chambers, A. D. (1976) The petrology and geochemistry of the North Qbroq Centre, Igaliko Complex, South Greenland. Unpubl. Ph.D. thesis, Univ. of Durham.Google Scholar
Charles, R. W. (1975) Am. Mineral. 60, 367–74.Google Scholar
Cox, K. G., Bell, J. D., and Pankhurst, R. J. (1979) The Interpretation of Igneous Rocks. Allen & Unwin, London.CrossRefGoogle Scholar
Emeleus, C. H., and Upton, B. G. J. (1976) The Gardar period in southern Greenland. In Escher, A., and Watt, W. S. (eds.) Geology of Greenland. Copenhagen: Grinlands Geol. Unders.Google Scholar
Ernst, W. G. (1962) J. Geol. 70, 689–736.CrossRefGoogle Scholar
Ernst, W. G. (1966) Am. 2. Sci. 264, 36–65.Google Scholar
Harry, W. T., and Pulvertaft, T. C. R. (1963) Greenland Geol. Surv. Bull. 36 (Meddels. Gronland 169).Google Scholar
Jones, A. P. (1980) The petrology and structure of the Motzfeldt Centre, Igaliko, South Greenland. Unpubl. Ph.D. thesis, Univ. of Durham.Google Scholar
Larsen, L. M. (1976) J. Petrol. 17, 258–90.CrossRefGoogle Scholar
McBirney, A. R., and Noyes, R. M. (1979) Ibid. 20, 487–554.Google Scholar
Macdonald, R., and Saunders, M. J. (1973). Mineral. Mag. 39, 97–111.CrossRefGoogle Scholar
Mitchell, R. H., and Platt, R. G. (1978) J. Petrol. 19, 627–51.CrossRefGoogle Scholar
Nash, W. P., and Wilkinson, J. F. G. (1970) Contrib. Mineral. Petrol. 25, 241–61.CrossRefGoogle Scholar
Neumann, E. R. (1976) Lithos 9, 85–109.CrossRefGoogle Scholar
Parsons, I. (1979) J. Petrol. 20, 653–94.CrossRefGoogle Scholar
Powell, M. (1978) Lithos 11, 99–120.CrossRefGoogle Scholar
Rowbotham, G. (1973) Hydrothermal synthesis and min¬eralogy of the alkali amphiboles. Unpubl. Ph.D. thesis, Univ. of Durham.Google Scholar
Simkin, T., and Smith, J. V. (1970) J. Geol. 78, 304–25.CrossRefGoogle Scholar
Stephenson, D. (1972) Lithos 5, 187–201.CrossRefGoogle Scholar
Stephenson, D. (1973) The petrology and mineralogy of the South Qbroq Centre, Igaliko Complex, South Greenland. Unpubl. Ph.D. thesis, Univ. of Durham.Google Scholar
Stephenson, D. (1974) Lithos 7, 35–41.CrossRefGoogle Scholar
Sweatman, T. R., and Long, J. V. P. (1969) J. Petrol. 10, 332–79.CrossRefGoogle Scholar
Upton, B. G. J. (1960). Bull. Gronlands geol. Unders. 27 (Meddels: Gronland 123).Google Scholar
Upton, B. G. J. and Thomas, J. E. (1980) J. Petrol. 21, 167–98.CrossRefGoogle Scholar
Upton, B. G. J. and Macdonald, R. (1971) Lithos 4, 163–84.CrossRefGoogle Scholar