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Liquid immiscibility and the origin of alkali-poor carbonatites

Published online by Cambridge University Press:  05 July 2018

B. A. Kjarsgaard  and
D. L. Hamilton
B. A. Kjarsgaard
Affiliation:
Department of Geology, The University, Manchester M13 9PL
D. L. Hamilton
Affiliation:
Department of Geology, The University, Manchester M13 9PL
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Abstract

The work on liquid immiscibility in carbonate-silicate systems of Freestone and Hamilton (1980) has been extended to include alkali-poor and alkali-free compositions. Immiscibility is shown to occur on the joins albite-calcite and anorthite-calcite at 5 kbar. These results make it possible to interpret ocellar structure between calcite-rich spheroids in lamproite or kimberlite host rock as products of liquid immiscibility. The common sequence of rock types found in carbonatite complexes of melilitite-ijolite-urtite-phonolite is interpreted as being the result of both fractional crystallization and liquid fractionation, the corresponding carbonatite composition changing from nearly pure CaCO3 (±MgCO3) progressively to natrocarbonate. A carbonate melt cooling in isolation will suffer crystal fractionation, the residual liquid producing the rarer ferrocarbonatites, etc., whilst the crystal accumulate of calcite (dolomite) plus other phases such as magnetite, apatite, baryte, pyrochlore, etc., are the raw material for the coarse-grained intrusive carbonatites commonly found in ring complexes.

Keywords

carbonatitesliquid immiscibilitycarbonate-silicate systems
Type
Recent Developments in Experimental Petrology and Mineralogy
Information
Mineralogical Magazine , Volume 52 , Issue 364 , March 1988 , pp. 43 - 55
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1988

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References

Aspden, J.A. (1977) Ph.D. thesis, University of Leicester. -(1981) Mineral. Mag. 44, 2014.Google Scholar
Amundsen, H.E. F. (1987) Nature 327, 692–5.CrossRefGoogle Scholar
Bailey, D.K. (1966) In Carbonatites (O. F. Tuttle and J. Gittins, eds.) Wiley, 127-54.Google Scholar
Bedson, P. (1983) The Origin Of The Carbonatites And Their Relations To Other Rocks By Liquid Immiscibility. Ph.D.thesis, University of Manchester.Google Scholar
Bogoch, R., and Magaritz, M. (1983) Contrib. Mineral. Petrol. 83, 227-30.CrossRefGoogle Scholar
Borley, G.D. (1967) Mineral. Mag. 36, 364-79.Google Scholar
Brey, G. (1977) IASPEI/IAVCEI Joint Assemblies, Durham, abstracts, 221.Google Scholar
Green, D.H. (1976) Contrib. Mineral. Petrol. 55, 217–30.Google Scholar
Cooper, A.F., Gittins, J., and Tuttle, O.F. (1975) Am. J. Sci. 275, 534–60.CrossRefGoogle Scholar
Dawson, J.B. (1962) Bull. Volcanol. 24, 349–88. -(1966) In Carbonatites (O. F. Tuttle and J. Gittins, eds.) Wiley 15568.CrossRefGoogle Scholar
Dawson, J.B. and Hawthorne, J.B. (1973) J. Geol. Soc. London 129, 61–85.CrossRefGoogle Scholar
Deans, T., and Roberts, B. (1984) Ibid. 141, 563–580.Google Scholar
Eggler, D.H. (1975) Trans. Am. geophys. Union (EOS) 56, 470.Google Scholar
Ferguson, J., and Currie, K.L. (1971) J. Petrol. 12, 561- 85.CrossRefGoogle Scholar
Freestone, I.C. (1978) Chem. Soc. 23, 115–23.Google Scholar
Freestone, I.C. and Hamilton, D.L. (1980) Contrib. Mineral. Petrol. 73, 105–17.CrossRefGoogle Scholar
Hamilton, D.L., Bedson, P., and Esson, J. (1988) Submitted chapter in book edited by K. Bell.Google Scholar
Holmes, A. (1952) Trans. Geol. Soc. Edinburgh 15, 187-213.CrossRefGoogle Scholar
King, B.C. (1949) Geol. Surv. of Uganda Mere. 5.Google Scholar
King, B.C. (1965) J. Petrol. 6, 67–100.CrossRefGoogle Scholar
King, B.C. and Sutherland, D.S. (1960) Sci. Prog. 48, 298- 321, 504–24. 709-20.Google Scholar
Koster Van Grogs, A.F. (1975) Am. J. Sci. 275, 163- 85.Google Scholar
Koster Van Grogs, A.F. and Wyllie, P.J. (1966) Ibid. 264, 234–55.Google Scholar
Koster Van Grogs, A.F. (1968) Ibid. 266, 932-67.Google Scholar
Koster Van Grogs, A.F. (1973) Ibid. 273, 465–87.Google Scholar
Le Bas, M. J. (1977) Carbonatite-Nephelinite Volcanism. Wiley, 263–93.Google Scholar
Le Bas, M. J. (1981) Mineral. Mag. 44, 133-40.CrossRefGoogle Scholar
Le Bas, M. J. (1987) Geol. Soc. Special Pub. No. 30.Google Scholar
Middlemost, E.A. K. (1974) Lithos 7, 2758.CrossRefGoogle Scholar
Verwoerd, W.J. (1978) Carnegie lnst. Washington Yearb. 11, 161–14.Google Scholar
von Eckermann, H. (1948) Internat. Geol. Congr. 18(3), 90–3.Google Scholar
von Eckermann, H. (1961) Bull. Geol. lnst. Uppsala 40, 2536.Google Scholar
von Eckermann, H. (1966) In Carbonatites (O. F. Turtle and J. Gittins, eds.) Wiley, 3–31.Google Scholar
Watkinson, D.H., and Wyllie, P.J. (1969) U.S. Geol. Surv. Bull. 80, 1565–76.CrossRefGoogle Scholar
Watkinson, D.H., and Wyllie, P.J. (1971) J. Petrol. 12, 357–78.CrossRefGoogle Scholar
Wendlandt, R.F., and Harrison, W.J. (1979) Contrib. Mineral. Petrol. 69, 409–19.CrossRefGoogle Scholar
Woolley, A.R. (1982) Mineral. Mag. 46, 1317.CrossRefGoogle Scholar
Wyllie, P.J. (1987) In Magmatic Processes: Physicochemical Principles (B. O. Mysen, ed.) The Geochemical Sot., 107-20.Google Scholar