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Volatile flux, geotherms, and the generation of the kimberlite-carbonatite-alkaline magma spectrum

Published online by Cambridge University Press:  05 July 2018

D. K. Bailey*
Affiliation:
Department of Geology, University of Reading, Whiteknights, Reading, RG6 2AB

Summary

A comparison of shield geotherms with the experimentally determined vapour-present solidus for kimberlite, indicates conditions of grazing incidence between 150–200 km, precisely where the mineral geotherms become disturbed. This relationship permits a new interpretation of kimberlite activity, by which volatiles migrating through cratonic lithosphere cause first metasomatism, and then incipient melting in the zone of incidence. Production of localized pockets of near-solidus liquid, erupted by accelerating crack propagation through the overlying lithosphere, is consistent with the unique set of features that characterize kimberlite. Volatile fluxing along steeper geotherms (away from craton nucleii) produces entirely different modes of magma eruption and development, by which highly under-saturated alkalic melts can reach the surface as liquids. Kimberlite activity is thus revealed as the limiting case of cratonic magmatism.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1980

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References

Bailey, (D. K.), 1970. Geol. J. Special Issue, No. 2, 177-86.Google Scholar
Bailey, (D. K.) 1972. J. Earth Sci., Leeds. 8, 225-39.Google Scholar
Bailey, (D. K.) 1974. In The Alkaline Rocks, H. Sørensen (ed.), Wiley, New York, 148-59.Google Scholar
Bailey, (D. K.) 1977. Jl. geol. Soc. Lond. 133, 103-6.CrossRefGoogle Scholar
Bailey, (D. K.) in press. Philos. Trans. R. Soc. London.Google Scholar
Boyd, (F. R.) and Nixon, (P. H.), 1973. Carnegie Inst. Washington Yearb. 72, 431-45.Google Scholar
Bailey, (D. K.) Boyd, (F. R.) 1975. In Phys. and Chem. of Earth. 9, 431-54.Google Scholar
Bailey, (D. K.) Boyd, (F. R.) 1978. Geochim. Cosmochim. Acta, 42, 1367-82.Google Scholar
Fujii, (T.), and Danchin, (R. V.), 1976. Carnegie Inst. Washington Yearb. 75, 523-31.Google Scholar
Boyd, (F. R.) and Pasteris, (J. D.), 1978. Ibid. 77, 866-70.Google Scholar
Danchin, (R. V.) and Boyd, (F. R.), 1976. Ibid. 75, 531-8.Google Scholar
Eggler, (D. H.), 1978. Geology. 6, 397-400.2.0.CO;2>CrossRefGoogle Scholar
Eggler, (D. H.) and McCallum, (M. E.), 1976. Carnegie Inst. Washington Yearb. 75, 538-41.Google Scholar
Eggler, (D. H.) and Wendlandt, (R. F.), 1978. Ibid. 77, 751-6.Google Scholar
Finnerty, (A. A.) and Boyd, (F. R.), 1978. Ibid. 77, 713-17.Google Scholar
Green, (H. W.) and Gueguen, (Y.), 1974. Nature, 249, 617-20.CrossRefGoogle Scholar
Lloyd, (F. E.) and Bailey, (D. K.), 1975. In Phys. and Chem. of Earth. 9, 389-416.CrossRefGoogle Scholar
Mysen, (B. O.) and Boettcher, (A. L.), 1975. d. Petrol. 16, 549-93.CrossRefGoogle Scholar
Wyllie, (P. J.), 1977. J. geol. soc. Lond. 134, 215-34.CrossRefGoogle Scholar