Hostname: page-component-78c5997874-mlc7c Total loading time: 0 Render date: 2024-11-19T04:37:54.307Z Has data issue: false hasContentIssue false
  • English
  • Français

Pyroxene fractionation in ferrobasalts from the Galapagos Spreading Centre

Published online by Cambridge University Press:  05 July 2018

I. D. Muir  and
D. A. Mattey
I. D. Muir
Affiliation:
Department of Earth Sciences, University of Cambridge
D. A. Mattey
Affiliation:
Department of Earth Sciences, University of Cambridge
Get access Rights & Permissions [Opens in a new window]

Abstract

The significance of metastable and equilibrium pyroxene fractionation trends in tholeiitic magmas is discussed, and the development of sector zoning and skeletal growth are considered in relation to Nakamura's (1973) hypothesis of protosites on growing clinopyroxene crystal surfaces. At the Galapagos Spreading Centre (GSC) basalts and ferrobasalts investigated behave paradoxically in that the slower-cooled basalts follow the quench trend while the faster-cooled ferrobasalts define a much closer approach to the equilibrium trend.

It is concluded that under metastable conditions fractionation trends in Ca-rich pyroxenes may be strongly influenced by textural features such as cotectic crystallization of plagioclase and the onset of liquid immiscibility, the latter leading to the development of strongly Fe-enriched ferroaugites. Even under plutonic conditions metastable crystallization can develop and severely reduce the pyroxene miscibility gap. A model for metastable crystallization is presented. These considerations are then addressed to the remarkable correspondence of the Skaergaard and Thingmuli pyroxene fractionation trends.

Type
Research Article
Information
Mineralogical Magazine , Volume 45 , Issue 337 , 1982 , pp. 193 - 200
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1982

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.)

Footnotes

*

Department of Earth Sciences, University of Cambridge, Contribution No. 195.

References

Barberi, F., Borsi, S., Ferrara, G., Marinelli, G., and Varet, J. (1970) Phil. Trans. R. Soc. London, Ser. A, 267, 293-311.Google Scholar
Barberi, F., Bizouard, H., and Varet, J. (1971) Contrib. Mineral. Petrol. 33, 93-107.CrossRefGoogle Scholar
Boyd, F. R., and Smith, D. (1971) J. Petrol. 12, 439-64,CrossRefGoogle Scholar
Brown, G. M. (1957) Mineral. Mag. 31, 511-43.Google Scholar
Brown, G. M. and Vincent, E. A. (1963) J. Petrol. 4, 175-97.CrossRefGoogle Scholar
Carmichael, I. S. E. (1967) Am. Mineral. 52, 1815-41.Google Scholar
Dixon, S., and Rutherford, M. J. (1979) Earth Planet. Sci. Lett. 45, 45-60.CrossRefGoogle Scholar
Evans, E. W., and Moore, J. G. (1968) Contrib. Mineral. Petrol. 17, 85-115.CrossRefGoogle Scholar
Fodor, R. V., and Keil, K. (1975) Ibid. 50, 173-95.Google Scholar
Fodor, R. V., Berkley, J. L., Keil, K., Husler, J. W., Ma, M. S., and Schmidt, R. A. (1980) Init. Rep. DSDP, 54, 737-50.Google Scholar
Gay, P., Bown, M. G., and Muir, I. D. with Bancroft, G. M., and Williams, P. G. L. (1971) Proc. 2nd Lunar Sci. Conf. 1, 377-92.Google Scholar
Gordon, P. (1968) Principles of Phase Diagrams in Materials Systems. McGraw Hill, New York, 232 pp.Google Scholar
Hollister, L. S., and Gancanz, A. J. (1971) Am. Mineral. 56, 959-79.Google Scholar
Kuno, H., Yamasaki, K., Iida, C., and Nagashima, K. (1957) Jap. J. Geol. Geogr. 27, 179-218.Google Scholar
Maaloe, S. (1978) Mineral. Ma9. 42, 337-45.CrossRefGoogle Scholar
McDougall, I. (1962) Geol. Soc. Am. Bull. 73, 279-315.CrossRefGoogle Scholar
Mattey, D. A., and Muir, I. D. (1980) lnit. Rep. DSDP, 54, 755-71.Google Scholar
Muir, I. D. (1954) Mineral. May. 30, 376-88,Google Scholar
Muir, I. D. and Long, J. V. P. (1965) Ibid. 34, 358-69.Google Scholar
Muir, I. D. and Tilley, C. E. (1957) Am. J. Sci. 255, 241-53.CrossRefGoogle Scholar
Muir, I. D. and Tilley, C. E. (1964) Geol. J. 4, 143-56.CrossRefGoogle Scholar
Murase, T., and McBirney, A. R. (1970) Science, 167, 1491-3.CrossRefGoogle Scholar
Nakamura, Y. (1973) Am. Mineral. 58, 986-90.Google Scholar
Nakamura, Y. and Kushiro, I. (1970) Contrib. Mineral. Petrol. 26, 265-75.CrossRefGoogle Scholar
Nwe, Y. Y. (1973) Ibid. 49, 285-300.Google Scholar
Prewitt, C. T., Papike, J. J., and Bence, A. E. (1970) Trans. AGU Supplement, 51.Google Scholar
Smith, P., and Lindsley, D. H. (1971) Am. Mineral. 58, 225-33.Google Scholar
Thompson, R. N., and Humphris, S. E. (1980) lnit. Rep. DSDP, 54, 651-69.Google Scholar
Wager, L. R., and Deer, W. A. (1939) Meddels. Gronland, 105, 1-352.Google Scholar
Wright, T. L., and Fiske, R. S. (1971) J. Petrol. 12, 1-65.CrossRefGoogle Scholar
Yamakawa, M. (1971) Contrib. Mineral. Petrol. 33, 232-8.CrossRefGoogle Scholar