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Differing Powers of Crystal Nucleation as a Factor Producing Diversity in Layered Igneous Intrusions

Published online by Cambridge University Press:  01 May 2009

L. R. Wager
Affiliation:
Department of Geology and Mineralogy, University Museum, Oxford.

Abstract

To account for a type of rhythmic unit found in the Bushveld complex of South Africa and probably in other layered intrusions, a hypothesis is put forward dependent on the different powers of crystal nucleation from supersaturated magma. It is suggested, for example, that the three common primary precipitate minerals, chromite, bronzite, and bytownite nucleated in this order which is probably dependent on the differing complexity of their crystal structures and that the common rhythmic unit, beginning with chromitite, passing upwards into bronzitite and ending with a bytownite-rich rock is the result of these crystals accumulating successively at the bottom'of the liquid.

Type
Articles
Copyright
Copyright © Cambridge University Press 1959

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References

Brown, G. M., 1956. The layered ultrabasic rocks of Rhum, Inner Hebrides. Trans. Royal Soc. London, Ser. B, ccxl, 153.Google Scholar
Eitel, W., 1954. The physical chemistry of the silicates. University of Chicago Press, Chicago, 569577.Google Scholar
Goldsmith, J. R., 1953. A “simplexity principle” and its relation to “ease” of crystallization. Journ. Geol., lxi, 439451.CrossRefGoogle Scholar
Lombaard, B. V., 1934. On the differentiation and relationships of the rocks of the Bushveld Complex. Trans. Geol. Soc. S. Africa, xxxvii, 552.Google Scholar
Wager, L. R. and Deer, W. A., 1939. Geological investigations in East Greenland. Part III. The petrology of the Skaergaard intrusion, Kangerdlugssuaq. Medd. am Grønland, cv, No. 4, 1352.Google Scholar
Wager, L. R., 1953. Layered intrusions. Medd. fra Dansk Geol. Forening, xii, 335349.Google Scholar
Worst, B. G., 1956. Thesis for the degree of D.Sc. at Pretoria University on the Great Dyke of Southern Rhodesia.Google Scholar