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The use of An and Sr data on plagioclase in a study of basic xenoliths in a gabbroic mass at Hamar, Somalia

Published online by Cambridge University Press:  14 March 2018

J. R. Butler
Affiliation:
Department of Geology, Imperial College, London, S.W. 7
W. Skiba
Affiliation:
Department of Geology, Imperial College, London, S.W. 7

Summary

In this paper we give data for An and Sr in plagioclase to demonstrate the presence of numerous amphibolite xenoliths within parts of a basic igneous mass where, after initial reconnaissance mapping, none was suspected. The data also show that the concentration of Sr in plagioclase from the margin of some amphibolite xenoliths is appreciably higher than in plagioclase from either the cores of the xenoliths or the enclosing metagabbro even though the modes and An contents of the plagioclase are similar. An explanation is offered, which implies that some of the xenoliths were amphibolites rather than anhydrous equivalents prior to their enclosure in the basic magma.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1966

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References

Butler, (J. R.), and Skiba, (W.), 1962. Min. Mag., vol. 33, pp. 213-225.Google Scholar
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