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IV.—A Contribution to the Petrology of North-Western Angola

Published online by Cambridge University Press:  01 May 2009

Arthur Holmes
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Extract

This remarkable rock occurs as a marginal phase of the granulitic albite granites which are found between Noqui and kilometre 16 on the road to San Salvador. In the hand-specimen it shows a finegrained slightly foliated structure with a characteristic pepper and salt appearance, due to the sprinkling of lustrous black plates of riebeckite among iron-stained granular crystals of quartz and felspar. A few small porphyritic crystals of orthoclase are embedded in the main mass of the rock, making up approximately 15 per cent of the whole.

Type
Original Articles
Information
Geological Magazine , Volume 2 , Issue 6 , June 1915 , pp. 267 - 272
Copyright
Copyright © Cambridge University Press 1915

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References

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page 270 note 1 Murgoci, p. 145.

page 270 note 2 Practically all Fe Si O3.

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