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On the biotite-bearing greenstones and on a rhyolitic pumice in the metamorphic aureole of the Falmouth granite

Published online by Cambridge University Press:  14 March 2018

P. K. Ghosh*
Affiliation:
Imperial College of Science and Technology, London

Extract

In the metamorphic aureole of the Falmouth. granite, the greenstones I which are largely referable to epidiorites form an important and interesting assemblage of rocks. These are lower Palaeozoic in age and are pre-granite and have suffered from metamorphism as all effect of the granite-intrusion in post-Carboniferous times.

The chief mineral constituents, viz. hornblende and plagioclase, are quite normal for a rock of this nature except that the former is clearly a derivative of augite, many relics of which are still preserved ; among the most important accessory minerals are biotite, chlorite, epidote, iron-ores, quartz, augite, axinite, and garnet. One may pass over some of the accessories as being quite usual, being partly primary and partly secondary in origin, but biotite is one of those the presence of which requires to be specially explained.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1928

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References

page 436 note 1 On the geology of Falmouth and Camborne. Mem. Geol. Survey of England and Wales, 1906, p. 41.

page 436 note 2 Op. cit., p. 43.

page 438 note 1 Op. cit., p. 41.