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Early Transverse Dykes in the Main Donegal Granite

Published online by Cambridge University Press:  01 May 2009

W. S. Pitcher
Affiliation:
King's College, Strand, London, W.C. 2.
H. H. Read
Affiliation:
Imperial College, South Kensington, London, S.W. 7.

Abstract

Certain microtonalite dykes cut across the flow banding of the Main Donegal Granite in the direction of an important cross-joint, yet they and their granite host are shown to have crystallized together and in the same manner as both the darker flow bands in the granite and the pelitic xenoliths within it. It appears that an embryonic joint system existed in the Donegal Granite before consolidation and crystallization were complete. It is suggested that the early dykes represent metasomatized pelitic enclave material and are not differentation products of granitic magma. Comparison is made with the basic analogue provided by the beerbachite enclaves and dykes of the hypersthene-gabbro of Ardnamurchan.

Type
Articles
Copyright
Copyright © Cambridge University Press 1960

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References

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