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Petrogenetic implications of garnets associated with lithium pegmatites from SE Ireland

Published online by Cambridge University Press:  05 July 2018

Martin P. Whitworth
Martin P. Whitworth*
Affiliation:
Department of Geology, Imperial College, London SW7 2BP, U.K.
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Abstract

Spodumene pegmatites, aplites and schists from the Aclare Li prospect of SE Ireland host sporadically developed, small, red, euhedral garnets. Chemical data indicate that the pegmatite- and aplite-hosted garnets are rich in spessartine and are similar to garnets in many African Li-rich pegmatites. Partial melting as a source of the garnets is unlikely due to the large spessartine component, the abundance of inclusions within the garnets and the general P-T-X evolution of the pegmatite body. It is suggested that an aqueous fluid was exsolved during pegmatite crystallisation and complexed available Mn. Movement of this fluid to the intermediate zone of the pegmatite body produced areas of high Mn concentrations which permitted the crystallisation of spessartine-rich garnets at low pressures (<3 kbar).

Keywords

garnetslithium pegmatitesmanganeseAclareIreland
Type
Research Article
Information
Mineralogical Magazine , Volume 56 , Issue 382 , March 1992 , pp. 75 - 83
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2014

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Footnotes

*

Present address: Primary Processes Department, Process Development Group, British Steel Technical, Teesside Laboratories, Middlesbrough TS6 6UB, UK

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