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Distinct cooling histories of troctolites from the Freetown layered gabbro

Published online by Cambridge University Press:  05 July 2018

John F. W. Bowles
John F. W. Bowles*
Affiliation:
Department of Geology, University College, London, WC1E 6BT
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Summary

The iron-titanium oxide minerals of three troctolites from the Freetown layered gabbro have been analysed using an electron microprobe. Comparisons of the analyses of the iron-titanium minerals with the data of Buddington and Lindsley (1964) provide temperature and oxygen fugacity information relating to particular magnetite-ilmenite grains. Magnetite-ilmenite grains occurring in different silicate environments within any one single troctolite rock have equilibrated at differing times in the cooling history of that rock and this enables part of that history to be established. The partial cooling histories established for the three specimens can be clearly distinguished, and are strongly influenced by the appropriate buffer reactions.

Type
Research Article
Information
Mineralogical Magazine , Volume 40 , Issue 315 , September 1976 , pp. 703 - 714
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1976

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Footnotes

1

Present address: Institute of Geological Sciences, 64/78 Gray's Inn Road, London, WCIX 8NG.

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