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A natural example of the disequilibrium breakdown of biotite at high temperature: TEM observations and comparison with experimental kinetic data

Published online by Cambridge University Press:  05 July 2018

A. J. Brearley
A. J. Brearley*
Affiliation:
Department of Geology, The University, Manchester M13 9PL
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Abstract

Transmission electron microscopy has been used to investigate the mechanism of natural biotite breakdown under pyrometamorphic disequilibrium conditions. Biotite in a xenolith of pelitic gneiss collected from a Tertiary dolerite sill, Isle of Mull, Scotland, shows evidence of an incipient reaction, characterised by a darkening in colour and the appearance of areas of fine-grained reaction products. TEM and analytical electron microscope data show that the reaction can be described as:

The orientations of the product phase are controlled by the crystallography of the reacting biotite, demonstrating that the transformation proceeds by a topotactic mechanism. An empirical method, based on the Mg/(Fe2+ + Fe3+) ratios of coexisting spinel and biotite from experimental data, is used to deduce that the reaction occurred above ∼ 770 °C. A comparison of the natural reaction microstructures with those produced experimentally suggest that the xenolith was probably above 800 °C for less than 48 hours and cooled to temperatures of 770 °C after ∼ 150–200 hours.

Keywords

transmission electron microscopybiotitepyrometamorphism
Type
Electron Microscopy in Mineralogy and Petrology
Information
Mineralogical Magazine , Volume 51 , Issue 359 , March 1987 , pp. 93 - 106
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1987

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Footnotes

*

Present address: Institute of Meteoritics, Dept. of Geology, University of New Mexico, Albuquerque, New Mexico 87131, USA.

References

Abraham, K. and Schreyer, W. (1973) Contrib. Mineral. Petrol., 40, 275-92.CrossRefGoogle Scholar
Barber, D.J. (1970) J. Mater. ScL, 5, 1-8.Google Scholar
Brearley, A.J. (1984) Unpubl. PhD. thesis. Univ. of Manchester.Google Scholar
Brearley, A.J. (1986) Mineral. Mag., 50, 385-97.CrossRefGoogle Scholar
Brearley, A.J. (1987) Bull. Mineral. in press.Google Scholar
Brearley, A.J. and Champness, P.E. (1986) Mineral. Mag., 50, 621-33.Google Scholar
Cliff, G.A. and Lorimer, G.W. (1975) J. Microsc., 103, 203-7.CrossRefGoogle Scholar
Eugster, H.P. and Wones, D.R. (1962) J. Petrol., 3, 82-125.CrossRefGoogle Scholar
Grapes, R.H. (1986) Ibid. 27, 343-96.Google Scholar
Jaeger, J.C. (1957) Am. J. Sci., 255, 306-18.CrossRefGoogle Scholar
Labotka, T.C. (1983) Am. Mineral., 68, 900-14.Google Scholar
Le Maitre, R.W. (1974) J. Petrol., 15, 403-12.CrossRefGoogle Scholar
McGitl, R.J. and Hubbard, F.H. (1981) In Qualitative microanalysis with high spatial resolution (Lorimer, G.W., Jacob, M.H., Doig, P., eds.) The Metals Society.Google Scholar
Putnis, A. and McConnell, J.D. C. (1980) Principles of mineral behaviour. Blackwell Scientific Publications.Google Scholar
Rubie, D.C. (1986) Mineral Mag., 50, 399-415.CrossRefGoogle Scholar
Rubie, D.C. and Brearley, A.J. (1986) Geol. Soc. Newsletter, 15, no. 2, 46-7.(abs.Google Scholar
Rubie, D.C. and Brearley, A.J. (1987) Bull. Mineral. in press.Google Scholar
Rutherford, M.J. (1973) J. Petrol., 14, 159-8.CrossRefGoogle Scholar
Spear, F.S., Rumble III, D. and Ferry, J.M. (1982) Reviews in Mineralogy., 10, 53-104. Min. Soc. A.Google Scholar
Smith, D.G. W. (1965) Am. Mineral., 50, 1982-2022.Google Scholar
Stewart, F.H. (1942) Mineral. Mag., 26, 260-6.Google Scholar
Wones, D.R. and Eugster, H.P. (1965) Am. Mineral., 50, 1228-72.Google Scholar
Burns, R.G. and Carroll, B.M. (1971) Trans. Am. Geophys. Un., 52, 369.Google Scholar
Worden, R., Champness, P.E., and Droop, G.T. R. (1987) Min. Mag., 51, 107-21.CrossRefGoogle Scholar