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Transmission Electron Microscope Study of Biotite Weathering

Published online by Cambridge University Press:  02 April 2024

Jillian F. Banfield  and
Richard A. Eggleton
Jillian F. Banfield*
Affiliation:
Department of Geology, Australian National University, P.O. Box 4, Canberra, A.C.T. 2601, Australia
Richard A. Eggleton
Affiliation:
Department of Geology, Australian National University, P.O. Box 4, Canberra, A.C.T. 2601, Australia
*
1Present address: Department of Earth and Planetary Sciences, The Johns Hopkins University, Baltimore, Maryland 21218
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Abstract

Transmission electron microscopy suggests that biotite transforms to vermiculite primarily by direct structural modification, involving the replacement of K+ by hydrated interlayer cations, and only minor reorganization of the 2:1 layer. A second relatively uncommon mechanism appears to involve redistribution of components from two biotite sheets to form a single vermiculite layer. Distortion of the surrounding structure initially inhibits growth of vermiculite in the surrounding biotite, and promotes the propagation of vermiculite layers in opposite directions. This phenomenon may contribute to the development of relatively regular, widely spaced interstratifications of biotite and vermiculite. Additional components and space are provided by the dissolution of biotite where access of solutions is greater.

During weathering, biotite and vermiculite become increasingly replaced by kaolinite, which crystallizes epitactically onto existing layers, and goethite, which develops from a poorly crystalline iron oxyhydroxide precursor to form oriented laths. In areas parts of strongly weathered samples kaolinite and goethite appear to develop in proportions consistent with a reaction that conserves both Al and Fe.

Keywords

BiotiteGoethiteGranodioriteKaoliniteLattice-fringe imagesTransmission electron microscopyVermiculiteWeathering
Type
Research Article
Information
Clays and Clay Minerals , Volume 36 , Issue 1 , February 1988 , pp. 47 - 60
Copyright
Copyright © 1988, The Clay Minerals Society

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References

Banfield, J. F., 1985 The mineralogy and chemistry of granite weathering .Google Scholar
Churchman, G. J., Whitton, J. S., Claridge, G. G. C. and Theng, B. K. G., 1984 Intercalation method using formamide for differentiating halloysite from kaolinite Clays & Clay Minerals 32 241 – 248.CrossRefGoogle Scholar
Coleman, N. T., Le Roux, F. H. and Cady, I. G., 1963 Biotite-hydrobiotite-vermiculite in soils Nature 198 409 – 410.CrossRefGoogle Scholar
Cowley, J. M., Iijima, S. and Wenk, H.-R., 1976 The direct imaging of crystal structures Electron Microscopy in Mineralogy Berlin Springer-Verlag 123 – 137.CrossRefGoogle Scholar
Gilkes, R. J. and Suddhiprakarn, A., 1979 Biotite in deeply weathered granite. I. Morphologic, mineralogical, and chemical properties. II. The oriented growth of secondary minerals Clays & Clay Minerals 27 349 – 367.CrossRefGoogle Scholar
MacEwan, D. M. C., 1953 Cardenite, a trioctahedral mont-morillonoid derived from biotite Clay Min. Bull. 2 120 – 126.CrossRefGoogle Scholar
Meunier, A., Velde, B., Mortland, M. M. and Farmer, V. C., 1979 Biotite weathering in granites of western France Proc. Int. Clay Conf., Oxford, 1978 Amsterdam Elsevier 405 – 415.Google Scholar
Norrish, K. (1973) Factors in the weathering of vermiculite: Proc. Int. Clay Conf., Madrid, 1972, Serratosa, J. M., ed. Div. Ciencias C.S.I.C., Madrid, 419–432.Google Scholar
Norrish, K., Chappell, B. W. and Zussman, J., 1977 X-ray fluorescence spectroscopy Physical Methods in Determinative Mineralogy New York Academic Press 201 – 272.Google Scholar
Walker, G. F., 1949 The decomposition of biotite in the soil Mineral. Mag. 28 693 – 703.Google Scholar
Wilson, M. J., 1966 The weathering of biotite in some Aberdeenshire soils Mineral Mag. 35 1080 – 1093.Google Scholar
Wilson, M. J., 1970 A study of weathering in a soil derived from a biotite-hornblende rock. I. Weathering of biotite Clay Miner. 8 291 – 303.CrossRefGoogle Scholar