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Supergene Vermiculitization of Phlogopite and Biotite in Ultramafic and Mafic Rocks, Central Korea

Published online by Cambridge University Press:  28 February 2024

Hi-Soo Moon
Affiliation:
Department of Geology, Yonsei University, 134 Shinchon-dong, Seodaemun-ku, Seoul 120-749, Korea
Yungoo Song
Affiliation:
Department of Geology, Yonsei University, 134 Shinchon-dong, Seodaemun-ku, Seoul 120-749, Korea
S. Y. Lee
Affiliation:
Environmental Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831, USA
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Abstract

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An X-ray diffraction study of vermiculitized micas in ultramafic and mafic intrusive rocks from Cheongyang, Korea, shows the following weathering sequence: mica → ordered mica/vermiculite interstratification → vermiculite. Electron microprobe analyses show the general trends of K leaching and Ca enrichment with increased weathering. The vermiculitization of phlogopite from ultramafic rocks proceeds by means of a continuous decrease in Al-for-Si tetrahedral substitutions and a progressive increase in Al-for-(Fe2+ + Mg) octahedral substitutions in the early stage of weathering. These substitutions occur to compensate for the excess of negative charge in the mica-like layer, in agreement with currently accepted vermiculitization mechanisms. They change to a slight increase of Al-for-Si tetrahedral substitutions in the late stage of the vermiculitization of phlogopite, owing to the oxidation of Fe despite its low content. However, the behavior of Fe in the late stage of the transformation of biotite into vermiculite is significantly different; that is, Fe increases substantially. The reason for this Fe increase in the late stage remains unresolved. Recalculations of the structural formulas on the basis of several assumptions indicate that the oxidation of Fe is necessary for the vermiculite derived from biotite to form the reasonable structural formulas.

Type
Research Article
Copyright
Copyright © 1994, Clay Minerals Society

References

April, R. H., Hluchy, M. M., and Newton, R. M., (1986) The nature of vermiculite in Adirondack soils and till: Clays & Clay Minerals 34, 549556.CrossRefGoogle Scholar
Bain, D. C., Mellor, A., and Wilson, M. J., (1990) Nature and origin of an aluminous vermiculitic weathering product in acid soil from upland and catchments in Scotland: Clay Miner. 25, 467475.CrossRefGoogle Scholar
Banfield, J. F., and Eggleton, R. A., (1988) Transmission electron microscope study of biotite weathering: Clays & Clay Minerals 36, 4760.CrossRefGoogle Scholar
Bence, A. E., and Albee, A. L., (1968) Empirical correction factors for the electron microanalysis of silicates and oxides: J. Geol. 76, 382403.CrossRefGoogle Scholar
Coleman, N. T., Le Roux, F. H., and Cady, K. G., (1963) Biotite-hydrobiotite-vermiculite in soils: Nature 198, 409410.CrossRefGoogle Scholar
Fordham, A. W., (1990a) Weathering of biotite into dioctahedral clay minerals: Clay Miner. 25, 5163.CrossRefGoogle Scholar
Fordham, A. W., (1990b) Treatment of microanalyses of intimately mixed products of mica weathering: Clays & Clay Minerals 38, 179186.CrossRefGoogle Scholar
Fordham, A. W., (1990c) Formation of trioctahedral illite from biotite in a soil profile over granite gneiss: Clays & Clay Minerals 38, 187195.CrossRefGoogle Scholar
Foster, M. D., (1960) Interpretation of the composition of trioctahedral micas: Geol. Survey Prof. Paper 354–B, 1148.Google Scholar
Ildefonse, P., Manceau, A., Proust, D., and Groke, M. C. T., (1986) Hydroxy-Cuvermiculite formed by the weathering of Fe-biotites at Salobo, Carajas, Brazil: Clays & Clay Minerals 34, 338345.CrossRefGoogle Scholar
Kim, H. Y., (1992) Mineralogical and chemical study of the vermiculites in the weathering profile, in the Cheongyang area: MSc. thesis, Yonsei University, 57 pp. (unpublished, in Korean).Google Scholar
Kiss, E., (1967) Chemical determination of some major constituents in rocks and minerals: Analy. Chim. Acta 39, 223234.CrossRefGoogle Scholar
MacKenzie, R. C., (1958) The evaluation of clay mineral composition with particular reference of smectites: Silicates Industries 25, 1218.Google Scholar
Meunier, A., and Velde, B., (1979) Biotite weathering in granites of western France: in Proc. Int. Clay Conf., Oxford, 1978, Mortland, M. M., and Farmer, V. C., eds., Elsevier, Amsterdam , 405415.Google Scholar
Newman, A. C. D., and Brown, G., (1987) The chemical constituent of clays: in Chemistry of Clays and Clay Minerals, Monograph No. 6, Newman, A. C. D., ed., Mineralogical Society, London, 1128.Google Scholar
Proust, D., Eymery, J. P., and Beaufort, D., (1986) Supergene vermiculitization of a magnesian chlorite: Iron and magnesium removal processes: Clays & Clay Minerals 34, 572580.CrossRefGoogle Scholar
Reynolds, R. C., (1980) Interstratified clay minerals: in Crystal Structures of Clay Minerals and Their X-ray Identification, Brindley, G. W., and Brown, G., eds., Mineralogical Society, London, 249303.CrossRefGoogle Scholar
Rhoades, J. D., and Coleman, N. T., (1967) Interstratification in vermiculite and biotite produced by potassium sorption: I. Evaluation by X-ray diffraction pattern inspection: Soil Sci. Soc. Amer. Proc. 31, 366372.CrossRefGoogle Scholar
Song, Y., Kwon, I. S., and Moon, H. S., (1990) Mineralogy of vermiculite occurring in the Cheongyang area: J. Miner. Soc. Korea 3, 60 (in Korean).Google Scholar