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The Transformation of Illite to Muscovite in Pelitic Rocks: Constraints from X-Ray Diffraction

Published online by Cambridge University Press:  28 February 2024

M. Gharrabi ,
B. Velde  and
J. -P. Sagon
M. Gharrabi
Affiliation:
Laboratoire de Géologie, Ecole Normale Supérieure, CNRS 1316, 24 rue Lhomond, 75231 Paris, France
B. Velde
Affiliation:
Laboratoire de Géologie, Ecole Normale Supérieure, CNRS 1316, 24 rue Lhomond, 75231 Paris, France
J. -P. Sagon
Affiliation:
Laboratoire de Pétrologie, Université de Paris VI, 4 pl. Jussieu, 75000, Paris, France
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Abstract

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The boundary between diagenesis and metamorphism most likely involves the change of illite into mica. Observations of this change can be made using decomposed X-ray diffraction (XRD) spectra of illitic clay mineral assemblages in pelitic sedimentary rocks.

XRD analysis of the (003) diffraction peak of diagenetic illites indicates that there are 2 components, one of small coherent diffraction domains and another of larger domain size. Peak width, shape and position define these fractions. The smaller domain size material in diagenetic rocks is highly illitic (>95%) but contains some smectite layers and can be best described by Gaussian shapes. The grains with larger diffracting domains show no expanding layers.

Metamorphic illites (probably muscovites) show no smectite interlayers in any fraction. In the transition from sedimentary and diagenetic to metamorphic illites, new grains of smectite-free illite are formed at the expense of the older minerals. This suggests that the new metamorphic minerals are recrystallized phases. Metamorphism of illites then produces new mica phases.

Keywords

DecompositionDiagenesisIlliteMetamorphism
Type
Research Article
Information
Clays and Clay Minerals , Volume 46 , Issue 1 , February 1998 , pp. 79 - 88
Copyright
Copyright © 1998, The Clay Minerals Society

References

Dalla Torre, M. Livi, K.J.T. Veblen, R.V. and Frey, M., 1996 White mica evolution from phengite to muscovite in shales and shale matrix melange, Diablo Range, California Contrib Mineral Petrol 123 390–405 10.1007/s004100050164.CrossRefGoogle Scholar
Dunoyer de Segonzac, G., 1970 The transformation of clay minerals during diagenesis and low-grade metamorphism: A review Sedimentology 15 281–346 10.1111/j.1365-3091.1970.tb02190.x.CrossRefGoogle Scholar
Eberl, D.D. and Środoń, J., 1988 Ostwald ripening and interparticle-diffraction effects for illite crystals Am Mineral 73 1335–1345.Google Scholar
Frey, M., 1987 The reaction isograd kaolinite quartz = pyrophyllite H2O, Helvetic Alps Switzerland. Schweiz Min Petr Mitt 67 1–11.Google Scholar
Frey, M. and Frey, M., 1987 Very low grade metamorphism of clastic sedimentary rocks Low-temperature metamorphism Glasgow Blackie 9–58.Google Scholar
Gharrabi, M. and Velde, B., 1995 Clay mineralogy evolution in the Illinois Basin and its causes Clay Miner 30 353–364 10.1180/claymin.1995.030.4.08.CrossRefGoogle Scholar
Kisch, H.J. and Frey, M., 1987 Correlation between indicators of very low-grade metamorphism Low temperature metamorphism London Blackie.Google Scholar
Kisch, H., 1990 Calibration of the anchizone: A critical comparison of illite “crystallinity” scales used for definition J Meta Geol 8 31–46 10.1111/j.1525-1314.1990.tb00455.x.CrossRefGoogle Scholar
Kübler, B., 1968 Evaluation quantitative du métamorphisme par la cristallinité de l’illite Bull Centre Rech Pau-SNAP 2 2 385–397.Google Scholar
Lanson, B., 1990 Mise en évidence des mécanismes réaction-nels des interstratifiés illite/smectite au cours de la diage-nese [thesis] Paris Université de Paris VI.Google Scholar
Lanson, B. and Besson, G., 1992 Characterisation of the end of smectite-to-illite transformation: Decomposition of X-ray patterns Clays Clay Miner 40 40–52 10.1346/CCMN.1992.0400106.CrossRefGoogle Scholar
Lanson, B. and Champion, D., 1991 The I-S-to-illite reaction in late stage diagenesis Am J Sci 291 473–506 10.2475/ajs.291.5.473.CrossRefGoogle Scholar
Lanson, B. and Velde, B., 1992 Decomposition of X-ray diffraction patterns: A convenient way to describe complex diagenetic evolution Clays Clay Miner 40 629–643 10.1346/CCMN.1992.0400602.CrossRefGoogle Scholar
Merriman, R.J. Roberts, B. and Peacor, D.R., 1990 A transmission electron microscope study of white mica crystallite size distribution in a mudstone to slate transitional sequence, North Wales, UK Contrib Mineral Petrol 106 27–40 10.1007/BF00306406.CrossRefGoogle Scholar
Meunier, A. and Velde, B., 1989 Solid solutions in I-S mixed layers and illite Am Mineral 74 1106–1112.Google Scholar
Moore, D.M. and Reynolds, R.C., 1989 X-ray diffraction identification and analysis of clay minerals Oxford Oxford Univ Pr..Google Scholar
Paradis, S. Velde, B. and Nicot, E., 1983 Chloritôid-pyrophyllite-rectorite facies rocks from Brittany, France Contrib Mineral Petrol 83 342–347 10.1007/BF00371202.CrossRefGoogle Scholar
Primmer, T.J., 1985 A transition from diagenesis to greenshist facies within a major Varsican fold/thrust complex in southwest England Mineral Mag 49 365–374 10.1180/minmag.1985.049.352.07.CrossRefGoogle Scholar
Reynolds, R.C., 1980 Interstratified clay minerals. In: Brindley GW, Brown G, editors. Crystal structures of clay minerals and their X-ray identification. London Mineral Soc. Memoir 4 249–359.Google Scholar
Robinson, D. Warr, L.N. and Bevins, R.E., 1990 The illite “crystal-linity” technique: A critical appraisal of its precision J Meta Geol 8 333–344 10.1111/j.1525-1314.1990.tb00476.x.CrossRefGoogle Scholar
Robinson, D., 1987 Transition from diagenesis to metamor-phism in extensional and collision settings Geology 15 866–869 10.1130/0091-7613(1987)15<866:TFDTMI>2.0.CO;2.2.0.CO;2>CrossRefGoogle Scholar
Sagon, J.-P., 1976 Contribution à l’étude géologique de la partie orientale du bassin de Câteaulin (Massif Armorican): Stratigraphie, volcanisme, métamorphisme tectonique [Thèse de Doctorat d’Etat] Paris Universite de Paris VI.Google Scholar
Stern, W.B. Mullis, J. Rahn, M. and Frey, M., 1991 Deconvolution of the first “illite” basal reflection Schweiz Min Petog Mitt 71 453–462.Google Scholar
Velde, B., 1968 The effect of chemical reduction on the stability of pyrophyllite and kaolinite in pelitic rocks J Sed Petrol 39 13–16.Google Scholar
Velde, B. and Brusewitz, A.-M., 1986 Compositional variation in component layers in natural illite/smectite Clays Clay Miner 34 651–657 10.1346/CCMN.1986.0340605.CrossRefGoogle Scholar
Velde, B. and Vasseur, G., 1992 Estimation of the diagenetic smectite to illite transformation in time-temperature space Am Mineral 77 967–976.Google Scholar
Wang, H. Sterni, W.B. and Frey, M., 1995 Deconvolution of the X-ray “illite” 10A complex: A case study of Helvetic sediments from eastern Switzerland Schweiz Min Pet Mitt 75 187–199.Google Scholar
Warr, L.N. Primmer, T.J. and Robinson, D., 1991 Varsican very low-grade metamorphism in southwest England: A diastather-mal and thrust-related origin J Meta Geol 9 751–764 10.1111/j.1525-1314.1991.tb00563.x.CrossRefGoogle Scholar
Warr, L.N. and Rice, A.H.N., 1994 Interlaboratory standardization and calibration of clay mineral crystallinity and crystallite size data J Meta Geol 12 141–152 10.1111/j.1525-1314.1994.tb00010.x.CrossRefGoogle Scholar
Weaver, C.E., 1989 Clays, muds and shales. Developments in sedimentology Amsterdam Elsevier.Google Scholar
Winkler, H.G.F., 1976 Petrogenesis of metamorphic rocks Berlin Springer Verlag 10.1007/978-3-662-22283-6.Google Scholar