Hostname: page-component-745bb68f8f-l4dxg Total loading time: 0 Render date: 2025-02-03T02:10:59.152Z Has data issue: false hasContentIssue false
  • English
  • Français

High-Resolution Transmission Electron Microscopy of Mixed-Layer Illite/Smectite: Computer Simulations

Published online by Cambridge University Press:  02 April 2024

George D. Guthrie Jr.  and
David R. Veblen
George D. Guthrie Jr.
Affiliation:
Department of Earth and Planetary Sciences, The Johns Hopkins University, Baltimore, Maryland 21218
David R. Veblen
Affiliation:
Department of Earth and Planetary Sciences, The Johns Hopkins University, Baltimore, Maryland 21218
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

High-resolution transmission electron microscope images of dioctahedral mixed-layer clay structures (illite/smectite) having various substitutional and polytypic schemes were modeled using computer simulation methods. Both one- and two-dimensional calculations were performed using parameters characteristic of a typical range of imaging conditions. One-dimensional images formed by imaging only 00/ diffractions show three important results: (1) The 20-Å periodicity resulting from rigorously ordered R1 illite/smectite can be imaged, but unconventional focus conditions may be necessary. (2) For crystals oriented with the electron beam perfectly parallel to the layers, the brightest fringes in the image correspond to either the octahedral sheets or the interlayer sites, depending on focus conditions. Misorientation of the crystal, however, by only 1° or 2° shifts the positions of the fringes by 1 to 3 Å. Furthermore, in tilted specimens, some defocus values produce images suggesting that smectite layers have a 11–13-Å periodicity, despite the uniform 10-Å periodicity present in the model structure. Thus, direct correlations between image and structure generally should not be made. (3) Two-layer polytypes of pure illite or pure smectite can also produce images with a 20-Å periodicity.

Two-dimensional images additionally showed that the cross fringes produced by some hkl diffractions can be imaged. The simulations showed that these cross fringes ideally might permit the determination of both layer stacking and compositional periodicity, but the fringes are lost by misorientations of a few degrees. These image simulations demonstrated, therefore, that mixed layering of illite and smectite theoretically can be directly imaged by transmission electron microscopy of chemically untreated specimens, but ambiguities may exist in the detailed intepretation of the images.

Keywords

High-resolution transmission electron microscopyIlliteImage simulationMixed layerSmectite
Type
Research Article
Information
Clays and Clay Minerals , Volume 37 , Issue 1 , February 1989 , pp. 1 - 11
Copyright
Copyright © 1989, The Clay Minerals Society

References

Ahn, J. H. and Peacor, D. R., 1985 Transmission electron microscopic study of diagenetic chlorite in Gulf Coast argillaceous sediments Clays & Clay Minerals 33 228 – 236.CrossRefGoogle Scholar
Ahn, J. H. and Peacor, D. R., 1986 Transmission and analytical electron microscopy of the smectite-to-illite transition Clays & Clay Minerals 34 165 – 179.Google Scholar
Ahn, J. H. and Peacor, D. R., 1986 Transmission electron microscope data for rectorite: Implications for the origin and structure of “fundamental particles” Clays & Clay Minerals 34 180 – 186.Google Scholar
Amouric, M., Mercuriot, G. and Baronnet, A., 1981 On computed and observed HRTEM images of perfect mica polytypes Bull. Mineral. 104 298 – 313.Google Scholar
Bell, T. E., 1986 Microstructure in mixed-layer illite/smec-tite and its relationship to the reaction of smectite to illite Clays & Clay Minerals 34 146 – 154.CrossRefGoogle Scholar
Brindley, G. W. and Longstaffe, F. J., 1981 Structures and chemical compositions of clay Clays and the Resource Geologist Toronto Mineral. Assoc. Canada 1 – 21.Google Scholar
Cowley, J. and Moodie, A. F., 1957 The scattering of electrons by atoms and crystals. I. A new theoretical approach Acta Crystallogr. 10 609 – 619.CrossRefGoogle Scholar
Hansen, P. L., Lindgreen, H. and Bailey, G. W., 1987 Structural investigations of mixed-layer smectite-illite clay minerals from North Sea oil source rocks Proc. Conf. Electron Micro. Soc. Amer. San Francisco San Francisco Press 374 – 375.Google Scholar
Iijima, S. and Buseck, P. R., 1978 Experimental study of disordered mica structures by high-resolution electron microscopy Acta Crystallogr. A34 709 – 719.CrossRefGoogle Scholar
Klimentidis, R. E. and Mackinnon, I. D. R., 1986 High-resolution imaging of ordered mixed-layer clays Clays & Clay Minerals 34 155 – 164.CrossRefGoogle Scholar
Lee, J. H., Ahn, J. H. and Peacor, D. R., 1985 Textures in layered silicates: Progressive changes through diagenesis and low-temperature metamorphism J. Sed. Petrol. 55 532 – 540.Google Scholar
Lee, J. H., Peacor, D. R., Lewis, D. D. and Wintsch, R. P., 1986 Evidence for syntectonic crystallization for the mudstone to slate transition at Lehigh Gap, Pennsylvania J. Struct. Geol. 8 767 – 780.CrossRefGoogle Scholar
McKee, T. R., Buseck, P. R. and Sturgess, J. M., 1978 HRTEM observations of stacking and ordered interstratification in rectorite Electron Microscopy 1978 Toronto Microscopical Society of Canada 272 – 273.Google Scholar
O’Keefe, M. A., 1984 Electron image simulation: A complementary processing technique Electron Optical Systems Chicago SEM Inc., AMF O’Hare 209 – 220.Google Scholar
O’Keefe, M. A., Buseck, P. R. and Iijima, S., 1978 Computed crystal structure images for high resolution electron microscopy Nature 274 322 – 324.CrossRefGoogle Scholar
Perry, E. and Hower, J., 1970 Burial diagenesis in Gulf Coast pelitic sediments Clays & Clay Minerals 18 165 – 177.CrossRefGoogle Scholar
Richardson, S. M. and Richardson, J. W. Jr., 1982 Crystal structure of a pink muscovite from Archer’s Post, Kenya: Implications for reverse pleochroism in dioctahedral micas Amer. Mineral. 67 69 – 75.Google Scholar
Self, P. G., O’Keefe, M. A., Buseck, P. R., Cowley, J. M. and Eyring, L., 1988 Calculation of diffraction patterns and images for fast electrons High Resolution Transmission Electron Microscopy .Google Scholar
Spence, J. C. H., 1981 Experimental Nigh-Resolution Electron Microscopy England Clarendon Press, Oxford.Google ScholarPubMed
Spinnler, G. E., Self, P. G., Iijima, S. and Buseck, P. R., 1984 Stacking disorder in clinochlore chlorite Amer. Mineral. 69 252 – 263.Google Scholar
Srodon, J., Eberl, D. D. and Bailey, S. W., 1984 Illite Micas, Reviews in Mineralogy Washington, D.C. Mineral. Soc. Amer. 495 – 544.Google Scholar
Veblen, D. R., 1983 Microstructures and mixed layering in intergrown wonesite, chlorite, talc, biotite, and kaolinite Amer. Mineral. 68 566 – 580.Google Scholar
Veblen, D. R. and White, J. C., 1985 High-resolution transmission electron microscopy Applications of Electron Microscopy in the Earth Sciences, Short Course Handbook, 1985 Toronto, Canada Mineral. Assoc. Canada 63 – 90.Google Scholar
Veblen, D. R., 1985 Direct TEM imaging of complex structures and defects in silicates Ann. Rev. Earth Planet. Sci. 13 119 – 146.CrossRefGoogle Scholar
Veblen, D. R., Mackinnon, I. D. R. and Mumpton, F. A., 1989 Transmission electron microscopy: Scattering processes, conventional TEM, and high-resolution imaging Electron Microscopy and Microprobe Techniques in Clay Analysis, CMS Workshop Lectures Indiana The Clay Mineral Society, Bloomington.Google Scholar