Hostname: page-component-78c5997874-fbnjt Total loading time: 0 Render date: 2024-11-18T16:39:34.427Z Has data issue: false hasContentIssue false
  • English
  • Français

Investigation of a K-Bentonite by X-Ray Powder Diffraction and Analytical Transmission Electron Microscopy

Published online by Cambridge University Press:  02 April 2024

W. D. Huff ,
J. A. Whiteman  and
C. D. Curtis
W. D. Huff
Affiliation:
Department of Geology, University of Cincinnati, Cincinnati, Ohio 45221
J. A. Whiteman
Affiliation:
Department of Metallurgy, University of Sheffield, Sheffield S1 3JD, United Kingdom
C. D. Curtis
Affiliation:
Department of Geology, University of Sheffield, Sheffield S1 3JD, United Kingdom
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.

The <0.1-μm size fraction of an Ordovician K-bentonite from northern Kentucky was characterized by X-ray powder diffraction (XRD). Using A.I.P.E. A. criteria for interstratification nomenclature and Reynolds’ computer algorithm the dominant clay mineral proved to be an R2 ordered illite/smectite. The best fit of observed and calculated XRD tracings was obtained using 12 > N > 5, where N is the number of layers within a diffracting domain.

Sections of the K-bentonite were prepared by ion-beam milling and examined in an analytical transmission electron microscope (ATEM). One-dimensional lattice images observed parallel to the a-b plane showed subparallel packets, about 50–100 Å thick, each of which consisted of about 10-Â thick unit layers. Somewhat thicker unit layers (as much as 14.5 Å) were also seen. The former are presumed to be illite, whereas the latter may be partially collapsed smectite. Selected-area electron diffraction patterns suggested simultaneous diffraction from several packets, each containing at least five layers. Both h0l and 0kl spacings were usually present, indicating that the stacking of the subparallel packets was random. Quantitative analysis by AEM and electron microprobe show the clay to be low in tetrahedral Al but high in octahedral Mg, the latter presumably contributing largely to the interlayer charge responsible for K fixation. The TEM data are broadly reconcilable with the accepted XRD interpretation of a two-component, mixed-layer clay. Alternatively, the TEM images may be interpreted as a single phase having numerous packet boundaries, the latter being responsible for swelling behavior. These two interpretations will not be fully reconciled until greater analytical precision and resolution permit individual packets to be studied. This work suggests that mineral definitions based purely on XRD interpretations may have to be reconsidered as more electron microscope data become available.

Keywords

Analytical transmission electron microscopyBentoniteIlliteInterstratificationPotassiumSelected area diffractionSmectiteX-ray powder diffraction
Type
Research Article
Information
Clays and Clay Minerals , Volume 36 , Issue 1 , February 1988 , pp. 83 - 93
Copyright
Copyright © 1988, The Clay Minerals Society

References

Ahn, J. H. and Peacor, D. R., 1985 Transmission electron microscope 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
Amouric, M. and Parron, C., 1985 Structure and growth mechanism of glauconite as seen by high-resolution transmission electron microscopy Clays & Clay Minerals 33 473 – 481.CrossRefGoogle Scholar
Eberl, D., 1978 Reaction series for dioctahedral smectites Clays & Clay Minerals 16 327 – 340.CrossRefGoogle Scholar
Eslinger, E., Highsmith, P., Albers, D. and DeMayo, B., 1979 Role of iron reduction in the conversion of smectite to illite in bentonites in the Disturbed Belt, Montana Clays & Clay Minerals 27 327 – 338.CrossRefGoogle Scholar
Hower, J., Eslinger, E. V., Hower, M. E. and Perry, E. A., 1976 Mechanism of burial metamorphism of argillaceous sediment: 1. Mineralogical and chemical evidence Geol. Soc. Amer. Bull. 87 725 – 737.2.0.CO;2>CrossRefGoogle Scholar
Hower, J. and Mowatt, T. C., 1966 The mineralogy of illites and mixed-layer illite-montmorillonite A mer. Mineral. 51 825 – 854.Google Scholar
Huff, W. D. and Türkmenoğlu, A. G., 1981 Chemical characteristics and origin of Ordovician K-bentonites along the Cincinnati arch Clays & Clay Minerals 29 113 – 123.CrossRefGoogle Scholar
Iijima, S. and Buseck, P. R., 1978 Experimental study of disordered mica structures by high-resolution electron microscopy Acta Crystallogr. 34 709 – 719.CrossRefGoogle Scholar
Inoue, A. and Utada, M., 1983 Further investigations of a conversion series of dioctahedral mica/smectites in the Shinzan hydrothermal alteration area, northeast Japan Clays & Clay Minerals 31 401 – 412.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
Lahann, R. W. and Roberson, H. E., 1980 Dissolution of silica from montmorillonite, effect of solution chemistry Geochim. Cosmochim. Acta A4 1937 – 1943.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. and Peacor, D. R., 1986 Expansion of smectite by laurylamine hydrochloride: Ambiguities in transmission electron microscope observations Clays & Clay Minerals 34 69 – 73.CrossRefGoogle Scholar
Lee, J. H., Peacor, D. R., Lewis, D. D. and Wintsch, R. P., 1984 Chlorite-illite/muscovite interlayered and inter-stratified crystals: A TEM/STEM study Contrib. Mineral. Petrol. 88 372 – 385.CrossRefGoogle Scholar
Nadeau, P. H. and Bain, D. C., 1986 Composition of some smectites and diagenetic illitic clays and implications for their origin Clays & Clay Minerals 34 455 – 464.CrossRefGoogle Scholar
Nadeau, P. H., Tait, J. M., McHardy, W. J. and Wilson, M. J., 1984 Interstratified XRD characteristics of physical mixtures of elementary clay particles Clay Mineral. 19 67 – 76.CrossRefGoogle Scholar
Nadeau, P. H., Wilson, M. J., McHardy, W. J. and Tait, J. M., 1984 Interstratified clays as fundamental particles Science 225 923 – 925.CrossRefGoogle ScholarPubMed
Reynolds, R. C., Brindley, G. W. and Brown, G., 1980 Interstratified clay minerals Crystal Structures of Clay Minerals and their X-ray Identification London Mineralogical Society 249 – 303.CrossRefGoogle Scholar
Środoń, J., 1980 Precise identification of illite/smectite interstratification by X-ray powder diffraction Clays & Clay Minerals 28 401 – 411.CrossRefGoogle Scholar
Środoń, J., Morgan, D. J., Eslinger, E. V., Eberl, D. D. and Karlinger, M. R., 1986 Chemistry of illite/smectite and end-member illite Clays & Clay Minerals 34 368 – 378.CrossRefGoogle Scholar
Vali, H. and Koster, H. M., 1986 Expanding behaviour, structural disorder, regular and random irregular interstratification of 2:1 layer-silicates studied by high-resolution images of transmission electron-microscopy Clay Mineral. 21 827 – 859.CrossRefGoogle Scholar
Velde, B., 1985 Clay Minerals: A Physio-Chemical Explanation of their Occurrence New York Elsevier.Google Scholar