Hostname: page-component-78c5997874-m6dg7 Total loading time: 0 Render date: 2024-11-06T01:00:39.420Z Has data issue: false hasContentIssue false
  • English
  • Français

Interstratified XRD characteristics of physical mixtures of elementary clay particles

Published online by Cambridge University Press:  09 July 2018

P. H. Nadeau ,
J. M. Tait ,
W. J. McHardy  and
M. J. Wilson
P. H. Nadeau
Affiliation:
The Macaulay Institute for Soil Research, Craigiebuckler, Aberdeen AB9 2QJ, UK
J. M. Tait
Affiliation:
The Macaulay Institute for Soil Research, Craigiebuckler, Aberdeen AB9 2QJ, UK
W. J. McHardy
Affiliation:
The Macaulay Institute for Soil Research, Craigiebuckler, Aberdeen AB9 2QJ, UK
M. J. Wilson
Affiliation:
The Macaulay Institute for Soil Research, Craigiebuckler, Aberdeen AB9 2QJ, UK
Get access Rights & Permissions [Opens in a new window]

Abstract

Transmission electron microscopic (TEM) examination of the <0·1-µm fraction of montmorillonite and regularly interstratified illite-smectite (I-S) shows that these clays, when dried from suspension, consist primarily of particles 10 Å and 20 Å thick respectively. However, X-ray diffraction (XRD) examination of sedimented aggregates of montmorillonite indicate that the effective number of unit cells that are diffracting coherently is ∼9. This discrepancy can be reconciled by postulating an interparticle diffraction effect from the sedimented aggregates of oriented particles. The interfaces of these particles are capable of adsorbing water, ethylene glycol etc. so that on this basis smectite is composed of elementary silicate particles 10 Å thick, and regularly interstratified I-S is primarily composed of elementary ‘illite’ particles 20 Å thick, values which are in agreement with the TEM observations. This concept is confirmed experimentally by XRD examination of sedimented aggregates from mixed suspensions of both materials; the resulting patterns are identical to those of randomly interstratified illite and smectite layers, which indicates that the layer sequence examined by XRD has been entirely rearranged. It is concluded that the use of XRD peak breadth to determine mean crystal thickness cannot be reliably applied to these systems. Standard XRD data from sedimented aggregates may not be able to distinguish between true interstratification and interparticle diffraction effects of intimate physical mixtures.

Type
Research Article
Information
Clay Minerals , Volume 19 , Issue 1 , February 1984 , pp. 67 - 76
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1984

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Brindley, G.W. (1980) Order-disorder in clay mineral structures. Pp. 125–195 in: Crystal Structures of Clay Minerals and Their X-ray Identification(Brindley, G. W. & Brown, G., editors). Mineralogical Society, London.CrossRefGoogle Scholar
Deer, W.A., Howie, R.A. & Zussman, J. (1962) Rock Forming Minerals, 3, Sheet Silicates. Longmans, Green&Co., London.Google Scholar
Frey, E. & Lagaly, G.H. (1979) Selective coagulation and mixed layer formation from sodium smectite solutions. Pp. 131–140 in: Proc. Int. Clay Conf. Oxford, 1978 (Mortland, M. M. & Farmer, V. C., editors). Elsevier, Amsterdam.Google Scholar
Güven, N., Hower, W.F. & Davies, D.K. (1980) Nature of authigenic illites in sandstone reservoirs. J. Sedim. Petrol. 50, 761–766.Google Scholar
James, R.W. (1948) The optical principles of the diffraction of X-rays. Pp. 513–589 in: The Crystalline State II. (Bragg, L., editor). G. Bell&Sons Ltd, London.Google Scholar
Méring, J. & Oberlin, A. (1971) The smectites. Pp. 193–229 in: The Electron-Optical Investigations of Clays (Gard, J. A., editor). Mineralogical Society, London.CrossRefGoogle Scholar
Mills, J.G. & Zwarich, M.A. (1972) Recognition of interstratified clays. Clays Clay Miner. 20, 169–174.CrossRefGoogle Scholar
McHardy, W.J., Wilson, M.J. & Tait, J.M. (1982) Electron microscope and X-ray diffraction studies of filamentous illitic clay from sandstones of the Magnus Field. Clay Miner. 17, 23–39.CrossRefGoogle Scholar
Nadeau, P.H. & Reynolds, R.C. (1981) Burial and contact metamorphism in the Mancos Shale. Clays Clay Miner. 29, 249–259.CrossRefGoogle Scholar
Reynolds, R.C. & Hower, J. (1970) The nature of interlayering in mixed-layer illite-montmorillonites. Clays Clay Miner. 18, 25–36.CrossRefGoogle Scholar
Reynolds, R.C. (1980) Interstratified clay minerals. Pp. 249–303 in: Crystal Structures of Clay Minerals and Their X-ray Identification (Brindley, G. W. & Brown, G., editors). Mineralogical Society, London.CrossRefGoogle Scholar
Roberson, H.E., Weir, A.H. & Woods, R.D. (1968) Morphology of particles in size-fractionated Na-montmorillonites. Clays Clay Miner. 16, 239–247.CrossRefGoogle Scholar
Rossel, N.C. (1982) Clay mineral diagenesis in Rotliegend aeolian sandstones of the Southern North Sea. Clay Miner. 17, 69–77.CrossRefGoogle Scholar
Tettenhorst, R. & Roberson, H.E. (1973) X-ray diffraction aspects of montmorillonites. Am. Miner. 58, 73–80.Google Scholar
Tettenhorst, R. & Grim, R.E. (1975) Interstratified clays. I. Theoretical. Am. Miner. 60, 49–59.Google Scholar
Weir, A.H., Nixon, H.L. & Woods, R.D. (1962) Measurement of thickness of dispersed clay flakes with the electron microscope. Clays Clay Miner. 9, 419–423.CrossRefGoogle Scholar