Hostname: page-component-76fb5796d-22dnz Total loading time: 0 Render date: 2024-04-27T04:24:21.221Z Has data issue: false hasContentIssue false

An interstratified illite-smectite from Denchworth series soil in weathered Oxford Clay

Published online by Cambridge University Press:  09 July 2018

A. H. Weir
Affiliation:
Rothamsted Experimental Station, Harpenden, Herts
J. H. Rayner
Affiliation:
Rothamsted Experimental Station, Harpenden, Herts

Abstract

The very fine (<0·04 µm) clay fraction of a Denchworth series subsoil in weathered Oxford Clay has been investigated in detail. It contains a layer silicate mineral, almost free from impurities, that is a randomly interstratified mixture of approximately 45% expanding and 55% non-expanding interlayers with the following unit formula: Na0.33K0.29(Al1.41Fe0.34Mg0.26)(Si3.60Al0.40)O11. Computer-simulated diffraction patterns showed that experimental patterns are best matched when an average diffracting packet consists of between 4 and 5 2:1 layer silicate units. Correction of the chemical composition for external exchangeable ions associated with such small packets gives non-expanding interlayers a charge density of 0·69K/Si4O11 and expanding interlayers one of 0·57M+/Si4O11. The relationship between these values and those of mica and regularly expanding minerals is briefly discussed.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1974

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

Brown, G., Edwards, B., Ormerod, E.C. & Weir, A.H. (1972) Clay Miner. 9, 407.CrossRefGoogle Scholar
Hashimoto, I. & Jackson, M.L. (1960) Clays Cluy Miner. 7, 102.CrossRefGoogle Scholar
Hower, J. & Mowatt, T.C. (1966) Am. Miner. 51, 825.Google Scholar
Johns, W.D. & Sen Gupta, P.K. (1967) Am. Miner. 52, 1706.Google Scholar
Klug, H.P. & Alexander, L.E. (1954) X-ray Diffraction Procedures. John Wiley & Sons Inc. New York.Google Scholar
Kodama, H. & Brydon, J.E. (1966) Clays Clay Miner. 13, 151.Google Scholar
Nomenclature Committee OF A.I.P.E.A. (1972) A.I.P.E.A. Newsletter No. 7, 13.Google Scholar
Norrish, K. & Hutton, J.T. (1969) Geochim. cosmochim. Acta, 33, 431.CrossRefGoogle Scholar
Norrish, K. & Rausell-Colom, J.A. (1963) Clays Clay Miner. 10, 123.Google Scholar
Reynolds, R.C. (1967) Am. Miner. 52, 661.Google Scholar
Reynolds, R.C. (1968) Acta Crystallogr. A24, 319.Google Scholar
Reynolds, R.C. & Hower, J. (1970) Clays Clay Miner. 18, 25.CrossRefGoogle Scholar
Rich, C.I. (1968) Clays Clay Miner. 16, 15.Google Scholar
Tettenhorst, R. & Roberson, H.E. (1973) Am. Miner. 58, 73.Google Scholar
Walker, G.F. (1957) Clay Miner. Bull. 3, 154.Google Scholar
Walker, G.F. (1958) Clay Miner. Bull. 3, 302.Google Scholar
Weiss, A., Koch, G. & Hofmann, U. (1955) Ber. dt. keram. Ges. 32, 12.Google Scholar