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X-ray diffraction of oriented clays in small quantities (0·1 mg)

Published online by Cambridge University Press:  09 July 2018

A. Meunier
Affiliation:
Laboratoire de Pédologie, ERA 220 du CNRS, UER Sciences de l'Université de Poitiers, 40, avenue du Recteur Pineau, 86022 Poitiers Cedex
B. Velde
Affiliation:
Laboratoire de Géologie de l'Ecole Normale Supérieure, 46, rue d'Ulm, 75230 Paris Cedex 05, France

Extract

Precise identification of clay minerals found in granular rocks has always posed a great problem to the clay petrographer. Even if it is possible to locate the position of authigenic clay mineral formation in a thin section, subsequent identification of this same material by X-ray diffractometry is usually very difficult. Attempts have been made using selected-area radiation of thin sections (Pawluck & Dumanski, 1973; Wicks & Zussman, 1975; Wilson & Clark, 1978) but the area analysed remains relatively large, i.e. of the order of several mm2. The other solution is micro-picking of material from a thin section and subsequent identification by Debye-Scherrer camera methods (Wallace, 1955; Rickwood, 1977). This method, however, does not allow preferred orientation, and thus precise identification, of many clay species. The ideal method is to combine micro-picking from thin sections from areas of several hundreds of square microns with an oriented sample preparation, which can then be treated in the traditional way (glycolation, heating, etc.) for characterization by X-ray diffractometry.

Type
Notes
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1982

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References

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