An Electron Optical Investigation of Aluminosilicate Cements in Silcretes

Balbir Singh1, R. J. Gilkes1 and C. R. M. Butt2
1 Soil Science and Plant Nutrition, School of Agriculture The University of Western Australia, Nedlands, W.A. 6009, Australia
2 CSIRO, Division of Exploration Geoscience, Private Bag P.O. Wembley, W.A. 6014, Australia

Abstract: Silcretes developed within the in situ regolith in the Barr Smith Range, Western Australia, were investigated using optical and electron-beam techniques. One of the cementing agents in these silcretes showed gel-like optical properties and had a variable aluminosilicate chemical composition at the scale of electron microprobe analysis so that it might he considered as allophane-like material High resolution transmission electron microscopy demonstrated that the material consists of a fine-grained and poorly ordered kaolinite embedded in a matrix of amorphous silica.

Key Words: Amorphous silica • Ion beam thinning • Kaolinite • Silcrete • Transmission electron microscopy

Clays and Clay Minerals; December 1992 v. 40; no. 6; p. 707-721; DOI: 10.1346/CCMN.1992.0400610
© 1992, The Clay Minerals Society
Clay Minerals Society (www.clays.org)