Arditto (1983) observed embayed quartz grains being invaded by kaolinite in thin-sections of the Pilliga Sandstone.
The absence of MI clays in the thin-sections of Arditto's (1980) Pilliga sandstone samples suggests that their presence in the sandstone at the study site may be due to near-surface weathering, where material within the clay lenses and cracks is being re-worked and deposited against apparent neogenetic smectite.
Thanks to Dr Pat Conaghan for his invaluable assistance with the petrological interpretation and for taking photomicrographs, Forests NSW for permission to work in the Pilliga East State Forest, Mr Tom Bradley for the manufacture of the thin-sections, and the 3 anonymous reviewers for their helpful comments on an earlier version of the manuscript.
Williams H, Turner FJ, Gilbert CM (1953) 'Petrography: an introduction to the study of rocks in thin-sections.' (W.