de Broekert: Stratigraphy and origin of regolith, SW Yilgarn Craton 
Westonia and Gibson Formations 
(composite section) 
Figure 8. Composite stratigraphic section of the Westonia and Gibson formations with representative optical photomicrographs. A: 
Westonia Formation clayey sandstone. B: Westonia Formation nodular sandstone. C: Gibson Formation grey bimodal sand. Note 
incipient pisolith nuclei (P) in Westonia Formation nodular sandstone, and combination of well rounded to rounded (R) and very 
angular to subangular (A) quartz grains in Westonia Formation nodular sandstone and Gibson Formation grey sand. A = sample EY2/ 
1C, B = sample EY2/2, C = sample EY65/1; all plane-polarized light. 
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