Journal of the Royal Society of Western Australia, 86(2), June 2003 
ages, whether they relate to deposition, weathering or 
some other form of near-surface alteration, are typically 
poorly constrained. 
Nomenclature 
Following Eggleton (2001), the term "regolith" is used 
here to refer to the entire succession of earth materials 
overlying fresh bedrock, which in the context of the 
south-western Yilgarn Craton generally equates to 
Precambrian granite, gneiss or dolerite (see below). The 
regolith therefore includes materials of widely different 
colour, induration, structure, fabric, texture, composition, 
age and origin. 
Some regolith "lithofacies", i.e. materials of similar 
lithological composition, stratigraphic position and 
presumably also genesis, may be produced by the 
chemical weathering of Precambrian basement. Other 
lithofacies may be distinct primary sediment types (that 
need not be weathered), whereas others still may be 
produced by alteration processes that overprint 
weathered bedrock and sediment in a like manner and 
therefore pass from one regolith type to the other with 
only a subtle change in lithological properties. A good 
example of this is ferruginous or aluminous "duricrust", 
which is an indurated, generally nodular to pisolitic 
lithofacies rich in secondary iron or aluminium minerals 
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