DESERT-AEOLIAN ORIGIN OF LATE CENOZOIC REGOLITH IN ARID AND SEMIARID SOUTHWESTERN AUSTRALIA

Using a sedimentary geology approach, the late Cenozoic regolith of So uthwestern Australia is interpreted as basement saprock and saprolite unconformably overlain by sequences of continental sedimentary deposit s. The sedimentary deposits which overlie saprock and saprolite are al lochthonous, variously altered, and mainly, partly to wholly, desert-a eolian sediments. They include: aeolian and fluvial sandy clayrock fac ies (e.g. deposits which resemble the pallid and mottled zones of weat hered Precambrian bedrock of the traditional ''laterite profile''); al tered aeolian sand and sandy dust facies (e.g.: ''hardpan'', lower par ts of ''duplex soils'', red sandy silt-claystone and calcrete valley f ills); altered sandy duststones (e.g. ''bauxite'', ''laterite'' and '' ferricrete'' of the traditional ''laterite profile''); and bioturbated aeolian sand-sheets (e.g. ''sandplain soils'', ''lateritic sandplains '' of the traditional ''laterite profile'', and upper parts of ''duple x soils''). The allochthonous and desert-aeolian views proposed here d iffer fundamentally from the traditional residual, colluvial, and eros ional views. Consequently there is a need for both traditional and alt ernative views to be critically appraised from the perspective of sedi mentary geology.