Engineers Australia

Precambrian rocks of the Darling Range

Bruce Bulley and Stuart Masterson

Abstract

Precambrian rocks, consisting largely of granitic and gneissic rocks that have been intruded by dolerites, occur in the Darling Range in Perth’s eastern suburbs. The Darling Fault separates the deep sediments of the Perth Basin from the Precambrian Yilgarn Craton to the east. The geology and engineering properties of the major rock types are discussed and related to development in the area. Important geotechnical factors that affect development include the deep and variable weathering profile, expansive clay soils developed from the weathering of dolerite, faults and contact zones, erodibility, potentially collapsible soils and slope instability.