Sandstone wedges observed at the palaeosurface of the Pandurra Formation in the Cattlegrid copper deposit are diagnostic of palaeopermafrost action. The breccia profile formed at Cattlegrid within the Tapley Hill Formation, both at mineralised localities and elsewhere, is a palaeoweathering profile of permafrost origin. The principal agents of brecciation, and of later-formed deformational structures found within the breccia and of mass displacements of the breccia, are believed to be glacial and periglacial processes. Periglacial conditions may have persisted during deposition of the basal Whyalla Sandstone. The interpreted glacial episode can be correlated with the Marinoan glaciation of the Adelaide Geosyncline. Indurated basal Whyalla Sandstone may subsequently have prevented erosion of the permafrost breccias, and could also have acted as a caprock which confined copper-mineralizing fluids. Mobilised redbed sulphates may have been partly responsible for the formation and deformation of the Cattlegrid breccia horizon, and may have been the source of sulphur for the biogenic production of sulphides.