Paleosurface contrasts between the eastern and western margins of the Great Australian Basin

Abstract

Epigene, etch, and exhumed surfaces of subCretaceous ages occur on the cratons bordering the Great Australian Basin on its western side. By contrast, and with the exception of the Einasleigh Uplands of north Queensland, the eastern margins, the western slopes of the Eastern Highlands, lack conclusive evidence of the age or ages of the planate palaeosurfaces that are preserved in the landscape. Yet the stratigraphy of the Basin sediments suggests that they ought to have overlapped on to the Palaeozoic rocks exposed in the Highlands, as they do on to the western cratons. The age of palaeosurface remnants on the western or inland slopes of much of the Eastern Highlands remains uncertain. The absence of diagnostic evidence is attributed basically to the magnitude and frequency of Phanerozoic tectonic events that have affected the eastern margin of the Basin. Recurrent uplift caused stream erosion that has eliminated critical evidence of landscape evolution.