The Great Escarpment of eastern Australia: Tectonic and geomorphic significance

Abstract

The Great Escarpment is a single escarpment that runs east of the Great Divide almost the length of eastern Australia and attains a height of several hundred metres. It separates two regions of vastly different geomorphology: the tablelands with many palaeoforms, low relief and slow process rates; and the coastal zone with few palaeoforms, moderate relief and rapid process rates. The Great Escarpment originated by scarp retreat from a new continental edge created by continental rifting at the eastern edge of Australia about 80 Ma ago. Rifting on the model of the Western Rift of East Africa is indicated, with an upwarp and watershed (the Great Divide) located tens or hundreds of kilometres west of the chasmic fault that marks the continental margin. Despite certain anomalies, a suggested relative chronology (oldest first) is: erosion of plain, initiation of major river pattern, widespread basalt flows, uplift and formation of Great Divide, formation and retreat of the Great Escarpment. The Great Escarpment is a major geomorphic feature related to global tectonics; the landscape of eastern Australia cannot be explained in terms of simple cycles of erosion.