Discussion on ‘Displacement of the Great Divide in north Queensland associated with Neogene lava flows’ by P. W Whitehead and P. N. Nelson

Abstract

One of the longest and most controversial debates in Australian geomorphology has centred around the issue of drainage evolution. Since E. C. Andrews began to extol the virtues of the Davisian geographic cycle in Australia in 1903, decades of research generated conclusions that in the words of Young (1978) were ‘often as much the product of theory as of fact.’ There was a lack of objective testing of hypotheses, which led to the persistence of error. Despite major challenges to the geographic cycle and its value in understanding the evolution of landscapes in eastern Australia throughout the latter part of the 20th century some aspects of its influence continue to the present day. Whitehead & Nelson's (2014) recent interpretation of drainage evolution in the Barron River catchment is a case in point. Their uncritical examination of field evidence has led them to conclude that Pleistocene basalt flows from a volcano 30 km upstream led to the blockage of the Barron River causing it to adopt a new eastwards course towards the Coral Sea. This, according to the authors, also resulted in the westward migration of the continental drainage divide in this region. As will be demonstrated here though, there is abundant field evidence to show this could not have happened and the present course of the Barron River developed well before the Pleistocene.