Quantitative resolution of the debate over antiquity of the central Australian landscape: implications for the tectonic and geomorphic stability of cratonic interiors

Abstract

We report the first measure of long- (∼100 Myr) and short- (∼1 Myr) term denudation rates from key geologically stable landforms in the Davenport Range, central Australia. These landforms have previously been assigned a Cambrian age, which arguably places them amongst the oldest persistent landforms on the continent, if not on Earth. Our results from combined apatite fission track thermochronology and in situ cosmogenic radionuclide analyses using ^(10)Be and ^(26)Al show that while average exhumation rates are low, the denudation history for this cratonic region is incompatible with extreme, sub-aerial longevity and long-term tectonic and geomorphic stability. Our revised model for the landscape evolution of this region is consistent with one of maximum burial prior to and during the Mesozoic, followed by a phase of kilometre-scale exhumation that was largely complete by the beginning of the Cainozoic. We suggest that a similar process of burial and exhumation has probably been responsible for the sub-aerial preservation of seemingly ancient landforms elsewhere in Australia.