Post-orogenic landscapes occupy by far and away the bulk of the Earth’s surface but their evolution remains under-researched and poorly understood, providing the central motivation for this proposal. The principal outcome will be the testing of competing models for post-orogenic landscape evolution. The proposal is strongly linked to studies that analyse how climatic and tectonic factors influence landscape evolution, and relies on leading-edge techniques such as cosmogenic nuclide analysis and DEM analyses; the work will have important implications for the parameterisation of numerical modelling of landscape evolution. The project will combine digital terrain analysis, long profile analysis and cosmogenic nuclide analysis in the 20,000 km2 Lachlan River catchment, a bedrock river catchment draining the inland (western) side of Australia's southeast highlands on the 90 Myr-old Tasman continental margin. The Lachlan drainage basin is a classic post-orogenic landscape that has a very well-constrained Cenozoic evolution. The aim of the proposal is to assess the key controls on the rate and style of landscape evolution in this typical post-orogenic setting (1) by quantifying rates of landscape evolution, and (2) by assessing the ways in which landscape evolution is slowed by resistant lithologies. Thus, the research will provide an assessment of one of the major neglected controls of post-orogenic landscape evolution, namely, lithology. The role of lithology in landscapes evolution lies at the heart of some of the enduring questions in geomorphology, such as: Do hard rocks slow landscape evolution, and if so, how do they do this? Providing answers to these questions using the most up-date-date techniques of cosmogenic nuclide analysis and DEM analyses will help to bring the much-neglected post-orogenic terrains back into 21st century main-stream geomorphological research.