Desert landscape processes on a timescale of millions of years, probed by cosmogenic nuclides

Abstract

Since their inception, cosmogenic nuclide methods have enhanced our understanding of Earth's surface processes by providing a basis for directly determining surface exposure times and erosion rates of landscape elements. The ability to measure exposure ages up to several million years and erosion rates as low as a decimetre per million years means that the method is particularly useful for environments where landscapes change very slowly, such as deserts in tectonically stable regions. In this paper, we review cosmogenic nuclide studies of various aspects of desert landscapes, including regional to continental-scale landscape evolution in arid-semiarid Australia and the hyper-arid Namib, Atacama and Negev Deserts, together with mechanisms and timescales of formation of desert pavements and dune fields that have been difficult to be evaluated by other methods. The timescales revealed by these studies range beyond the Quaternary into the Miocene, and provide links between desert landscapes and late Cenozoic climate changes.