Australia has subsided and tilted towards the northeast over the past 50 million years. Numerical modelling shows that the sinking results from the interplay of downwelling and upwelling in Earth's mantle.
Lydia DiCaprio at the University of Sydney and colleagues used plate tectonic reconstructions and a numerical model of mantle flow to recreate the subsidence of Australia as recorded by ancient shorelines. Movement of the continent towards subduction zones in the western Pacific Ocean could explain the northeastward tilting of Australia. Subduction of cold, dense oceanic crust creates cool regions of downwelling in the mantle that cause the overlying crust to sink. However, subduction alone could not explain the observed continent-wide sinking.
To recreate all of the subsidence experienced by Australia since the Eocene epoch also required the entire continent to have moved northwards, away from hot mantle upwelling beneath Antarctica in the south, into regions with cooler underlying mantle.
Rights and permissions
About this article
Cite this article
Whitchurch, A. Australia askew. Nature Geosci 4, 734 (2011). https://doi.org/10.1038/ngeo1319
Published:
Issue Date:
DOI: https://doi.org/10.1038/ngeo1319
