Abstract

Australia is distinctive because it experienced first-order, broad-scale vertical motions during the Cenozoic. Here, we use plate-tectonic reconstructions and a model of mantle convection to quantitatively link the large-scale flooding history of the continent to mantle convection since 50 Ma. Subduction-driven geodynamic models show that Australia undergoes a 200 m northeast downward tilt as it approaches and overrides subducted slabs between Melanesia and the proto–Tonga-Kermadec subduction systems. However, the model only produces the observed continentwide subsidence, with 300 m of northeast downward tilt since the Eocene, if we assume that Australia has moved northward away from a relatively hot mantle anomaly. The models suggest that Australia's paleoshoreline evolution can only be reproduced if the continent moved northward, away from a large buoyant anomaly. This results in continentwide subsidence of ∼200 m. The additional progressive, continentwide tilting down to the northeast can be attributed to the horizontal motion of the continent toward subducted slabs sinking below Melanesia.

You do not currently have access to this article.