Why the Supercontinent Broke Up: Continental Plates Creep, Lurch, Rupture, Speed Up Unexpectedly

The findings are published today in the journal Nature.

The research comes just over a month after a paper co-authored by researchers from the EarthByte Group – which explained why there are just a few large tectonic plates and many tiny plates – was highlighted on the cover of Nature.

“Plates tend to shift around quite slowly because they’re sitting on an otherwise very viscous mantle,” said co-author at the University of Sydney’s School of Geosciences, Professor Dietmar Müller, about the latest paper.

“However, throughout Earth’s history, there have been plenty of instances where plates have suddenly sped up during supercontinent breakup. This has puzzled us for decades, as this behavior can’t easily be reconciled with our understanding of what drives plate motion.”

A simple analogy can help explain why plates are suddenly able to reach these high speeds, Professor Müller said: “Imagine you’re pulling apart a thick piece of dough. At first, separating it requires a lot of effort because the dough resists your pulling and stretches slowly between your hands.

“If you’re persistent, you’ll eventually reach a point where the dough becomes thin enough to separate quite easily and quickly. The same principle applies to rifting continents once the connection between them has been thinned sufficiently.”

Lead author Dr Sascha Brune, from the University of Potsdam, said the split did not tend to end amicably: “This breakup process leads to margin segmentation, where rapid subsidence, high heat flow, and enhanced volcanism characterize the outer margin.”

The result: a full-margin rupture that sends the outer rims of the continents plunging into the sea.

“The Earth’s submerged continental shelves play an indelible role in biogeochemical cycles such as carbon burial and nutrient cycling,” added Dr Brune.

“They are also favorable environments for cultivating and preserving the energy resources upon which our modern society still relies, for instance natural gas.”

This work comprises a core finding of the Australian Research Council and industry-funded Basin Genenis Hub, which Professor Müller heads at the University of Sydney. The five-year project aims to improve our understanding of the evolution of sedimentary basins and continental margins by connecting big data analysis and high-performance computing in an open-innovation framework.