Making a Difference 2019-2020

ARC-supported researchers at Curtin University have analysed thousands of rock samples to uncover the movements of mountains of rock deep within the earth, adding to our understanding of the driver for the formation and break-up of supercontinents like Pangaea, and plate tectonics in general. ARC Australian Laureate Fellow, John Curtin Distinguished Professor Zheng-Xiang Li, and members of his team from Curtin University’s School of Earth and Planetary Sciences utilised data from over 40,000 basalt rock samples taken from Earth’s continents and the ocean floors. Professor Li says that nearly 3,000 kilometres below the Earth’s surface, just above the boundary between the Earth’s liquid outer core and solid mantle layer, is where these hot, dense piles of rocks are located. THE MAKING OF A SUPERPLUME: HUGE UNDERGROUND MOUNTAINS OF HOT ROCK

These mountains are hundreds of kilometres high and thousands of kilometres in diameter, and are known as Large Low Shear Velocity Provinces, or ‘superplumes’. The researchers found that these superplumes form and disintegrate in a cyclical manner over hundreds of millions of years. More surprising is that their activity is almost exactly synchronised with a 500 to 700 million-years-long cycle of supercontinents forming and breaking up through the last two billion years of the Earth’s history. Professor Li says that the supercontinent cycle leads to the superplume cycle, but at the same time, the superplumes cause the break up of the supercontinents, leading to a ‘chicken-and-egg’ relationship. However, scientists think that the plates appear to have a slight upper hand in the process.



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