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Ancient Australia’s Super-Eruptions

Credit: Microstocker/Adobe

Credit: Microstocker/Adobe

By Milo Barham

Sediments beneath the Nullarbor Plain have revealed that super-eruptions in eastern Australia more than 100 million years ago were powerful enough to blast crystals right across the country.

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The raw power of volcanic eruptions has long captured the human imagination. While their effects have been historically catastrophic – think of what Mt Vesuvius did to Pompeii and Herculaneum – they have also produced fertile soils and geothermal power.

Yet the scale of the volcanic episodes that have been documented historically are mild compared with “super-eruptive” events evident in the geological record. Recent work in Western Australia has found evidence that ancient volcanoes along the eastern margin of Australia were so violent ~106 million years ago that they blasted volcanic material more than 2000 km away to the western side of the landmass, making them some of the most powerful eruptions known.

Previous work on the eroded plumbing of these volcanoes, in particular the Whitsunday Islands region, had hinted at their explosivity, but the eruptive power of volcanoes in this large igneous province (LIP) has been underappreciated. By analysing distinctive minerals such as zircon recovered from Western Australia, a collaboration of researchers from Curtin University and the Geological Survey of Western Australia have, for the first time, been able to demonstrate the destructive magnitude of eruptions in the eastern Australian LIP.

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The full text of this article can be purchased from Informit.