It was one of the biggest explosions in the history of the world.
In just moments, one of a series of blasts that collectively threw at least 150,000 kilometres cubed of New England soil into the air had sent hot ash as far as the stratosphere. When it came down, perhaps months later, the deposits covered most of Eastern Australia, up to metres deep.
New research points to these explosions, 252 million years ago, as among the main causes of the climate change which caused the largest mass extinction ever seen on Earth.
University of New England professor Timothy Chapman said the blasts were the most dangerous volcanic explosions, taking place with almost no warning - 'explosive eruptions' similar to the blast at White Island in 2019, except 1000 times bigger. They dwarfed the Mt St Helens eruption in 1980, by 150,000 times.
"In the immediate area around New England we'd have had these big, prominent hot ash clouds. They would have been horrible places to be ... that would have burnt everything and incinerated everything in its path," he said.
"Then we would have had these huge ash clouds that would have gone way up into the atmosphere, and we can see that spread all the way from North Queensland, central Queensland down past south of Sydney. That would have cause initially a cooling effect... [but the] long term influence is we had a lot of greenhouse gas emissions that would have driven heating of the earth."
Dr Chapman said the New England's active volcanoes - there were about 20 that blew up over a four million year period - helped kick off a period known as the 'Great Dying', wiping out about 95 per cent of the species on earth.
The cause of the Great Dying - global warming - had long been known to science. But the climate change itself was somewhat unexplained until a UNE team looked closer at the local volcanic history of the region.
In research published in Nature this month, they found the evidence that a previously unknown group of more than a dozen gigantic volcanic sites - stretching from about Inverell to Tenterfield - were the likely culprit.
It was the long term effects that were most devastating.
The climate change generated super-intense fires that burned up and down the region - even though it was akin to modern Sweden, cold and swampy - for 500,000 years or so. They wiped out the ancient forests of eastern Australia, exterminating all the animals that relied on the woods as well.
It took millions of years for the world's biodiversity to recover.
Dr Chapman said the next steps of research will take the UNE team to looking at the volcanic bombs that didn't go off, granite bodies that remain intact "frozen magma chambers" in the New England, today.
Tenterfield's Bald Rock is just one of those unexploded munitions.
Other implications of the research are less positive.
In a world staring down the risk of climate change, Dr Chapman said the research could help illustrate the severe escalating fire risks of a warmer world - "potentially".
By spewing our own form of ash into the sky, in the form of carbon emissions, humans could create a similar endless series of bushfires followed by near-universal mass-extinction, he said.
"The warming back then was probably slower than what's going on at the moment," he said.
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