Scientists have shed new light on how the largest mass extinction in the history of Earth wiped out 90 per cent of all life on the planet around 250 million years ago.
The Permian Extinction, dubbed 'The Great Dying', killed off plants up to 400,000 years before animals and marine species were hit.
It was caused when the planet's continental crust mashed into the supercontinent called Pangaea, volcanoes in modern-day Siberia began erupting.
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The Great Dying was a hugely catastrophic event was triggered by a massive volcanic eruption that ran for almost one million years in what is today Siberia (stock image)
Spewing carbon and methane into the atmosphere for roughly 2 million years, the eruption helped extinguish about 96 percent of oceanic life and 70 percent of land-based vertebrates - the largest extinction event in Earth's history.
The new study suggests that a byproduct of the eruption, nickel, started wiping out some Australian plant life nearly 400,000 years before most marine species perished.
'That's big news,' said lead author Christopher Fielding of the University of Nebraska-Lincoln.
'People have hinted at that, but nobody's previously pinned it down.
'Now we have a timeline.'
Around 248 million years ago, the Permian period ended and the Triassic period started on Earth.
Marking the boundary between these two geologic eras is the Permian mass extinction, nicknamed 'The Great Dying'.
This catastrophic event saw almost all life on Earth wiped out.
Scientists believe around 95 per cent of all marine life perished during the mass extinction, and less than a third of life on land survived the event.
In total, it is believed that 90 per cent of all life was wiped out.
All life on Earth today is descended from the roughly ten per cent of animals, plants and microbes that survived the Permian mass extinction.
Previously, it was believed a huge eruption blanketed the Earth in thick smog, blocking the sun's rays from reaching the planet's surface.
However, new findings suggest a massive volcanic eruption that ran for almost one million years released a huge reservoir of deadly chemicals into the atmosphere that stripped Earth of its ozone layer.
This eradicated the only protection Earth's inhabitants had against the sun's deadly UV rays.
This high-energy form of radiation can cause significant damage to living organisms, causing the death toll to skyrocket.
The researchers studied fossilized pollen, the chemical composition and age of rock, and the layering of sediment on the southeastern cliffsides of Australia.
They discovered surprisingly high concentrations of nickel in the Sydney Basin's mud-rock - where there are no local sources of the element.
This led them to conclude the finding points to the eruption of lava through nickel deposits in Siberia.
That volcanism could have converted the nickel into an aerosol that drifted thousands of miles southward before descending on, and poisoning, much of the plant life there, according to Tracy Frank, professor and chair of Earth and atmospheric sciences.
Similar spikes in nickel have been recorded in other parts of the world, she said.
'So it was a combination of circumstances,' Fielding said.
The Permian Extinction, dubbed 'The Great Dying', killed off plants up to 400,000 years before animals and marine species were hit. It was caused when the planet's continental crust mashed into the supercontinent called Pangaea, volcanoes in modern-day Siberia began erupting.
'And that's a recurring theme through all five of the major mass extinctions in Earth's history.'
If true, the phenomenon may have triggered a series of others: herbivores dying from the lack of plants, carnivores dying from a lack of herbivores, and toxic sediment eventually flushing into seas already