Posted on 05/10/2022 11:02:42 AM PDT by Red Badger
Artist's impression of the catastrophe. (Katrina Kenny © 2022, author provided)
Some 252 million years ago the world was going through a tumultuous period of rapid global warming.
To understand what caused it, scientists have looked to one particular event in which a volcanic eruption in what is now Siberia spewed huge volumes of greenhouse gas into the atmosphere.
However, there is evidence the climate was already changing before this.
Sea surface temperatures had increased by more than 6-8 ℃ in the hundreds of thousands of years leading up to the Siberian outpouring. Temperatures increased again after it, so much so that 85-95 percent of all living species eventually went extinct.
The eruption in Siberia obviously made a mark on the planet, but experts remained puzzled about what caused the initial warming before it.
Our research reveals Australia's own ancient volcanoes played a big role. Prior to the event in Siberia, catastrophic eruptions in northern New South Wales spewed volcanic ash across the east coast.
These eruptions were so large they initiated the world's biggest ever climate catastrophe – the evidence for which is now hidden deep in Australia's thick piles of sediment.
Ancient volcanoes Our study, published today in Nature, confirms eastern Australia was shaken by repeated "super eruptions" between 256 and 252 million years ago.
Super eruptions are different to the more passive Siberian event. These catastrophic explosions spewed massive amounts of ash and gasses high into the atmosphere.
Today we see evidence of this in light-coloured layers of volcanic ash in sedimentary rock. These layers are found across huge areas of NSW and Queensland, all the way from Sydney to near Townsville.
Multiple light-colored ash layers through dark coal, representing volcanic eruptions. (Ian Metcalfe)
Our study has identified the source of this ash in the New England region of NSW, where the eroded remnants of volcanoes are preserved.
Though erosion has removed much of the evidence, the now innocuous-looking rocks are our record of terrifying eruptions. The thickness and spread of the ash produced is consistent with some of the largest volcanic eruptions known.
How big were the super eruptions?
At least 150,000 km³ of material erupted from the northern NSW volcanoes over 4 million years. This makes them similar to the supervolcanoes of Yellowstone in the United States and Taupo in New Zealand.
To put it into perspective, the 79 CE eruption of Mt Vesuvius, which obliterated the Italian city of Pompeii, produced just 3-4km³ of rock and ash. And the deadly Mt St Helens eruption in 1980 was about 1km³.
The Australian eruptions would have repeatedly covered the entire east coast in ash – meters thick in some places. And a massive outpouring of greenhouse gases would have triggered global climate change.
Environmental devastation
Ancient sedimentary rocks provide us with a timeline of the environmental damage caused by the eruptions. Ironically, the evidence is preserved in coal measures.
Today's coal deposits in eastern Australia show ancient forests used to cover much of this land. After the super eruptions, however, these forests were abruptly terminated in a series of bushfires over some 500,000 years, 252.5–253 million years ago.
Typically the plant matter accumulated in swamps and was then buried under sediments. The burial process provided heat and pressure which enabled the conversion of the plant matter into coal.
Without the forests, there was no plant matter to accumulate. The ecosystem collapsed and most animals became extinct.
The subsequent eruptions in Siberia only exaggerated the devastation started by Australia's supervolcanoes.
And this collapse of ecosystems was not limited to Australia, either. The catastrophic event affected all of the ancient continents. It had a substantial influence on the evolution of life – which eventually led to the rise of the dinosaurs.
Australia's super eruptions were a key marker of change in the ancient world. As we look to achieving a more habitable climate in the future, who knew the clues to environmental catastrophe lay buried beneath our feet?
Acknowledgement: We would like to thank our colleague Phil Blevin from the Geological Survey of New South Wales for his contribution to this work. Timothy Chapman, Postdoctoral Fellow in Geology, University of New England; Ian Metcalfe, Adjunct Professor, University of New England, and Luke Milan, , University of New England.
Regarding the later K-T extinction:
[snip] Disney’s 1940 animated film Fantasia shows the dinosaurs dying off as the result of an intense drought. The theory of mass extinction as the result of an astroid strike wasn’t proposed until 1980. [/snip]
https://www.reddit.com/r/MovieDetails/comments/gbkmx0/disneys_1940_animated_film_fantasia_shows_the/
Rapid global warming 250 million years ago... No humans involved.... There goes that theory....
Some 252 million years ago the world was going through a tumultuous period of rapid global warming.
This is obviously false and misinformation. The world is only getting hotter (warmer) because of the number of people on the planet and our vehicles, the cows burping and farting, etc. It is NOT a natural phenomena for the planet to go through cycles of extreme heat and cold (ice ages).
/sarc tag needed?
I thought volcanic eruptions caused cooling not warming?🙄
“..252 Million Years ago...was that before, or after, the invention of the Internal Combustion Engine?...”
Well...that depends on which brain-dead, moronic lib one asks. IF you ask pedoJoe, he’d tell exactly that them there, you know...those things, existed well before the invention of time.
Ha Ha!
Both wrong. It was a smoking slant six.
Before the snakes, spiders, crocodiles, sharks and jellyfish and drop bears could kill you in Australia you had watch out for volcanoes.
That land is cursed.
Everything in Australia is still trying to kill you.
Just like their supervolcanoes.
Whatever killed the dinosaurs was QUICK, MASSIVE and LONG LASTING.
In certain areas, massive piles of dinosaur fossils are found all jumbled together in one huge formation, as if they had all been washed away in a catastrophe so powerful that they could not stand or run away from it. And these animals were huge, powerful beasts.
And in other places, dinosaur footprints are embedded in stone, that was once mud. As if the dinosaur footprints were never exposed to weather or any type of erosion immediately after they were made, IOW, the place became frozen in time, for millions of years.
And other places, fossils, large and small, are found intact, as if no scavenger ever touched the rotting carcasses after their death and no weather ever dislodged the skeleton’s bones after the flesh was gone.
So whatever happened, happened in a flash, and caused the entire earth to basically stand still for a million or so years..................
DROP BEARS!
And not for the first time, nor probably the last. Later known large impacts were not as massive as the K-T event, though, apparently.
I have a hard time figuring out why Pompeii & Herculaneum were ‘lost’ for so long.
If they were the popular resorts of their era, wouldn’t there be people outside of the destruction zone that would go and try and recover their properties? Real estate is valuable in any era......................
The Romans probably were a bit gun-shy after the volcano wiped out everything. There were salvage efforts carried out by surviving homeowners (or maybe thieves) who figured out where their homes were buried, and dug down into their former residences, presumably to recover their personal wealth, or maybe in hope of finding survivors.
“..Both wrong. It was a smoking slant six....”
ROTFLMAO!!!
Especially the little nasty ones that ended up in ‘65 Plymouth Valiant StationWagons with a torqueflite, a little 450cfm Holly 4bbl carb, a slightly “hotter” cam and a set of 4.10 gears added to em....nasty, nasty little critters...debilitating mustang and climate haters, for sure. Whatever glaciers the big HEMI didn’t melt with just it’s exhaust song, these little buggers quickly gobbled up “the crumbs”. There was absolutely no climate in the entire universe that was safe with these evil buggers running around.
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