A new model has revealed that a mega volcanic eruption drove dinosaurs to extinction – not the infamous Meteor Chicxulub that crashed into the Yucatán Peninsula more than 66 million years ago.
Scientists at Dartmouth University designed a simulation using real geological data to analyze more than 300,000 possible scenarios.
The system was asked to explain the fossil record over a million years before and after the extinction of the dinosaurs.
The model revealed that climate change and toxic gases from hundreds of thousands of years of emissions from the Deccan Traps were the nail in the coffin of the extinct creatures.
India’s ‘Deccan Traps’ mega-volcano is estimated to have pumped up to 10.4 trillion tonnes of carbon dioxide and 9.3 trillion tonnes of sulfur dioxide into the Earth’s atmosphere during its eruptions of nearly a million tons. ‘years.
The culprit: India’s Deccan Traps megavolcano, which is estimated to have pumped up to 10.4 trillion tons of carbon dioxide and 9.3 trillion tons of sulfur dioxide into the Earth’s atmosphere during its eruptions almost a million years old.
A simulation developed at Dartmouth used 130 processors to test more than 300,000 likely dinosaur extinction scenarios. Greenhouse gases emitted by India’s “Deccan Trap” volcanoes were sufficient to cause extinction 300,000 years before the asteroid impact.
The Dartmouth researchers decided to try leaving human emotions among scientists out of the debate, or, as they put it, to “see what you’d get if you let the code decide.”
Researchers fThey collected geological and climate data from three deep-sea core samples into their computer model. Each core contained fossils dating from 67 to 65 million years ago.
Carbon and oxygen isotopes contained in the microscopic shells of the samples’ many fossilized creatures, called foraminifera, were used to estimate ancient global temperatures in the years before and after the extinction of the dinosaurs.
“We have known for a long time that volcanoes can cause mass extinctions,” explains one of the study’s authors. “But this is the first independent estimate of volatile emissions based on evidence of their environmental effects.”
“Our model analyzed the data independently and without human bias to determine the amount of carbon dioxide and sulfur dioxide needed to produce the climate and carbon cycle disruptions we see in the geological record,” said the study’s co-author and assistant professor of Earth sciences. at Dartmouth, Brenhin Keller.
The scientists fed geological data collected from deep-sea core samples into their computer model. Each core contained foraminiferal microfossils dating from 67 to 65 million years ago. Above are ten species of planktonic foraminifera, each about the size of a grain of sand.
“These quantities,” Keller said, “turned out to be consistent with what we expect to see in emissions from the Deccan traps.”
Keller and his co-author, Dartmouth graduate student Alex Cox, used the “Long-term reservoir of the ocean-atmosphere-sediment carbon cycle‘ (LOSCAR) to calculate the movement of carbon atoms a million years before and after the extinction of the dinosaurs.
Their LOSCAR modeling used raw geological data from these deep-sea core samples to simulate the ancient “carbon cycle” – tracking the fluxes of the element from carbon dioxide in the atmosphere to forms of carbon-based life like the tiny foraminifera of the ocean to the foraminifera. fossils embedded in the sediments below.
To help reduce bias and assumptions, Cox and Keller ran their simulation backwards in time, using a statistical process called “Bayesian inversion” to determine which scenarios were most likely to have led to their fossil record.
“Most models go forward,” Cox noted in a press release.
“We adapted a model of the carbon cycle to work the other way, using the effect to find the cause through statistics.”
This helped eliminate any preconceived notions, Cox said, by giving the computer model “only the bare minimum of prior information as it worked toward a particular outcome.”
But running these tasks backwards required a lot of computing power.
As reported in their new study, published today in Science magazine128 computer processors running scenarios on a total of 512 cores in parallel were harnessed to simulate the atmosphere before and after the last days of the dinosaurs.
Run these simulations, synchronized in parallel, as Cox said Scientific newssignificantly accelerated the process, reducing calculations that could have taken a year to just a few days.
“All processors then compared their performance at the end of each model run, like classmates comparing their answers,” he said.
The result was a version of dangerously high levels of carbon dioxide (CO2) and sulfur dioxide (SO2) emissions during what paleontologists call the “Cretaceous-Paleogene extinction event” that could be attributed entirely to Indian megavolcanoes.
But not all of Cox and Keller’s peers are fully convinced.
For example, Sierra Petersen, a geochemist at the University of Michigan in Ann Arbor, told Science News that the ratios of oxygen isotopes found in fossil foraminiferal shells can change due to water composition. sea, and not just climate.
“It’s a bit of a stretch to say that this study shows that the (asteroid) impact did not cause the extinction,” she said.
“I think what they show is that the impact was probably not associated with a significant release (of CO2 and SO2 gases).”
Another researcher, paleoclimatologist Clay Tabor of the University of Connecticut, pointed out that Chicxulub’s impact would have been amplified. apocalyptic amounts of soot and dust this may have plunged Earth into a grim and fatal winter.
As the debate rages, the Dartmouth researchers emphasize that they are just the messenger transmitting what their computer model said.
“At the end of the day, it doesn’t matter what we think or what we previously thought,” according to Cox.
“The model shows us how we arrived at what we see in the geological record.”
