A new model has found that a mega volcanic eruption drove dinosaurs to extinction – not the infamous ones Chicxulub meteor The struck the Yucatán Peninsula over 66 million years ago.
Scientists at Dartmouth University developed a simulation that used real geological data to calculate more than 300,000 possible scenarios.
The system was designed to explain the fossil record from before and after the extinction of the dinosaurs.
The model showed that climate change and toxic gases from thousands of years of emissions from the Deccan Traps were the nail in the coffin for the extinct creatures.
India’s Deccan Traps megavolcano 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 nearly million-year eruptions.
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 nearly million-year eruptions.
A simulation developed at Dartmouth used 130 processors to test over 300,000 likely extinction scenarios for the dinosaurs. They found that climate-warming gases from the Deccan Traps volcanoes in India were enough to cause an extinction event 300,000 years before the asteroid hit
The Dartmouth researchers decided to leave human emotions between scientists out of the debate, or as they put it, “See what you would get if you let the code decide.”
The researchers fhave processed geological and climatic data from three deep-sea core samples in their computer model. Each core sample contained fossils from 67 to 65 million years ago.
The carbon and oxygen isotopes in the microscopic shells of many fossilized creatures, called foraminifera, have been used to estimate ancient global temperatures in the years before and after the extinction of the dinosaurs.
“We know from the past that volcanoes can cause massive extinctions,” explained one of the study authors. “However, this is the first independent estimate of fugitive emissions based on the evidence of their impact on the environment.”
“Our model worked through the data independently and without human bias to determine the amount of carbon dioxide and sulfur dioxide required to produce the climate and carbon cycle perturbations we see in the geological record,” co-author said of the study and assistant professor of geosciences at Dartmouth, Brenhin Keller.
The scientists fed geological data from deep-sea core samples into their computer model. Each core sample contained foraminiferal microfossils dating to 67 to 65 million years ago. Above, ten species of planktonic foraminifera, each the size of a grain of sand
“These amounts,” Keller said, “were consistent with what we expect from emissions from the Deccan traps.”
Keller and his co-author, Dartmouth graduate student Alex Cox, used the “Long-term ocean-atmosphere-sediment carbon cycle reservoir (LOSCAR) model for calculating 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” – tracing the element’s flows from carbon dioxide gas in the atmosphere to carbon-based life forms like the tiny foraminifera in the ocean to the foraminiferous fossils found in the sediment embedded underneath.
To reduce bias and assumptions, Cox and Keller pushed their simulation back in time and used a statistical process called Bayesian inversion to determine which scenarios were most likely to have led to their fossil discoveries.
“Most models are moving forward,” Cox noted in a press release.
“We adapted a model of the carbon cycle to work in reverse and used the effect to use statistics to find the cause.”
This helped eliminate any preconceptions, Cox said, by giving the computer model “only the bare minimum of prior information as it worked toward a specific outcome.”
But performing these tasks backwards required a lot of computing power.
As their new study published today in the journal Science found, 128 computer processors running scenarios in parallel on a total of 512 cores were used to simulate the atmosphere before and after the last days of the dinosaurs.
Running these simulations in parallel, Cox told Science News, sped up the process significantly, 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, just as classmates compare their answers,” he said.
The result was a version of the dangerously high levels of carbon dioxide (CO2) and sulfur dioxide (SO2) emissions during what paleontologists called the “Cretaceous-Paleogene extinction event,” which could be attributed entirely to megavolcanoes in India.
But not all of Cox and Keller’s colleagues are completely convinced.
For example, Sierra Petersen, a geochemist at the University of Michigan in Ann Arbor, told Science News that the ratios of oxygen isotopes in the fossil shells of foraminifera can change based on the composition of seawater, not just climate.
“It’s a bit of a leap to say this study shows that.” [asteroid] “The impact did not cause extinction,” she said.
“I think what they show is that the impact probably wasn’t on a large scale.” [CO2 and SO2 gas] release.’
Another researcher, paleoclimatologist Clay Tabor of the University of Connecticut, pointed out that the Chicxulub impact is estimated to have kicked up apocalyptic amounts of soot and dust that may have sent Earth into a bleak, deadly winter.
As the debate rages on, the Dartmouth researchers emphasize that they are only the messenger delivering what their computer model has said.
“At the end of the day, it doesn’t matter what we think or what we thought before,” Cox said.
“The model shows us how we got what we see in the geological record.”
How the dinosaurs died out around 66 million years ago
About 66 million years ago, dinosaurs ruled and dominated the earth before they suddenly went extinct.
This mass extinction is known as the Cretaceous-Tertiary extinction event.
For many years it was believed that climate change was destroying the giant reptiles’ food chain.
In the 1980s, paleontologists discovered a layer of iridium.
This is an element that is rare on Earth but is found in large quantities in space.
When this was dated, it coincided exactly with the point in time when dinosaurs disappeared from the fossil record.
A decade later, scientists discovered the giant Chicxulub crater at the tip of Mexico’s Yucatán Peninsula, which dates to this period.
Scientific consensus now holds that these two factors are linked and both were likely caused by a giant asteroid crashing into Earth.
At the predicted size and impact speed, the collision would have caused an enormous shock wave and likely triggered seismic activity.
The fallout would have created ash clouds that likely covered the entire planet, making survival of the dinosaurs impossible.
Other animal and plant species had a shorter time between generations, which allowed them to survive.
There are several other theories as to what caused the famous animals’ demise.
One early theory was that small mammals ate dinosaur eggs, and another is that poisonous angiosperms (flowering plants) killed them.