Did the dinosaurs die because of an asteroid impact, or was it caused by a massive volcanic eruption? The computer model now settles the dispute.
Hanover – Dinosaurs and many other animals and plants became extinct 66 million years ago – but why? The common explanation for this is the collision of an asteroid said to be between ten and 15 kilometers in diameter. One of the remains of this crater is the Chicxulub crater, which is located in what is now known as Mexico. Another theory, less well-known outside the scientific community, posits that the mass extinction 66 million years ago was due to strong volcanic activity over a long period of time.
But which theory is correct? To settle the dispute and solve the puzzle, a research team from Dartmouth College in the US state of New Hampshire used a computer model. The goal was to determine how the famous mass extinction occurred with almost no human intervention.
Mass extinction 66 million years ago: impact of asteroids or volcanic eruptions?
Both scenarios have one thing in common: Both large asteroid impacts and massive volcanic eruptions release large amounts of carbon dioxide and sulfur dioxide, which can change the composition of the atmosphere. This could lead to the collapse of the food chain, as happened 66 million years ago.
The new computer model used by researchers Alexander Cox and Brenhen Keller in their study can process large amounts of geological and climate data without human intervention. The researchers fed the model with data from fossils and analyzed what led to the mass extinction 66 million years ago.
A new study excludes the human factor and allows computer models to perform the calculations
“Part of our motivation was to evaluate this question without a pre-specified hypothesis or bias,” lead author Cox emphasizes in the article. notice. “Most models move in a forward direction. We adapted the carbon cycle model to work in the other direction, using effect to find cause using statistics, and giving it only minimal prior information as it works toward a specific outcome.”
The computer model calculated more than 300,000 possible scenarios to arrive at a scenario that matches the data revealed by the excavations. The result is very exciting: It suggests that the emission of climate-changing gases from volcanoes in the Deccan region of western India could be enough to trigger a mass extinction. Although the asteroid also had an impact, it is clear that the extinction event would have occurred even without it.
Deccan Trap is a volcanic region in western India. Massive volcanic eruptions created a terraced formation (the so-called trap) made of flood basalt.
A massive volcanic eruption in India may have caused a mass extinction
According to the computer model, the volcanoes in Deccan Trap erupted 300,000 years before the asteroid impact, and the eruption continued for about a million years. During this time, the model calculates that up to 10.4 trillion tons of carbon dioxide and 9.3 trillion tons of sulfur were released into the atmosphere. “We have long known that volcanoes can cause massive extinctions, but this is the first independent estimate of fugitive emissions based on evidence regarding their environmental impact,” explains co-author Keller.
The researcher continues: “Our model evaluated the data independently and without human intervention to determine how much carbon dioxide and sulfur dioxide would be required to cause the climate and carbon cycle disturbances that we see in the geological record. These quantities turn out to be consistent with what we would expect for emissions from a decane collapse.
Asteroid impacts contributed to the extinction of dinosaurs, as did volcanoes
In the model, the researchers were able to see a sharp decline in the accumulation of organic carbon in the deep sea, as the asteroid caused the extinction of many animal and plant species. Meanwhile, the records contain traces of a temperature drop caused by large amounts of sulfur thrown into the air by the asteroid. However, the researchers were unable to see a sudden increase in carbon dioxide and sulfur dioxide in the model, an indication that the asteroid did not make a significant contribution to the extinction, at least not through its gaseous emissions.
First author Cox is satisfied with the result In the specialized magazine Sciences published “The most encouraging thing is that our results are quite plausible in physical terms, which is impressive considering that technically the model could have gotten completely out of control without stronger prior constraints,” he says happily. No matter what we think or have been thinking, the model shows us how we got to what we see in the geological record. (unpaid bill)
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