What killed the dinosaurs? For many, the matter is settled, and there is a huge crater in Mexico to serve as proof. However, a minority of experts were not convinced, and argued instead that the Chicxulub meteorite impact was merely the bombastic end to an extinction that was already underway – an extinction that was caused by a seemingly endless period of massive volcanic eruptions in what is now central India.
However, a new research paper by scientists at Utrecht University and the University of Manchester claims to have strongly refuted this hypothesis. By analyzing the lipids in ancient fossil peat from Pyramid Butte, North Dakota, and West Bijou, Colorado, researchers were able to reconstruct average annual air temperatures from the period leading up to the K-Pg boundary—that is, the point at which the Cretaceous period ended and the Cretaceous began. Paleogene.
“We were able to create a detailed ‘temperature timeline’ for the years leading up to the extinction of the dinosaurs,” explained Dr. Lauren O’Connor, a researcher in organic geochemistry at Utrecht University and lead author of the new paper. statement“Which we can compare to the fossil record to understand the relative timing of events.”
What they found was enough to rewrite the story of the last days of the dinosaurs, but not much. The researchers found evidence of a previously unknown cooling event, in which the world became 2 to 5 degrees Celsius (2.6 to 9 degrees Fahrenheit) cooler over a period of no more than 10,000 years. That was it probably Because of volcanoes — the timeline certainly adds up — but it was too early to wipe out the dinosaurs, the team says.
“These volcanic eruptions and the associated carbon dioxide2 “The sulfur emission could have had serious consequences for life on Earth,” O’Connor said. “But these events occurred thousands of years before the meteorite impact and may have played only a small role in the extinction of the dinosaurs.”
More importantly, the team found that temperatures had largely returned to their pre-eruption state long before the meteorite first appeared — as in, 20,000 years before. This does not mean that the volcanoes had no effect at all, as the eruptions continued for about 800000 years and left behind 1.3 million cubic kilometers of basalt, so it’s not a stretch to think it would have affected the climate as well.
But those impacts simply weren’t the kind that could cause a mass extinction of dinosaurs, the team concluded. “By comparison, the asteroid impact unleashed a cascade of catastrophes, including bushfires, earthquakes, tsunamis and asteroid impacts,” said Rhodri Gerrett, lecturer in geology at the University of Manchester and co-author of the paper. “Winter” blocked sunlight and destroyed ecosystems.
“We believe [it was] The asteroid that ultimately dealt the fatal blow.”
The paper is published in the journal Advancement of science.
