McGill University researchers have discovered a link between volcanic eruptions and climate change, challenging current understanding of the extinction of the dinosaurs. New research shows that global cooling caused by volcanic eruptions was an important reason for the extinction of the dinosaurs, challenging the long-held view that meteorites were the only cause.
What caused the extinction of the dinosaurs? A new study suggests that meteorites falling to Earth are only part of the story. Climate changes triggered by massive volcanic eruptions may have ultimately contributed to the extinction of the dinosaurs, challenging the conventional wisdom that meteorites alone delivered the final blow to the ancient behemoths.
Don Baker, a professor in the Department of Earth and Planetary Sciences at McGill University, is a co-author of the study.
The team took an in-depth look at volcanic eruptions in the Deccan Traps - vast, rugged plateaus formed by molten magma in western India. About 65 million years ago, the Deccan Trap volcano erupted 1 million cubic kilometers of rock and may have played a key role in cooling the global climate. From hammering rocks in the Deccan Traps to analyzing samples in England and Sweden, researchers have traveled the world.
In the laboratory, scientists estimated how much sulfur and fluorine were injected into the atmosphere by massive volcanic eruptions 200,000 years before the dinosaurs became extinct. Notably, they found that the release of sulfur may have triggered a drop in global temperatures - a phenomenon known as volcanic winter.
"Our study shows that climate conditions were almost certainly unstable before the dinosaurs went extinct, with recurring volcanic winters likely lasting for decades. This instability would have made life difficult for all plants and animals and set the stage for the dinosaur extinction event," Professor Don-Baker said: "Our work therefore helps explain this major extinction event that led to the rise of mammals and the evolution of humans."
Finding clues in ancient rock samples is no easy task. In fact, a new technique developed at McGill University could help decode volcanic history. The technique for estimating sulfur and fluorine releases is a complex combination of chemistry and experimentation, a bit like cooking pasta. "Imagine making pasta at home. You boil water, add salt, and cook the pasta. Some of the salt in the water will get into the noodles, but not too much," Baker explains.
Likewise, some elements become trapped in minerals as they cool after a volcanic eruption. Just like analyzing the salt in noodles can calculate the salt concentration in the water in which they are cooked, new technology allows scientists to measure sulfur and fluorine in rock samples. With this information, scientists can calculate how much of these gases are released when a volcano erupts.
Researchers from Italy, Norway, Sweden, the United Kingdom, the United States and Canada participated in the study.
Their discovery marks a step forward in piecing together Earth's ancient secrets and paves the way for smarter responses to our own changing climate.