“The Cold Factor” – The volcanic plot twist in The Extinction of the Dinosaurs

McGill researchers challenge current understanding of dinosaur extinction by discovering a link between volcanic eruptions and climate change.

What wiped out the dinosaurs? A new study suggests that the meteorite falling to Earth is only part of the story. Climate change caused by massive volcanic eruptions may have ultimately paved the way for the extinction of the dinosaurs, challenging the traditional narrative that a meteorite alone dealt the final blow to the ancient giants.

This is according to a study recently published in Advancement of science, Co-authored by Don Baker, professor in the Department of Earth and Planetary Sciences at McGill University.

The research team looked at volcanic eruptions in the Deccan Traps, a vast, rugged plateau in western India formed from molten lava. Its eruption of 1 million cubic kilometers of rock may have played a major role in cooling the global climate about 65 million years ago.

This work took researchers from all over the world, from hammering rocks in the Deccan traps to analyzing samples in England and Sweden.

Volcanic winter and the extinction of dinosaurs

In the laboratory, scientists estimated how much sulfur and fluorine were injected into the atmosphere by massive volcanic eruptions during the 200,000 years before the extinction of the dinosaurs.

Remarkably, they found that the release of sulfur could lead to a global drop in temperatures around the world, a phenomenon known as volcanic winter.

“Our research shows that climate conditions were almost certainly unstable, with recurring volcanic winters that could have lasted decades, before the extinction of the dinosaurs. This instability would have made life difficult for all plants and animals and set the stage for a dinosaur extinction event. Thus Our work helps explain this major extinction event that led to the emergence of mammals and the evolution of humans ClassifyProfessor Don Baker said.

Innovative search techniques

Uncovering the clues inside ancient rock samples was no easy feat. In fact, a new technique developed at McGill has helped decipher volcanic history.

The technology for estimating sulfur and fluorine emissions – a complex mix of chemistry and experiments – is a bit like cooking pasta.

“Imagine making pasta at home. You boil water, add salt, and then the pasta. Some of the salt in the water gets into the pasta, but not a lot of it,” Baker explains.

Likewise, some elements become trapped in minerals when they cool after a volcanic eruption. Just as you can calculate salt concentrations in the water in which pasta is cooked by analyzing the salt in the pasta itself, the new technique has allowed scientists to measure sulfur and fluorine in rock samples. With this information, scientists were able to calculate the amount of these gases emitted during explosions.

The study included researchers from Italy, Norway, Sweden, the United Kingdom, the United States and Canada.

Their findings represent a step forward in piecing together Earth’s ancient secrets and pave the way for a more informed approach to our changing climate.

Reference: “Recurring volcanic winters during the last Cretaceous period“Sulfur and Fluorine Budgets in Deccan Traps Lava” by Sarah Calligaro, Don R. Baker, Paul R. Ren, Leon Meloso, Kalutina Geracki, Martin J. Whitehouse, Angelo De Min and Andrea Marzoli, October 4, 2023, Advancement of science.
doi: 10.1126/sciadv.adg8284