It’s been 66 million years since dinosaurs walked the Earth, and the prevailing theory has long held that an asteroid’s cataclysmic collision with our planet marked the end of their reign. However, an ongoing scientific debate questions whether the asteroid alone was responsible for this infamous mass extinction event or if other earthly forces also played a crucial role.
Rekindling this debate, a recent study suggests that volcanic eruptions may have already plunged the ecosystem into chaos, endangering non-avian dinosaurs even before the asteroid struck Earth, delivering the final blow. A team of international researchers argues that the world inhabited by dinosaurs was saturated with elevated levels of sulfur, setting the stage for their demise. This instability triggered a worldwide drop in temperatures, rendering the environment hostile to life.
Published in October in the journal Science Advances and revealed in a recent press release, the team’s findings shed light on the potential factors that contributed to the extinction of dinosaurs. According to study co-author Don Baker, a geologist at McGill University, “Our research demonstrates that climatic conditions were almost certainly unstable, with repeated volcanic winters that could have lasted decades, prior to the extinction of the dinosaurs. Our work helps explain this significant extinction event that led to the rise of mammals and the evolution of our species.”
The study adds to the long-standing scientific debate surrounding the causes of the mass extinction event that wiped out 75% of life on Earth, including the dinosaurs, and marked the end of the Cretaceous period. Did the asteroid impact in present-day Mexico alone cause the mass extinction, unleashing devastating tsunamis and obscuring the sun with ash? Or were massive volcanic eruptions at the Deccan Traps in India responsible for dooming life on Earth long before the asteroid’s arrival?
To answer these questions, researchers turned their attention to the vast, rugged plateau in Western India formed by molten lava known as the Deccan Traps. Here, they collected rock samples and conducted analyses to estimate the amount of sulfur and fluorine released into the atmosphere by volcanic eruptions 200,000 years prior to the dinosaurs’ extinction. Their findings indicated that a sufficient quantity of sulfur was emitted to initiate a significant drop in global temperatures, leading to a “volcanic winter.”
To uncover further clues about the dinosaurs’ demise, the researchers developed a novel technique to study the volcanic history of ancient rocks. By measuring the sulfur content in rock formations and applying a chemical process akin to cooking pasta, they were able to calculate the sulfur and fluorine levels in the rock samples. This data suggests that sulfur emissions occurred in bursts during volcanic activity, causing repeated, short-lived global temperature drops, ultimately ushering in catastrophic climate change and marking the transition from the Cretaceous to the Paleogene period.