For decades, scientists have argued about what caused the global mass extinction event that killed the dinosaurs. While there is general consensus that climate change is to blame, scientists disagree over what event occurred that triggered a rapid transformation of the planet’s weather systems. Though some believe that the environmental impact was caused by massive volcanic eruptions in India, most scientists think that an asteroid impact is to blame. Now, a new research paper published in Science is hoped to end the debate, as the researchers found that the volcanic eruptions occurred too far before the extinction event that took place 66 million years ago to have been its cause.
With this research, the scientists are hoping to put to rest the theory that K-Pg, which is the scientific notation for the Cretaceous-Paleogene extinction event, was caused by volcanic activity. According to Yale assistant professor of geology & geophysics Pincelli Hull, who helped author the research paper, “a lot of people have speculated that volcanoes mattered to K-Pg, and we’re saying, ‘No, they didn’t.’”
According to Hill, “volcanic activity in the late Cretaceous caused a gradual global warming event of about two degrees, but not mass extinction.” In other words, although climate change caused by volcanic activity had an impact on the global ecosystem, it was not rapid or dramatic enough of a warming event to cause the extinction of 75% of life on Earth, as is observed in K-Pg. The study also offers an answer to a question that has for years remained a mystery, which is why massive eruptions that took place in India in the immediate aftermath of the extinction event did not cause a corresponding warming event. According to this study, the ocean absorbed an enormous amount of CO2 in the aftermath of the asteroid impact, which may have hid the warming effect of the volcanic activity.
The asteroid impact which is now widely believed to have been the cause of K-Pg was first discovered in 1990, after samples from the Chicxulub crater in Mexico were analyzed by scientists who determined that the crater was caused by an asteroid impact that took place around 66 million years ago, at precisely the same time as the extinction event. Since the discovery of the crater, further research has produced evidence that this in fact was the impact site of the asteroid that killed the dinosaurs. In 2016, for instance, a drilling project drilled into the impact crater, obtaining rock core samples that seemed to confirm the theory, as materials extracted from the impact site match the geological record across the world that was formed in the wake of the asteroid impact.