Before the dinosaurs roamed the earth, a number of other species did — including other large sea reptiles and mollusks. But they abruptly died off about 200 million years ago, marking the end of the Triassic period, one of five major extinction events that scientists have identified throughout Earth's history. Today, an international team scientists from MIT, Colombia, Rutgers, and other prestigious universities in Canada and Morocco released what they say is the best evidence that a series of powerful volcanic eruptions caused this mass extinction event, which opened the door for the dinosaurs to take over millions of years later. "There’s no question the extinction occurred at the same time as the first eruption," said one of the scientists involved, MIT's Sam Bowring, in a statement.
"There’s no question the extinction occurred at the same time as the first eruption."
Specifically, the researchers looked at the geologic record of fossilized lava in each of their various regions around the globe, which at the time of the extinction were linked on one supercontinent called Pangaea. The researchers broke open rock samples to locate crystals called zircons, which were used to date the lava more precisely than previous studies, showing that it was formed from four outbreaks of volcanic activity that occurred over a relatively brief (in geologic time) period of 600,000 years. These massive eruptions released carbon dioxide and other chemicals that warmed the globe and ruined the climate for the species.
Eruptions released carbon dioxide and other chemicals that warmed the globe
The lead author of the study, MIT's Terrence Blackburn, noted that the global warming event his team identified could be used to help us understand what could happen to our planet today. "Much insight on the possible future impact of doubling atmospheric CO2 on global temperatures, ocean acidity and life on earth may be gained by studying the geologic record," he said in a statement. The results were published in a paper in the journal Science.