A recent study by a team of researchers from Italy, Norway, Canada and the United States suggests that before their eventual extinction, dinosaurs may have experienced repeated “volcanic winters” that left them in a state of weakness.
These findings come from an analysis of sulfur and fluorine gases trapped in ancient volcanic rocks from the Deccan Traps supervolcano, which erupted about 200,000 years before an asteroid impact that is believed to have caused the extinction of dinosaurs.
Purpose of the study
The study, which focuses on these gases, concludes that their release may have caused global temperatures to fall by up to 10 degrees Celsius.
This discovery adds to the ongoing debate between paleontologists and scientists about the exact cause of the dinosaurs’ disappearance. The research is consistent with the “pressure impulse model of extinction,” which suggests that a combination of factors led to the extinction.
Unstable climatic conditions
“Our research shows that climatic conditions were almost certainly unstable, with repeated volcanic winters that may have lasted decades before the dinosaurs went extinct,” said study co-author Don Baker, a geologist at McGill University Montreal.
“Our work helps explain this major extinction event that led to the rise of mammals and the evolution of our species. »
How the research was conducted
The team analyzed sulfur and fluorine compounds in samples from the Deccan Traps in India’s Western Ghats, near Bombay. They used synchrotron radiation X-ray fluorescence spectrometry to measure the concentrations of these compounds. Baker compared the process to cooking pasta, where a small amount of salt in the boiling water is absorbed into the pasta.
Likewise, the team estimated the amount of sulfur and fluorinated gases released into the atmosphere during the Cretaceous period based on the presence of these compounds in lava rocks.
Critical information
Specifically, the researchers found that peak sulfur levels, up to 1,800 parts per million, correlated with a drop in temperature at the end of the Cretaceous. They estimated that between 86,000 and 466,000 cubic kilometers of sulfur gas was released into the atmosphere, causing significant climate change.
Although the team did not attribute major climate changes to fluorinated gases, they did note toxic local effects of these gases, including acid rain, crop failure and livestock poisoning, as observed in historical accounts of eruptions from Iceland’s Laki volcano in the 18th century. These effects may have had similar effects on the dinosaur environment.
Multiple triggers
The researchers conclude that volcanic activity in the Deccan Traps created the conditions for a global biotic crisis by triggering repeated short volcanic winters.
However, they believe that the “final blow” was the impact of the Chicxulub asteroid in Mexico, which caused massive environmental destruction. This impact, combined with earlier volcanic activity, likely accelerated the extinction of the dinosaurs.
Implications of the study
The study, published in the journal Scientific Advances, sheds light on the complex interplay of environmental factors that led to one of the most significant species extinctions on Earth.
“Our data set suggests that volcanic climate disruption was already underway,” the researchers noted, highlighting the complexity of the events that led to the end of the Age of Dinosaurs.
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