Dinosaurs Became Extinct Due To 'Curtain Of Fire'
Researchers found that prolonged volcanic eruptions and asteroid impacts played a major role in the mass extinction period during the earth's early history, according to a study at the University of Leeds in the UK.
The researchers' new findings could draw a "curtain of fire" on the dinosaurs' extinction theory.
The researchers found that prolonged volcanic eruptions called continental flood basalts along with asteroid impacts released great amounts of dust and gas into the earth's atmosphere. The release of sulfur dioxide gradually changed the earth's climate.
"At the time when the dinosaurs reigned, numerous long-lasting eruptions took place over the course of about a million years," Dr. Anja Schmidt, lead author of the study, said. "Each eruption is likely to have lasted years, even decades, and eruptions were separated by periods without volcanic activity."
The researchers' study is one of the first to examine the effects that these eruptions had on the earth's climate, the oceans and vegetation. By using a state-of-the-art computer simulation model, they were able to determine how gas and aerosol particles dispersed. Continuous flood basalts lasted for hundreds of years, which had major climatic effects and this ultimately affected plants and animals.
Some eruptions produced so much lava that they could fill 150 olympic-size swimming pools per minute, according to Schmidt.
The researchers were able to determine how large amounts of sulphur dioxide emissions affected the environment and climate, by examining the extent of the Deccan Traps eruptions, which took place 65 million years ago.
"Perhaps most intriguingly, we found that the effects of acid rain on vegetation were rather selective," said Schmidt. "Vegetation in some but not all parts of the world would have died off, whereas in other areas the effects would have been negligible."
Due to the eruptions, the earth was much cooler, about 4.5 degrees Celsius. However, that temperature returned to its normal state 50 years later once the eruptions had stopped. The researchers study is calling on scientists to reexamine previous mass extinction theories and to consider the effects of volcanic eruptions.
"We now need to better understand how long both the individual eruptions and the periods without volcanic activity lasted," Schmidt said.
The findings of this study were published in in Nature Geoscience.
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