The methane release led to an increase in atmospheric temperature around the globe.
Half of Earth's marine life may have been decimated as the result of methane from the seafloor released into the air.
The previous theory blamed the extinction on a period of intense volcanism.
Understanding this period could help with further research in the field of climate change.
Micha Ruhl and researchers from the Nordic Center for Earth Evolution at the University of Copenhagen in Denmark have found that the mass extinction of half of Earth's marine life over 200 million years ago was likely the result of a giant release of methane into the atmosphere.
This massive methane "burp" led to an increase in atmospheric temperature around the globe -- and organisms and ecosystems were simply unable adapt to their hotter environment.
"We measured the isotopes of carbon in plants, from before the mass extinction event and then after the mass extinction. We found two different types of carbons and the molecules that were produced during that event," Micha Ruhl told FoxNews.com. "So we started thinking of other sources of carbon that could have changed the atmosphere." Methane, (CH4), contains carbon and hydrogen.
The original theory blamed the extinction and atmospheric change on carbon released during a period of intense volcanism -- a large surge in volcanic activity brought about by continental shift when Pangaea broke apart. But Ruhl and his partners discovered that this volcanic episode occurred 600,000 years prior to the end of the Triassic Period. The mass extinction occurred only 20,000 to 40,000 years prior.
Extensive calculations and research by Ruhl's team revealed that the burp pumped over 12,000 gigatons of methane into the atmosphere during the final years of the Triassic. While volcanism was revealed not to have caused the extinction itself, the researchers believe that the volcanoes indirectly set the events in motion by triggering the methane release.
"A small release of carbon dioxide carbon dioxide from volcanism initiated global warming of the atmosphere, increasing temperatures in the oceans," Ruhl told FoxNews.com. "Methane is stored in the sea floor -- it's a molecule which is caught in some kind of ice structure. As soon as the temperatures got above a certain threshold, the ice melted and that methane was released."
For those unconcerned with an event hundreds of millions of years in the past, Ruhl's research is a little more than a history lesson. Ruhl argues that better understanding the Triassic period extinction could help with further research in the field of climate change.
"People are worried nowadays that the release of carbon dioxide from fossil fuel burning could melt glaciers in the same way," Ruhl told FoxNews.com. "That's the big question of course" -- and a big leap to make.
Ruhl noted that events far back in history when the planet was dramatically different are hardly comparable to the modern world.
"What we don't know is what the thresholds are today," he explained, saying simply that the findings dictate further study, not panic.
"We have to remember that the world in the past was a very different. All the continents were still together, there were no glaciers. Ocean currents were probably very different."
"But it will be interesting to see how animals and ecosystems cope nowadays compared to those in the young Triassic," Ruhl added.