Toxic Gases Caused World's Worst Extinction

Feb. 4, 2009 -- An ancient killer is hiding in the remote forests of Siberia. Scientists are starting to uncover the remnants of a supervolcano, that was walled off from western eyes during the Soviet era and that rained Hell on Earth 250 million years ago, killing 90 percent of all life.

Researchers have known about the volcano -- the Siberian Traps, for years. And they've speculated that the volcanic rocks, which cover an area about the size of Alaska, played a role in runaway global warming that led to the end -- Permian mass extinction, the worst dying the planet has ever seen.

Now a team of researchers led by Henrik Svenson of the University of Oslo in Norway have performed a series of experiments, showing the volcano employed an arsenal of deadly weapons during its 200,000-year-long assault on the biosphere.

WATCH VIDEO: Best Five Volcano Webcams and Videos

Related Content:

• Did Magnetic Blip Trigger Mass Extinction?
• The Supervolcano Under Yellowstone
• How Stuff Works: How Volcanoes Can Cause Mass Extinctions
• More Discovery News

Prime among them was carbon. Searing magmas from the volcano intruded into the Tunguska Basin in eastern Siberia, a region laden with thick deposits of coal, oil and gas. Heat from the molten rock baked the hydrocarbons, turning the area into the world's largest fossil fuel-burning plant. In all, the volcano may have belched as much as 100,000 gigatons of carbon into the air (all of humanity emits about eight gigatons of carbon annually).

That's more than enough to cause a global climate apocalypse. But the team also wanted to know what happened when lava infiltrated the area's abundant salt deposits. When heated in a laboratory to 275 degrees Centigrade (527 degrees Fahrenheit), the salts released a host of toxic gases, chief among them methyl chloride, an efficient ozone-killer.

"This is the first geologically realistic evidence that ozone collapse during the end-Permian could have actually happened," Svenson said.