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Prehistoric Wipeout

Picture a land of volcanoes that explode without stop for a million years. Imagine so much lava gushing out that it would cover an area as big as the United States in a layer 1,000 feet deep. Think of smoke and ash filling the sky, blocking out the sun and wiping out almost all living creatures.

What you have imagined is not from a science-fiction movie, but rather a scene that some scientists say unfolded right here on earth.

The Biggest Disaster In History
A team of scientists from the United States and China recently found evidence that huge volcanic eruptions during the Permian period, about 250 million years ago, may have caused the greatest extinction of life in the history of the planet. This "mass extinction" was even greater than the disaster that would wipe out the dinosaurs 185 million years later.

The scientists studied thick layers of volcanic rock in Siberia, in northern Russia. In layers dating back to the Permian era, they found tuff--a kind of rock that is formed only by powerful explosions. Geologist Paul Renne says the tuff proves that the Permian explosions were forceful enough to have hurled dust and ash miles into the air. These dusty clouds would have blocked the sun, causing the earth to grow colder and large areas of the oceans to freeze. Such changes in climate would have doomed many living creatures.

DID THE VOLCANOES DO IT?
Scientists already knew from studying fossils that most species died out around the time the volcanoes erupted. Up to 95% of the ocean creatures and at least 70% of land animals disappeared. Among the victims were giant amphibians; sleek, jaguar-like reptiles; and the last trilobites, which were armored sea animals. Coral reefs and forests of fernlike trees also vanished.

There have been many theories about what caused "The Great Dying." The new research offers strong evidence that the volcanoes were responsible. But there are still many questions. One of the biggest is how life manages to bounce back after such a disaster.

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