devastation caused by volcanoes of the past

April 24, 2010

Brown team documents devastation caused by volcanoes

April 8, 2010 By C. Eugene Emery Jr. Journal Staff Writer

PROVIDENCE — A surge in volcanic activity 201 million years ago that coincided

with the creation of the Atlantic Ocean produced an increase in the amount of

carbon dioxide in the air, paving the way for the era of the dinosaurs,

according to research by a Brown University-led team.

The climate catastrophe wiped out half the plants and four-legged tetrapods on

land, and was so devastating that 30 percent of the shellfish (or what then

would have been characterized as shellfish) became extinct.

Just as a giant meteor collision 65 million years ago is believed to have wiped

out the dinosaurs, making it easier for mammals to thrive, the volcanic activity

201 million years ago, which lasted about 600,000 years, upset the balance of

nature. It killed off the animals that preyed on the dinosaurs' ancestors,

according to Whiteside, a specialist in prehistoric biology at Brown.

Scientists have long known that there was a massive destruction of life when

Earth was suddenly overwhelmed with volcanic activity, she said, " but we're the

first people to document it. This marks one of the five big mass extinctions

since the dawn of animal life. "

" In the wake of the eruptions, life was faced with the release of massive

amounts of the greenhouse gas carbon dioxide and sulfur aerosols from a colossal

outpouring of lava from fissures, similar to what we see in Iceland today, but

on a much larger scale, " said Whiteside.

" Rapid climate change ensued and, for whatever reason, the dinosaurs won the

extinction lottery and rose to dominance, " she said.

The researchers, reporting in the Proceedings of the National Academy of

Sciences, used fossils and the carbon profile of wax from ancient leaves and

wood to show " that the extinction begins at — or very, very close to — the time

of the first eruptions and continued a few tens of thousands of years after the

first eruptions, " said Whiteside.

At that time — which would come to be known as the end of the Triassic era —

there was one major land mass known as Pangea. When Pangea split apart to form

the Atlantic Ocean, it produced massive, widespread volcanic activity that

allowed molten rock to emerge from deep within the planet.

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