The event took place more than 250 million years ago

Jan 11, 2012 13:14 GMT  ·  By
The Siberian Traps were created about 250 million years ago by massive volcanic eruptions
   The Siberian Traps were created about 250 million years ago by massive volcanic eruptions

Data from the latest investigations conducted by researchers in the United States demonstrate that the Permian-Triassic (P-Tr) extinction event may have indeed been caused by massive volcanic eruptions.

The idea was one of the first to be proposed as an explanation, right alongside the formation of the supercontinent Pangaea and a massive asteroid impact. However, evidence to support this hypothesis have been scarce until recently.

Establishing what caused the event is very important since the P-Tr. Extinction was the most brutal in our planet's history. More than 90 percent of marine species and 70 percent of land-dwelling creatures were destroyed about 250 million years ago. This was the only extinction to affect insects.

Scientists at the Massachusetts Institute of Technology (MIT) say that the wide expanses of volcanic rock in present-day Russia, known collectively as the Siberian Traps, may have been formed by the same volcanic eruptions that nearly put an end to life on Earth.

The end-Permian collapse may have been caused not by the eruptions themselves, but by the cascade of ecological failures that releasing massive amounts of greenhouse gases had on the planet's atmosphere.

Some of these gases were undoubtedly poisonous to all species, but many of them may have acted indirectly, such as for instance by blocking out sunlight and stopping photosynthesis in plants. The effects of this happening would have been equally devastating.

Details of how the MIT team believes this happened were published in the latest online issue of the journal Earth and Planetary Science Letters. The lead author of the study is MIT Department of Earth, Atmospheric and Planetary Sciences PhD student Benjamin Black.

He believes that the Siberian Traps may have been releasing one million times the amount of sulfur, chlorine and fluorine all volcanoes on Earth release nowadays in a year. This may have gone on for centuries, maybe even millennia.

“We have concrete numbers that we can put on these gases that would have been erupting about 250 million years ago. These numbers give us a much better chance of being able to evaluate whether the Siberian Traps caused the extinction,” the PhD student adds.

Washington State University research associate Michael Rowe and University of Iowa assistant professor of geoscience Ingrid Ukstins Peate were also a part of the research effort.