Wednesday, May 21, 2008

The Fiery Extinction

A new theory posits massive oil fires led to the dinos' demise
By Matt Ransford

What exactly killed the dinosaurs? One of the most popular theories holds that the extinction event was driven by an asteroid collision. Evidence for the theory can be found in a thin layer of iridium in what's known as the K-T boundary, a (similarly thin) layer of sediment in the ground which marks where the surface of the Earth was 65 million years ago. Iridium is common in asteroids and not common on Earth. Its presence in the sediment would indicate an impact and release of the material. What happened next is still a matter of debate.
Did the collision kick up a tremendous cloud of dust and debris which ultimately blocked out the sun? Or start a massive forest fire whose CO2 release literally cooked life to death?

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