Report Ties Dinosaur’s Demise to Firestorm From Comet Crash

Scientists have taken a popular dinosaur extinction theory a step further by suggesting that a comet or an asteroid started continent-spanning wildfires when it smashed into Earth 65 million years, according to a report Friday.

Such an immense firestorm would have sent thick soot into the atmosphere that could have blocked the sunlight for months, shut down plant photosynthesis and drastically cooled the planet.

Presence of Deadly Gases

In addition, the University of Chicago researchers supporting the theory said that such wildfires, which perhaps extended around the world, would have spread deadly gases in the atmosphere.

The result of such conditions could have been the deaths of thousands of species of plants and animals, including the giant reptiles, said Edward Anders, Roy Lewis and Wendy Wolbach in a report published Friday in the journal Science.

Search for Cause of Cooling

The idea that an asteroid or a comet collision wiped out the dinosaurs and many other life forms at the end of the Cretaceous Period was first developed five years ago.

Luis Alvarez, of the Lawrence Berkeley Laboratory in California, and his son, Walter, at UC Berkeley, theorized that such an impact would kick up a global dust cloud that could block out sunlight.

The new report says that a global layer of smoke in the atmosphere would be far more efficient at sunlight absorption than dust.

Evidence of such a firestorm catastrophe was found in clays from 65-million-year-old sediments in Denmark, New Zealand and Spain. The scientists were looking for traces of gases that might have been left over from the impact of a giant meteorite, but instead they found a surprisingly thick layer of carbon.

The researchers said examination of the carbon under an electron microscope found irregular clusters of spheres less than one micron--one 25,000th of an inch--in diameter. This is characteristic of carbon deposited from flames.

Larger carbon particles, which the scientists said resembled charcoal from forest fires, were found also.