If you wanted evidence that a giant comet wiped out the wooly mammoth, you might look for a giant crater.
But so far, you’d be out of luck.
“Some of our critics have said, ‘Where’s the crater?’” says Christopher Moore, an archaeologist at the University of South Carolina. “As of now, we don’t have a crater or craters.”
But Moore says that by looking below the surface, you can find strong evidence for the Younger-Dryas impact hypothesis, which states that large comet fragments hit Earth or exploded in the atmosphere shortly after the last ice age, setting off cataclysmic changes in the environment, crater or not.
Moore’s research involves digging down to layers of soil that would have been exposed in the Younger Dryas period, around 12,800 years ago when the climate suddenly cooled in the northern hemisphere. He analyzes minerals and artifacts found there in search for “proxies” of a comet strike—findings that are not direct evidence, but which do tell a story.
In Greenland’s ice cores, Moore and others have found elevated levels of chemicals, called combustion aerosols, indicating a large, prehistoric fire raged at the beginning of the Younger Dryas climate event.
Hellbound and Down 