Extraterrestrial Comet Explosion Blamed for Ice Age Extinctions

Northern Arizona University's (NAU) team of international researchers reports evidence that a comet or other low-density object that was barreling toward Earth and exploded in the upper atmosphere is responsible for the extinctions during the Ice Age.

Most of the large animals, their habitat and the humans of that period were annihilated by a devastating swath of destruction. According to Ted Bunch, NAU adjunct professor of geology and former NASA researcher who specializes in impact craters, "The detonation either fried them or compressed them because of the shock wave...It was a mini nuclear winter."

Bunch and Jim Wittke, a geologic materials analyst at NAU, are co-authors of the upcoming paper that describes an extraterrestrial comet impact as the cause of the event 12,900 years ago leading to the documented mass extinctions at the end of the Ice Age.

Evidence of a comet that would have been about two and a half to three miles in diameter is offered by the researchers. This comet would have detonated 30 to 60 miles above the earth, triggering a massive shockwave, firestorms and a subsequent drastic cooling effect across most of North America and northern Europe, with multiple detonation sites across these two continents.

Evidence for multiple detonations comes from a four-inch-thick "black mat" of carbon-rich material from sites on the North American continent. The black mat appears as far north as Canada, Greenland as well as in Europe and to the south as far as the Channel Islands off the coast of California and also eastward from California to the Carolinas, with two sites in Arizona.

Upon examining this black mat, evidence of mammoths and other megafauna and early human hunters, who were known as the Clovis culture, was found beneath the black mat, but it is missing entirely within or above it. It is this significant discovery that has led the research team to conclude that an extraterrestrial impact wiped out many of the inhabitants of the Late Pleistocene era.

Bunch added the interesting comment that some animals may have survived in protected niches. Bunch further stated: "The comet may have broken up into smaller pieces as it neared the Earth and then these pieces detonated in various places above [the] two continents."

Another finding in the black mat was the presence of nanodiamonds. These are formed in interstellar medium, outside the solar system. They are also formed by high-explosive detonation.

In relation to these nanodiamonds, Bunch says: "Either these things came in with the impactor or they were made during impact detonation. We have no other explanation for their presence."

The team believes that the Laurentide Ice Sheet was destabilized by the multiple detonations. This vast ice sheet covered most of what is now Canada and the northern United States. Heat from the detonation and firestorms would have melted much of the ice sheet and water vapor would have been released into the atmosphere.

Catastrophic extraterrestrial impacts are not new. The Tunguska event is the most recent incident and it occurred in 1908 in Russia. The Tunguska explosion was an airburst of a comet or meteorite estimated at 10-15-megatons. It destroyed tens of millions of trees across more than 800 square miles in Russia. Scientists theorize that a much larger asteroid impact annihilated the dinosaurs along with about 85 percent of the Earth's biomass approximately 65 million years ago.

The paper was just released online in the Proceedings of the National Academy of Sciences. The research team includes several members of the U.S. National Academy of Sciences and researchers from Hungary and the Netherlands.

"Research team says extraterrestrial impact to blame for Ice Age extinctions," Northern Arizona University.