Cosmic Impact May Not Have Caused Mammoth Die-Offs
A cosmic impact may not have caused mammoth die-offs contrary to what one controversial theory says, according to a new study.
This is evidenced by rock soil droplets found in northern Syria datin back 10,000 to 13,000 years ago, the report describes in the Journal of Archaeological Science. The Younger Dryas cold period, which lasted thousands of years, supposedly began when a comet or meteorite struck North America. This event - which also fell between two major glaciations - led to the extinction of mammoths and other great beasts found roaming these lands, as well as the disappearance of the Paleo-Indian Clovis people.
Researchers from the University of California (UC), Davis put forward a new, rather simpler theory to explain these mass die-offs. According to their new study, the soil droplets came from Stone Age house fires with early agricultural settlements, rather than a catastrophic cosmic impact, some 12,900 years ago.
"For the Syria side, the impact theory is out," lead author Peter Thy said in a statement. "There's no way that can be done."
The UC Davis team compared siliceous scoria droplets - porous granules associated with melting - to similar droplets that supposedly were from a cosmic event that occurred at the onset of the Younger Dryas. Their findings cast some serious doubt on the mammoth-killing impact.
For instance, a major blow to the theory came when researchers realized that the Syria droplets spanned a period of 3,000 years.
"If there was one cosmic impact," Thy explained, "they should be connected by one date and not a period of 3,000 years."
Also, thermodynamic modeling showed that the scoria droplets were the result of modest temperatures and a short-lived heating event - not the intense, high temperatures associated with a large cosmic impact. Furthermore, if such an intercontinental event did occur, the composition of the droplets would be of soil from several continents, and not just local soil as was the case.
While house fires, which created a mixture of local soil and straw to form the scoria droplets, are not the most dramatic or cosmic explanation, according to this study it is the most likely.
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