DAVIS, Calif., Jan. 6 (UPI) -- Soil from Syria suggests evidence of ancient heating was caused by Stone Age house fires, not a cosmic impact -- that according a new study by researchers at the University of California, Davis.
It's the latest scientific paper to question the theory that a massive meteor instigated the Younger Dryas cold period, the centuries-long frigid drought blamed for snuffing out mammoths and most megafaunal life (including the Paleo-Indian Clovis people) between 10,800 and 9500 BCE.
The theory goes that a series of impacts or air bursts from near impacts set a larger portion of the Earth on fire and disrupted the planet's climate. But as part of a recent experiment testing that hypothesis, analysis of siliceous scoria samples (porous rock granules associated with melting) dated to the time of the supposed impact suggested brief periods of exposure to moderate heat -- not the kind of long, intense heat expected from a meteor impact.
Researchers say that the fact that Clovis archaeological sites -- from which the soil droplets were collected -- span a period of 3,000 years is proof that their disappearance wasn't sudden and dramatic, but relatively gradual.
"If there was one cosmic impact," explained Peter Thy, researcher at the UC Davis Department of Earth and Planetary Sciences. "They should be connected by one date and not a period of 3,000 years."
While cosmic impacts may have played some role in hastening megafaunal decline in North America, scientists say this latest evidence excludes the possibility of an intercontinental impact event during the period just after the Ice Age.
"For the Syria side, the impact theory is out," Thy said. "There's no way that can be done."
The new study was published in the Journal of Archaeological Science.