The U.K.’s Daily Mail news outlet has covered the research of SMU archaeologist David J. Meltzer with the article “A comet impact DIDN’T spark climate change and trigger a mass extinction 12,800 years ago, study claims.”
A member of the National Academy of Sciences, Meltzer researches the origins, antiquity, and adaptations of the first Americans who colonized the North American continent at the end of the Ice Age. He focuses on how these hunter-gatherers met the challenges of moving across and adapting to the vast, ecologically diverse landscape of Late Glacial North America during a time of significant climate change.
The Daily Mail piece by Jonathan O’Callaghn highlights Meltzer’s latest study to show that a comet, or any other kind of extraterrestrial impact, was not responsible for sudden climate change at the end of the Ice Age 12,800 years ago. Proponents of the comet-impact theory have pointed to sedimentary deposits that they say prove that an object from outer space hit the Earth, extinguishing the Clovis culture and causing the mass extinction of many animals.
By Jonathan O’Callaghan
It has long been though that a comet struck Earth 12,800 years ago, bringing an end to the Ice Age.
This event was thought to have not only sparked climate change, but also killed America’s earliest people and caused a mass animal extinction.
But a new study suggests this comet theory is false, as most supposed impact indicators at 29 sites are too old or too young to be remnants of an ancient comet.
Controversy over what sparked the Younger Dryas, a brief return to near glacial conditions at the end of the Ice Age, includes a theory that it was caused by a comet hitting the Earth.
As proof, proponents point to sediments containing deposits they believe could result only from a cosmic impact.
Now a new study disproves that theory, said archaeologist David Meltzer of the Southern Methodist University in Dallas.
Meltzer is lead author on the study and an expert in the Clovis culture, the peoples who lived in North America at the end of the Ice Age.
His research team found that nearly all sediment layers purported to be from the Ice Age at 29 sites in North America and on three other continents are actually either much younger or much older.
Scientists agree that the brief episode at the end of the Ice Age – officially known as the Younger Dryas after a flower that flourished at that time – sparked widespread cooling of the Earth 12,800 years ago and that this cool period lasted for 1,000 years.
But theories about the cause of this abrupt climate change are numerous; they range from changes in ocean circulation patterns caused by glacial meltwater entering the ocean to the cosmic-impact theory.
The cosmic-impact theory is said to be supported by the presence of geological indicators that are extraterrestrial in origin.
However a review of the dating of the sediments at the 29 sites reported to have such indicators proves the cosmic-impact theory false, said Meltzer.
Meltzer and his co-authors found that only three of 29 sites commonly referenced to support the cosmic-impact theory actually date to the window of time for the Ice Age.
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