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Meteor May Have Doomed Megafauna



Megafauna, such as these mammoths, may have fallen victim to a meteor impact 13,000 years ago.

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By Gail Gallessich


New scientific findings suggest that a large, extraterrestrial rock may have exploded over North America 13,000 years ago, possibly explaining riddles that scientists have wrestled with for decades.
Two scientists from UC Santa Barbara presented the discovery along with two other researchers last week at the annual meeting of the American Geophysical Union, held in Acapulco, Mexico. Over 20 scientists contributed to the discovery.
James Kennett, paleoceanographer and professor emeritus in the Department of Earth Science, told the international journal Nature that the discovery potentially explains three of the most debated controversies of recent decades: the abrupt cooling of the atmosphere, the sudden extinction of large mammals, and the ending of Clovis culture.
“This is what happens when you do interdisciplinary science,” said Luann Becker, research scientist with the Institute of Crustal Studies and a participant.
The time period in question is called the “Younger Dryas,” a time of abrupt cooling that lasted for about 1,000 years and occurred during an inter-glacial warm period.
According to the scientists, the extraterrestrial rock must have been about five kilometers across, and either exploded in the atmosphere or directly hit the Laurentide ice sheet, then located in the northeastern section of North America. Wildfires across the continent would have resulted from the fiery impact, killing off the food supply of many of the larger mammals like the woolly mammoths, causing them to go extinct.
The impact of the space rock melted a large portion of the ice sheet, causing enormous amounts of cool, fresh water to flow into the Atlantic and Arctic oceans. This would have disrupted the circulation of warm and cold water, leading to the glaciation of the Younger Dryas period.
Since the Clovis people of North America hunted mammoths as a major source of their food they, too, were affected by the impact and their culture died out, explained Becker.
The scientific team visited over a dozen archaeological sites in North America where they found high concentrations of iridium, an element that is rare on Earth, and is almost exclusively associated with meteors. They found microspherules of glass-like carbon, which form at high temperatures and are thought to be a result of an impact blast.
Impact evidence was discovered on Santa Rosa Island among the Santa Barbara Channel Islands, Kennett told Nature - HLG Posted Article Courtesy of UCSB