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According to the study, the last ice age was not caused by the impact of a meteorite
The last ice age, which lasted around 1,200 years, began about 12,900 years ago in a few years. The thesis that it was caused by the impact of a meteorite has now been refuted by an international team of researchers in the journal “PNAS”.
The Ice Age, known as the “Younger Dryas Age” about 12,000 years ago, halted the global warming trend of that time. It was not yet known in detail when and where exactly it began and ended. To improve this, the research team combined two data sources: ice cores and drip stones.
They used existing drill core data from the two polar regions, as well as stalactite samples from caves in China, India, Uzbekistan, Brazil and Spain.
The cold period started in the North Atlantic
“With this approach we were able to improve the temporal accuracy from 20 to 40 years,” said geologist Christoph Spötl from the University of Innsbruck. That means a three times more accurate look at the “Younger Dryas Period,” which consequently lasted from 12,900 to 11,700 years ago.
The exact resolution also allowed the scientists to determine the course of the glacial period. The cold period started in the North Atlantic and then spread globally from there. The end of the last ice age went the opposite way: in the southern hemisphere and / or in the tropical Pacific, the end of the 1200-year cold phase was probably heralded.
The meteorite is probably not the trigger for the Ice Age
Because the Ice Age began so abruptly, scientists have suspected for several years that it was triggered by a meteorite impact. The researchers relied on platinum enrichment in Greenland’s ice cores, among other things. Platinum is rare on Earth, but it is more common in meteorites.
This thesis was not confirmed in the current study. “According to our data, the onset of rapid climate cooling will be established 12,870 years ago with a fluctuation range of 30 years in the North Atlantic. The meteorite impact is dated at 12,820 years, 50 years later, ”said Spötl. Furthermore, no major climate change can be detected in Greenland at the presumed time of impact.
(sda / what)
