Scientists know the date of a meteorite, which caused the last glaciation – RIA Novosti

1/2

© Photo: Sonia Fernandez

© Photo: Anton Mauricio

MOSCOW, July 28 – RIA Novosti. The geologists have discovered traces of a meteorite that caused the beginning of the last glaciation in the history of the world, on four continents, and with the help of them have found that this cataclysm occurred 12.835 years ago, according to a paper published in the journal Proceedings of the National Academy of Sciences.

“The exact chronological assessment of this event is very important because in the past we have worked long and hard trying to figure out what caused this mysterious and abnormal cooling. We believe that our work provides a comprehensive answer to this question, and we hope that it will encourage our colleagues used statistical analysis in these investigations “, – said James Kennett (James Kennett) from the University of California at Santa Barbara (USA).

The last cold snap and the subsequent onset of glaciers on Earth happened about 12.9 Thousands of years ago, this period in the history of our planet known as junior or later, Dryas. Abrupt climate change is believed to be caused, for example, to the extinction of megafauna in North America – mastodons, giant sloths, megatherium, saber-toothed cats and other species.

Kennett explains, he and his colleague Richard Firestone found the first evidence that this cooling was caused by the fall of an asteroid in 2007, and in sedimentary rocks at the bottom of a lake in Mexico, but their findings are not many geologists believe.

They thought found Kennett and his associates ” space “metals and microspheres should not be a meteorite allegedly falling on the territory of the province of Quebec, as the result of some local geochemical processes. If the fall really happened, they wrote, then traces of it in the form of a thin layer of “meteor” species could be found on all continents of the world.

Kennett and his colleagues presented evidence of the existence of such a “boundary layer” how geologists call this layer at least four continents, excavated in 12 countries in Europe, North and South America, Asia and Africa. According to the researchers, the likelihood that they were left the same event, exceed 95% of that in practice proves that “driasovy meteorite” still existed.

By calculating and comparing the age of these “border layers “, the authors concluded that the cataclysm took place about 12,835 years ago, plus or minus 100 years. This date is almost one in one coincides with the time of the fall of the meteorite, which traces in the form of platinum inclusions were found in Greenland ice.

“The main thing is that all the indirect indicators suggest the existence of a causal link between the fall and driasovym cooling. In other words, we can now say that this cataclysm caused a sharp drop in temperature, “- concludes Kennett.