New evidence that cosmic impact caused Younger Dryas extinctions
(Phys.org) —A period of rapid, intense cooling, known as the Younger Dryas, took place about 13,000 years ago. Scientists think this sudden change in climate caused the extinction of many large mammals, such as the mammoth, and was the reason for the disappearance of North America's Clovis people. According to one hypothesis, a cosmic impact caused the climate to cool. Using data from the Greenland ice core, Michail Petaev and his colleagues at Harvard University have found what appears to be evidence of this impact. Their research appears in the Proceedings of the National Academy of Sciences.
Measurements of oxygen isotopes in the Greenland ice core show that around 13,000 years ago an episode of rapid cooling, which lasted only about 1,000 years, occurred. During this time, many megafauna became extinct and evidence of the Clovis people, one of the earliest human societies to inhabit the Americas, disappeared from the archeological record.
According to one hypothesis, a cometary airburst triggered massive wildfires, which caused the climate to cool. Many scientists have rejected this hypothesis, citing lack of sufficient evidence, in favor of others. The most widely accepted one says that during the deglaciation process, fresh water from the proglacial lake Agassiz discharged into the Arctic Ocean, altering ocean currents.
http://phys.org/news/2013-08-evidence-cosmic-impact-younger-dryas.html
also here
http://www.livescience.com/7283-catastrophic-comet-chilled-killed-ice-age-beasts.html
And here
http://www.space.com/14793-comet-earth-impact-younger-dryas.html
and here too
http://wattsupwiththat.com/2014/08/29/younger-dryas-climate-event-solved-via-nanodiamonds-it-was-a-planetary-impact-event/
meteor showers are leftover comets
http://www.space.com/9376-comets-meteor-showers.html
= new reply since forum marked as read