miércoles, 15 de febrero de 2017

Clovis Culture, Ice Age Fauna Weren’t Wiped Out by Cosmic Impact, Study Finds

A physicist says his latest research may finally put to rest one of the most vexing theories about America’s natural history: that the giant fauna of the Ice Age — and the culture of humans who hunted them — were wiped out by a cosmic impact.

Studies of rock samples from the Channel Islands of California to the creeks of Oklahoma have failed to turn up any evidence, he says, that supports what’s known as the Younger Dryas Impact Hypothesis.

The missing evidence? Diamonds.

For a decade, the impact theory has posited that a period of sudden cooling that occurred around 12,900 years ago, known as the Younger Dryas event, was caused by a collision with Earth by a meteorite, comet, or some other celestial object.

Experts don’t dispute that Younger Dryas cold snap actually happened. The most widely held theory is that it was caused by rapid melting of glaciers at the end of the Ice Age, which inundated the northern oceans with fresh water and created a sudden change in ocean currents and, therefore, climate patterns. [...] Western Digs