Signs of giant comet impacts found in cores

Copious ammonium may be evidence of a 50-billion-ton strike at the end of the ice age

By Sid Perkins, 15:45 PM March 30, 2010

A new study cites spikes of ammonium in Greenland ice cores as evidence for a giant comet impact at the end of the last ice age, and suggests that the collision may have caused a brief, final cold snap before the climate warmed up for good.

In the April Geology, researchers describe finding chemical similarities in the cores between a layer corresponding to 1908, when a 50,000-metric-ton extraterrestrial object exploded over Tunguska, Siberia, and a deeper stratum dating to 12,900 years ag...

Source URL: https://www.sciencenews.org/article/signs-giant-comet-impacts-found-cores