A giant crater left by the impact of a 30-kilometer asteroid three billion years ago was found in western Greenland by a joint team of Russian and EU researchers.
The crater was first discovered in 2009 by geologist Adam Garde who found structural anomalies in rock formations near the town of Maniitsoq, according to an article to be published in Earth and Planetary Science Letters.
However, it took researchers three years to establish that the crater was left by a celestial body and not volcanic activity.
Three billion years of ongoing geological processes wiped away most traces of the impact near Maniitsoq, but the rock anomalies remained, waiting for the researchers to study them.
The crater is 100 kilometers in diameter but under different circumstances the impact trace could have spanned up to 600 kilometers, the study said.
The Earth's largest impact crater, Vredefort in South Africa, is 300 kilometers in diameter. At two billion years, it was also the oldest until the new discovery. Chicxulub Crater in Mexico, believed to be the trace of the asteroid that killed the dinosaurs 65 million years ago, is 170 kilometers in diameter.
The impact of a 30-kilometer asteroid can evaporate an average country and even trigger a new mass extinction event, killing all higher life-forms, geologists said.
