A team from NASA has announced the discovery of a new giant crater which is covered by almost two kilometers of ice in the North West of Greenland. The details of the study have been published in the Geophysical Research Letters.
Craters under ice
It is becoming increasingly rare to stumble across new craters which have been formed by asteroids hitting Earth. So how has this new discovery come about? Last November the discovery of an enormous crater 500 m under Greenland ice was announced. It was created by an asteroid measuring about 1 km wide which hit Earth several thousand years ago. This was an out of the ordinary discovery. However only a few days ago another crater has been discovered only 180 km away from the first crater discover in November last year. Measuring more than 36 km, this newly discovered crater is now the 22nd biggest crater from an asteroid impact found on Earth. The biggest crater is Vredefort crater which stretches out more than 300 km in South Africa.
“We have studied the Earth in different ways from the ground, sky and from space – it is exciting to announce that such discoveries are still possible,” declared Joe MacGregor, a glaciologist at the Goddard Space Flight Center, from NASA in Greenbelt, Maryland. This is a big surprise for researchers. Before the two craters were discovered researchers believed that these formations had long since eroded due the the continuous movement of the ice covering the surface.
The researcher managed to stumble across the second crater by checking the topography maps of the rocks under Greenland ice after the first discovery. If the two impacts seem to be quite close, they don’t appear to come from the same event. “The layers of ice underneath the second crater are clearly much older than those found above the Hiawatha. The second crater is also above two times more eroded,” explains the researcher. Everything that is known about the first crater is that it was formed prior to the Pleistocene period (about 12, 000 years ago.)
Just like the first crater, this second discovery would have been formed by an asteroid that measured about several hundred metres wide. Such an impact would have projected tonnes of debris into the atmosphere and could have potentially affected the global climate. The ice melt and the resulting cold water could have also affected the sea current around the entire region.