They discover the crater that produced an asteroid under the ice of Greenland



Only by its dimensions is it historical. It is one of the 25 largest in the world

They discover the crater that produced an asteroid under the ice of Greenland

Map of the rocky topography under the ice cap and the ice-free soil around the impact crater / The natural history museum of Denmark

In 2015, the geochemist at the University of Copenhagen, Kurt Kjær, noticed a strange depression under the Greenlandian Hiawatha glacier. A study now reveals that what he had just found was an impact crater of more than 30 kilometers wide. The origin: an asteroid.

It is only because of its dimensions that the crater is already historic, because it is one of the 25 largest found on earth. Its history and origin, however, is what really interests science. When and how do we have a huge impact on the continental ice sheet in Greenland?

It appears that not so long ago, not at least in terms of the history of our planet since a meteorite of at least one kilometer wide has created it.

extraordinary evidendias

As Kjær has explained, extraordinary discoveries require extraordinary proof. We have more than a decade of radar research data, a technique to look through the ice with which we build a map of the topography on the glacier. In 2015, we encountered the large circular depression under the layer. We knew immediately that this was something special, but at the same time it was clear that it would be difficult to confirm the origin of the depression.

continue with the studies

Since then, the past three years have worked and studied the area, photographed and used a new radar developed by the University of Kansas.

You can see the round structure at the edge of the ice cap, especially if you fly high enough. For the most part, the crater can not be seen through the window of the aircraft. It is funny that no one thought so far: "Hey, what is that semicircular property in there? & # 39; From the plane it is subtle and difficult to see unless you already know it is there.

By using satellite images made with a low sun angle and accentuating the hills and valleys in the ice cap terrain, you can see the circle of the entire crater in these images.

Kjær has also explained that the stranger reminded him from the beginning of the meteor of Cape York that crashed in Greenland about 10,000 years ago, the same one that left large pieces of iron in the same region as the glacier, could there be a link to it? impact event?

The recently published work does not conclude that this is the case, but they do present several convincing lines of evidence that suggest that the crater has probably been formed in the last 100,000 years.

The geochemical analysis of the sediments at the glacier also showed evidence of impact processes, indicating the presence of iron. These include quartz, which is often found in impact zones, and glass, which is made of silica in the soil due to the intense heat of impact.

As far as age is concerned, the researchers believe that the evidence they provide is strong enough to think that it happened before Greenland covered itself with ice.

It is hard to be wrong if we think that the range from 3 million years ago to just 12 thousand years ago, runs towards the end of the last ice age. According to Kjær: I think it happened when Greenland was covered with ice and therefore would melt a considerable amount of meltwater. This meltwater will go to the south to a sensitive point in the climate system.

they want to know the exact date of the impact

Currently, however, they try to drill through the ice to obtain samples of the rock that can be used for dating and the exact date of impact.

A crater as big as the window he has opened for science. His study raises all kinds of questions, such as the possibility of a rain of asteroids or the fact that the impact caused a global cooling event that could have a major impact on the old populations of people.


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