An international team, led by researchers from the University of Copenhagen (Denmark), discovered a 31-km impact crater hidden under an ice layer in northern Greenland. This is the first time a crater has been discovered on one of the continental ice sheets of the Earth. Researchers worked for three years to test their discovery, originally made in 2015.
The crater is exceptionally well preserved, and this is surprising, because the glacier is an incredibly effective erosion agent that would erase traces of impact. This means that it must be quite young from a geological point of view. The condition of the crater convincingly testifies to its formation already after the ice began to cover Greenland, so it did not appear earlier than 3 million years ago, and perhaps only 12,000 years ago, that is, at the end of the last ice age.
-Professor Kurt Kjar , lead author of the study from the Center for Geogenetics Museum of Natural History at the University of Copenhagen
The diameter of the crater places it among the 25 largest impact craters on Earth. It was formed when a metal meteorite crashed into northern Greenland, and then was hidden under a kilometer-long layer of ice.
Giant crater
The crater was discovered in July 2015, when researchers tested a new topographic map under the ice layer of Greenland. They noticed a huge but previously undetected circular depression beneath the Hyavath Glacier, at the very edge of the ice sheet in northern Greenland.
We immediately realized that this was something special, but at the same time it became clear that it would be difficult to determine the origin of the depression,.
-Professor Kurt Kyar
In the courtyard of the Geological Museum in Copenhagen, not far from the windows of the Geogenetic Center, there is a 20-ton iron meteorite found in North Greenland near the Hyavath Glacier. “We immediately suggested that the deepening may be a previously undescribed meteor crater, but we lacked evidence,” says Associate Professor Nikolai Larsen of Aarhus University (Denmark).
Key evidence
Suspicions that the giant depression was a meteor crater intensified when the team sent a research aircraft from the Institute of Polar and Marine Research. Alfred Wegener (Germany) to fly over the Hyavath Glacier and display the crater and overlying ice using the latest ice radar.
The previous radar measurements of the Hyavath glacier were part of NASA’s long-term effort to map the Greenland ice sheet. To test the hypothesis required targeted radar research. Scientists from the Alfred Wegener Institute and the University of Kansas (USA) used the next-generation radar system, which exceeded all expectations and showed depression in stunning detail: a clear circular rim, central elevation, ice stratification and basal debris.
In the summer months of 2016 and 2017, the research team returned to the site to display tectonic structures at the foot of the glacier and collect sediment samples washed out of the depression through the melt-water channel.
Some particles of quartz, washed out of the crater, had flat deformation signs indicating a strong impact, and this irrefutably proves that the depression under the Hyavath glacier is a meteorite crater.
-Nikolai Larsen
Consequences of the impact on the climate and life of the Earth
Earlier studies have shown that large impacts can significantly affect the Earth’s climate, which in turn has serious consequences for life on the planet. Therefore, it is very important to find out when and how this influence of a meteorite on the Hyavath Glacier affected the history of the Earth.
The next step of the investigation will be to determine the impact impact. This is a problem, as material from the bottom of the structure that melted during the collision will be needed, but it is crucial if we want to understand how the impact on the Hyavath glacier affected life on Earth.
-Professor Kurt Kjar
Under the glacier in Greenland discovered a giant crater from a kilometer diameter meteorite
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