In November 2018, an international team of researchers announced the discovery of a 31-kilometer impact crater hidden under an ice layer in northern Greenland, but according to NASA, an even larger scar from a meteorite is located at a distance of only 183 kilometers. If the discovery is confirmed, the newly discovered almost 36 kilometer crater will be among the 22 largest on Earth.
For many years we have been exploring the Earth in various ways: from the surface, from the air and from space. All the more surprising that such discoveries are still possible.
-Joe McGregor from the NASA Center for Space Flight. Goddard, who participated in the opening of both craters
Previously it was thought that most of the evidence of past impacts in Greenland and Antarctica was erased due to the inexorable erosion caused by overlying layers of ice. However, after the discovery of the first crater, Joe McGregor and his team more thoroughly analyzed the topographic maps of the regions in Greenland, compiled using spectroradiometers on board the NASA satellites Terra and Aqua. As a result, scientists stumbled upon a “drawing” resembling a crater, 183 kilometers south-east of the Hiawat Glacier.
To confirm their suggestion of the presence of a second impact crater, the researchers studied the raw radar images used to map the bedrock topography under the ice. What they saw are distinctive features of the influence of meteorites: a bowl-shaped depression surrounded by a rock raised along the edges, with centrally located hills. And, although the structure found in the images was not as round as the crater under the Hiawat Glacier, the scientists were able to determine its diameter. In addition, measurements in the framework of the research program IceBridge showed in this area a negative gravitational anomaly, which is typical for impact craters.
The only other circular structure that could have reached a similar size is the destroyed volcanic caldera. However, areas of known volcanic activity in Greenland are located at a distance of several hundred kilometers from this place. In addition, the volcano should have a clear magnetic anomaly, and we do not observe this.
-Joe MacGregor
Craters, according to researchers, were likely to have been formed at different times, but the possibility that they are “twins” cut out on the surface of the Earth as a result of the fall of a double asteroid is not excluded.
New giant crater found under the ice in Greenland
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