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An international team of researchers has discovered a large meteorite impact crater concealed under more than half a mile (about 1 km) of ice in northwestern Greenland. The crater – the first of any size under Greenland's icecap – is one of the 25 largest craters of impact on Earth, measuring about 300 meters deep and over 30 km in diameter, larger than Paris. or the ring road around Washington, DC
According to the study, the crater was formed less than 3 million years ago, when an iron meteorite of more than one kilometer wide s & # 39; is crushed in northwestern Greenland. The resulting depression was then covered with ice.
Kurt Kjær is a professor at the Center for GeoGenetics of the Natural History Museum of Denmark and lead author of the study, published on 14 November 2018 in a peer-reviewed journal. Progress of science. Kjær said the state of the crater indicates that the impact could have occurred towards the end of the last ice age, which would place the crater among the youngest on the planet. Kjær said:
The crater is exceptionally well preserved, which is surprising because glacier ice is an extremely effective erosive agent that would have quickly eliminated traces of impact.
Location of the crater of the Hiawatha Glacier in Greenland. Image via Wikipedia.
Radar data from an intensive aerial survey of the Hiawatha crater in May 2016 are presented here as aqua-colored curtains. A blue arrow points to the central summit of the crater. Image via NASA / Cindy Starr.
The researchers first discovered the crater in July 2015 as they inspected a new map of the topography beneath the Greenland icecap. The chart was made using ice-penetrating radar data primarily from NASA's IceBridge Operation, a multi-year airborne mission to track changes in polar ice, as well as previous NASA missions. Scientists have noticed a huge circular depression previously unexamined under the Hiawatha Glacier, located at the edge of the ice cap in northwestern Greenland.
Using satellite images, the team also examined the ice surface in the Hiawatha Glacier region and quickly found the trace of a circular pattern on the surface of the ice that corresponds to the one observed on the topography map of the bed.
The Hiawatha impact crater is covered by the Greenland Ice Cap, which flows just beyond the edge of the crater, forming a semicircular edge. Part of this edge (top of the photo) and a tongue of ice that crosses the edge of the crater are shown in this photo taken during a NASA Operation IceBridge flight on April 17, 2018. Image by NASA / John Sonntag .
To confirm their suspicions, in May 2016, the team sent a search aircraft to fly over the Hiawatha Glacier and map the crater and the overlying ice with the help of a state-of-the-art radar of technology. In the summer of 2016 and 2017, the research team returned to the Hiawatha Glacier to map tectonic structures in the rock at the foot of the glacier and collect sediment samples removed from the depression through a meltwater channel. .
Nicolaj Larsen from the University of Aarhus in Denmark is one of the authors of the study. Larsen said in a statement:
Part of the quartz sand from the crater had flat deformation characteristics indicating a violent impact; this is conclusive proof that the depression under the Hiawatha Glacier is a meteorite crater.
Conclusion: The researchers have identified a large meteorite impact crater that is hiding under the ice of Greenland.
Source: A large impact crater under the Hiawatha Glacier in northwestern Greenland
Via NASA
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