What appears to be an impact crater measuring approximately 31 km (19¼ mi.) across has been found buried under up to a kilometer of ice beneath Hiawatha Glacier in northwest Greenland by researchers using high-powered ice-penetrating radar and lasers. If confirmed this relatively recent impact crater which is wider than Washington D.C. or Paris, France would rank among the top 25 largest known craters in the world. It would also be the only one known in Greenland.
The circular formation possesses a clearly defined rim all the way around its circumference that is around 320 meters (1050') above the floor of the crater along with an uplifted area 50 to 70 meters (164 to 230') high in the center of the crater which Kurt Kjær, a geologist at the Natural History Museum of Denmark at the University of Copenhagen and lead author of the study that examined the formation, said is an expected feature and the result of the force of the strike.
And while the ice prevents direct examination of the site, sediment from it carried by meltwater appears to contain bits of shocked quartz which is typically associated with impact sites. Some of the grains also showed a brown color known as "toasting", which is also a sign of intense energy release. Chemical analysis of the samples revealed traces of rhodium, platinum and palladium all of which are rare in earth rocks.
Finally, a large fragment of iron meteorite at the University of Copenhagen was originally found some 300 km (186 mi.) from the possible crater.
The researchers estimate that, based on the size of the crater, the asteroid was likely some 1.2 km (0.75 mi.) across and would have weighed between 11 and 12 billion tons as it entered the atmosphere. And while it isn't possible to date the crater directly Kjær says that its condition strongly indicates that it formed after ice began to cover Greenland, meaning it is less than than 3 myo.
Still more research is needed to confirm these initial findings.
Here is the abstract which was published in the open access journal Science Advances:
Further Reading:
A large impact crater beneath Hiawatha Glacier in northwest Greenland Full Paper
Scientists Spot What May Be a Giant Impact Crater Hidden Under Greenland Ice
City-size impact crater found under Greenland ice
Massive impact crater from a kilometer-wide iron meteorite discovered in Greenland
The circular formation possesses a clearly defined rim all the way around its circumference that is around 320 meters (1050') above the floor of the crater along with an uplifted area 50 to 70 meters (164 to 230') high in the center of the crater which Kurt Kjær, a geologist at the Natural History Museum of Denmark at the University of Copenhagen and lead author of the study that examined the formation, said is an expected feature and the result of the force of the strike.
And while the ice prevents direct examination of the site, sediment from it carried by meltwater appears to contain bits of shocked quartz which is typically associated with impact sites. Some of the grains also showed a brown color known as "toasting", which is also a sign of intense energy release. Chemical analysis of the samples revealed traces of rhodium, platinum and palladium all of which are rare in earth rocks.
Finally, a large fragment of iron meteorite at the University of Copenhagen was originally found some 300 km (186 mi.) from the possible crater.
The researchers estimate that, based on the size of the crater, the asteroid was likely some 1.2 km (0.75 mi.) across and would have weighed between 11 and 12 billion tons as it entered the atmosphere. And while it isn't possible to date the crater directly Kjær says that its condition strongly indicates that it formed after ice began to cover Greenland, meaning it is less than than 3 myo.
Still more research is needed to confirm these initial findings.
Here is the abstract which was published in the open access journal Science Advances:
Further Reading:
A large impact crater beneath Hiawatha Glacier in northwest Greenland Full Paper
Scientists Spot What May Be a Giant Impact Crater Hidden Under Greenland Ice
City-size impact crater found under Greenland ice
Massive impact crater from a kilometer-wide iron meteorite discovered in Greenland
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