Discovery of a meteorite crater in Greenland: a crater under the ice indicates a huge impact

Like all the inner planets of the solar system, the Earth has repeatedly been the target of asteroids and meteorites throughout its history. These missiles would bring to our planet vital elements of life such as carbon and hydrogen, but they also triggered global disasters – such as the disappearance of dinosaurs. Many of these craters still show many craters.

Circle under the ice

Such a trace of a past impact that researchers have discovered in Greenland: hidden under the ice. In the footsteps of this crater, Kurt Kjær of the University of Copenhagen and his colleagues performed a radar badysis. "We have collected a lot of data over the last few decades to find out what Greenland looks like under the ice," said co-author John Paden of the University of Kansas at Lawrence.

One day, the research team noticed a crater-like depression of about 31 kilometers in diameter and 320 meters deep under the Hiawatha Glacier, in northwestern Greenland. On the satellite images also, a circular structure was visible at this place. Has there really been an impact here? In order to shed more light on this issue, the scientists then conducted new targeted radar investigations – and confirmed their suspicions.

An iron meteorite?

The data revealed that the young ice on the job in question is flawless. About one kilometer deep, however, show obvious traces of destruction and the ice is strewn with debris. Sediment samples from the bed of a river coming out of the Hiawatha Glacier, among other things, brought quartz grains to light, mineral minerals with distinct shock characteristics.

In subsequent research, researchers also observed high concentrations of nickel, cobalt, chromium, and gold in the sediments of the river. In his opinion, this suggests that the impact was caused by a rare ferrous meteorite. These meteorites probably originate from the core of ancient asteroids and would account for only about five percent of all meteorites.

"Relatively young"

In addition, the size of the projectile can limit the team to approximately. According to his calculations, the meteorite that would have left the huge crater under the pack ice would have had a diameter of at least one kilometer. It would have been about as big as the Brocken, which struck 15 million years ago in the Nördlinger Ries.

However, it is difficult to know when exactly the meteorite fell to the ground. "We have not been able to go out directly with someone," Kjær said. "Because the crater is exceptionally well preserved despite the huge eroding forces of ice, we badume that it is still relatively young from a geological point of view." Specifically, the researchers clbadified the impact of Hiawatha in the Pleistocene era. Thus, the meteorite could have been taken a little less than three million years ago, but also only 12,000 years ago.

Consecutive event

But every time it fell, it seemed obvious that the consequences for life on earth could have been enormous. "Wrecks have been thrown into the atmosphere, have affected the climate – and eventually caused the ice to melt, which could have had a sudden impact on the Nares Strait, between Canada and Greenland, and affect about the ocean currents in the area, "says Paden.

"The next step will be to date the impact accurately, before we can fully understand the impact of the Hiawatha impact on our planet," Kjær said. (Science Advances, 2018, doi: 10.1126 / sciadv.aar8173)