Greenland is covered with one of the largest ice sheets on the planet, but under its frozen outlook the landscape is sharper than we ever thought.
Buried under two miles of ice, researchers believe they have found a second massive impact crater hidden in the northwest corner of the world's largest island.
As scientists are exploring more and more of our planet, new shooters are rarely found, especially in icy places like Greenland or Antarctica.
In fact, before we found the first crater of Hiawatha last November, most experts simply assumed that any evidence of past impact would be blunted by the relentless erosion of the ice in these regions.
So it's quite an exception that within a few months, we've now revealed how it looks Two of these ranges, both of them in Greenland.
"We have explored the Earth in many different ways, from land, air and space ̵
The discovery is made by the possibility through a combination of satellite imagery and radar data, allowing researchers to "see" deep under the ice. 19659002] It was here that they noticed a circular pattern, only 183 km (114 miles) from the first shot crater. With dimensions more than 36 km (22 miles), the model is found to have similar characteristics to the adjacent impact crater – in particular, a flat, cup-shaped depression surrounded by a raised ridge and centrally located peaks.
Although it is not as clearly defined as the Haayav's crater, if it is confirmed that this second impression is the fingerprint of a meteorite, it will be the 22nd largest crater of impact ever found on the Earth – three points in front of the Hiatus. "The only other circular structure that could reach that size would be a collapsed volcanic caldera," McGregor said. "But areas with a known volcanic activity in Greenland are a few hundred kilometers of positive magnetic anomaly, and we do not see it at all."
But even if Hajava has a brother or sister, it is unlikely that both craters The authors predict that the second one is not only larger but also older
Analyzing the ice cores being tested nearby, McGregor and his team have come to the conclusion that the area has not been disturbed by a strong strength for at least 79 000. This may mean two things: the impact is which occurred more than 79 000 years ago, or has happened quite recently, and the broken ice just left off.
However, the assumption of age for the crater is a tough business, in which case the researchers have calculated that it should have been between hundreds of thousands of years one hundred million years ago, the ice would erode the crater to its present form. "The ice layers above this second crater are unmistakably older than those over Hiawatha, and the second crater is about twice as eroded," explains MacGregor. "If both are formed at the same time, then thick ice over the second crater would be more balanced with the crater much faster than Hiawatha.
Also, it is not so unusual, statistically speaking, that two different meteorites land so close together. Two sets of neighboring craters of different ages have already been discovered in Ukraine and Canada, and computer models confirm that these events are not so unheard of in record for Earth craters.
"The existence of a third pair of unrelated craters is modestly surprising, but we do not think it is unlikely," McGregor said.
"In general, the evidence we have gathered shows that this new structure is very likely a crash, but at the moment it seems unlikely to be a twin."
This study was published in Geophysical Research Letters .