A glaciologist has discovered another huge impact crater under more than a mile of ice in Greenland. This is the continuation of the November 2009 discovery of an impact crater in the same area under the Hiawatha glacier. The November discovery was the first crater ever found under the ice on Earth.
The two craters are only 183 km (114 miles) away. The November crater is 30.5 km wide (19 miles), while the new one is 35.4 km (22 miles) wide. If the most recent can be definitively confirmed as an impact crater, it will be the 22nd largest on Earth.
Joe MacGregor is the glaciologist who discovered this new crater. He works at NASA's Goddard Space Flight Center in Greenbelt, Maryland. He was also involved in the first discovery. The discovery of this new crater was published in a document in Geophysical Research Letters on February 1
The geology of the polar regions of the Earth is not well understood. Thick layers of ice obscure the rock and the characteristics of the surface. But thanks to aerofoil data and satellite data, scientists are starting to get a better idea of this. Finding craters is of great interest because they can have a global impact on the history of the climate.
A previous 2015 study examined the inventory of impact craters and concluded that finding other craters of this size was unlikely but not impossible. That study said that finding other craters larger than 6 km was not very likely, although we will probably find another 90 craters between 1 and 6 km wide. This discovery was largely based on erosion rates.
But under the ice, erosion rates are different. Will we find even more of these larger craters under the ice?
In an interview with NBC News, MacGregor said, "Once we knew from Hiawatha that there could be craters under the ice caps, it was easy enough to find the next one using a set of NASA data available to the public."  Craters under the ice in Greenland. The previously discovered crater Hiawatha is at the top left and the newly discovered crater is at the bottom right. Image Credit: J.A. MacGregor et. to the. 2019. ” class=”wp-image-141501″ srcset=”https://www.universetoday.com/wp-content/uploads/2019/02/Capture.png 853w, https://www.universetoday.com/wp-content/uploads/2019/02/Capture-250×248.png 250w, https://www.universetoday.com/wp-content/uploads/2019/02/Capture-580×575.png 580w, https://www.universetoday.com/wp-content/uploads/2019/02/Capture-768×762.png 768w, https://www.universetoday.com/wp-content/uploads/2019/02/Capture-100×100.png 100w” sizes=”(max-width: 767px) 89vw, (max-width: 1000px) 54vw, (max-width: 1071px) 543px, 580px”/>
Scientists used elevation, structure, and topography data, as well as magnetic and gravitational data, to look for other impact craters. According to MacGregor, it was not difficult to identify the potential second crater.
Because the two craters are so close, the team wondered if the two were from the same event. Although they are of similar size, there are significant differences. The second crater seems to be more eroded, and the ice on it is much less disturbed. In the paper, the authors state: "The statistical analysis of the frequency of two foreign but nearby impacts indicated that it is unlikely but not impossible that this pair is unrelated."
Asteroids are known to exist in binary pairs. About 15% of the asteroids near the Earth are binary. So it is possible that the crater pair is twin. However, surveys of asteroid populations near Earth did not find binary pairs of similarly sized asteroids. Statistically speaking, it is unlikely that these two are pairs.
There are two other pairs of craters on Earth: the first pair is the Boltysh and Obolon craters in Ukraine, the second is the Clearwater Lakes craters in Quebec, Canada. Those couples were thought to be twins of the same events, but dating with Argon and other techniques revealed large differences in age between them.
The same techniques can not be used to determine the age of these two new craters under the ice, but much of the detailed data in the study suggests that they are not the same age. For example, the overlying ice appears to be a different age for each crater. Above the first crater, the ice seems to be no more than 12,800 years old, while on the newly discovered crater, the ice seems to be at least 79,000 years old.
This discovery is still awaiting confirmation, but the morphology clearly recalls an impact crater. The question is: how many more of these craters will we find buried under the ice on Earth?
Will we find others, and will they be connected to climate change in the history of the Earth? Will they be connected to the extinctions, such as the Chicxulub impact that caused so many dinosaur problems?
Who knows. But with better remote sensing technology, we'll find them if they're there.