A possible second large subglacial impact crater in northwest Greenland

It is increasingly rare to find new large impact craters on Earth, let alone such craters buried beneath ice. This study by MacGregor et al. describes a possible impact crater buried beneath two kilometers of ice in northwest Greenland. The circular structure is more than 36 kilometers wide, and both its shape and other geophysical properties are consistent with an impact origin. If eventually confirmed as an impact crater, it would be only the second found beneath either of Earth’s ice sheets. The first was the Hiawatha impact crater, which is also in northwest Greenland and only 183 kilometers away from this new structure, so this team also evaluated whether these two craters could be related. They are similarly sized, but the candidate second crater appears more eroded and ice above it is much less disturbed than above the Hiawatha impact crater. Statistical analysis of the frequency of two unrelated but nearby large impacts indicates that it is improbable but not impossible that this pair is unrelated. This study expands knowledge of the impact history of the Earth and raises the question as to how many other impact craters buried beneath ice have yet to be found.