MacGregor, NASA colleagues and a team of fellow earth scientists believe they have detected an immense impact crater beneath the ice sheet that underpins Greenland. The first such finding came to light this past November when researchers alerted the world to the presence, elsewhere in northwest Greenland, of a 31-kilometre-wide subglacial structure they dubbed the Hiawatha crater. Of the 200 or so earthly impact craters whose existence scientists have confirmed, only two pairs are as spatially close despite forming at vastly different times. Though the craters’ sizes and circular shapes are similar, the second crater looks as though it is twice as eroded, and the ice above it is significantly less disturbed, leading the researchers to surmise that the Hiawatha crater is younger. That task, MacGregor said, will be simpler at the Hiawatha crater than at the second crater, where the ice is twice as thick at two kilometres deep.

Source: National Post February 13, 2019 23:37 UTC