NASA has revealed that researchers have discovered what may be a second impact crater in Greenland, this one buried under more than a mile of ice. The site measures 22-miles-wide and would be the 22nd largest impact crater on Earth, assuming researchers verify it as such. The discovery follows an announcement in November 2018 that revealed the existence of a 19-mile-wide crater under Greenland’s Hiawatha Glacier.
The November 2018 discovery marked the first time humans have found a meteorite impact crater beneath an ice sheet. The newest possible crater is located only 114 miles from the first, though scientists say they likely weren’t created at the same time. The second (potential) impact site is larger at more than 22 miles across, possibly making it the 22nd largest impact crater to be discovered on our planet.
The first crater’s discovery was exciting for multiple reasons, not the least of which is that until that point, researchers had believed that evidence of impacts in Greenland’s past would have been eliminated by erosion. Following the discovery, researchers have looked for signs of other craters using topographic maps and satellite imagery.
It was during that project that NASA glaciologist Joe MacGregor noticed what NASA describes as a circular pattern located about 114 miles from the first site. Raw radar images of the bedrock located below the ice were found to have characteristics akin to impact craters, including an elevated rim and bowl-shaped depression.
The potential exists that a collapsed volcanic caldera could have created the impression, but evidence indicating a volcano are absent. Signs point toward the newest impact crater being older than the one discovered in November, though the potential remains that both craters were created at the same time. This wouldn’t be the first time nearby craters have been discovered on Earth that formed at different times.