A Possible Second Large Subglacial Impact Crater in Northwest Greenland

• Published in: Geophysical research letters Vol. 46; no. 3; pp. 1496 - 1504
• Main Authors: MacGregor, Joseph A., Jr, William F. Bottke, Fahnestock, Mark A, Harbeck, Jeremy P., Kjaer, Kurt H., Paden, John D., Stillman, David E., Studinger, Michael
• Format: Journal Article
• Language: English
• Published: Goddard Space Flight Center Wiley / American Geophysical Union 16-02-2019; John Wiley & Sons, Inc
• Subjects: Buried structures; Craters; Earth; Geophysics; Geosciences (General); Glaciation; Gravity; Gravity anomalies; Greenland; Greenland ice sheet; Ice; ice sheet; Ice sheets; Impact analysis; impact crater; Morphology; Satellites; Statistical analysis; Statistical methods; Uplift; Greenland; Ice Sheet; Greenland; Impact Crater
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2018GL078126

Following the discovery of the Hiawatha impact crater beneath the northwest margin of the Greenland Ice Sheet, we explored satellite and aerogeophysical data in search of additional such craters. Here we report the discovery of a possible second subglacial impact crater that is 36.5‐km wide and 183 km southeast of the Hiawatha impact crater. Although buried by 2 km of ice, the structure's rim induces a conspicuously circular surface expression, it possesses a central uplift, and it causes a negative gravity anomaly. The existence of two closely spaced and similarly sized complex craters raises the possibility that they formed during related impact events. However, the second structure's morphology is shallower, its overlying ice is conformal and older, and such an event can be explained by chance. We conclude that the identified structure is very likely an impact crater, but it is unlikely to be a twin of the Hiawatha impact crater.