A large impact crater beneath Hiawatha Glacier in northwest Greenland
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A large impact crater beneath Hiawatha Glacier in northwest Greenland. / Kjær, Kurt H.; Larsen, Nicolaj Krog; Binder, Tobias; Bjørk, Anders Anker; Eisen, Olaf; Fahnestock, Mark; Funder, Svend Visby; Garde, Adam A.; Haack, Henning; Helm, Veit; Houmark-Nielsen, Michael; Kjeldsen, Kristian Kjellerup; Khan, Shfaqat; Machguth, Horst; McDonald, Iain; Morlighem, Mathieu; Mouginot, Jéremie; Paden, John D.; Waight, Tod Earle; Weikusat, Christian; Willerslev, Eske; MacGregor, Joseph.
In: Science Advances, Vol. 4, No. 11, eaar8173, 2018.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - A large impact crater beneath Hiawatha Glacier in northwest Greenland
AU - Kjær, Kurt H.
AU - Larsen, Nicolaj Krog
AU - Binder, Tobias
AU - Bjørk, Anders Anker
AU - Eisen, Olaf
AU - Fahnestock, Mark
AU - Funder, Svend Visby
AU - Garde, Adam A.
AU - Haack, Henning
AU - Helm, Veit
AU - Houmark-Nielsen, Michael
AU - Kjeldsen, Kristian Kjellerup
AU - Khan, Shfaqat
AU - Machguth, Horst
AU - McDonald, Iain
AU - Morlighem, Mathieu
AU - Mouginot, Jéremie
AU - Paden, John D.
AU - Waight, Tod Earle
AU - Weikusat, Christian
AU - Willerslev, Eske
AU - MacGregor, Joseph
PY - 2018
Y1 - 2018
N2 - We report the discovery of a large impact crater beneath Hiawatha Glacier in northwest Greenland. From airborne radar surveys, we identify a 31-kilometer-wide, circular bedrock depression beneath up to a kilometer of ice. This depression has an elevated rim that cross-cuts tributary subglacial channels and a subdued central uplift that appears to be actively eroding. From ground investigations of the deglaciated foreland, we identify overprinted structures within Precambrian bedrock along the ice margin that strike tangent to the subglacial rim. Glaciofluvial sediment from the largest river draining the crater contains shocked quartz and other impact-related grains. Geochemical analysis of this sediment indicates that the impactor was a fractionated iron asteroid, which must have been more than a kilometer wide to produce the identified crater. Radiostratigraphy of the ice in the crater shows that the Holocene ice is continuous and conformable, but all deeper and older ice appears to be debris rich or heavily disturbed. The age of this impact crater is presently unknown, but from our geological and geophysical evidence, we conclude that it is unlikely to predate the Pleistocene inception of the Greenland Ice Sheet.
AB - We report the discovery of a large impact crater beneath Hiawatha Glacier in northwest Greenland. From airborne radar surveys, we identify a 31-kilometer-wide, circular bedrock depression beneath up to a kilometer of ice. This depression has an elevated rim that cross-cuts tributary subglacial channels and a subdued central uplift that appears to be actively eroding. From ground investigations of the deglaciated foreland, we identify overprinted structures within Precambrian bedrock along the ice margin that strike tangent to the subglacial rim. Glaciofluvial sediment from the largest river draining the crater contains shocked quartz and other impact-related grains. Geochemical analysis of this sediment indicates that the impactor was a fractionated iron asteroid, which must have been more than a kilometer wide to produce the identified crater. Radiostratigraphy of the ice in the crater shows that the Holocene ice is continuous and conformable, but all deeper and older ice appears to be debris rich or heavily disturbed. The age of this impact crater is presently unknown, but from our geological and geophysical evidence, we conclude that it is unlikely to predate the Pleistocene inception of the Greenland Ice Sheet.
U2 - 10.1126/sciadv.aar8173
DO - 10.1126/sciadv.aar8173
M3 - Journal article
C2 - 30443592
VL - 4
JO - Science advances
JF - Science advances
SN - 2375-2548
IS - 11
M1 - eaar8173
ER -
ID: 209140455