A large impact crater beneath the ice in northwest Greenland
A rarely considered element of Arctic system change in the Pleistocene is the possibility and consequences of any large high-latitude impact. We report the discovery of a large impact crater hidden beneath Hiawatha Glacier in northwest Greenland. From airborne radar surveys, we identify a 31-kilomet...
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2018
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ftcopenhagenunip:oai:pure.atira.dk:publications/75a59a46-3f1b-4c82-80c5-e1c83c44f0d6 2023-05-15T14:58:32+02:00 A large impact crater beneath the ice in northwest Greenland MacGregor, J. A. Kjær, K. H. Larsen, N. K. Binder, T. Bjork, A. A. Eisen, O. Fahnestock, M. A. Funder, S. Garde, A. A. Haack, H. Helm, V. Houmark-Nielsen, M. Kjeldsen, K. K. Khan, S. A. Machguth, H. McDonald, Iain Morlighem, Mathieu Mouginot, J. Paden, J. D. Waight, T. E. Weikusat, C. Willerslev, E. 2018 https://curis.ku.dk/portal/da/publications/a-large-impact-crater-beneath-the-ice-in-northwest-greenland(75a59a46-3f1b-4c82-80c5-e1c83c44f0d6).html http://adsabs.harvard.edu/abs/2018AGUFMPP41B.01M eng eng info:eu-repo/semantics/closedAccess MacGregor , J A , Kjær , K H , Larsen , N K , Binder , T , Bjork , A A , Eisen , O , Fahnestock , M A , Funder , S , Garde , A A , Haack , H , Helm , V , Houmark-Nielsen , M , Kjeldsen , K K , Khan , S A , Machguth , H , McDonald , I , Morlighem , M , Mouginot , J , Paden , J D , Waight , T E , Weikusat , C & Willerslev , E 2018 , ' A large impact crater beneath the ice in northwest Greenland ' . < http://adsabs.harvard.edu/abs/2018AGUFMPP41B.01M > 9315 Arctic region GEOGRAPHIC LOCATIONDE: 1621 Cryospheric change GLOBAL CHANGEDE: 1630 Impacts of global change GLOBAL CHANGEDE: 1637 Regional climate change GLOBAL CHANGE conferenceObject 2018 ftcopenhagenunip 2022-11-23T23:53:27Z A rarely considered element of Arctic system change in the Pleistocene is the possibility and consequences of any large high-latitude impact. We report the discovery of a large impact crater hidden 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. Conference Object Arctic Climate change glacier Greenland Ice Sheet University of Copenhagen: Research Arctic Greenland |
institution |
Open Polar |
collection |
University of Copenhagen: Research |
op_collection_id |
ftcopenhagenunip |
language |
English |
topic |
9315 Arctic region GEOGRAPHIC LOCATIONDE: 1621 Cryospheric change GLOBAL CHANGEDE: 1630 Impacts of global change GLOBAL CHANGEDE: 1637 Regional climate change GLOBAL CHANGE |
spellingShingle |
9315 Arctic region GEOGRAPHIC LOCATIONDE: 1621 Cryospheric change GLOBAL CHANGEDE: 1630 Impacts of global change GLOBAL CHANGEDE: 1637 Regional climate change GLOBAL CHANGE MacGregor, J. A. Kjær, K. H. Larsen, N. K. Binder, T. Bjork, A. A. Eisen, O. Fahnestock, M. A. Funder, S. Garde, A. A. Haack, H. Helm, V. Houmark-Nielsen, M. Kjeldsen, K. K. Khan, S. A. Machguth, H. McDonald, Iain Morlighem, Mathieu Mouginot, J. Paden, J. D. Waight, T. E. Weikusat, C. Willerslev, E. A large impact crater beneath the ice in northwest Greenland |
topic_facet |
9315 Arctic region GEOGRAPHIC LOCATIONDE: 1621 Cryospheric change GLOBAL CHANGEDE: 1630 Impacts of global change GLOBAL CHANGEDE: 1637 Regional climate change GLOBAL CHANGE |
description |
A rarely considered element of Arctic system change in the Pleistocene is the possibility and consequences of any large high-latitude impact. We report the discovery of a large impact crater hidden 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. |
format |
Conference Object |
author |
MacGregor, J. A. Kjær, K. H. Larsen, N. K. Binder, T. Bjork, A. A. Eisen, O. Fahnestock, M. A. Funder, S. Garde, A. A. Haack, H. Helm, V. Houmark-Nielsen, M. Kjeldsen, K. K. Khan, S. A. Machguth, H. McDonald, Iain Morlighem, Mathieu Mouginot, J. Paden, J. D. Waight, T. E. Weikusat, C. Willerslev, E. |
author_facet |
MacGregor, J. A. Kjær, K. H. Larsen, N. K. Binder, T. Bjork, A. A. Eisen, O. Fahnestock, M. A. Funder, S. Garde, A. A. Haack, H. Helm, V. Houmark-Nielsen, M. Kjeldsen, K. K. Khan, S. A. Machguth, H. McDonald, Iain Morlighem, Mathieu Mouginot, J. Paden, J. D. Waight, T. E. Weikusat, C. Willerslev, E. |
author_sort |
MacGregor, J. A. |
title |
A large impact crater beneath the ice in northwest Greenland |
title_short |
A large impact crater beneath the ice in northwest Greenland |
title_full |
A large impact crater beneath the ice in northwest Greenland |
title_fullStr |
A large impact crater beneath the ice in northwest Greenland |
title_full_unstemmed |
A large impact crater beneath the ice in northwest Greenland |
title_sort |
large impact crater beneath the ice in northwest greenland |
publishDate |
2018 |
url |
https://curis.ku.dk/portal/da/publications/a-large-impact-crater-beneath-the-ice-in-northwest-greenland(75a59a46-3f1b-4c82-80c5-e1c83c44f0d6).html http://adsabs.harvard.edu/abs/2018AGUFMPP41B.01M |
geographic |
Arctic Greenland |
geographic_facet |
Arctic Greenland |
genre |
Arctic Climate change glacier Greenland Ice Sheet |
genre_facet |
Arctic Climate change glacier Greenland Ice Sheet |
op_source |
MacGregor , J A , Kjær , K H , Larsen , N K , Binder , T , Bjork , A A , Eisen , O , Fahnestock , M A , Funder , S , Garde , A A , Haack , H , Helm , V , Houmark-Nielsen , M , Kjeldsen , K K , Khan , S A , Machguth , H , McDonald , I , Morlighem , M , Mouginot , J , Paden , J D , Waight , T E , Weikusat , C & Willerslev , E 2018 , ' A large impact crater beneath the ice in northwest Greenland ' . < http://adsabs.harvard.edu/abs/2018AGUFMPP41B.01M > |
op_rights |
info:eu-repo/semantics/closedAccess |
_version_ |
1766330678210723840 |