A large impact crater beneath Hiawatha Glacier in northwest Greenland

Kjær, Kurt H.; Larsen, Nicolaj K.; Binder, Tobias; Bjørk, Anders A.; Eisen, Olaf; Fahnestock, M. A.; Funder, Svend; Garde, Adam A.; Haack, H.; Helm, Veit; Houmark‐Nielsen, Michael; Kjeldsen, Kristian K.; Khan, Shfaqat Abbas; Machguth, Horst; McDonald, Iain; Morlighem, Mathieu; Mouginot, J.; Paden, John; Waight, Tod E.; Weikusat, Christian; Willerslev, Eske; MacGregor, Joseph A.

doi:10.1126/sciadv.aar8173

Cited by 103 publications

(116 citation statements)

References 42 publications

(52 reference statements)

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“…Also observed in this region are elevated ξ values coincident with the Hiawatha impact crater (Kjaer et al, 2018), associated 25 with channelised features (triangle; Fig. 11).…”

Section: Camp Centurymentioning

confidence: 90%

Subglacial roughness of the Greenland Ice Sheet: relationship with contemporary ice velocity and geology

Cooper¹,

Jordan²,

Schroeder³

et al. 2019

Preprint

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The subglacial environment of the Greenland Ice Sheet (GrIS) is poorly constrained, both in its bulk properties, for example geology, presence of sediment, and of water, and interfacial conditions, such as roughness and bed rheology.There is, therefore, limited understanding of how spatially heterogeneous subglacial properties relate to ice-sheet motion.Here, via analysis of two decades worth of radio-echo sounding data, we present a new systematic analysis of subglacial roughness beneath the GrIS. We use two independent methods to quantify subglacial roughness: first, the variability of along-5 track topography-enabling an assessment of roughness anisotropy from pairs of orthogonal transects aligned perpendicular and parallel to ice flow; and second, from bed-echo scattering-enabling assessment of fine-scale bed characteristics. We establish the spatial distribution of subglacial roughness and quantify its relationship with ice flow speed and direction. Overall, the beds of fast-flowing regions are observed to be rougher than the slow-flowing interior. Topographic roughness exhibits an exponential scaling relationship with ice surface velocity parallel, but not perpendicular, to flow direction in fast-flowing 10 regions, and the degree of anisotropy is correlated with ice surface speed. In many slow-flowing regions both roughness methods indicate spatially coherent regions of smooth bed, which, through combination with analyses of underlying geology, we conclude is likely due to the presence of a hard flat bed. Consequently, the study provides scope for a spatially variable hard bed/soft bed boundary constraint for ice-sheet models.

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“…Also observed in this region are elevated ξ values coincident with the Hiawatha impact crater (Kjaer et al, 2018), associated 25 with channelised features (triangle; Fig. 11).…”

Section: Camp Centurymentioning

confidence: 90%

Subglacial roughness of the Greenland Ice Sheet: relationship with contemporary ice velocity and geology

Cooper¹,

Jordan²,

Schroeder³

et al. 2019

Preprint

View full text Add to dashboard Cite

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“…These reflections are clearly conformal with each other, drape smoothly over the bed and appear generally undisturbed. This englacial age structure contrasts significantly with that of the ice overlying the Hiawatha impact crater, for which no conformal ice is unambiguously older than the beginning of the Younger Dryas at 12.8 ka and whose basal ice is heavily disturbed (Kjær et al, ).…”

Section: Resultsmentioning

confidence: 95%

“…The discovery of a new subaerial terrestrial impact crater greater than 6 km in diameter is considered improbable but not impossible (Hergarten & Kenkmann, ), while the probability of finding new subsurface craters is likely higher. The recent discovery of the subglacial Hiawatha impact crater in northwest Greenland (Kjær et al, ), new high‐resolution maps of subglacial topography (Bamber, Griggs, et al, ; Fretwell et al, ; Morlighem et al, ) and the large range of subglacial erosion rates (e.g., Koppes et al, ) all suggest that the rarely considered possibility of large subglacial impact craters beneath either ice sheet should be revisited.…”

Section: Introductionmentioning

confidence: 99%

A Possible Second Large Subglacial Impact Crater in Northwest Greenland

MacGregor

Bottke

Fahnestock

et al. 2019

Geophysical Research Letters

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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.

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“…The result was similarly when we moved the Ireland for the place of the Svalbard Island. The source of this was the hitting of the Earth with the space body in north Canada, Greenland Island [6]. This event changed the humidity in the air in whole Europe, north and middle part of Africa and on Near East.…”

Section: Why Was the City Created?mentioning

confidence: 99%

Urban Logistics: Spreading of the City Increases Food Costs

Lewandowski¹

2018

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If you want to live in city. You want to have, a house, garden and no less than two cars. Of course, you want to life in city centre. However, if price of ground is high you has decide to buy a house outside the city centre. You are not alone, because many other people think the same. Then around Your new house are placing other new houses. This process is called an urban sprawl. That is source to increasing the price of food in the shops. New territories of houses around city has extend a way of food. That is important to show how is possible to reduce these costs.

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A large impact crater beneath Hiawatha Glacier in northwest Greenland

Abstract: Researchers present the first unambiguous discovery of a 31-km-wide impact crater buried beneath the Greenland Ice Sheet.

Cited by 103 publications

References 42 publications

Subglacial roughness of the Greenland Ice Sheet: relationship with contemporary ice velocity and geology

Subglacial roughness of the Greenland Ice Sheet: relationship with contemporary ice velocity and geology

A Possible Second Large Subglacial Impact Crater in Northwest Greenland

Urban Logistics: Spreading of the City Increases Food Costs

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