Hiawatha - Hypervelocity Impact Crater

Alternate Names
Local Language
Coordinates 78° 43' 49" N; 66° 10' 57" W
Notes
  1. Located beneath the Hiawatha Glacier in NW Greenland.
Country Greenland
Region Avannaata
Date Confirmed 2018
Notes
  1. Confirmed by planar deformation features in quartz grains, post-shock hydrothermal alteration of shock lamellae, and glassy microbreccia all found within glaciofluvial sediments near the structure (Kjaer et al., 2018).
Buried? Yes
Notes
  1. Beneath a glacier (Kjaer et al., 2018).
Drilled? No
Target Type Crystalline
Notes
  1. (Kjaer et al., 2018)
Sub-Type Gneiss, Granitoid
Apparent Crater Diameter (km) 31 km
Age (Ma) 57.99 ± 0.54
Notes :
  1. 57.99 ± 0.54 Ma determined by U-Pb of shocked zircon from impact melt rock pebbles (Kenny et al., 2022) Previous age constraints: Impact structure was thought unlikely to predate the Pleistocene inception of the Greenland Ice Sheet around 2.6 Ma and the minimum age was roughly constrained by distinctive debris-containing ice detected within the crater from 12.8 to 11.7 ka (Kjaer et al., 2018).

Method :
  1. U-Pb
Impactor Type Iron
Notes
  1. (Kjaer et al., 2018) geochemical analysis of sediment indicates impactor was a fractionated iron asteroid, must have been greater than 1 km in diameter.

Advanced Data Fields

Notes

Erosion
3
  1. Rim appears to be preserved (Kjaer et al., 2018).
Final Rim Diameter
Unknown
Apparent Rim Diameter
31 km
  1. (Kjaer et al., 2018)
Rim Reliability Index
2
  1. Subdued central uplift (Kjaer et al., 2018).
Crater Morphology
Complex
Central Uplift Diameter
8km
Central Uplift Height
Unknown
Uplift Reliability Index
2
Structural Uplift
Unknown
Thickness of Seds
Target Age
Precambrian
Marine
No
Impactor Type
Iron
  1. (Kjaer et al., 2018) geochemical analysis of sediment indicates impactor was a fractionated iron asteroid, must have been greater than 1 km in diameter.
Other Shock Metamorphism
Shatter Cones
No
Planar Fractures
No
Planar Deformation Features
Yes
  1. PDF found in quartz grains (Kjaer et al., 2018).
Diaplectic Glass
No
Coesite
No
Stisovite
No
Crater Fill
Proximal Ejecta
Distal Ejecta
Dykes
Volume of Melt
Depth of Melting

References

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K H Kjær, N K Larsen, T Binder, A A Bjørk, O Eisen, M A Fahnestock, S Funder, A A Garde, H Haack, V Helm, M Houmark-Nielsen, K K Kjeldsen, S A Khan, H Machguth, I McDonald, M Morlighem, J Mouginot, J D Paden, T E Waight, C Weikusat, E Willerslev, J A MacGregor (2018) A large impact crater beneath Hiawatha Glacier in northwest Greenland, Science Advances 4(11), p. 1-11, url, doi:10.1126/sciadv.aar8173

William R. Hyde, Gavin G. Kenny, Martin J. Whitehouse, Richard Wirth, Vladimir Roddatis, Anja Schreiber, Adam A. Garde, Anders Plan, Nicolaj K. Larsen (2024) Microstructural and isotopic analysis of shocked monazite from the Hiawatha impact structure: development of porosity and its utility in dating impact craters, Contributions to Mineralogy and Petrology 179(3), Springer Science and Business Media Deutschland GmbH, doi:10.1007/s00410-024-02097-1