A large impact crater beneath Hiawatha Glacier in northwest GreenlandOPEN ACCESS 

· by · in

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

Science Advances 14 Nov 2018:
Vol. 4, no. 11, eaar8173
DOI: 10.1126/sciadv.aar8173

LINK (OPEN ACCESS)
PDF (OPEN ACCESS)

“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.”

Related posts (automatically generated):

  1. A Late Paleocene age for Greenland’s Hiawatha impact structureOPEN ACCESS 
  2. Effect of ice sheet thickness on formation of the Hiawatha impact crater
  3. A Possible Second Large Subglacial Impact Crater in Northwest GreenlandOPEN ACCESS 
  4. Evidence for a large Paleozoic Impact Crater Strewn Field in the Rocky Mountains
  5. Dating a small impact crater: An age of Kaali crater (Estonia) based on charcoal emplaced within proximal ejecta.
  6. Impact glasses from Belize represent tektites from the Pleistocene Pantasma impact crater in NicaraguaOPEN ACCESS 
  7. The two Suvasvesi impact structures, Finland: Argon isotopic evidence for a “false” impact crater doublet.
  8. A high-precision 40Ar/39Ar age for the Nördlinger Ries impact crater, Germany, and implications for the accurate dating of terrestrial impact events
  9. Evidence for a chondritic impactor, evaporation-condensation effects and melting of the Precambrian basement beneath the ‘target’ Deccan basalts at Lonar crater, India
  10. Thermoluminescence dating of the Kamil impact crater (Egypt)
Tags: , ,