Crater Found in Greenland: Impact Rocked the Northern Hemisphere

The 19-mile-wide impact crater has remained hidden under a half-mile-thick ice sheet until now.  (Image: via   pixabay  /  CC0 1.0)
The 19-mile-wide impact crater has remained hidden under a half-mile-thick ice sheet until now. (Image: via pixabay / CC0 1.0)

A survey of ice in Greenland has uncovered evidence suggesting a kilometer-wide iron asteroid slammed into that island, perhaps as recently as 12,000 years ago during the end of the Pleistocene. The resulting 19-mile-wide impact crater has remained hidden under a half-mile-thick ice sheet until now. It recently was exposed by an ultra-wideband chirp radar system developed at the Center for the Remote Sensing of Ice Sheets (CReSIS), headquartered at the University of Kansas.

Photo illustration of the airplane during the survey, radar waves and the actual radar image. (Credit: NASA)

Photo illustration of the airplane during the survey, radar waves, and the actual radar image. (Image: NASA)

The impact crater beneath the Hiawatha Glacier in remote northwest Greenland is detailed in a new paper in Science Advances. It was identified with data collected between 1997 and 2014 by KU for NASA’s Program for Arctic Regional Climate Assessment and Operation IceBridge, and supplemented with more data collected in May 2016 using the Multichannel Coherent Radar Depth Sounder (MCoRDS) developed at KU.

Map of the bedrock topography beneath the ice sheet and the ice-free land surrounding the Hiawatha impact crater. The structure is 31 kilometers wide, with a prominent rim surrounding the structure. In the central part of the impact structure, an area with elevated terrain is seen, which is typical for larger impact craters. Calculations show that in order to generate an impact crater of this size, the Earth was struck by a meteorite more than one kilometer wide. (Credit: Natural History Museum of Denmark, Cryospheric Sciences Lab, NASA Goddard Space Flight Center, Greenbelt, MD, USA)

Map of the bedrock topography beneath the ice sheet and the ice-free land surrounding the Hiawatha impact crater. The structure is 31 kilometers wide, with a prominent rim surrounding the structure. In the central part of the impact structure, an area with elevated terrain is seen, which is typical for larger impact craters. Calculations show that in order to generate an impact crater of this size, the Earth was struck by a meteorite more than one kilometer wide. (Image: Natural History Museum of Denmark, Cryospheric Sciences Lab, NASA Goddard Space Flight Center, Greenbelt, MD, USA)

Co-author John Paden, courtesy associate professor of electrical engineering and computer science at KU and associate scientist at CReSIS, said:

Paden, who helped develop the MCoRDS radar signal processing software, participated in low-altitude flights in a grid pattern over the impact crater to detail its dimensions, said:

To confirm the satellite and radar findings, the research team performed subsequent ground-based studies of glaciofluvial sediment from the largest river draining the crater. The work showed the presence of “shocked quartz and other impact-related grains” that include glass. The research team believes these rocks and glassy grains are likely produced from the impact melting grains in the meta-sedimentary bedrock.

Geomorphological and glaciological setting of Hiawatha Glacier, northwest Greenland. (A) Regional view of northwest Greenland. Inset map shows location relative to whole of Greenland. Magenta box identifies location of panels B-D. (B) 5-m ArcticDEM mosaic over eastern Inglefield Land. Colors are ice surface velocity. Blue line illustrates an active basal drainage path inferred from radargrams. (C) Hillshade surface relief based on the ArcticDEM mosaic which illustrates characteristics such as surface undulations. Dashed red lines are the outlines of the two subglacial paleo-channels. Blue lines are catchment outlines, i.e., solid blue line is subglacial and hatched is supraglacial. (D) Bed topography based on airborne radar sounding from 1997-2014 NASA data and 2016 AWI data. Black triangles represent elevated rim picks from the radargrams and the dark purple circles represent peaks in the central uplift. Hatched red lines are field measurements of the strike of ice-marginal bedrock structures. Black circles show location of the three glaciofluvial sediment. (Credit: University of Kansas/John Paden)

Geomorphological and glaciological setting of Hiawatha Glacier, northwest Greenland. (A) Regional view of northwest Greenland. Inset map shows location relative to the whole of Greenland. Magenta box identifies the location of panels B-D. (B) 5-m ArcticDEM mosaic over eastern Inglefield Land. Colors are ice surface velocity. Blue line illustrates an active basal drainage path inferred from radargrams. (C) Hillshade surface relief based on the ArcticDEM mosaic which illustrates characteristics such as surface undulations. Dashed red lines are the outlines of the two subglacial paleo-channels. Blue lines are catchment outlines, i.e., the solid blue line is subglacial and hatched is supraglacial. (D) Bed topography based on airborne radar sounding from 1997-2014 NASA data and 2016 AWI data. Black triangles represent elevated rim picks from the radargrams and the dark purple circles represent peaks in the central uplift. Hatched red lines are field measurements of the strike of ice-marginal bedrock structures. Black circles show the location of the three glaciofluvial sediments. (Image: University of Kansas / John Paden)

Work remains to determine with more precision the timing of the asteroid impact on Greenland. The authors write evidence “suggests that the Hiawatha impact crater formed during the Pleistocene, as this age is most consistent with inferences from presently available data.” However, even this broad range in time remains “uncertain.” Southwest of the crater, the team has found a region rich in possible debris ejected from the impact, which could help to narrow the date range. Paden said:

Paden said during the three years between the crater discovery and publication of the team’s findings, it was gratifying and exciting to be part of the exclusive group of scientists that knew of the massive impact, adding:

Provided by: University of Kansas [Note: Materials may be edited for content and length.]

Like this article? Subscribe to our weekly email for more!     

Meet the Square Iceberg From Antarctica
World’s First AI News Anchor Launched in China
#article-ad-block-->