LAWRENCE – An ice survey in Greenland revealed evidence that one kilometer iron asteroid hit the island at the end of the Pleistocene about 12,000 years ago. The resulting 30-kilometer crater was below the half-mile thick layer of ice. Recently, an ultra-broadband radar system was developed in CRSSIS at the University of Kansas.
The impact crater under the Hiawatha glaciers in the far northwest of Greenland is described in detail in a recent article in Scientific Developments.
The NASA North Pole Regional Climate Assessment and Operation was supplemented by data collected from the University of Canada for the IceBridge program from 1997 to 2014 and with additional data collected in May 2016 using the Multi-Channel Coherent Radar Depth Siren. Developed by KU (MCoRDS).
"In the last few decades, we've had a lot of radar data, and the glaciers have gathered these radar data files to create Greenland maps under the ice," said John Paden, a professor of electrical engineering and computer science at KSU and a researcher at CReSIS. Said. "Danish scientists looked at the map and saw this huge, crater collapse underneath the ice sheet and looked at satellite imagery, and – because the crater stands at the edge of the ice sheet – you can see a circular pattern." The combination of these two things showed it was a crater. Based on this discovery, a detailed radar survey was conducted in May 2016 using the latest technology radar designed and built by KU for the Alfred Wegener Institute in Germany.
Paden, which helped develop MCoRDS software for radar signal processing, participated in low-height flights in the grid model on the impact crater to examine the dimensions in more detail.
”You can see a rounded structure on the edge of the ice sheet, especially when you fly at high altitude,“ he said. Ir For the most part, the crater doesn't show up from the plane's window, and it's not funny at all that no one ever thinks, eres Hey, what's the semicircle's main line there? . Difficult to see on the plane if you don't know that you are there. When the sun comes down the horizon, you can see the crater circle by highlighting the hills and valleys in the terrain of the ice sheet. "
To validate satellite and radar findings, the research team carried out further groundwork of the glaciofluvial sediment from the largest river running the crater. This emphasized the presence of the effect of glass-containing "quartz and other affected grains". The research team believes that these rocks and glassy grains probably collide with the grain melt in the meta-sedimentary basement rock.
Asteroid is still required to indicate the time to fall in Greenland. The authors argue that the evidence suggests that "the Hiawatha crater was created during the Pleistocene, because this era is largely consistent with the results from the available data." However, this wide time interval remains "unclear". In the southwestern crater, he found a rich zone of possible fragments created during the accident, which can help narrow the date range.
"The atmosphere would lead to a pollution that would affect the climate and would have the potential to melt too much ice. For this reason, clean water flowing suddenly across Nares Strait between Canada and Greenland will affect the flow of oceans in the region," Paden said. "The evidence suggests that after the icing of Greenland, the impact can occur, but the research team is still working on correct dating."
Credit: University of Kansas
Other KU personnel participating in the survey and revealing the impact of the crater are Rick Hale, Deputy Director of Air Engineering and Deputy Director of CReSIS; Carla Leuschena, Director of Electrical Engineering and Informatics and CReSIS, and Fernando Rodriguez-Morales, Professor of Electrical Engineering and Computer Science. KU researchers worked closely with colleagues at the University of Copenhagen and the Alfred Wegener Institute in Germany.
During the three years between discovering the crater and publishing this discovery, Paden was happy and excited to be part of a group of scientists who knew a great deal of influence.
En It was so cool – it was something I told my kids when I got home, hav Paden said. "Look, look at this, it's under the ice." It was one of those fun moments, they were shocked many times, my research wasn't interesting for them, but this effect was something that caught them in the crater. "