Lawrence – An ice survey in Greenland has revealed evidence suggesting that a kilometer-long iron asteroid hit the island about 12,000 years ago at the end of the Pleistocene. The 30-kilometer crater remains hidden under a thick sheet of ice of half a kilometer. Recently, he was given an ultra-broadband radar research system developed at CRSSIS based at the University of Kansas.
The impact crater under the Hiawatha glaciers in the northwestern part of Greenland is detailed in a new article in Science Advances.
It was identified by data collected between 1997 and 2014 by the Canadian University of Arkansas Arctic Regional Climate Assessment Program and Operation IceBridge plus additional data collected in May 2016 using a coherent radar sound depth circuit (MCoRDS) developed by the KU.
"Over the past few decades, we have acquired a lot of radar data and Glaciologists have put these data radar files together to create maps of Greenland under ice," said co-author John Paden, a professor of electrical engineering and computer science at KSU And a researcher at CReSIS. "Danish scientists looked at the map and saw the great depression, under the ice crater, and looked at satellite images, and because the crater is on the edge of the ice layer, you can see a circular pattern." Based on this discovery, a detailed radar survey was conducted in May 2016, using the country's newest radar, designed and built by the KU for the Alfred Wagner Institute in Germany. "
Padan, who helped develop MCoRDS for radar signal processing, took low-altitude flights over the impact crater to test the dimensions in more detail.
"You can see a curved structure at the edge of the ice, especially when you fly high," he said. "Usually, the crater is not visible from the plane window, and it's funny that no one ever thought," Hey, what's that slippery outline there? "It's hard to see in an airplane if you do not know it's there, when the sun was low over the horizon, emphasizing the hills and valleys in the ice-covered ground, you can see the crater circle in these pictures."
In order to confirm the satellite and radar findings, the research team carried out successive studies of the glaciofluvial precipitation from the largest river operating the crater.This emphasized the presence of "the effect of quartz and other affected grains," which include glass.The research team believes that these rocks and grains Glazed and probably originated from a collision with granule smelting in the sedimentary rock sediment.
It is still necessary to note the time of the asteroid's fall to Greenland. The authors write that the evidence "suggests that the Huehta crater was created during the Pleistocene, because this age largely corresponds to the conclusions from today's data." However, this wide time interval remains "unclear". In the southwestern crater, he found an area rich in possible fractures created during the crash, which could help narrow the date range.
"The atmosphere will bring dirt that will affect the climate and has the potential to dissolve a lot of ice, so a sudden flood of fresh water could enter the Nares Strait between Canada and Greenland, which will affect the flow of oceans across the region," Padan said. "Evidence shows that the effect is likely to occur after Greenland's ice glass was created, but the research team is still working on accurate dates."
Credit: University of Kansas
Other KU members who participated in the study who uncovered the impact of the crater included Rick Hale, Air Engineering Chairman and Managing Director of CReSIS, Carla Leoshana, Professor of Electrical Engineering and Informatics and CReSIS Director, and Fernando Rodriguez Morales, Professor of Electrical Engineering and Computer Science. In close cooperation with colleagues from the University of Copenhagen and the Alfred Wagner Institute in Germany.
Padan says that for three years between the discovery of the crater and the publication of this discovery, it was a pleasure and exciting to be part of a unique group of scientists who knew massive influence.
"It was really cool-it was the kind of thing I said to my kids when I got home," Padan said. "I said, 'Look at it, it's under the ice. It was one of those moments of pleasure, they were amazed, many times, my research did not interest them, but this crater was something that caught them."