LAWRENCE – An ice exploration in Greenland revealed evidence that a kilometer iron asteroid had hit the island 12,000 years ago at the end of Pleistocene. The resulting 30-kilometer-long crater has remained hidden for half a mile of thick ice. Recently, it was exposed to an ultra-wide band radar scirp system research developed at CRSSIS based at Kansas University.
The war craters of the Hiawatha glaciers in the far northwestern part of Greenland are described in a new article in Science Advances.
It was identified by data collected from 1997 to 2014 by the Canadian University of the NASA Arctic Regional Climate Assessment and Operation IceBridge program and supplemented with additional data collected in May 2016 using the Multi-Channel Coherent Radar Depth Sounder (MCoRDS) developed by the KU .
"Over the last few decades we have received a lot of radar data and glaciologists have put these radar data files together to create maps of Greenland under ice," said co-author John Paden, associate professor of electrical engineering and computer science at KSU and a researcher at CReSIS. "The Danish scientists looked at the map and saw this great crater depression under the ice, watching satellite imagery, and because the crater is on the edge of the ice layer, one can see a circular pattern." The combination of these two things showed strongly that it was a crater. Based on this discovery, a detailed radar survey was carried out in May 2016 using the latest radar designed and built by the University of Alfred Wegener Institute in Germany. "
The paths, which helped develop the MCoRDS radar signal processing software, participated in low-altitude flights in the chart above the battlefield to investigate the dimensions in detail.
"You can see a rounded structure at the edge of the ice, especially when flying high," he said. "Most of the time, the crater is not visible from the airplane window, and it's fun no-one ever thought:" Hi, what's the semicircular contour there? "It's hard to see the planet if you do not know it's there. When the sun lay over the horizon, the hills and valleys mark the terrain of the iceberg – you can actually see the crater in these pictures."
In order to confirm satellite and radar findings, the research group conducted the following basic studies of the glaciophile sediment from the largest river running the crater. This has marked the presence of "influence of quartz and other affected grains", which includes glass. The research team believes that these stones and glassy grains probably resulted from the collision of the melting of grain in the Meta sedimentary bedrock.
It is still necessary to specify the time for the asteroid case to Greenland. The authors write that the evidence "suggests that the Hiawatha crater was created during Pleistocene, as this age is largely in line with the conclusions of current available data." However, this wide range of times remains "uncertain". In the southwest crater, he found a region rich in potential fragments created during the crash, which may help limit the date range.
"The atmosphere would have dirt that would affect the climate and have the potential to melt a lot of ice, so a sudden flood of freshwater could enter the Naresundet between Canada and Greenland, which would affect the flow of oceans across the region," said Paden. "Evidence suggests that the effect is likely to have occurred after the ice sheet of Greenland has been created, but the research group is still working with exact match."
Credit: University of Kansas
Other Co-personnel who participated in the research that revealed the effects of the crater, include Rick Hale, chairman of aeronautics and deputy director of CReSIS; Carla Leuschena, Professor of Electrical Engineering and Informatics and Director of CReSIS, and Fernando Rodriguez-Morales, Professor of Electrical Engineering and Computer Science. Co-researchers have worked closely with colleagues from the University of Copenhagen and the Alfred Wegener Institute in Germany.
The path says that for three years between discovering the crater and publishing this discovery, it was a pleasure and excitement to be part of an exclusive group of scientists who felt a huge impact.
"It was really cool – that was the kind I told my children when I got home," said Paden. "I said," Look here, this is under the ice. "It was one of the fun moments, they were surprised, many times, my research is not interesting for them, but this crater was something that caught them."