Copenhagen (dpa) – researchers have an impact crater 31 km wide. Greenland Ice cover discovered. With a larger area than Paris, it is one of the world's 25 largest known impact craters and informs its team in Science Advances magazine.
Never before have such a crater been discovered under one of the continental ice sheets of the earth.
At one point, according to researchers around Kurt Kjær from the GeoGenetics Center at the University of Copenhagen Natural History Museum, an iron meteor was supposed to be one kilometer in diameter. A dating that lies beneath the one-kilometer ice crater was not possible before. It can be quite young, very well preserved, from a geological point of view.
According to Kjær, it may even be 12,000 years ago towards the end of the last glacial period. The timing of the impact was very important to understand the impact of the impact on life on Earth. Large meteor effects can have a lasting impact on the climate.
The main crater under the Hiawatha glacier in North Greenland was first discovered in 2015. On the edge of the ice sheet, there was a huge circular collapse. But scientists were not sure whether there were any footprints at the beginning. Only when a team of the Alfred Wegener Institute (AWI) in Bremerhaven mapped the area of the aircraft with a powerful ice radar, the assumption was confirmed.
, The new radar system of the AWI research aircraft was the kind of instrument we needed for measurements, ğ said Olaf Eisen, a gladiologist at the Alfred Wegener Institute. The structure had to be fully recognized. «Clearly a rounded edge, a central height, an uncomfortable layer of ice and basal debris. Everything that characterizes a meteorite effect. »
In the summer of 2016 and 2017, the research team returned to the site to collect samples of sediments and to map the rock's tectonic structures at the bottom of the glacier. K Part of the quartz sand removed from the crater had deformation properties that only had a severe effect, sahip explained Nicolaj Larsen of Aarhus University. This is the definitive proof that depression under the glacier is a meteorite crater.
The impact of an asteroid 66 million years ago in North America has probably contributed significantly to the extinction of dinosaurs. The diameter is approximately 180 kilometers. In a scenario presented in the magazine "Current Biology" at the beginning of the year, the blast swept all the trees within a radius of about 1,500 kilometers. Others disappeared during forest fires around the world. The emission of sulfurous vapors has probably led to acid rain, large amounts of institutions have prevented the photosynthesis of plants for years and cooled the world.
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