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European and Russian geologists have found in Greenland in the vicinity of the town Maniitsoq the oldest on Earth crater with a diameter of 100 kilometers, which arose three billion years ago after falling 30 kilometer asteroid, according to a paper published in the journal Earth and Planetary Science Letters.
"This is a unique discovery means that we can now examine the consequences of meteoritic bombardment of Earth in the form of a crater formed by a billion years earlier than previously thought possible. It took us three years to convince colleagues and the scientific community. Industrialists were more trusting - canadian company began the study of the crater, trying to find deposits of Nickel and platinum, and already in 2011" - said the head of group of scientists Ian McDonald (Iain McDonald) from Cardiff University (UK).
McDonald and his colleagues, including Russian scientist Boris Ivanov from the Institute of dynamics of geospheres RAS in Moscow, made the discovery during expeditions in the southern part of Greenland in 2010 and 2011.
As the researchers note, the crater was accidentally discovered by one of the authors of article - geologist Adam Garda (Adam Garde) of the Geological survey of Denmark and Greenland - in 2009, when he analyzed the geological map of the surroundings of town of Maniitsoq for one of the Danish mining companies.
Garda found a strange anomalies in the structure of rocks in this area, similar to the trace from heavy duty impact of a meteorite. A scientist involved in the work of their colleagues from Russia, the UK and Sweden, which have made two expeditions to the area of Maniitsoq and gathered detailed data on the structure and other properties strange education.
"The process of learning was like a detective with the participation of Sherlock Holmes. Gradually we have dropped all possible terrestrial processes as impossible and realized that this anomaly is a giant trace of the impact of a meteorite" - said MacDonald.
As the researchers note, breed on the site of a meteorite strike was formed about three billion years ago. Such a respectful age of the crater explains why the crater there is no usual bowl-shaped form. According to the researchers, for three billion years, Greenland has experienced several periods of formation of mountains and glaciations, which destroyed all traces of a meteorite, except deformations of breed, caused a shock wave.
According to the estimates of geologists, this "scar" arose as a result of collision of the Earth with an asteroid with a diameter of more than 30 kilometers. If this meteorite fell on the territory of the continent, it would have left a crater with a diameter of 500-600 kilometers, which is about two times higher than the previous record holder - Vredefort crater in South Africa. According to geologists, celestial body that size capable "evaporate" the state is medium in size and erase from the face of the Earth all higher life forms.
Scientists believe that their discovery will help astrophysicists, and the planetary community to better understand the conditions under which formed the planets and meteorites during adolescence Solar system.