A massive meteorite impact hit Earth 280 million years ago

Un impact météoritique majeur a été retrouvé grâce à l'étude de cratères secondaires. © JohanSwanepoel, Adobe Stock

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They make dinosaurs disappear and their grooves adorn the surface of the earth. Every day, the planet is hit by hundreds of meteorites.

In southeastern Wyoming, USA, scientists have discovered a whole series of small craters 10 to 70 meters in diameter. The Burmese age (280 million years) was deposited in the sediments, and the number of these impact structures was the first to cause a major decay. Asteroid When entering the atmosphere. In fact, no large crater is visible in the landscape of the surrounding area. However, during field studies, the field of impacts is so vast that it cannot be explained by this hypothesis.

A ballistic probe to detect the appearance of grooves

Like the detectives, the scientists conducted a ballistic study of each small crater to determine its appearance. Thirty-one impacts are thus screened, but more than 60 other structures may also be part of the groove field. The distribution of impacts first shows that the grooves are not roughly distributed: they form several small groups, which define Corridor 30-45 points in a certain direction. Grooves a Morphology Indicated in the ellipse. This shape refers to objects that cause grooves hitting the ground at a relatively flat angle. This data helped researchers reconstruct the path of objects. Taken together, these paths show a radial shape: all objects in the origin of the groove field come from the same source.

Brands that make a big impact

All the results show that the dozens of small craters identified in Wyoming are not connected to its decay. Asteroid In the atmosphere but as a result of blocks expelled during a major impact. So these are secondary grooves, Scattered around a main abyss, In the form of the crown of the ejaculate. This type of formation is very common நிலா Where in Mars For example, it has not yet been found on Earth.

This deficiency is mainly associated with erosion processes, which are especially useful on our planet. Quickly clear traces of meteorite impacts, Especially small ones. Tectonic function and Sediment Making the earth’s surface constantly “renew” as well as old Scars Destroyed quickly. We must also not forget that the surface of the earth is mainly occupied by the oceans. So statistically more likely More than a meteorite It falls into an ocean rather than a continent, so there is little or no trace.

Multi-meter blocks are planned over 200 km

The main crater that was the origin of Wyoming’s secondary craters has disappeared. Thanks for the calculations of the paths and Number simulations, Scientists were able to model the formation of craters and locate the main crater. Their results, published Bulletin of Geographical Society of America, The main crater now buried under the younger sediments was originally 50 to 65 km in diameter. The impact of the meteorite will throw blocks four to eight meters wide over 150 to 200 kilometers, leading to the formation of a secondary crater field. The debris would have hit the still uncoordinated sediments Speed 700 to 1,000 m / s.

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