Even when Wisconsin and Western Russia split south of the equator, a violent collision in the asteroid belt exposed the Earth to meteorites.
Space rocks, which were 100 times larger than today's meteorites, crumbled to Earth (rocks the size of a football field fall to Earth approximately every 10,000 years). However, a dozen impact craters were discovered, formed as a result of the ancient bombardment of 470,000,000 years ago during the Ordovician period. Most of them are located in North America, Sweden and Western Russia. There are approximately 185 known impact craters on Earth of various ages, while the Moon has more than 100,000.
But the number of craters of the Ordovician period may soon change. This is because the technology of searching for evidence that confirms the presence of a shock crater has become easier and cheaper. “The images of Google Earth are not detailed enough to determine the structure of the impact,” said planetary geologist Christian Koublel during the annual meeting of the Geological Society of America on October 22 in Vancouver, British Columbia. During a meeting in Vancouver, researchers presented new evidence that would allow the inclusion of impact craters in Wisconsin, Kentucky and Tennessee in the Ordovician period craters. Three mysterious structures retained their round shape, but lost most of their original functions as a result of erosion. In the last century, open-pit mining also led to the destruction of a crater in Wisconsin. Only the central elevation has been preserved. When a meteorite hits the Earth, the impact force can lift the rock upward. In each state, researchers searched for traces of destroyed minerals or heat effects. But so far no one has found irrefutable evidence when studying craters.
But even without irrefutable evidence, the impact meteorite, located in Brussels Hill in Dor County, Wisconsin, is the best example of a perfect round crater. The flat top is filled with shattered Cambrian sandstone, which should be located 1,300 feet below junior carbonate rocks.