A scientific report showed on Friday pointed out that a group of comets may have hit North America around 13,000 years ago. The scientists draw this conclusion after they found tiny diamonds scattered across the continent.

The team of researchers stated that these comets caused severe temperature drops and led many species to extinction, including mammoths. One of the researchers compared the image of the falling comets to a series of simultaneous exploding atomic bombs.

Similar tiny diamonds, also called nanodiamonds, were found around the Tunguska area in Siberia, following the airburst of a meteor in 1908. Scientists believe that nanodiamonds are the result of a high-pressure and high-temperature environment caused by the impact of celestial bodies.

Doug Kennett, professor at the University of Oregon and head of the research team found traces of little diamonds in some areas in Arizona, South Carolina, but also in Canada, in Alberta and Manitoba. According to the study, the depth where the nanodiamonds were found corresponded to the Younger Dryas era, a cold spell that lasted for about 1,300 years and that leaded mammoths and camels to extinction.

The study, which was published in the journal Science, revealed that the scientists found nanodiamonds in six sites in North America. These observations support the theory of multiple meteors exploding above Earth that dramatically increased temperature and pressure across North America.

Professor Kennett added that nanodiamonds were only found in Young Dryas layers at all six locations in North America and Canada.