Chicxulub Asteroid Not Responsible for Dinosaur Extinction

According to a new set of scientific investigations carried out at the site of the Chicxulub crater, in the northern Yucatan Peninsula, New Mexico, the asteroid that hit our planet more than 65 million years ago was not the reason for the extinction of dinosaurs and about 65 percent of all other species on Earth. The crater, which was discovered in 1978 and has a diameter of 180 kilometers (110 miles), was thoroughly investigated by a team of scientists led by researcher Gerta Kelle, from the Princeton University in New Jersey, and geology expert Thierry Adatte, from the University of Lausanne, in Switzerland.

The new paper, which will appear in today's issue of the Journal of the Geological Society, shows that the traces left behind by the impact are at least 300,000 years older than the Cretaceous–Paleogene (K-T) extinction event, which means that it couldn't have possibly caused such a widespread extinction. The K-T boundary also marks the end of the Mesozoic era and the beginning of the Cenozoic one.

Above this geological layer, archaeologists failed to find any traces of non-avian dinosaurs. Seeing that this holds true around the world, it stands to reason that the animals must have become extinct shortly before, or shortly after the asteroid impact.

At first, when the Chicxulub Crater was found, geologists rejoiced, believing that they had discovered the long-sought-for cause of dinosaurs' disappearance. In the early 1980s, when the site was being investigated for the first time, geologists found spherules from the impact just below the (K-T) boundary, and immediately concluded that this event was the one that caused the extinction of countless species of animals and plants around the world.

“Keller and colleagues continue to amass detailed stratigraphic information supporting new thinking about the Chicxulub impact, and the mass extinction at the end of the Cretaceous. The two may not be linked after all,” National Science Foundation (NSF)'s Division of Earth Sciences Program Director H. Richard Lane said. The NSF was in charge with funding the current research.

“We found that not a single species went extinct as a result of the Chicxulub impact,” Keller added. After analyzing the boundary at several locations, the team concluded that the old hypothesis simply did not stand. “We know that between four and nine meters of sediments were deposited at about two to three centimeters per thousand years after the impact. The mass extinction level can be seen in the sediments above this interval,” the expert shared.

The team stated that the number of species found above and below the K-T boundary was exactly the same, like the structure of the soil. This, of course, shouldn't have happened if the asteroid had, indeed, caused the mass extinction event. The two experts believe that the Deccan Traps volcano in India was responsible for the extinction, throwing impressive amounts of pyroclastic materials into the air, including ash and toxic chemicals.