Scientists believe more than one asteroid wiped out the dinosaurs.
Researchers from Heriot-Watt University, UK have discovered a new impact crater under the Atlantic Ocean off the coast of West Africa. It most likely formed 66 million years ago, just as the famous Chicxulub crater in Mexico did after a large asteroid hit, which is thought to have wiped out almost all the dinosaurs. But a new study could change our knowledge of how dinosaurs went extinct, as two or even more asteroids could have wiped them out, Inverse reports.
Scientists from Heriot-Watt University were conducting seismic surveys off the coast of West Africa and discovered a new impact crater, which they named Nadir, 400 metres below the bottom of the Atlantic Ocean.
This crater is 8.5 km in diameter and sits atop a layer of rock which marks the boundary of the Cretaceous-Paleogene extinction. This is the mass extinction of 75% of the living things on Earth, causing the extinction of virtually all the dinosaurs. The event occurred 66 million years ago at the end of the Cretaceous Period and it is thought that the major cause of the extinction was the impact of a huge asteroid 12 km in diameter.
But scientists believe a much smaller asteroid with a diameter of 400m caused the crater they discovered. And this asteroid could have fallen shortly after the fall of the Chickshulub asteroid. Scientists believe that the fall of the smaller asteroid triggered massive earthquakes and tsunamis, and these events could also have affected the fate of the dinosaurs.
"We believe that no one but at least two asteroids fell on Earth 66 million years ago, leading to the mass extinction of dinosaurs and other living creatures on the planet. Of the dinosaurs, only the ancestors of modern birds remained then,' says Wasdin Nicholson of Heriot-Watt University.
Scientists have also put forward the theory that not two asteroids could have fallen to Earth but more, craters from the fall of which have yet to be discovered. Scientists also speculate that these asteroids may have once been part of a space rock of incredible size that collided with other rocks near Earth and fell apart. And it was this debris that fell to the planet.
According to Nicholson, so far this is only speculation and the Chickshulub asteroid could have fallen much earlier than the smaller asteroid that created the Nadir crater. It is possible that their falls are thousands of years apart. Scientists plan to drill the seabed near the discovery of the Nadir crater in a couple of years to find out exactly what rocks it consists of and what their exact age is. After all, the possibility remains that it is not an impact crater from an asteroid impact but the result of volcanic processes.
"I am still inclined to believe that it is an impact crater from an asteroid impact. But we need to get samples of the rocks to study their chemical composition. Perhaps this composition will be identical to that of the rocks in the Chickshulub crater and then we can say that the two asteroids were once one. On the other hand, there are too few of these impact craters yet to be discovered on Earth and they may also have been the result of falling space rocks that influenced the evolution of life on Earth," says Nicholson.
As Focus previously wrote, a recent study by scientists has revealed when a new mass extinction of living things on Earth will occur.
Focus also wrote that scientists have figured out which creatures were the first to recover from the mass extinction on Earth 250 million years ago.