Credit: DALL-E by OpenAI (image generated by artificial intelligence)
The extinction of the dinosaurs some 66 million years ago may have been caused by more than one asteroid. This idea is suggested by a study published in Science Advances by researchers who discovered a new asteroid impact crater in the seabed off the coast of Africa.
Impact of an asteroid off the coast of Yucatan
We know that what started the chain of events that ultimately led to the mass extinction in which even the dinosaurs died out was most likely an asteroid that crashed into Mexico’s Yucatan Peninsula, it some 66 million years ago.
Discovery of a new crater off the coast of Guinea
The researchers behind this new study have detailed the characteristics of another impact crater located off the coast of Guinea, West Africa. This crater, named Nadir by the researchers, is located at a depth of regarding 400 meters and, according to the researchers, was created around the time of the impact of the asteroid Chicxulub (the one that ended up offshore coasts of Mexico), near the Cretaceous-Paleogene boundary.
The asteroid measured regarding eight kilometers
This asteroid, which had a diameter of regarding eight kilometers (a size comparable to that of the better known asteroid Bennu), was discovered thanks to seismic measurements thanks to which the researchers were able to probe the depths of the sea. think that this crater might have been formed by the impact of a fragment caused by the rupture of a larger asteroid or by an asteroid swarm. Very few marine asteroid impact craters have been discovered, not even twenty identified around the globe.
Computer simulations of tsunamis and earthquakes
In order to know these characteristics, the researchers carried out computer simulations. These determined the type of collision and the effects of the collision. The collision at sea probably generated a huge tsunami, with waves nearly 1,000 meters high. A tsunami regarding 1000 times larger than that caused by the eruption of the Hunga Tonga-Hunga Ha’apai volcano on January 15.
The same impact with the seafloor then triggered an earthquake with a magnitude greater than 6.5, says Veronica Bray, a researcher at the University of Arizona’s Lunar and Planetary Laboratory, who specializes in craters not only on Earth. but also on other bodies of the solar system. The Chicxulub asteroid caused an even bigger cataclysm, but the Nadir asteroid still caused major local devastation.
Unusual features of craters
The crater is formed by a depression regarding 8.5 km in diameter. The unusual features (an unusually high rim and central uplift) indicate an asteroid impact crater. In addition, traces of material were found that appear to have been ejected from the crater at the time of impact. These are “chaotic” sedimentary deposits that stretch for tens of kilometres, as explained by Uisdean Nicholson, a geologist at Heriot-Watt University in Edinburgh, the researcher who discovered the crater.
