The crater, which is more than 5 miles (8 kilometers) in diameter, was discovered through seismic surveys, which allow scientists to probe deep beneath the Earth’s surface.
Veronica Bray, a research scientist at the University of Arizona’s Lunar and Planetary Laboratory, is a co-author of the study detailing the discovery in Science Advances. She specializes in craters throughout the solar system.
Nadir Crater, named after a nearby seamount, is buried 1,300 feet (400 meters) below the seabed about 250 miles (400 kilometers) off the coast of Guinea in West Africa. According to the research team, the asteroid responsible for the newly discovered Nadir crater may have been formed by a parent asteroid breakup or by a swarm of asteroids from the period. If confirmed, the crater would be one of less than 20 confirmed oceanic impact craters found on Earth.
What impact will this asteroid have?
Bray used computer simulations to determine what kind of collision happened and what impact it might have. Simulations suggest that the crater was created by a collision of a 1,300-foot-wide (400-meter-wide) asteroid in 1,600 to 2,600 feet (500 to 800 meters) of water.
“This will produce a tsunami over 3,000 feet high and an earthquake of over 6.5 magnitude,” Bray said. “Although it’s a much smaller global catastrophe than the Chicxulub hit, Nadir will do a lot of damage locally.” Significant contribution. If we find a ‘sibling’ of Chicxulub, that raises the question. Are there others?”
The asteroid’s estimated size would put it roughly on par with asteroid Bennu, the target of NASA’s asteroid sample return mission led by Arizona State University. According to Bray’s calculations, the impact that caused Nadir’s crater released about 1,000 times the energy of the tsunami caused by the massive underwater eruption of the Hunga-Henga-Hapai volcano in the Polynesian country of Tonga on January 15.
“These are preliminary simulations that will need to be refined as we get more data, but they provide important new insights into the likely depth of the ocean in this region at the time of the impact,” Bray said.
What does this impact crater look like?
Geologist Uisdean Nicholson of Heriot-Watt University in Edinburgh discovered the crater in a way. In a project devoted to seafloor spreading, he’s examining seismic reflection data from the seafloor, a geological process that causes Africa and the Americas to drift apart and open up the Atlantic Ocean.
“I’ve interpreted a lot of seismic data in my time, but I’ve never seen anything like it,” Nicholoson said. “Instead of seeing the flat sedimentary sequence I expected on the plateau, I found one on the seafloor. The 8.5 km depression, it has very unusual features. It has special features that suggest a meteor impact crater. It has a raised rim and a very prominent central bulge, which is consistent with a large impact crater. “
In addition, he added: “It also had what looked like projectiles outside the crater, and there were very chaotic sediments extending tens of kilometers outside the crater. These features are not consistent with other crater formation processes, such as salt the withdrawal of the volcano or the collapse of the volcano.”
Asteroid and dinosaur killer fell at the same time
Sean Gulick, an impact expert at the University of Texas at Austin and lead author of the study, said: “The Nadir crater is an incredible discovery, with a second impact on the same scale as the Cretaceous-Paleozoic. The extinction was close. While this was much smaller than the Chicxulub impactor that caused the mass extinction, its existence required us to investigate the possibility of an impact group in the most recent Cretaceous.”
Based on the seismic data, the sediments struck by the asteroid likely corresponded to the Cretaceous-Paleozoic boundary — the sediment layer that delineated the end of the Cretaceous period and the appearance of the last known dinosaurs. However, due to limitations in data resolution, there is some uncertainty about the precise timing of the impact.
“Despite 4 billion years of impactors hitting Earth, only 200 have been discovered. So it’s exciting news whenever new potential impacts are discovered, especially in hard-to-explore marine environments,” Gulick said.
Nicholson has applied for funding to drill the seabed to confirm it is an asteroid crater and test its precise age.