Massive impact crater under North Atlantic reveals dinosaur-killing asteroid wasn’t alone

Asteroids Hitting Earth

The discovery of a large impact crater under the North Atlantic Ocean reveals that more than one asteroid could have killed the dinosaurs.

A newly discovered impact crater beneath the seafloor suggests that more than one asteroid may have hit Earth around the time the dinosaurs went extinct.

Scientists have discovered evidence of an asteroid impact crater under the North Atlantic Ocean. It could force researchers to rethink how dinosaurs came to the end of their reign.

The team believes the crater was caused by an asteroid that collided with Earth about 66 million years ago. It is at the same time that the asteroid Chicxulub hit the Earth off the coast of present-day Yucatan, Mexico, and wiped out the dinosaurs.

“This would have generated a tsunami over 3,000 feet high, as well as an earthquake over magnitude 6.5.” — Veronica Bray

Spanning more than 8 km in diameter, the crater was discovered through seismic measurements, which allow scientists to probe what lies beneath the Earth’s surface.

Veronica Bray, a research scientist at the University of Arizona’s Lunar and Planetary Laboratory, co-authored a study in Advances in Science detailing the discovery. She specializes in craters found throughout the solar system.

Named after a nearby seamount, Nadir Crater is buried up to 1,300 feet (400 meters) below the sea floor about 250 miles (400 km) off the coast of Guinea, West Africa. According to the research team, the asteroid that created the newly discovered Nadir Crater could have been formed by the breakup of a parent asteroid or by an asteroid swarm in that time period. If confirmed, the crater will be one of less than 20 confirmed marine impact craters on Earth.

Veronica Bray

Veronica Bray, pictured here during a visit to Meteor Crater in northern Arizona, is an expert on cratering. Credit: Sarah Sutton/Lunar and Planetary Laboratory

What impact would the asteroid have had?

Bray used computer simulations to determine what type of collision took place and what the effects might have been. Simulations suggest the crater was caused by a 1,300-foot-wide (400-meter-wide) asteroid crashing into 1,600 to 2,600 feet (500 to 800 meters) of water.

“This would have generated a tsunami over 3,000 feet high, as well as an earthquake over magnitude 6.5,” Bray said. “Although much smaller than the global cataclysm of the Chicxulub impact, Nadir will have contributed significantly to the local devastation. And if we have found a Chicxulub ‘brother’, it begs the question: Is there a ‘others?’

The asteroid’s estimated size would put it about the size of asteroid Bennu, the target of UArizona-led OSIRIS-REx.

NASA
Founded in 1958, the National Aeronautics and Space Administration (NASA) is an independent agency of the United States federal government that succeeded the National Advisory Committee for Aeronautics (NACA). It is responsible for the civilian space program as well as aeronautical and aerospace research. His vision is "Discover and expand knowledge for the benefit of humanity." Its core values ​​are "safety, integrity, teamwork, excellence and inclusion."

” data-gt-translate-attributes=”[{” attribute=””>NASA asteroid sample return mission. According to Bray’s calculations, the energy released from the impact that caused the Nadir crater would have been around 1,000 times greater than the tsunami caused by the massive underwater eruption of the Hunga Tonga-Hunga Ha’apai volcano in the Polynesian country of Tonga on January 15.

“These are preliminary simulations and need to be refined when we get more data,” Bray said, “but they provide important new insights into the possible ocean depths in this area at the time of impact.”

What does the crater look like?

The crater was discovered somewhat by accident by Uisdean Nicholson, a geologist at Heriot-Watt University in Edinburgh. He was examining seismic reflection data from the seabed during a research project dedicated to seafloor spreading, the geologic process that caused the African and American continents to drift apart, thereby opening the Atlantic Ocean.

“I’ve interpreted lots of seismic data in my time, but had never seen anything like this. Instead of the flat sedimentary sequences I was expecting on the plateau, I found an 8.5-kilometer depression under the seabed, with very unusual characteristics,” Nicholson said. “It has particular features that point to a meteor impact crater. It has a raised rim and a very prominent central uplift, which is consistent for large impact craters.

“It also has what looks like ejecta outside the crater, with very chaotic sedimentary deposits extending for tens of kilometers outside of the crater,” he added. “The characteristics are just not consistent with other crater-forming processes like salt withdrawal or the collapse of a volcano.”

The asteroid crashed around same time as the dinosaur killer

“The Nadir Crater is an incredibly exciting discovery of a second impact close in time to the

Nicholson has already applied for funding to drill into the seabed to confirm that it’s an asteroid impact crater and test its precise age.

Reference: “The Nadir Crater offshore West Africa: A candidate Cretaceous-Paleogene impact structure” by Uisdean Nicholson, Veronica J. Bray, Sean P. S. Gulick and Benedict Aduomahor, 17 August 2022, Science Advances.
DOI: 10.1126/sciadv.abn3096


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