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


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Asteroids hitting Earth

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

A newly discovered impact crater beneath the seafloor suggests that more than one asteroid may have hit Earth around the time of the dinosaur extinctions.

Evidence of an asteroid impact crater under the North Atlantic Ocean has been discovered by scientists. This could force researchers to rethink how dinosaurs reached the end of their reign.

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

“It would have generated a tsunami more than 3,000 feet high, as well as an earthquake of magnitude greater than 6.5.” — Veronique Bray

Stretching more than 8 km in diameter, the crater was discovered using seismic measurements, which allow scientists to probe what lies deep below the Earth’s surface.

Veronica Bray, a researcher at the University of Arizona’s Lunar and Planetary Laboratory, is co-author of a study on Scientists progress detailing the discovery. She specializes in craters found throughout the solar system.

Named after a nearby seamount, the Nadir crater is buried up to 1,300 feet (400 meters) below the seafloor about 250 miles (400 km) off the coast of Guinea, South Africa. ‘West. According to the research team, the asteroid that created the newly discovered Nadir crater may have formed by the bursting of a parent asteroid or by an asteroid swarm during this period. If confirmed, the crater will be one of less than 20 confirmed marine impact craters found on Earth.

Veronique Bray

Veronica Bray, pictured here during a visit to Meteor Crater in northern Arizona, is an expert in crater formation. 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 colliding in 1,600 to 2,600 feet (500 to 800 meters) of water.

“It would have generated a tsunami more than 3,000 feet high, as well as an earthquake greater than magnitude 6.5,” Bray said. “While much smaller than the global cataclysm of Chicxulub impact, Nadir will have contributed significantly to the local devastation. are there others?

The asteroid’s estimated size would put it roughly on par with Bennu asteroidthe target of OSIRIS-RExUArizona-run[{” 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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