Double Asteroid Impact Could Have Spelled Doom For The Dinosaurs

Science Double Asteroid Impact Could Have Spelled Doom For The Dinosaurs David Bressan Contributor Opinions expressed by Forbes Contributors are their own. I deal with the rocky road to our modern understanding of earth New! Follow this author to stay notified about their latest stories. Got it! Aug 18, 2022, 02:31pm EDT | New! Click on the conversation bubble to join the conversation Got it! Share to Facebook Share to Twitter Share to Linkedin The Chicxulub impact on the Yucatan Peninsula is believed to have led to the death of the dinosaurs .

. . [+] some 65 million years ago.

Getty A newly discovered impact crater in the Atlantic Ocean hints at the possibility that more than one asteroid hit Earth during the time when dinosaurs went extinct. The presumed impact crater was found during a scientific expedition mapping tectonic structures of the continental shelf along the coast of West Africa. Not visible on the surface, the crater was discovered using seismic measurements, which allow scientists to probe what lies deep below Earth’s surface.

Named after a nearby seamount, the Nadir crater is buried up to 400 meters below the seabed about 400 kilometers off the coast. Based on sediment thickness, the researchers assume that the crater dates around the end-Cretaceous period, around 65 to 66 million years ago. This puts the impact in the same time intervall as the famous Chicxulub impact .

In 1993, scientists proposed that the extinction of the dinosaurs was the result of a large asteroid hitting Earth. Vaporized during the impact, the asteroid formed a 180-kilometer-wide crater on the Yucatan peninsula (south-eastern Mexico), called after a nearby town Chicxulub – meaning the devil’s tail. The team believes the meteorite that created the newly discovered Nadir crater could have formed by breakup of a parent body, maybe even the Chicxulub asteroid.

The new impact crater is significnatly smaller, just 8 kilometers wide, and was likely formed by a 400-meter-wide asteroid hitting a shallow sea. Seismic profile and interpretation by the researchers of the structures as an impact crater. Nicholson et al.

2022/Science Advances MORE FOR YOU New Research Finds A Connection Between Domestic Violence And These Two Personality Disorders This Scientist Helps Andean Forests And Ecuador’s Women In STEM Exceptional Fossil Preservation Suggests That Discovering Dinosaur DNA May Not Be Impossible “This would have generated a tsunami over 900 meters high, as well as an earthquake of more than magnitude 6. 5,” co-author Veronica Bray, a research scientist in the University of Arizona Lunar and Planetary Laboratory, said. “Although it is a lot smaller than the global cataclysm of the Chicxulub impact, Nadir will have contributed significantly to the local devastation.

And if we have found one ‘sibling’ to Chicxulub, it opens the question: Are there others?” “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. ” Study author Uisdean Nicholson, a geologist at Heriot-Watt University in Edinburgh, discovered the crater somewhat by accident, while 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 Nadir Crater is an incredibly exciting discovery of a second impact close in time to the Cretaceous–Paleogene extinction,” said study co-author Sean Gulick, an impact expert at the University of Texas at Austin. “While much smaller than the extinction causing Chicxulub impactor, its very existence requires us to investigate the possibility of an impact cluster in the latest Cretaceous. ” While the seismic data indicate that the sediments impacted by the asteroid correspond with the Cretaceous-Paleogene boundary—a sedimentary layer demarcating the end of the Cretaceous period and last known occurrence of dinosaurs—there is some uncertainty about the precise time of impact, limited by the resolution of the data.

Despite 4 billion years of impactors hitting Earth, only 200 have been discovered, and only 20 confirmed marine impact craters are known, Gulick said. “It is thus exciting news whenever a new potential impact is discovered, especially in the hard-to-explore marine environment. ” Nicholson has applied for funding to drill into the seabed to confirm that it’s an asteroid impact crater and test its precise age.

The paper ” The Nadir Crater offshore West Africa: A candidate Cretaceous-Paleogene impact structure ” is published in Science Advances (2022). Materials provided by Daniel Stolte, University of Arizona . David Bressan Editorial Standards Print Reprints & Permissions.