Clear three-dimensional seismic data from an undersea crater near Guinea appear to confirm that a second asteroid struck Earth at about the same time as the behemoth that struck North America 66 million years ago, ending the reign of the dinosaurs.
A team of researchers recently imaged a 5.28-mile-wide (8.5 kilometers) depression off the coast of Africa, allowing the team to better characterize the crater’s features. Based on the analysis, the research team confirmed the age of the crater and considered the immediate consequences of the impact.
According to a 2020 paper, the dinosaurs — except, of course, the ancestors of modern birds — went extinct 66 million years ago when a giant asteroid struck what is now Yuca, Mexico, at “the deadliest angle” Tan Peninsula. Research published in 2021 suggested that the asteroid could hit in the spring, but regardless of the weather, the results would be catastrophic: a 100-megaton force that would send the Earth system into chaos.
Part of the difficulty faced by the dinosaurs and most other ancient creatures was that the asteroid triggered tsunamis measured in miles, along with dust, soot, sulfur and more dust that wiped out about 75% of life. In other words, it wasn’t just the catastrophic impact of a boulder from space;
But the Chicxulub asteroid clearly doesn’t operate alone. In 2022, a team that included several members of the most recent team revealed the bowl-shaped feature and dubbed it “Nader Crater.” The crater is buried under about 1,300 feet (400 meters) of sediments on the Guinea Plateau, a continental crust about 250 miles (400 kilometers) off the coast of Guinea and Guinea-Bissau.
In the new paper, the team released images of the asteroid’s impact crater, confirmed its age at 66 million years, and predicted what would have happened immediately after the impact. The team’s research is published today in Communications Earth & Environment.
In the 2022 paper, the team proposed three potential origins for the crater. Researchers say one possibility is that a large asteroid broke away from the same parent body as the Chicxulub asteroid in the Yucatan Peninsula as it approached Earth. Another option is that some collision in the asteroid belt launched a series of asteroids toward Earth over the same, roughly one-million-year time frame. A final option is that the timing of the two impacts was pure coincidence: two giant space rocks hitting Earth at almost the same time was just extra bad luck for the dinosaurs.
Uisdean Nicholson, a geoscientist at Heriot-Watt University in Scotland and lead author of both papers, told Gizmodo in 2022: “The size of Chicxulub is much larger than what we thought the size of Nadir was. We The asteroid is expected to be about 10,000 times larger, so the nadir impact pales in comparison to the Chicxulub impact.
Just last month, another research team published a paper in the journal Science, arguing that the parent bodies of the Chicxulub and Nadir asteroids came from beyond Jupiter, which provides support for the hypothesis of the origin of the asteroid belt. evidence.
The research team estimates that the Nadir asteroid hit Earth at about 12.43 miles per second (20 kilometers per second), which is nearly 45,000 miles per hour (72,000 kilometers per hour). The earthquakes caused by the impact “liquefied sediments beneath the seafloor across the plateau” and triggered massive underwater landslides, Nicholson said in a Heriot-Watt University news release. Based on clear images of the crater, the team also predicts that the impact triggered a tsunami half a mile high (800 meters) or higher.
As we all know, 66 million years ago was a pretty bad time for life on Earth. But confirmation of the age of Nadir crater lends credence to the idea. The team has applied to drill into the seafloor to recover a sediment core from the crater itself, which will further clarify the force with which the ancient asteroid struck the seafloor and how the immediate aftermath of the event may have unfolded.
