Scientists: The asteroid that wiped out the dinosaurs is not alone

2024-10-06 09:42:00, Kuriozitete CNA

The massive asteroid that brought the end of the dinosaurs' reign when it slammed into Earth 66 million years ago was not alone, researchers say.

Detailed scans of an underwater crater off the coast of Guinea in West Africa suggest it was created when another large asteroid slammed into the planet at the same time at the end of the Cretaceous period.

The violent collision between 65 and 67 million years ago produced a crater more than five miles wide, the scans reveal, with scientists estimating the asteroid was a quarter-mile wide and hit Earth at nearly 45,000 mph.

Although smaller than the asteroid that caused the mass extinction, it was still large enough to leave marks on the face of the planet. "The new images paint a picture of the catastrophic event," said Dr Uisdean Nicholson, a marine geologist at Heriot-Watt University in Edinburgh, who first discovered the Nadir crater in 2022. At the time, details of the impact were unclear. .

To understand more about the impact, scientists used 3D seismic imaging to map the crater's rim and geological scars, which extend 300 meters below the ocean floor. "There are about 20 confirmed sea craters worldwide, and none of them have been captured in anything close to this level of detail," Nicholson said. "It's brilliant."

The collision appears to have caused strong tremors that liquefied sediments beneath the ocean floor, causing faults to form beneath the seabed, the researchers found. The impact caused landslides with traces of damage visible for thousands of square miles beyond the crater rim, and also triggered a huge tsunami more than 800 meters high that would have traveled across the Atlantic.

Researchers cannot determine when the asteroid hit Earth, but the discovery of the crater and its approximate age have fueled speculation that it may have belonged to a cluster of impacts at the end of the Cretaceous period. The asteroid associated with the extinction of the dinosaurs was much larger than the rock that produced Nadir Crater. It left a 100-mile-wide crater in what is now Chicxulub on the Yucatan Peninsula in Mexico.

"The closest people have seen anything like this is the Tunguska event of 1908, when a 50-meter asteroid entered the Earth's atmosphere and exploded in the sky over Siberia," Nicholson said. "The new 3D seismic data across Nadir Crater is an unprecedented opportunity to test impact cratering hypotheses, develop new models of crater formation in the marine environment, and understand the consequences of such an event. "/ The Guardian.