The massive asteroid that ended the dinosaurs 66 million years ago was not an isolated event, new research has revealed. The study, published in Nature, detailed scans of an underwater crater off the coast of Guinea. It revealed that another large asteroid struck Earth around the same time, potentially contributing to the cataclysmic conditions that led to the dinosaurs' extinction.
Scientists recently mapped the Nadir crater, spanning over 8 km in diameter, and revealed that it was created by an asteroid measuring 400 metres wide. This asteroid struck the planet at nearly 72,000 kmph between 65 million and 67 million years ago. While it was smaller than the asteroid linked to the mass extinction, it was still powerful enough to leave a significant mark on Earth.
“The new images paint a picture of the catastrophic event,” said Dr Uisdean Nicholson, a marine geologist at Heriot-Watt University in Edinburgh. He discovered the Nadir crater in 2022, but the impact details were unclear until now.
Using advanced 3D seismic imaging, researchers managed to explore the crater's rim and the geological features lying 300 metres beneath the ocean floor. Dr Nicholson called it “exquisite,” saying, “There are around 20 confirmed marine craters worldwide, and none of them has been captured in anything close to this level of detail.”
The findings suggest the impact triggered intense tremors that liquefied sediments beneath the sea bed, resulting in faults and landslides that left traces of damage visible for thousands of square miles beyond the crater's edge. Furthermore, the collision unleashed a massive tsunami, estimated to have exceeded 800 metres in height, which would have surged across the Atlantic Ocean.
Although the exact timing of this asteroid's impact remains uncertain, its discovery raises intriguing possibilities about a cluster of impacts occurring at the end of the Cretaceous period – 145 million years ago to 66 million years ago. The asteroid responsible for the extinction of the dinosaurs created a much larger crater – 160 km wide – at Chicxulub on the Yucatan Peninsula in Mexico.
Dr Nicholson said the “closest humans have come to seeing something like this is the 1908 Tunguska event”, when a 50-metre asteroid entered Earth's atmosphere and exploded in the skies above Siberia. He pointed out that the new 3D seismic data across the Nadir crater provides an unrivalled opportunity to test impact crater hypotheses and develop new models of crater formation in marine environments.
