The age of dinosaurs lasted 165 million years, but that changed one lucky spring day 66 million years ago. Scientists have long known that a large object hit the region we now know as the Yucatan Peninsula, causing a mass extinction that ended the dinosaurs’ reign on Earth. After the discovery of a second impact crater off the coast of Africa, we may have to rethink the end of the Cretaceous period.
Scientists call the potential impact structure a nadir crater. They say it formed around the same time as the famous 100-mile-wide Chicxulub crater in the Gulf of Mexico. The new crater is smaller, about 5 miles in diameter, and is covered by several hundred feet of sediment. It was discovered by accident when researcher Wisdean Nicholson of Heriot-Watt University used seismic data to study the tectonic plate divide between South America and Africa. And there it was – something that looked a lot like an impact crater.
The newly published study says the structure has all the typical features of an impact crater, with a long rim and a central rise. The Chicxulub impact was undoubtedly the primary threat to life on Earth 66 million years ago. That event rained fire on much of Earth and blotted out the Sun for years, but a second major impact certainly didn’t help matters. The Nadir impactor was probably about 1,300 feet (400 m) across and sank through half a mile of water before hitting Bedrow.
Nicholson told CNN that such an impact could cause powerful earthquakes across Africa and tsunamis across the Atlantic Ocean, which existed but were much narrower at the time. Living organisms that survived the Chicxulub event may have been wiped out by this second impact.
If confirmed, the Nadi crater could rewrite geological history. We can tell right away that there is something underwater off the coast of Guinea that looks like an impact crater. Although Nicholson’s preliminary dating shows that the nadir event occurred at the same time as Chicxulub, there is a margin of error of 1 million years. If Nadir and Chicxulub are related, they may have been part of a cloud of objects that fell to Earth, or perhaps they were part of the same object that broke up in the atmosphere before landing in two different places. To confirm this is the result of an asteroid strike, we need to drill into the seabed and analyze the minerals. Sooner or later, someone is going to do it.
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