There are questions about whether the asteroid that wiped out the dinosaurs had a smaller sibling that struck around the same time.

The crater is hidden under 900 meters of water and 1,300 meters of silt, but it hasn't been directly studied. Scientists will need to drill into the structure and find minerals shocked by extreme heat and pressure to prove that the crater is from an asteroid. David Kring, who was not involved in the current study but was one of the discoverers of the impact site, said that the crater's shape points to an extraterrestrial origin.

The team has found a probable impact crater, according to Kring. We don't have many impact craters on the planet. The geological processes that shape them and their effects on biological evolution of Earth can be found in every single one of them.

The new crater was formed very close to the impact.


What happened when the asteroid hit?

They weren't looking for signs of space rocks when they started poring through the data. South America and Africa were separated 100 million years ago because of the tectonics.

The waves that bounce back from the ocean are recorded in the data. The result is a visualization of the structure of the underground. The researchers were surprised to find evidence of an object in the rock layers on the ocean floor.

Nicholson said the crater was unlike anything he'd seen before.

The researchers were able to see a hole up to 131 feet from floor to rim. The edge of the crater showed signs of faulting and rock degradation, as well as material thrown out of the main crater after it was hit. A structure under the crater floor was one of the telltale features. After impacts where the shock pressure is high enough to cause the grains in the rock to act like a fluid, Nicholson said, the rock essentially sloshes apart, splashes back together and is frozen in that configuration.

Intense impact

Today, the researchers reported their findings in the journal Science Advances.

The crater was caused by an asteroid that was 1,213 feet wide. It wouldn't have been good to be a fish. The researchers calculated that the asteroid hit the ocean bed with the power of 5,000 megaton of TNT, and that it would have produced a fireball. It would have killed a lot of water and rock. The impact would have created a magnitude-7 earthquake that could have caused a series of submarine slides. Waves that reached the West African coastline may have been over 100 miles high, and the splash at the impact site would have towered at least 1.2 miles. The South American coast would have seen large waves.

The formation of the Nadir impact crater, which would have been accompanied by magnitude-7 earthquakes and enormous tsunami waves.

The formation of the Nadir impact crater, which would have been accompanied by magnitude-7 earthquakes and enormous tsunami waves. (Image credit: Data courtesy of the Republic of Guinea, TGS and Western Geco)

Marine life would have rebounded quickly despite this short-term destruction. In a marine crater on dry land in Nevada, researchers have found that the bottom of the crater has been colonized by new life.

A dino-killing barrage?

It was created by an asteroid that was 25 times larger than the one that hit West Africa. There is a question of whether the two were related.

It is difficult to say. It's possible that the impacts occurred far apart in time and had nothing to do with each other, since the new crater's age is only about 800,000 years old. It's easy to forget that impacts are relatively common because craters are often eroded or destroyed by tectonics.

There are a few scenarios in which the two craters could be linked. Nicholson said that the asteroid could have hit the planet in a few volleys, hours or a few days. It's possible that the two space rocks are from the same parent asteroid that broke apart in the asteroid belt and wreaked havoc on Earth.

Getting any further details on the crater would require drilling into the crater floor and pulling up rock samples, which could show impact-shocked minerals that could be analyzed to get a better date. There are fragments in the crater. Even if the International Ocean Discovery Program approves the proposal, it won't happen until at least the year 2025.

It costs a lot to drill undersea. After it was identified in 1991, it took 10 years for scientists to conduct marine drilling at the site. The Nadir crater is a good place to explore.

He said drilling into that structure would be a lot of fun.

It was originally published on Live Science