The hole in the Atlantic that could change the theory of the extinction of the dinosaurs

Chicxulub is one of the few remaining traces of the end of the dinosaur world: a 120-mile-wide crater on Mexico’s Yucatan Peninsula. The culprit for this huge hole was an asteroid that fell nearly 66 million years ago, and the destruction it caused is considered the end of the Cretaceous period and the beginning of the Paleogene. Not only the dinosaurs were wiped out from the Earth, but also half of the species that inhabited the planet at that time. However, history may change soon because scientists believe they have discovered a second guilty of this mass extinction.

Nadir is the name scientists have just given to a second crater that dates back to the same time as Chicxulub that they discovered 400 kilometers from the coasts of Guinea and Guinea-Bissau, in the middle of the Atlantic Ocean. There is still much to study, but it seems that its origin may also be an asteroid that is precisely related to the one that fell in the Yucatan. In other words, the Cretaceous-Paleogene mass extinction may have been caused by two space rocks, not just one, as previously thought.

In any case, the asteroid that could have formed Nadir appears to be much smaller than Chicxulub; specifically, 25 times smaller. The rock that hit the Yucatan is believed to have been between ten and eleven kilometers wide the one that fell near Africa, measuring approximately 400 meters wide. Now this meteor is no a little boy. In this article on lifescience they compare it to the Empire State Building, and that’s actually why the nadir is 8.5 kilometers wide and 40 meters deep.

Other possible impact

The team of scientists who discovered Nadir Crater was led by Wisdean Nicholson, a geologist at Heriot-Watt University in the UK, and they published their findings this Wednesday in the journal Scientific progress. However, the investigators were not on the trail of this geographical feature, but they found it by accident. The real purpose of this work was to investigate the tectonic plates responsible for the distance between Africa and South America about 100 million years ago.

[El meteorito que acabó con los dinosaurios chocó con la Tierra en primavera]

Using the seismic reflection technique, the researchers discovered the Nadir Crater, hidden under 900 meters of water and another 400 meters of sediment. In the study, they describe this feature as “a raised rim above a terraced crater floor, with marked central uplift and extensive subsurface deformation.” Examination of the strata that make up the crater allowed it to be dated to 66 million years ago, “roughly the same age as the Chicxulub Crater impact.”

Although scientists still need to drill and take samples from the crater to confirm that it was caused by an asteroid, they already have a hypothesis in this regard. The research team believes that both Chicxulub Crater and Nadir Crater were formed by a meteorite impact very close in time, or even that both come from the same original asteroid that fell apart. That is, both meteorites may have been brothers both were responsible for the extinction of the dinosaurs.

The cataclysm begins

In addition to the information these meteorites can provide about the extinction of dinosaurs and other species before humans, the discovery of a crater has been highly praised by the scientific community. They are very important because we have very few preserved impact craters on Earth. Each one we’ve discovered provides a new window, new insights into the geological process that created them and their effects on the biological evolution of our planet,” David Kring of the Lunar and Planetary Institute (LPI) told Live Science.

The researchers estimate in the study that the meteorite that formed Nadir Crater must have hit the Atlantic seafloor with a force of 5,000 megatons of TNT and could have produced a fireball 10 kilometers across. The immediate effects were the evaporation of large amounts of water and rock and a magnitude 7 earthquake that must have triggered landslides and huge waves. The waves that reached West Africa reached 100 kilometers in height and those that reached South America, five meters.

[Ésta es la mejor arma para evitar que un meteorito aniquile la Tierra: el estudio que lo demuestra]

Therefore, the mass extinction that occurred at the end of the Cretaceous may have been caused by two meteorite impacts instead of one. In any case, theories about the origin of this extinction also point to intense volcanic activity as the starting point for the phenomena that followed. A cataclysm in which climate change, ash blocking sunlight and sea level changes, among other phenomena.

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