Scientists Discover Second Asteroid Impact From Dinosaur Extinction Era

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Facts

  • Scientists have discovered evidence of a second large asteroid impact that occurred around the same time as the dinosaur extinction event 66M years ago.[1][2]
  • According to a study published in Nature Communications Earth & Environment on Thursday, the newly studied Nadir crater, located off the coast of Guinea in West Africa, is presumed to have been created by an asteroid estimated at 450-500 meters (492-547 yards) wide.[3][4]
  • Using 3D seismic imaging, scientists mapped the crater rim and geological scars 300 meters (328 yards) beneath the ocean floor, providing granular detail of a marine impact crater.[2]
  • The asteroid that created the Nadir crater is believed to have struck Earth at approximately 72K km/hr (44K mph), coming from 20-40 degrees to the northeast.[5][1]
  • The impact triggered intense tremors, liquefying sediments beneath the ocean floor, causing faults to form, and unleashing a massive tsunami over 800 meters (875 yards) high that would have propagated across the Atlantic.[2][6]
  • While smaller than the 'Chicxulub,' Yucatan impact linked to dinosaur extinction, the Nadir crater discovery suggests the possibility of a cluster of asteroid impacts at the end of the Cretaceous period.[7][8]

Sources: [1]Daily Mail, [2]Guardian, [3]Nature, [4]BBC News, [5]NDTV.com, [6]Mashable India, [7]Scientific American and [8]WION.

Narratives

  • Narrative A, as provided by Guardian. This discovery is a game-changer for understanding Earth's history. Multiple giant asteroid impacts around the same time could have had a cumulative effect on the planet's climate and ecosystems — potentially explaining the severity of the mass extinction event. The detailed imaging of the Nadir crater provides valuable insights into impact processes and their consequences.
  • Narrative B, as provided by Daily Mail. While the Nadir crater is significant, it's unclear if it rivals the Chicxulub impact. Its effects could have been localized and it may or may not have contributed significantly to global climate change or mass extinction. When discussing the end-Cretaceous extinction, the focus should remain on the cataclysmic Chicxulub event.
  • Narrative C, as provided by Big Think. While scientists appear to be understanding the dinosaurs' abrupt extinction, the species was likely on its way out — albeit at a slower rate — without the help of a celestial attack. At the time, the Earth was cooling and turning widespread tropical climates into less vegetative climates. Like most species throughout Earth's history, dinosaurs likely lost their food source.

Predictions