Scientists have identified a rare ‘eccentric’ meteorite that was behind the mass extinction of dinosaurs 66 million years ago

66 million years ago, dinosaurs, apex predators, roamed the Earth, dominating the land, sea and sky. Scientists have known for decades that these magnificent creatures became extinct after a massive meteorite hit Earth.

However, they were not sure what type of projectile would have caused such an impact, eliminating 75% of species on Earth, including non-bird dinosaurs. Now researchers think they’ve finally found the answer. The massive space rock that wiped out the dinosaurs is a member of an extremely rare class of meteorites known as carbon dioxide chondrites. Researchers at the University of British Columbia (UBC), along with teams in Paris, Brussels and Vienna, say they have solved a mystery that has vexed scientists for decades. The results were published in the journal Science Advances.

A space rock changed everything

The researchers used advanced nickel isotope analysis of the samples to trace the meteorite’s chemical signature to the deadly Cretaceous-Paleogene impactor. It turns out that the meteorite that wiped out most life on the planet was no ordinary chondrite. It was a carbon dioxide chondrite, one of the rarest known.“The Ornan-class carbonaceous chondrites are certainly not like the typical meteorites you find in museum collections,” said Dr. Philip Claes, who worked on the study as a visiting professor at the University of British Columbia.

“CO2 chondrites contain much fewer volatile elements, such as carbon, zinc, water and especially sulfur, than other classes of meteorites we have discovered so far on Earth. This does not change our theory about the cause of the extinction event, but it makes it unlikely that the sulfur in the meteorite was the smoke evidence. Fine debris thrown into the atmosphere was the primary factor.”Using high-resolution nickel isotope analysis, researchers from the World Institute of Physics and the University of Paris examined samples collected over years of a thin layer of clay formed around the world by the impact.“This is difficult work. Only a small portion of the ejecta was preserved in the planet’s KT clay layer because the entire meteorite vaporized on impact,” said Dr. Claes, a professor at Vrije Universiteit Brussel, who is currently visiting the Pacific Center for Isotopic and Geochemical Research with Earth, Oceanic and Atmospheric Sciences at the University of British Columbia.There are still unanswered questions about the origin of this world-shattering meteorite.

They likely originated far from Earth, perhaps in the outer regions of the asteroid belt near Jupiter or in distant regions laden with extraplanetary debris.

A rare disaster

This remarkable discovery also revealed something almost unlucky about the extinction of dinosaurs. Of all the space rocks that could have ended a lineage spanning 165 million years, they hit Earth with one of the strangest possible celestial rolls of the dice. These carbonaceous chondrites make up only five percent of the meteorites sampled on Earth so far.

Ornan-class carbonaceous chondrites, or CO chondrites, make up a small part of that group.

It is among the most primitive and untouched materials in the solar system.

Dr Claes said: “Being affected by such a rare and distant projectile underscores how unlucky the dinosaurs were.”

This Cretaceous-Paleogene impactor is about 10 to 15 kilometers across, or nearly six miles. This massive meteorite struck at an estimated speed of 64,000 km/h, creating the vast Chicxulub crater. The effect was immediate and sweeping. The meteorite completely vaporized, releasing its energy in a flash that created a 180-kilometre-wide crater in the limestone of Mexico. Three-quarters of all species on Earth disappeared within months.

The impact area is now buried under Mexico’s Yucatán Peninsula.