Dinosaur-Killing Meteorite Was Extremely Rare Type, Study Finds

The meteorite responsible for the extinction of 75% of Earth's species, including non-avian dinosaurs, 66 million years ago was likely an exceptionally rare type of carbonaceous chondrite, according to a new study published in Science Advances. This finding adds a layer of cosmic misfortune to the already catastrophic event.

Researchers analyzed nickel isotopes in marine clays collected globally, which formed a thin layer from the vaporized meteorite. Their findings point to the impactor belonging to the Ornans class of carbonaceous chondrites. Philippe Claeys of the University of British Columbia, a co-author of the study, noted that these meteorites are unlike typical ones found in museum collections.

Carbonaceous chondrites themselves are rare, constituting only about 5% of all meteorite samples recovered on Earth. The Ornans (CO) class represents an even smaller subset of this already scarce group. "The fact that they were hit by such a rare and distant projectile really highlights how unlucky the dinosaurs were," Claeys stated, emphasizing the improbability of such an event.

The impactor, estimated to be between 10 and 15 kilometers in diameter, struck Earth at approximately 64,000 kilometers per hour, creating the Chicxulub crater in Mexico. The study's analysis of nickel isotopes provides crucial insights into the composition of this ancient, devastating space rock, which was rich in primitive, volatile materials like carbon and sulfur.

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The fact that they were hit by such a rare and distant projectile really highlights how unlucky the dinosaurs were.