Asteroid That Killed the Dinosaurs Was Stranger Than We Thought

Analysis of nickel isotopes in clay at the Cretaceous-Paleogene boundary shows the Chicxulub impactor was a CO chondrite, a rare type of carbonaceous chondrite. The impact of a 10-15 km body at about 64,000 km/h 66 million years ago wiped out 75% of species, including non-avian dinosaurs.

• Impactor classified as CO chondrite of the Ornans class, a rarest meteorite group
• Impact occurred 66 million years ago at about 64,000 km/h
• Body estimated at 10-15 km in diameter; 75% of species went extinct
• CO chondrites are sulfur-poor, so sulfur release was not the main extinction cause