The asteroid that killed the dinosaurs was an exceptionally rare carbonaceous chondrite of the Ornans class (specifically a CO chondrite), why is this unusual?
It's unusual because CO (Ornans-type) carbonaceous chondrites are among the rarer types of meteorites reaching Earth , and they likely represent only a small fraction of the asteroid population. If the Chicxulub impactor really was a CO chondrite, it means the object that caused one of Earth's most consequential events belonged to an uncommon class. Here's why that's surprising: 1. Most asteroids are not CO chondrites Asteroids are classified by their composition. The main groups are: Stony asteroids (S-type): Common in the inner asteroid belt. Carbonaceous asteroids (C-type): Common overall, especially farther from the Sun. Metallic asteroids (M-type): Less common. However, CO chondrites are only one very specific subgroup of carbonaceous chondrites . Other carbonaceous groups include CI, CM, CV, CR, CK, and others. Among meteorites collected on Earth, CO chondrites account for only around 0.5–1% of observed meteorite falls . 2. Carbonaceous chondrites ...