Overview
- A multinational team published a peer‑reviewed paper in Science Advances on Friday that used new isotope data to identify the Chicxulub impactor as an Ornans (CO) carbonaceous chondrite.
- Researchers extracted a nickel isotope signal from the thin, worldwide K–Pg clay layer left by the impact and used high‑precision measurements to match the projectile’s signature.
- Ornans‑class CO rocks are an extremely rare and very primitive type of meteorite that contain much lower amounts of volatile elements, including sulfur, than many other meteorites.
- Because the impactor was low in volatiles, the authors say sulfur released by the rock is less likely to have been the main kill mechanism and that fine particles lofted into the atmosphere played a larger role.
- The study reaffirms size and speed estimates of a roughly 10–15 km object striking at high velocity, but the impactor’s exact origin in the solar system remains unresolved, which will guide follow‑up work on delivery pathways and extinction models.