Overview
- The peer‑reviewed study published Monday used high‑precision nickel‑isotope measurements from the global K–Pg clay layer to match the impactor’s trace signature to a CO‑chondrite.
- CO‑chondrites contain much lower amounts of volatile elements including sulfur, so the finding makes it less likely that sulfur released from the meteorite itself drove the mass extinction.
- Researchers argue that the impact injected vast amounts of fine rock and dust into the atmosphere that blocked sunlight and cooled the planet, a mechanism consistent with the new compositional evidence.
- The identification relied on tiny residues left in a worldwide thin clay layer because the roughly 10–15 km body was mostly vaporized on impact, leaving only trace nickel isotopes for study.
- CO‑chondrites are an uncommon meteorite class and the impactor’s exact origin in the solar system remains unresolved, so follow‑up isotope work and orbital modeling are needed to locate its source.