Overview
- The peer-reviewed paper published Friday in Science Advances used nickel isotope measurements from the global K–Pg clay layer to link the Chicxulub projectile to an Ornans-type (CO) carbonaceous chondrite.
- CO chondrites are a very rare class of primitive meteorite that contain much less volatile material and sulfur than many other meteorite types.
- Because the identified CO composition is low in sulfur, the authors say it is less likely that sulfur released from the rock was the main cause of the mass extinction and that fine dust and aerosols thrown into the atmosphere played the primary role.
- The impactor is still estimated to have been about 10 to 15 km across and to have struck at roughly 64,000 km/h, producing the buried Chicxulub crater in the Yucatán Peninsula.
- The study tightens a key compositional constraint on the 66-million-year-old event but leaves the projectile’s exact origin unresolved, with the team suggesting possible sources in the outer asteroid belt or more distant solar-system reservoirs.