Research Spotlight: New study casts doubt on evidence for Younger Dryas impact theory


  • Leslie Ofori,

  • Ernie Tretkoff


A new study challenges a previous hypothesis that a comet explosion or impact about 12,900 years ago caused devastating fires over much of North America and Europe and triggered an abrupt global cold period known as the Younger Dryas. Proponents of the impact theory claim that carbonaceous spherules and nanodiamonds found in deposits from the Younger Dryas formed through intense heat following a comet impact. The new study, however, finds that the carbon spherules are actually fossilized balls of fungus, charcoal, and fecal pellets created by low-intensity wildfires.