Supports· moderateYDIH-E010
Kennett et al. 2009: nanodiamonds reported in the boundary layer
- what the source states
- The authors reported nanodiamonds (including cubic and hexagonal forms) within the Younger Dryas boundary sediment layer at multiple North American locations, interpreted as consistent with a cosmic impact event at ~12.9 ka.
- what we infer
- The proxy that gave the hypothesis its most exotic-sounding physical evidence. Its evidential weight rests on identification calls (diamond versus graphene-family aggregates; hexagonal versus cubic) that independent microscopy subsequently rejected — the dispute below is not about whether the sediments were analyzed but about what was in them.
- limitations
- A one-page report; the detailed identification evidence lives in supplements and follow-ups whose interpretations remain contested.