Have the Younger Dryas nanodiamonds been debunked?

Challenged twice, independently, and not abandoned. Daulton, Pinter and Scott reported in 2010 that they found no supporting nanodiamond evidence. Tian, Schryvers and Claeys argued in 2011 that nanodiamonds, even where present, are not unique evidence of an impact. The marker still appears on both sides of the 2021 to 2024 exchange.

Are the Daulton and Tian nanodiamond papers the same paper?

No, and they are frequently conflated. Daulton, Pinter and Scott published in PNAS 107 in 2010; Tian, Schryvers and Claeys published in PNAS 108 in 2011. Different authors, different arguments, a year apart.

Checked · The Younger Dryas

Nanodiamonds: three papers, two teams, and a citation that does not exist

Q: What do nanodiamonds have to do with the Younger Dryas?

They are one of three headline markers in the 2007 impact proposal, alongside excess platinum and quench-melted materials. The argument is that the conditions required to form them at a sediment boundary point to a cosmic impact.

The claim

Nanodiamonds at the Younger Dryas boundary are evidence of a cosmic impact.

Our verdict

Under review

The marker has been attacked by two separate teams in two separate papers, and it has not been abandoned. Worth knowing before you cite any of it: the two papers are routinely conflated, including by us in an early draft, which produced a citation that would send a reader to a paper that does not exist.

Nanodiamonds are one of the three headline markers in the original 2007 proposal, alongside excess platinum and quench-melted materials. The argument is that the temperatures and pressures needed to form them at a sediment boundary point to an impact.

Two challenges, two teams

Paper	Team	Finding
Daulton, Pinter and Scott, PNAS 107(37), 2010	Daulton, Pinter, Scott	No evidence of nanodiamonds in Younger Dryas sediments to support an impact event.
Tian, Schryvers and Claeys, PNAS 108, 2011	Tian, Schryvers, Claeys	Nanodiamonds do not provide unique evidence for a Younger Dryas impact.

Two different papers, two different author teams, two different arguments, published a year apart in the same journal.

The two are not the same objection. The first is about whether the nanodiamonds are there. The second is about whether, granting they are there, they can only have come from an impact. A proponent has to answer both, and they are answered differently.

The mistake we made

Refuted

An early draft of book 4 welded the Tian title onto the Daulton authors. Anybody checking that citation would have looked for a paper that does not exist, in a chapter whose entire subject is checking other people's citations. It was caught by a second cold checker, not by the first, and not by us.

Book 4 source ledger, correction recorded 6 August 2026. The corrected citations are Daulton, T. L., Pinter, N., Scott, A. C., PNAS 107(37), 16043 to 16047, DOI 10.1073/pnas.1003904107, and Tian, H., Schryvers, D., Claeys, P., PNAS 108, 40 to 44, DOI 10.1073/pnas.1007695108.

We are publishing that because it is the most instructive thing on this page. The two papers sit next to each other in every reading list on this subject, they attack the same marker, and merging them requires no bad intent at all. It requires working from memory for one sentence.

Every number and name in that broken citation was real. The sentence was still false. That is a whole class of error, and no fact-checker looking for invented facts will catch it.

Where the marker stands

Contested, in both senses. The nanodiamond argument continued past 2011 and appears on both sides of the 2021 to 2024 Earth-Science Reviews exchange. It has not been withdrawn and it has not been vindicated.

The honest summary is that a marker challenged independently by two teams, and still defended, is a marker doing much less work than a single confirmed observation would. It is not nothing, and it is not the thing that settles the question.

Where this leaves things

The five labels, applied to this question. Nothing is left unlabelled.

Published

Two independent papers, in 2010 and 2011, challenge the nanodiamond marker on different grounds.

Under review

Whether nanodiamonds at the boundary indicate an impact. Contested continuously since 2010.

Refuted

Our own earlier citation, which attributed the Tian title to the Daulton authors. Corrected, and published here rather than quietly fixed.

Candidate

Any single geochemical marker offered as decisive on its own.

Speculative

Summaries of this literature that cite one of these two papers and not the other.

Sources

Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling. Firestone, R. B. et al., PNAS 104(41), pages 16016 to 16021, 2007.
No evidence of nanodiamonds in Younger-Dryas sediments to support an impact event. Daulton, T. L., Pinter, N., Scott, A. C., PNAS 107(37), pages 16043 to 16047, 2010.
Nanodiamonds do not provide unique evidence for a Younger Dryas impact. Tian, H., Schryvers, D., Claeys, P., PNAS 108, pages 40 to 44, 2011.
The Younger Dryas impact hypothesis: Review of the impact evidence. Sweatman, M. B., Earth-Science Reviews 218, article 103677, 2021.
Comprehensive refutation of the Younger Dryas Impact Hypothesis (YDIH). Holliday, V. T. et al., Earth-Science Reviews 247, article 104502, 2023.

Where this is argued in full

Answering the Architect Question

Both cases at the same length, measured and printed at the back. The argument runs across four papers in one journal and you can read all of it.

Both cases at the same length, measured and printed at the back. It is written and not on sale, and advance readers can read it first.