# Airbursts and impacts from a large fragmenting comet deposited a synchronous boundary layer with impact…

> Disputed: Airbursts and impacts from a large fragmenting comet deposited a synchronous boundary layer with impact markers across at least four continents.

Source: https://mysteriesdept.com/mysteries/younger-dryas-impact/answers/ANS0D51XA183EE5/airbursts-and-impacts-from-a-large-fragmenting-comet  
Publisher: Mysteries Department  
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[Questions](https://mysteriesdept.com/questions)[Younger Dryas impact hypothesis](https://mysteriesdept.com/mysteries/younger-dryas-impact)[Did an extraterrestrial impact or airburst occur at the onset of the Younger Dryas, about 12,800 years ago?](https://mysteriesdept.com/mysteries/younger-dryas-impact/questions/QST0D51X8AJ1304/did-an-extraterrestrial-impact-or-airburst-occur-at-the)Answer

Answer · Younger Dryas impact hypothesis

# Airbursts and impacts from a large fragmenting comet deposited a synchronous boundary layer with impact…

Airbursts and impacts from a large fragmenting comet deposited a synchronous boundary layer with impact markers across at least four continents.

**Disputed** Answers **1** questionPublished0

## Where it stands

**Disputed** Two pieces of evidence for, four against. It needs two reviews to be accepted.

## What it predicts

- The markers (microspherules, nanodiamonds, shocked quartz, platinum) peak in one thin layer and are rare above and below it.
- Independent laboratories, working blind, find the same peaks in the same samples.
- The layer has the same age, within dating error, at every site.
- Somewhere there is a crater, a strewn field or a melt deposit of that age.

## What would rule it out

- Blind tests on complete, well-dated sections find the markers at other levels as often as at the boundary, or the boundary ages at the key sites differ by more than dating error.

## Evidence 2 for · 4 against

[A Bayesian model of 354 dates from 23 sections gives 12,835–12,735 cal BP and is consistent with synchrony.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XAGW6QP0/a-bayesian-model-of-354-dates-from-23-sections-gives-12)

Suggestive

FOR

[Proponents report boundary-layer peaks at dozens of sites in North America, Europe, the Middle East and…](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XA922RG4/proponents-report-boundary-layer-peaks-at-dozens-of-sites-in)

Suggestive

FOR

[Independent and blind tests did not reproduce the markers at the boundary, and found them at other levels.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XARP3WTK/independent-and-blind-tests-did-not-reproduce-the-markers-at)

Supported

AGAINST

[No crater dates to the onset; the Hiawatha structure is about 58 million years old.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XB8A7G9W/no-crater-dates-to-the-onset-the-hiawatha-structure-is-about)

Established

AGAINST

[Only 3 of the 29 claimed sites have age control placing the layer at the onset.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XB0G7CCW/only-3-of-the-29-claimed-sites-have-age-control-placing-the)

Supported

AGAINST

[Two 2025 papers adding Baffin Bay cores and shocked quartz were retracted for failures of age model and…](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XBG43AKY/two-2025-papers-adding-baffin-bay-cores-and-shocked-quartz)

Supported

AGAINST

## The questions it answers

[Did an extraterrestrial impact or airburst occur at the onset of the Younger Dryas, about 12,800 years ago?](https://mysteriesdept.com/mysteries/younger-dryas-impact/questions/QST0D51X8AJ1304/did-an-extraterrestrial-impact-or-airburst-occur-at-the)

Most likelyNo impact or airburst occurred; the proposed markers are terrestrial or background cosmic material…

## Cite it

```
Mysteries Department. (2026). Airbursts and impacts from a large fragmenting comet deposited a synchronous boundary layer with impact… [Answer ANS0D51XA183EE5]. https://mysteriesdept.com/r/ANS0D51XA183EE5
```

Key

**ANS** 0D51XA183EE5

Kind

Answer · hypothesis

Origin

Published

Version

1

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