Nanodiamonds in the Younger Dryas Boundary Sediment Layer

  title={Nanodiamonds in the Younger Dryas Boundary Sediment Layer},
  author={Douglas J. Kennett and James P. Kennett and Alfred P. West and Chris Mercer and Shane S. Que. Hee and Lee Bement and Theodore E. Bunch and Marilee Sellers and Wendy S Wolbach},
  pages={94 - 94}
We report abundant nanodiamonds in sediments dating to 12.9 ± 0.1 thousand calendar years before the present at multiple locations across North America. Selected area electron diffraction patterns reveal two diamond allotropes in this boundary layer but not above or below that interval. Cubic diamonds form under high temperature-pressure regimes, and n-diamonds also require extraordinary conditions, well outside the range of Earth's typical surficial processes but common to cosmic impacts. N… 

Nanodiamond-Rich Layer across Three Continents Consistent with Major Cosmic Impact at 12,800 Cal BP

A major cosmic-impact event has been proposed at the onset of the Younger Dryas (YD) cooling episode at ≈12,800 ± 150 years before present, forming the YD Boundary (YDB) layer, distributed over >50

Comprehensive analysis of nanodiamond evidence relating to the Younger Dryas Impact Hypothesis

During the end of the last glacial period in the Northern Hemisphere near 12.9k cal a BP, deglacial warming of the Bølling–Ållerod interstadial ceased abruptly and the climate returned to glacial

No evidence of nanodiamonds in Younger–Dryas sediments to support an impact event

The results cast doubt upon one of the last widely discussed pieces of evidence supporting the YD impact hypothesis, as it is demonstrated that previous studies misidentified graphene/graphane-oxide aggregates as hexagonal diamond and likely mis identified graphene as cubic diamond.

Discovery of a nanodiamond-rich layer in the Greenland ice sheet

Abstract We report the discovery in the Greenland ice sheet of a discrete layer of free nanodiamonds (NDs) in very high abundances, implying most likely either an unprecedented influx of

Quantifying the distribution of nanodiamonds in pre-Younger Dryas to recent age deposits along Bull Creek, Oklahoma Panhandle, USA

This hypothesis that the start of the Younger Dryas (YD) chronozone and late Pleistocene extinctions resulted from the explosion of a comet in the earth’s atmosphere is evaluated by establishing the distribution of nanodiamonds within the Bull Creek drainage of the Beaver River basin in the Oklahoma panhandle.

Nanodiamonds and wildfire evidence in the Usselo horizon postdate the Allerød-Younger Dryas boundary

The accelerator mass spectrometry radiocarbon dates of 14 individual charcoal particles are internally consistent and show that wildfires occurred well after the proposed impact, providing no support for the Younger Dryas impact hypothesis.

Shock-synthesized hexagonal diamonds in Younger Dryas boundary sediments

The presence of shock-synthesized hexagonal nanodiamonds (lonsdaleite) in YDB sediments dating to ≈12,950 ± 50 cal BP at Arlington Canyon, Santa Rosa Island, California is reported, consistent with abrupt ecosystem change and megafaunal extinction possibly triggered by a cosmic impact over North America.

Evidence from central Mexico supporting the Younger Dryas extraterrestrial impact hypothesis

We report the discovery in Lake Cuitzeo in central Mexico of a black, carbon-rich, lacustrine layer, containing nanodiamonds, microspherules, and other unusual materials that date to the early

Nanodiamonds do not provide unique evidence for a Younger Dryas impact

Microstructural, δ13C isotope and C/N ratio investigations were conducted on excavated material from the black Younger Dryas boundary in Lommel, Belgium, aiming for a characterisation of the carbon content and structures, finding no unique evidence for an exogenic impact related to the investigated layer.

Did Nanodiamonds Rain from the Sky as Woolly Mammoths Fell in their Tracks Across North America 12,900 Years Ago?

The Younger Dryas (YD) Impact Hypothesis proposes that the Late Pleistocene megafauna extinctions, the YD stadial (a period at the end of the last glaciation marked by rapid climate change at its



Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling

It is proposed that one or more large, low-density ET objects exploded over northern North America, partially destabilizing the Laurentide Ice Sheet and triggering YD cooling, which contributed to end-Pleistocene megafaunal extinctions and adaptive shifts among PaleoAmericans in North America.

Younger Dryas “black mats” and the Rancholabrean termination in North America

  • C. Haynes
  • Environmental Science, Geography
    Proceedings of the National Academy of Sciences
  • 2008
Of the 97 geoarchaeological sites of this study that bridge the Pleistocene-Holocene transition (last deglaciation), approximately two thirds have a black organic-rich layer or “black mat” in the

Diamonds from the iridium-rich K-T boundary layer at Arroyo el Mimbral, Tamaulipas, Mexico

Diamonds, up to 30 µm in size, were found in the iridium-rich layer from the K-T boundary site at Arroyo El Mimbral and the spherule bed from Arroyo El Penon, northeastern Mexico. Stepped heating

The 1908 Tunguska explosion: atmospheric disruption of a stony asteroid

The explosion over Tunguska, Central Siberia, in 1908 released 10 to 20 megatons (high explosive equivalent) of energy at an altitude of about 10 km. This event represents a typical fate for stony

Synthesis and crystal structure of n-diamond

Abstract Allotropes of carbon based materials, such as graphite, fullerenes and nanotubes, and diamond are currently a focus of great interest. New diamond (n-diamond) has been proposed as a new

HST and VLT Investigations of the Fragments of Comet C/1999 S4 (LINEAR)

At least 16 fragments were detected in images of comet C/1999 S4 (LINEAR) taken on 5 August 2000 with the Hubble Space Telescope and on 6 August with the Very Large Telescope, which implies that the total mass in the observed fragments was about 2 × 109 kilograms.

Atmospheric concentrations of radiocarbon are known to have varied unevenly across past millennia; accordingly, 10,900 radiocarbon years before present has been recalibrated and is equivalent to 12

    This research was funded by the NSF (grant ATM-0713769). We thank three anonymous reviewers and V. Haynes for assistance