Arguments and Evidence Against a Younger Dryas Impact Event

  title={Arguments and Evidence Against a Younger Dryas Impact Event},
  author={Mark Boslough and Kathleen Nicoll and Vance T. Holliday and Tyrone L. Daulton and David J. Meltzer and Nicholas Pinter and Andrew C. Scott and Todd A. Surovell and Philippe Claeys and Jacquelyn L. Gill and François S. Paquay and Jennifer R. Marlon and Patrick J. Bartlein and Cathy Whitlock and Donald K. Grayson and A. J. Timothy Jull},
  journal={Geophysical monograph},
We present arguments and evidence against the hypothesis that a large impact or airburst caused a significant abrupt climate change, extinction event, and termination of the Clovis culture at 12.9 ka. It should be noted that there is not one single Younger Dryas (YD) impact hypothesis but several that conflict with one another regarding many significant details. Fragmentation and explosion mechanisms proposed for some of the versions do not conserve energy or momentum, no physics-based model… 

Figures from this paper

The Younger Dryas impact hypothesis: a cosmic catastrophe

In this paper we review the evidence for the Younger Dryas impact hypothesis (YDIH), which proposes that at ∼12.9k cal a BP North America, South America, Europe and the Middle East were subjected to

Chronological evidence fails to support claim of an isochronous widespread layer of cosmic impact indicators dated to 12,800 years ago

The Younger Dryas Impact Hypothesis fails the critical chronological test of an isochronous event at the YD onset, which, coupled with the many published concerns about the extraterrestrial origin of the purported impact markers, renders the YDIH unsupported.

A Blind Test of the Younger Dryas Impact Hypothesis

A test reported here presents the results of analyses that address questions about Reproducibility of at least some analyses of purported impact indicators, finding that no standard criteria exist for identification of magnetic spheres and the purported impact proxies are not unique to the YDB.

Extraordinary Biomass-Burning Episode and Impact Winter Triggered by the Younger Dryas Cosmic Impact ∼12,800 Years Ago, Parts 1 and 2: A Discussion

Wolbach et al. published two papers on the Younger Dryas Impact Hypothesis (YDIH)—the paleoenvironmental effects of a purported cosmic impact at the beginning of the Younger Dryas Chronozone (YDC).

Younger Dryas impact model confuses comet facts, defies airburst physics

Evidence is presented that supports major airbursts and/or impacts at the beginning of the Younger Dryas, as proposed by Firestone et al. (2), and a preliminary impact model is proposed that diverges significantly from the original but still provides no physics-based argument.

Evidence from Pilauco, Chile Suggests a Catastrophic Cosmic Impact Occurred Near the Site ∼12,800 Years Ago

The Younger Dryas (YD) impact hypothesis proposes that fragments of a large, disintegrating asteroid/comet struck the Earth ∼12,800 years ago. This event simultaneously deposited high concentrations

Greenland Pt anomaly may point to noncataclysmic Cape York meteorite entry

  • M. Boslough
  • Geology, Environmental Science
    Proceedings of the National Academy of Sciences
  • 2013
The authors identify a large Pt anomaly in the Greenland Ice Sheet Project 2 (GISP2) core and suggest that it hints at an extraterrestrial source and challenge the impact hypothesis by proposing a highly fractionated iron meteorite.

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

Sedimentary record from Patagonia, southern Chile supports cosmic-impact triggering of biomass burning, climate change, and megafaunal extinctions at 12.8 ka

In the most extensive investigation south of the equator, a ~12,800-year-old sequence at Pilauco, Chile, that exhibits peak YD boundary concentrations of platinum, gold, high-temperature iron- and chromium-rich spherules, and native iron particles rarely found in nature is reported.



Absence of geochemical evidence for an impact event at the Bølling–Allerød/Younger Dryas transition

The data show no evidence of an extraterrestrial (ET)-PGE enrichment anomaly in any of the investigated depositional settings investigated across North America and in one section in Belgium.

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.

Environmental perturbations caused by the impacts of asteroids and comets

We review the major impact‐associated mechanisms proposed to cause extinctions at the Cretaceous‐Tertiary geological boundary. We then discuss how the proposed extinction mechanisms may relate to the

An independent evaluation of the Younger Dryas extraterrestrial impact hypothesis

An independent analysis of magnetic minerals and microspherules from seven sites of similar age finds no support for Younger Dryas extraterrestrial impact.

Environmental Perturbations Caused by the Impacts of Asteroids and Comets

We review the major mechanisms proposed to cause extinctions at the Cretaceous-Tertiary geological boundary following an asteroid impact. We then discuss how the proposed extinction mechanisms may

The 12.9-ka ET Impact Hypothesis and North American Paleoindians

A hypothesized extraterrestrial impact in North America at ∼12,900 calendar years BP (12.9 ka) has been proposed as the cause of Younger Dryas climate changes, terminal Pleistocene mammalian

Numerical Modeling of the Eltanin Impact

Introduction. Eltanin [1] is the only presently known impact structure formed during the fall of a cosmic body into a deep (4-5 km) oceanic basin. The evidence for the impact origin of this structure