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New Papers a nd Talks Dispute Younger Dryas Extraterrestrial Impact Hypothesis
A number of new papers and talks dispute the Younger Dryas
Extraterrestrial Impact Hypothesis. They are:
North America comet theory questioned. No evidence of an
extraterrestrial impact 13,000 years ago, studies say by Rex
Dalton, Nature News, Published online October 12, 2009,
The paper is:
Surovell, T. A., V. T. Holliday, J. A. M. Gingerich, C. Ketron, C. Vance
Haynes, Jr., I. Hilman, D. P. Wagner, E. Johnson, and P. Claeyse. 2009,
An independent evaluation of the Younger Dryas extraterrestrial
impact hypothesis. Published online before print October 12, 2009,
Another recent paper disputed the Younger Dryas impact hypothesis.
Marlon, J. R., P. J. Bartlein, M. K. Walsh, S. P. Harrison, K. J.
Brown, M. E. Edwards, P. E. Higuera, M. J. Power, R. S. Anderson,
C. Briles, A. Brunelle, C. Carcaillet, M. Daniels, F. S. Hu, M.
Lavoiem, C. Longn, T. Minckley, P. J. H. Richard, A. C. Scott,
D. S. Shafer, W. Tinners, C. E. Umbanhowar, Jr., and C. Whitlock,
2009, Wildfire responses to abrupt climate change in North
America. Proceedinds of the National Academy of Sciences.
vol. 106, no. 8, pp. 2519-2524. doi: 10.1073/pnas.0808212106
The abstract in part states:
"We also test the hypothesis that a comet impact initiated
continental-scale wildfires at 12.9 ka; the data do not support
this idea, nor are continent-wide fires indicated at any time
"Biomass burning gradually increased from the glacial period to
the beginning of the Younger Dryas. Although there are changes
in biomass burning during the Younger Dryas, there is no
systematic trend. There is a further increase in biomass burning
after the Younger Dryas. Intervals of rapid climate change at
13.9, 13.2, and 11.7 ka are marked by large increases in fire
This paper conclu
wide fire response is observed at the beginning
of the Younger Dryas chronozone, the time of the hypothesized
comet impact. The results provide no evidence of synchronous
continent-wide biomass burning at any time during the LGIT."
Note "LGIT" = last glacialâinterglacial transition.
Four papers about the Younger Dryas Impact Hypothesis were
presented at the 2009 GSA Meeting in Portland, Oregon "T94. Impact
Cratering from the Microscopic to the Planetary Scale II (GSA
Planetary Geology Division; International Continental Scientific
Drilling Program [ICDP]; GSA Sedimentary Geology Division; GSA
Structural Geology and Tectonics Division; GSA Geophysics Division;
Paleontological Society; GSA International Division) at
1. Dryas. Pinter, N., A. C. Andrew, and D. Ebel, 2009,
Extraterrestrial and Terrestrial Signatures at the Onset of
the Younger Geological Society of America Abstracts with
2. Holliday, V. T., and D. J. Meltzer, 2009, Geoarchaeology
of the 12.9ka Impact hypothesis. Geological Society of
America Abstracts with Programs.
3. Paquay, F., S. Goderis, G. Ravizza, and P. Claeys, 2009, No
evidence of of extraterrestrial geochemical components at the
Bolling-Allerod/Younger Dryas Transition. Geological Society
of America Abstracts with Programs.
4. Surovell, T. A., and V. T. Holliday, 2009, Non-
reproducibility of Younger Dryas Extraterrestrial Impact
Results. Geological Society of America Abstracts with
Finally, two recently published papers related to the Younger
Dryas Impact Hypothesis are:
Woodman, N., and N. B. Athfiel, 2009, Post-Clovis survival of
American Mastodon in the southern Great Lakes Region of North
ry Research. vol. 72, no. 3, pp. 359-363.
One statement in the paper is:
"Previous study of relative numbers of preserved spores of
the dung fungus Sporormiella, used as a proxy for megafaunal
biomass, suggests that populations of large mammals were in
steep decline in northeastern North America before the onset
of the YDC."
Another paper with a related topic is:
Newby, P., J. Bradley, A. Spiess, B. Shuman, and P. Leduc, 2009, A
Paleoindian response to Younger Dryas climate change.Quaternary
Science Reviews. vol. 24, no. 1-2, pp. 141-154.
This reminds me of the claims made by a group of researchers, which
included Luann Becker, for indicators of an extraterrestrial impact
at the Permian - Triassic and the Bedout High structure being the
impact crater. Papers were published arguing that evidence of
extraterrestrial impact, including fullerenes containing extraterrestrial
3He, are found at the Permian - Triassic boundary. Later researchers, who
restudied various Permian - Triassic boundary outcrops, including the
ones studied by Becker, and could not replicate their findings. The
evidence used to argue for Bedout High being an impact structure either
could not be replicated or turned out to be open to alternative
Finally, there is a considerable amount of controversy whether the
fullerenes found in these sediments are even of extraterrestrial origin.
It would be revealing to have a neutral third party collect samples
for both sides of the Younger Dryas extraterrestrial impact
hypothesis to analyze from critical outcrops or cores containing a
well-preserved and continuous record including the time of this
hypothesized event. In addition, the samples would be coded by
the neutral third party such that neither side would know the
depth and stratigraphic position of the sample until after they
had conducted their analyzes as a form of a do